development process of new bumper beam for passenger car: a
TRANSCRIPT
Accepted Manuscript
Development Process of New Bumper Beam for Passenger Car: A Review
M.M. Davoodi, S.M. Sapuan, A. Aidy, N.A. Abu Osman, A.A. Oshkour,
W.A.B. Wan Abas
PII: S0261-3069(12)00234-8
DOI: 10.1016/j.matdes.2012.03.060
Reference: JMAD 4455
To appear in: Materials and Design
Received Date: 27 December 2011
Accepted Date: 31 March 2012
Please cite this article as: Davoodi, M.M., Sapuan, S.M., Aidy, A., Abu Osman, N.A., Oshkour, A.A., Abas, A.B.W.,
Development Process of New Bumper Beam for Passenger Car: A Review, Materials and Design (2012), doi:
10.1016/j.matdes.2012.03.060
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers
we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and
review of the resulting proof before it is published in its final form. Please note that during the production process
errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
1
Development Process of New Bumper Beam for Passenger Car: A Review
M.M.Davoodi1, 2
*, S.M. Sapuan2, A. Aidy
3, N.A. Abu Osman
1 A.A. Oshkour
1
W.A.B Wan Abas1
1 Department of Biomedical Engineering, Faculty of Engineering, University of Malaya,
50603, Kuala Lumpur, Malaysia
2
Department of Mechanical and Manufacturing Engineering, University Putra Malaysia
43400, UPM, Serdang, Selangor, Malaysia
3
Department of Mechanical Engineering, National Defence University of Malaysia
57000, UPNM, Kuala Lumpur, Malaysia
E-mail: [email protected]
Tel: 006(0)16 65 65 296
Fax: 006(0)3 8656 7122
Abstract
Bumper beam absorbs the accidental kinetic energy by deflection in low-speed impact and by
deformation in high-speed impact. The safety regulations “low-, and high-speed, and
pedestrian impacts” along with new environmental restrictions “end-of-life vehicles”
increased the complexity level of bumper system design. The new bumper design must be
flexible enough to reduce the passenger and occupant injury and stay intact in low-speed
impact besides being stiff enough to dissipate the kinetic energy in high-speed impact. The
reinforcement beam plays a vital role in safety and it must be validated through finite-
element analysis (FEA) and experimental tests before mass production. The careful design
and analysis of bumper beam effective parameters can optimize the strength, reduce the
weight, and increase the possibility of utilizing biodegradable and recyclable materials to
reduce the environmental pollution. Developing the correct design and analysis procedures
prevents design re-modification. On the other hand, analysis of the most effective parameters
conducive to high bumper beam strength increases the efficiency of product development.
Cross section, longitudinal curvature, fixing method, rib thickness, and strength are some of
the significant design parameters in bumper beam production. This study critically reviews
the related literature on bumper design to come up with the optimal bumper beam design
process. It particularly focuses on the effective parameters in the design of bumper beam and
their most suitable values or ranges of values. The results can help designers and researchers
in performing functional analysis of the bumper beam determinant variables.
Keywords: Developing process, Bumper beam, Design parameters
2
1. Introduction
Design is the preliminary stage of product development and analysis. The embodiment stage
of the design process fairly predicts the failure(s), if any, before mass production. Passenger
vehicles make up over 90% of the fleet of registered vehicles. In 2009 it was estimated that
9,640,000 vehicles were involved in police-reported crashes, 95% (9,161,000) of which were
passenger vehicles. Furthermore, there, 45,435 vehicles of these were involved in fatal
crashes and eighty percent of which (36,252) were passenger vehicles. More than 23,000
passenger vehicle travelers lost their lives in traffic crashes in 2009 and an estimated 1.97
million persons were injured [1]. Therefore, vehicle safety requirements forced by
Governments and insurance companies increase frequently [2]. In most of the accidents, the
bumper system is the first vehicle part that receives the collision and which may to some
extent protect the car body and passengers. This system comprises three main parts: fascia,
energy absorber, and bumper beam [3]. The fascia is a non-structural aesthetics component
that reduces the aerodynamic drag force while the energy absorber dissipates part of the
kinetic energy during collision. The bumper beam is a structural component which absorbs
the low-impact energy by bending resistance and dissipates the high-impact energy by
collision [4].
There are some investigations of new material development, property improvement, and FEA
of bumper beam structures by researchers and car manufacturers. These parties are mainly
interested in substituting the conventional material with lighter and stronger material[5].
Renault used SMC in a passenger car bumper in 1972 instead of steel [6] and General Motors
(GM), used the sheet-moulding compound (SMC) beam in Pontiac Bonneville Cadillac
Seville and Cadillac Eldorado instead of steel which was used in previous models [7]. Cheon,
Choi JH [8] found that the polymer composite bumper beam offers 30% less weight than
steel without scarifying the bumper beam‘s bending strength. Wakeman, Cain [9] found that
holding time pressure is the most effective parameter among five processing parameters in
microstructure and macrostructure properties of glass mat thermoplastic (GMT) in a bumper
beam. Peterson, Spencer [10] from Azdel company developed the GMT with a high surface
finish for aesthetic components. Raghavendran and Haque [11] also developed a lightweight
GMT composite containing long-chopped fiber strands to be used in headliner and other
automotive interior applications. Suddin, Salit [12] used the weight analysis method to select
fascia for a desired vehicle. He used the knowledge-based system (KBS) approach to select
3
the material for bumper beam development [13]. Sapuan, Maleque [3] studied the conceptual
design and material selection for development of a polymeric-based composite automotive
bumper system. Hosseinzadeh, Shokrieh [14] studied the shape, material, and impact
conditions of the bumper beam and compared the results with conventional metals like steel
and aluminium. He found that GMT can replace SMC as a recyclable material. Kokkula,
Langseth [15] experimentally studied bumper beam performance at 40% offset impact
crashworthiness and concluded that materials with moderate strain-hardening properties are
preferable over the higher strain-hardening materials for his studied system. Hambali, Sapuan
[16] studied employed the analytical hierarchy process (AHP) in concept selection of bumper
beam during the conceptual design stage of product development. Marzbanrad, Alijanpour
[17] studied bumper beam crashworthiness improvement by analyzing bumper beam
material, thickness, and shape as well as impact condition parameters. He found that a
modified SMC bumper beam is preferable to the ribbed GMT bumper beam as the former has
the potential to minimize the bumper beam deflection, impact force, and stress distribution
and to maximize the elastic strain energy while exhibiting almost the same energy absorption
of the unribbed SMC bumper beam. Park, Jang [18] developed an optimized bumper beam
cross section that satisfies both the safety requirements for a front rigid-wall impact and
lower leg injuries in a pedestrian impact test. Most of the abovementioned research
emphasizes on material and concept selection for, and numerical analysis of, bumper beam.
However, no articles regarding procedure(s) for new bumper beam development could be
found in the open literature. This study therefore focuses on the process of bumper beam
development and summarizes the method of design and analysis of the new bumper beam in
new vehicle development based on the previous research and the authors‘ personal
experiences. In consequence, this article helps the designer to follow the right procedure for
bumper beam development. It emphasizes on the parameters that have to be considered in the
design of bumper beams and illustrates the procedure for FE analysis the bumper system.
2. Bumper system
2.1. Bumper system definition
A bumper system is a set of components in the front and rear parts of the vehicle designed for
damping the kinetic energy without any damage to the vehicle in low-speed impact and for
energy dissipation in high-speed impact conditions besides serving aesthetic and aerodynamic
4
purposes [19, 20]. A bumper system mainly comprises three components: fascia, energy
absorber, and beam [3]. The bumper system has changed over the last three decades due to
new government safety regulations and styling concepts. The ability to maintain the vehicle
intact at high-speed impact conditions and to damp the kinetic energy are the most important
factors in bumper system selection besides its weight, manufacturability, cost, reparability,
and formability of materials [21] (Fig. 1).
Fig. 1. Common Bumper systems
The American Iron and Steel Institute [22] offered four proposals for bumper systems: (1)
metal face bar, (2) plastic fascia and reinforcing beam, (3) plastic fascia reinforcing beam and
mechanical energy absorbers, and (4) plastic fascia reinforcing beam and foam, or
honeycomb, energy absorbers. According to the new regulation, the pedestrian leg impact test
was due to be enacted and implemented starting from 2010. Some research has been carried
out to offer methods for complying with the pedestrian impact test. The energy absorption
density in the low-impact test approximately doubled in comparison with the pedestrian
impact [23]. Choi, Shin [24] came up with the concept of locating the energy absorber
between the bumper fascia and the reinforcement beam to absorb the impact energy when the
second energy absorber is subjected to an impact greater than its critical elastic force.
Therefore, this concept (to be referred to hereafter as concept number 5 or concept No. 5) can
be added to the four bumper system components which the American Iron and Steel Institute
(AISI) offered in 2003 (Fig. 2) which is a schematic view of a concept No. 5 system modified
from AISI for car bumper system. In this method, two types of energy absorbers are
considered: firstly, a low stiffener absorber, which is called the reversible absorber, is
designed for protection against low and pedestrian impact; and secondly, the irreversible
energy absorber, which comprises the beam and the crushable energy absorber and is usually
located at the back of the beam and attached to the main face bar.
Fig. 2. Pedestrian, low impact and crash impact system
2.2. Bumper beam definition and function
The bumper beam is the backbone of the energy-absorption mechanism of the bumper system
[8]. It is usually located in the front, and sometimes in the rear, sides of the vehicles.
5
However, the testing process for both sides is almost the same; the forward system should be
stronger than the backward one for driver safety. On the other hand, the current trends in
bumper design focus on aerodynamic efficiency where the designed curve should be
embraced with the same style in other parts of the bumper system [22]. So, the conformable
composite material solves this dilemma by providing the required curvature and lowering the
manufacturing cost, e.g., by multi-stage stamping of the metallic bumper beam, and decreases
the beam weight [25].
Dissipation of energy by the bumper beam can be determined both by material and structural
energy absorption [26]. The effective parameters in energy absorption of composite materials
depend on type of fibre [27], matrix [28], fibre orientation [29], fabricating conditions [30],
inter-laminar bond quality [31], and toughness [32]. The effective parameters of structural
energy absorption are longitudinal curvature, cross-section profile [33], strengthening ribs
[34], thickness [35], and the overall dimensions of the cross-section [36]. The energy
absorption of material and structure was investigated by [37, 38]. The crashworthiness of the
vehicle and bumper system, which identifies the safety and performance of the vehicle in
response to impact load, is a challenging issue. The enhanced performance of
crashworthiness presents low damage to the vehicle and to occupants [39]. The impact energy
in the bumper system can be dissipated reversibly (low impact) or irreversibly
(crashworthiness)[40]. If the magnitude of the load does not exceed the elastic region ―low-
impact condition,‖ then the structure returns to its previous position after releasing the load
[4]. However, if the impact load goes beyond the elastic region ―crashworthiness,‖ then most
of the collision load is absorbed by plastic deformation (irreversible energy absorption). The
bumper system should overcome both scenarios and sustain the intense load which results in
large deformation, strain hardening, and various interactions between different deformation
modes such as bending and stretching [41] (Fig. 3).
Fig. 3. GMT bumper beam of Samand [42]
The proportion of energy reversibly absorbed by the bumper beam should be confined and
the high kinetic energy should be preferably dissipated by plastic deformation. Otherwise, the
collision energy maximizes the structural strain energy and release the same kinetic energy in
return, which causes subsequent damage to the occupants or adjacent vehicles. Accordingly,
the structural strain energy of the bumper beam should be optimized during the design
6
process. Besides, ductility of material improves the plastic energy absorption. Within this
context, plastic composites, polymer foams, and aluminium alloys are commonly used in the
bumper systems when plastic energy damping and weight are critical design and performance
criteria[41, 43].
2.3. Bumper beam design parameters
The stream of new materials, products, and process development has enforced a rethinking of
the role of structural design and of the effective parameters for their improvement. The
bumper beam can be improved by adjusting a number of effective parameters. The efficiency
of the parameters can be identified by any of a number of methods such as design of
experiments (DOE)[44], reliability-based design optimization (RBDO) [45], and design
sensitivity analysis. However, the current study is not intended to identify the viability of the
parameters. Variables such as thickness, bumper beam curvature, rib strength, and cross-
section profile are some of the most important parameters which can improve the energy
absorption of the bumper beam and sustain the desired deflection of the bumper system as
defined in the product design specifications (PDSs). The optimal thickness of a bumper beam
can construct a balance between the weight and strength of the structure in order to provide
further effective energy absorption [46]. The nominal thickness of the bumper beam is 4 mm.
However, it is not completely constant in all beam parts. Surplus thickness of the polymer
products has some manufacturing constraints. As an illustration, it increases the cooling time
and makes warps in the flat surfaces and sink marks on the surface of the ribs‘ interface,
which is not suitable in visible products.
Strengthened ribs increases distortion resistance, rigidity, and structural stiffness through
using little material in the slender walls [47] and providing the required impact severity [48].
Pattern, thickness, tip, and end fillet of the ribs should be designed according to load
direction, impact position, material, and the manufacturing process available. Since the
material thickness is high at the rib‗s contact area, it causes sink marks, but this is not much
important a consideration, as a non-aesthetic part, for the bumper beam. It has been reported
that the strengthened ribs increase the impact energy by 7% and decrease elongation by 19%
[14, 17, 49]. Zhang , Liu [20] showed that the optimized reinforced ribs have higher-energy
absorption performance than the empty and foam-filled beams.
7
Optimizing the cross-section of a bumper beam magnifies its strength, dimensional stability,
and damping capability. It has significant effects on the energy damping rate and bending
resistance compared with other parameters [27, 37]. The right cross section can increase
bumper beam strength and dimensional stability. Kim. and Won [50] found that the section
height is the most effective variable in torsional stiffness of the bumper beam. Additional
strength permits more energy absorption with less consequent bumper beam distortion [51].
Frontal curvature increases the room between fixing points and top extremity beam curvature
and increases the stability of the beam and the energy absorption. It enhances the beam
stability and extends the required collision displacement. Besides the aesthetic purposes, the
curve facilitates additional load impact distribution through the frontal beam and fixing points
during the energy damping process. When an impact load is applied to the bumper, the beam
initial curvature tends to restore its original shape. So, some designers mounted a bar link
between the beam fixing points in order to strengthen the outward motion and the energy
absorption tendency [51, 52]. The bumper beam is an offset of the front bumper fascia that is
intended to provide a consistent level of protection across the vehicle [53].
3. Material selection steps
Selecting a suitable material in bumper beam development is crucial and bad selection may
cause poor performance, frequent maintenance or failure. Proper material selection for
bumper beam requires information about type of loading (axial, bending, torsion or their
combination), mode of loading (static, dynamic, fatigue, impact), operating environment
(temperature, humidity, chemical conditions), manufacturing process, cost (raw material,
manufacturing, assembly)[54].
Environmental constraints, economical demands, and performance enhancement are main
issues for material selection[55]. Material usually should be finalized in preliminary design
stage, while the material properties requirements are coupled with main structural function
[56]. The product function requirements usually identify through product design specification
(PDS) prior to development process to guide the designer for precise selection of design
parameters and material selection. Then based on the translated of product design
specification, constraints, objectives, geometry and process, which have interaction together
8
the list of material should be narrow down to the best candidate to comply with the defined
properties [57].
Physical, chemical, and mechanical properties along with manufacturing and economic issues
should be considered in selection of a favorite material for a bumper beam [58]. Proper
material selection can be achieved by constructing a balance or compromise between
function, material, shape, and process [57]. The general properties, processing, and
performance of materials are considered in the conceptual design phase and are refined into
specific requirements in the subsequent steps to ensure the performance of the final product.
Material selection of a bumper system usually considers new environmental constraints,
safety regulations, cost reduction, reliability improvement, and performance enhancement.
Normally, the results of the failure analysis of previous products enable the designer to be
more aware of material selection for the next product (Fig. 4)
Fig. 4. Material selection in bumper beam design process [57, 59, 60]
There are two approaches for material selection of the bumper beam. Since manufacturing of
the bumper beam is costly, the designers usually attempt to find the most consistent material
for the available process that offers the desired properties. Otherwise, the material is selected
initially and the optimized favorable manufacturing process is developed to meet the desired
performance. Incorrect material selection and manufacturing method may lead to product
failure, performance reduction, and cost increase.
The material selection process requires knowledge about structural mechanics, material
strength, material thermal properties, economics, and market demand. It entails knowledge of
the types of loading (axial, bending, torsion, or a combination of all or any two), mode of
loading (static, fatigue, or impact), environmental conditions (temperature and humidity),
manufacturing processes (structure or components) and cost of manufacturing and assembly
[54].
Review of the literature points out that there are some studies where discussion of material
selection of automotive products has been be provided. For instance, Sapuan [61] selected the
appropriate material for polymeric-based composite automotive pedal box system using an
expert system with a comfortable graphical user interface. He developed a prototype KBS for
material selection of ceramic matrix composites for engine components such as the piston,
9
connecting rod, and piston ring [62]. In another example, Sudin, Harun [13] used the KBS for
material selection in bumper beam design.
4. Design process of bumper beam
The design process is the solution steps for developing new products in a very specific way to
prevent rework and reduce the production time and cost. It compromises between market
requirements and production and converts the customer requirements into a product within
the optimum economic conditions. The engineering design is combination of knowledge for
generating new ideas, evaluating these ideas, and selecting the best concept. A successful
bumper beam design needs interdisciplinary team work, mainly involving product design
engineer, manufacturing engineer, materials specialist, quality assurance specialist, and an
analyst [63].
A successful bumper beam design starts with market research and customer requirement
investigation so as to develop an idea about the available products and their manufacturing
technologies. These requirements are then finalized by converting the customer‘s
requirements into technical demands, i.e., PDSs. The design process usually starts with
conceptual design generation followed by parameter identification in order for concept
evaluation to come up with reliable and feasible concept [64]. In a later stage; the design
embodiment design stage, the separated components, configuration of subassemblies [65],
and layout of the new bumper beam must be refined and evaluated against the related
technical and economic criteria. In the last stage, detailed design, precise dimensioning,
tolerancing, material specification, configuration, and weight must be finalized[66, 67]. This
means that by this stage the final drawing of the whole parts with the specified materials and
dimensions is obtained.
Since the bumper beam surface should follow the style of the fascia (inner surface), the new
concept of the bumper beam will be released when the final version of fascia surface is
issued. At the final stage of vehicle development, the latest clay model of the vehicle (full-
scale) is released and the outer surface is scanned with a digitizer and a separation line for
every visible component is identified as well. Then, the 3D model of every separated part,
which is extracted from the clay model after reconstruction, is transferred to the appointed
original equipment manufacturer (OEM) [68]. The appointed OEM makes the inner surface
10
(B-surface) and designs other components such as bumper beam, absorbers, brackets, and
bumper grills in addition to specifying the method of fixing them to the body in white (BIW),
mainframe, or elements together. The positions and fixing method(s) of the fog lamps, toe
cap, and rubbing strip‘s too should be considered during the bumper design stage. Besides,
design for assembly (DFA), design for manufacturing (DFM), maintenance, and other
parameters have to be considered [69]. To release the final product, finite-element analysis
should be employed to virtually validate the structural strength of the developed product
under working conditions. However, it is essential to make the soft mould for the main parts
to fabricate some samples under similar production conditions with the selected material so
as to obtain the exact shrinkage and conduct the actual structural test (Fig. 5).
Fig. 5. Bumper beam design process flowchart
4.1 Product design specifications (PDSs)
The design validation of the bumper beam is subject to material and structural acceptance and
should be presented in functional approval under working conditions. The design criteria
compromise between the margins of safety value, damage criteria, environmental issues,
manufacturing process, and maintenance [70]. The new composite structure should be
precisely analyzed before going through the fabrication. It must be assured that all criteria
and customer requirements (that‘s, PDSs) are satisfied. The finalized designed structure
should be analyzed by FEA software followed by production of a prototype for real test and
analysis before mass production.
The PDSs are a list of the product specifications corresponding to customer‘s requirements or
expectations compiled in a detailed technical document [71]. The PDSs must present the
margin or exact value of each property clearly. It is quite difficult to prepare perfect PDSs in
the early stage of product development wherein knowledge of design requirements is
imprecise and incomplete [72]. The PDSs are prepared by a disorganized brainstorming team
with various specialities and experiences, e.g., manufacturing, design, sales, assembly, and
maintenance. Nonetheless, the PDSs can be modified in response to unforeseen changes in
product or manufacturing specifications or constraints. In the case of the bumper beam, the
PDSs address safety, performance, weight, size, cost, environmental issues, and appearance
(Fig. ). In other respects, the PDS parameters in general can be classified into three main
11
subdivisions: material, manufacturing, and design. Since energy absorption of different
bumper beam ideas and designs is the core competency of this study, it is emphasized in the
safety parameters of the PDSs. Some of the specifications of the mechanical and physical
properties presented here has been drawn from experimental results while others were
managed from existing PDS data.
Fig. 6. Product design specification of bumper beam [12, 73]
Safety: A number of different bumper safety regulations for passenger‘s cars have been
issued by governmental safety organizations, insurance companies, or OEMs [74]. Insurance
companies usually offer more rigorous conditions than other engaged organizations in order
to decrease their own monetary losses. Examples on safety regulations for the passenger‘s
cars bumper systems include those issued by The United Nations Economic Commission for
Europe (ECE) Regulation No. 42 [75]; the International Highway Traffic Safety
Administration (NHTSA) [1]; and the Canadian Motor Vehicle Safety Regulation (CMVSR)
[76].Size: Dimensions of the bumper beam depend on the size and weight of the vehicle and
on the target value of energy absorption. Maintenance: Design for assembly and DFM should
be considered during product design. Performance: The defined goal of the product should be
attainable [77]. Installation: Design for manufacturing and assembly (DFMA) helps in
minimizing the bumper components in the product or assembly to allow for easy assembling
with optimized fixing point. The material should be selected according to the preset
properties or desired problem solution. Materials of the bumper should be light, cost-
competitive, accessible, producible, recyclable, and rather biodegradable.
4.2 Conceptual design of the bumper beam
The preliminary stage of every product development starts with conceptual design, which is
derived from the customer requirements ―voice of the customer‖ [65, 78], in order to find a
solution that satisfies the design criteria [64]. Inaccurate engineering calculation in bumper
beam design and material selection can lead to an increase of up to 70% of the total product
cost for redesigning, selecting material, or changing the manufacturing equipment [79]. In
other words, the designer has to select the most suitable idea from different possible solutions
to meet the desired PDSs in each design stage, i.e. total design, subsystem or component‘s
level total design, and subsystem level [77, 80], to decrease the rework expenses to less than
12
twice the design and manufacturing costs [80-82]. Therefore, bumper beam design concept
selection (DCS) has recently been under focus of the designers. Many tools have been
developed for DCS to evaluate and compromise different effective factors such as customer
requirements, designer intentions, and market desire to eventually propose the best
conceptual design.
4.2.1 Concept design selection
Developing different concepts drives decision makers to narrow down the selected concepts
to the best feasible solution and to cut the redesign cost and production delay in the early
stage of the design process. The previous research presented different approaches to selection
of the best concepts. The decision matrix-based methods (e.g., Pugh‘s method [77]) offer a
qualitative comparison and quality function deployment (QFD) to perform the best concept
selection [83]. Selecting the most suitable concept by analysis and manipulation of
experimental tests along with comparisons with the product standards help the designer in
selecting the optimal solution with the minimum risk [84]. The fuzzy ANP-based approach is
useful for valuation of a set of conceptual design alternatives to satisfy both customer‘s
satisfaction and the engineering specifications [85]. The AHP developed a mathematically-
based technique for analyzing complex situations [86]. Multi-criteria decision-making
(MCDM) is an effective method for single selection when mixed criteria are involved. The
multi-attribute decision-making technique (MADM) was developed to solve conflicting
preferences among criteria for single decision makers. The TOPSIS is a technique well suited
to dealing with multi-attribute or multi-criteria decision-making (MADM/MCDM) problems
in real world ideal solutions [87]. Its methodology is based on the principle of selecting an
alternative having the shortest distance from the positive ideal solution and the farthest
distance from the negative ideal solution. It helps in organizing problems and in comparing
and ranking alternatives to search for better options [88]. This method has been used to select
the best concept in this research.
4.2.2 Embodiment
In the embodiment design stage, the bumper beam is investigated with reference to technical
and economic criteria. It makes highly accurate modeling of the values of forces when
analyzing the final dimensions of components. The appropriate function and safety
13
requirements must be approved before evaluating other parameters such as ease of
production; low investment; ease of assembly, transportation, maintenance; material
recyclability; and cost.
The best shape, size, arrangements, and layouts stem from the combined ideas and solutions
from other professions‘ points of view. This can eliminate the weak spot or combine the
appropriate solutions to propose the best layout. It is often crucial that the designer produces
several preliminary methods of bumper system layout with whole components to analyze and
compare their advantages or disadvantages and select the most proper one. The best layout is
the one that can fulfill the required function with the minimum parts, process, and optimum
possible standard parts in order to decrease the production cost. The selected material should
have the desired strength, corrosion resistance, energy absorption, service life, availability,
and recyclability.
4.2.3 Detailed design
In the detailed design phase, all the information about the parts must be placed on the
drawing. All the individual component drawings of the bumper system must have the
required manufacturing dimensions, material specifications, tolerance, surface roughness,
part list, and bill of material (BOM) [89]. Use of 3D CAD software facilitates implementation
of the various processes involved in the detailed design phase since by this stage all parts
have been modeled with the real dimensions in their position and with the required fitting
tolerance. Hence, a 2D drawing can be extracted easily from the assembly model and fully
dimensioned. Moreover, it allows for using the data for manufacturing, production planning,
and toll making. The detailed design must be critically checked and approved by an
experienced designer to validate the fit and function of the final design and prevent any error
in the fabrication phase. However, the perfect detailed design cannot cover the poor
conceptual design, if any, and investigation showed that most of the errors during production
are caused by flawed conceptual design [66, 90].
Shrinkage (mold shrinkage, post-molding shrinkage, and end-use shrinkage)[91] of the
polymer material depends on a variety of parameters (thickness, geometry, temperature,
flowing speed) and cannot be exactly estimated in complicated parts. The moulding operation
could not make a uniform temperature in the fabricated products. A small-scale deviation in
14
shrinkage percentage in huge parts such as bumper results in unfitness in the adjacent parts
after production. Consequently, it is essential to make a real sample from the big parts by
soft-mould with the same material and production conditions in order to find the exact value
of shrinkage, provide a proof-of-concept, and implement a mechanical test as well [92].
5. Analyzing the bumper beam
Two main analyses of a bumper beam should be carried out in. First, the designer must be
confident about that the selected material fulfills the defined PDS properties (material
properties). Then, it must be assured that the structure developed with the selected material
can achieve the main functions, safety parameters, and the desired performance.
5.1. Analysis of material
Based on the desired product design specifications (PDSs) the plan for testing the material
should be written to confirm that the test method addresses loading sequence, gauge
placemen, and acceptance criteria of the material [69]. The test plan is usually prepared by a
material developer and approved by an authorized certifying agency.
Since the performance of the material is closely related to the manufacturing conditions, the
manufacturing parameters should be set to achieve the anticipated specification. However,
the final approval of the bumper beam can be issued after the structural test. Sometimes a
manufacturer modifies the production parameters for different applications or various
conditions. Totally, the test may include mechanical tests such as tensile and compressive
strength, yield strength, and toughness [93] with a consideration of the environmental
conditions, like humidity (20%- 95%) and temperature (-30 °C to 85 °C) [94], to which the
bumper beam may be exposed. Besides, advances in numerical methods for product analysis
and material processing analysis made it possible to optimize the product, manufacturing
process, and structural components.
5.2. Structural analysis
The next step in bumper beam analysis is to ensure the proper structural performance of the
selected material. The most reliable method is to fabricate the samples from selected
15
materials and appointed production methods and to carry-out the test under real conditions,
which is cost-, and time-consuming. The FE analysis does not offer 100% reliable results, but
its cost is considerably less than that of the experimental test.
Numerical analysis of the developed bumper beam is the preliminary stage of approving the
bumper beam. The final geometry with defined longitudinal curvature, thickness, cross
section profile, material, rib strength, and overall dimensions should be performed to obtain
the final geometry of the bumper beam FE model. A reasonable prediction of the bumper
beam performance depends on the accuracy of the simulated geometry, i.e., the longitudinal
curvature, cross section, thickness, ribs, and material model. However, the real-scaled
bumper beam with defined material and geometry should be tested under actual conditions
for final verification. The value of numerical analysis is strongly dependent on a validated
modelling technology with accurate material models and fracture criteria.
5.2.1. Low speed impact test
The procedure of low speed impact test in European countries is different compare with
American countries. Three low speed impact tests with their criteria explained as follows.
The criteria for the low-impact test in European countries is a pendulum test at 4.0 km/h (2.5
mph) with no damage to the bumper, and in the USA and North America, it is the same test at
8 km/h (5 mph), but damage to the fascia is not considered [1, 75, 95].
The United Nations Economic Commission for Europe (ECE) Regulation No. 42: Requires
that a car's safety systems continue to operate normally after the car has been impacted by a
pendulum or moving barrier on the front or rear longitudinally at 4 kilometers per hour (about
2.5 mph) and on the front and rear corner at 2.5 kilometers per hour (about 1.5 mph) at 455
mm (about 18 inches) above the ground under loaded and unloaded conditions, which calls
for no serious damage (light bulbs may be changed) [75].
National Highway Traffic Safety Administration (NHTSA) - Code 49 Part 58: Longitudinal
pendulum impact test 4 km/h at the curb position of bumper and 2.5 km/h bumper at the
corner [96].
16
Canadian Motor Vehicle Safety Regulation (CMVSR): Canadian safety regulation has the
same limitation and safety damage as NHTSA (pendulum test4 km/h of bumper face and 2.5
km/h bumper corner), but the speed is double [96].
After the test, any damage to bumper visual and functional should not occur. The lights,
bonnet, boot, doors operate in the normal manner, and all the essential features for safe
operation of the vehicle must still be serviceable. EU regulation allows greater damage in the
car in low-impact test compare with US regulation. Moreover, US regulation uses lower
speed, permits running lamps, fog lamps and equipment on the bumper face bar to be remove
if they are optional and requires no visual damage to all non-bumper parts, while Canadian
uses higher regulation speed, and does not allow anything to be removed, and it requires no
damage to safety and functional items.
5.2.2. High-speed impact test
Besides the low-impact test, the bumper system has to be able to absorb enough energy in
high-speed impact to meet the OEM‗s internal bumper standard in design stage. The new
bumper systems are not design to overcome entire of the high-speed impact energy.
However, systems are being developed that can damp about 15% of energy under the high-
speed impact. The design criterion for a high-speed impact for bumper system is defined as
follows [22]:
• No bumper damage or yielding after 8 km/h (5mph) frontal impact into a flat, rigid barrier.
This criterion does not apply to low speed bumpers, where controlled yielding and
deformation are beneficial.
• No intrusion by the bumper system rearward of the engine compartment rails for all impact
speeds less than15 km/h (9mph).
• Minimize the lateral loads during impacts in order to reduce the possibility of lateral
buckling of the rails.
• Full collapse of the system during Danner (RCAR), NCAP, and IIHS high speed crash
without inducing buckling of the rails.
• Absorb 1% of the total energy every millisecond and 15% of the total energy in the NCAP
crash, including engine hit.
17
5.2.3. Pedestrian impact test
The pedestrian impact test needs lower stiffness in dissipation of impact energy over a longer
time span. Bumper system requires elastic energy absorption before any plastic yielding of
the bumper beam takes place.
The second phase of pedestrian impact test consists of three test procedures and each using
different sub-system impactors.
– A leg-form impactor representing the adult lower limb to indicate lateral knee-joint shear
displacement and bending angle, and tibia acceleration, caused by contact of the bumper.
– An upper leg-form impactor representing the adult upper leg and pelvis to record bending
moments and forces caused by contact of the bonnet leading edge.
– Child and adult head-form impactors to record head accelerations caused by contact with
the bonnet top [23, 97]
Fig. 7. Pedestrian ‗leg-form‘ injury criteria [23]
In pedestrian leg impact test, a ‗leg-form‘ impactor is propelled toward a stationary vehicle‘s
longitudinal velocity of 40 km/h parallel to the vehicle‘s longitudinal axis. The test can be
performed at any location across the face of the vehicle; between the 30° bumper corners
(Fig. 7).
The above regulation is defined for bumper system not specifically for bumper beam, but
since the bumper is the main components in energy absorption, so the regulation can be
extended for bumper beam. It might be used another mechanism between bumper beam and
fascia to fulfill the pedestrian criteria.
6. Future trend in automotive bumper
The automotive safety and environmental legislations became more stringent in last few
decades. On the other hand, the high production demand besides raising the cost of the
petroleum resources encourage the automaker to exploit the natural resources in their new
products for staying in the competitive edge. Other impact for future bumper is new safety
regulation. There are totally two parallel trends for future bumper safety system. Passive
18
safety which emphasize on helping to the occupants during the crashes by improving he
structure of the vehicles, bumper damping system, seatbelts and primarily airbags and active
system to prevent of crash by using intelligent mechanism.
Fig. 8. Automotive intelligent pre-collision system [98]
Development of new material to comply with safety and environmental regulations, and
development of various intelligent pre-crash systems to prevent or decrease the injury
(pedestrian impact test) by fully automated controlled of car safety mechanism (Fig. 8)[99].
In first approaches, based on the environmental regulation, automakers investigated to utilize
the natural fiber in their new product, but poor mechanical properties of natural fibers do not
allow to be used in automotive structural components. There is plenty of research to improve
the mechanical properties of natural fibers in order to improve their performance. Increasing
the interfacial adhesion between fiber and matrix [100] , incorporating Z-direction fibers (3D
composite) [101], improving the properties of the matrix [102], and manufacturing method
[103]. The investigation trends shows that in early future the natural fiber will be used in
automotive structural components.
In second approaches based on the EU Parliament regulation, automakers should use the
advanced emergency braking systems from November 2015 for all new light and heavy
commercial vehicles. Also National Highway Traffic Safety Administration (NHTSA) began
studying ―lane departure warning systems‖ and ―frontal collision warning systems‖ on
vehicles [104]. These recent investigations are an intelligent preventing system (pre-crash
system) with non-contact safety mechanism to reduce the severity of an accident. However, it
is not more sufficient to prevent injury or damage at higher operating speeds [105].
7. Conclusions
The new safety regulations concerning bumper system specifications besides the automaker
environmental legislations (end of life vehicle) make it quite complicated and much costly for
the design of this structure to fulfil all broad requirements. Finding the best procedure for
bumper beam development poses extra loads on the designer and may influence his/her
performance. The previous research discussed the design process, material selection, and
analysis and verification of the developed product functionality by FEM tools, but there is
19
limited information about the approaches to bumper system development. The present study
concentrated on the bumper beam development process based on findings of previous studies.
It analyzed comprehensive information to determine the optimum method for bumper beam
development and to identify the settings for the effective structural variables (thickness, rib
strength, cross-section, and frontal curvature) conducive to the optimal bumper beam
strength.
References
[1] National Highway Teraffic Safety Administration (NHTSA). Laboratory Test Procedure
for Regulation Part 581 Bumper Standard Safety Assurance. 1990.
[2] Huang M. Vehicle crash mechanics: CRC Press; 2002.
[3] Sapuan S, Maleque M, Hameedullah M, Suddin M, Ismail N. A note on the conceptual
design of polymeric composite automotive bumper system. J Mater Process Technol.
2005;159:145-51.
[4] Davoodi MM, Sapuan SM, Yunus R. Conceptual design of a polymer composite
automotive bumper energy absorber. J Mater Des. 2008;29:1447–52.
[5] Cole GS, Sherman AM. Light weight materials for automotive applications. Mater
Charact. 1995;35:3-9.
[6] Murphy J. The reinforced plastics handbook. Oxford: Elsevier; 1998.
[7] General Motors. SMC bumper beams improve productivity for GM. Reinforced Plastics.
1992;36:7.
[8] Cheon S, Choi JH, DG. L. Development of the composite bumper beam for passenger
cars. Compos Struct. 1995;32:4919.
[9] Wakeman M, Cain T, Rudd C, Brooks R, Long A. Compression moulding of glass and
polypropylene composites for optimised macro-and micro-mechanical properties--1
commingled glass and polypropylene. Compos Sci Technol. 1998;58:1879-98.
[10] Peterson CW, Spencer DO, Rosin J, Hauqe E. High consistency glass mat reinforced
thermoplastic (GMT): thin wall structural applications with surface requirements. SAE
Technical Paper Series 2001-01-0098.
[11] Raghavendran V, Haque E. Development of low density glass mat thermoplastic
composites for structural applications. SAE Technical Paper Series. 2001-01-0100.
[12] Suddin MN, Salit MS, Ismail N, Abd M, Zainuddin S. Total design of polymer
composite automotive bumper fascia. J Sci Technol. 2004;12:39-45.
[13] Sudin MN, Harun MR, Hamzah AT, Anuar S. A prototype of KBS for material selection
in bumper beam design. J Sci Technol. 2007;14:215-22.
[14] Hosseinzadeh R, Shokrieh M, Lessard L. Parametric study of automotive composite
bumper beams subjected to low-velocity impacts. Compos Struct. 2005;68:419-27.
[15] Kokkula S, Langseth M, Hopperstad O, Lademo O. Offset impact behaviour of bumper
beam—longitudinal systems: experimental investigations. Int J Crashworthiness.
2006;11:299-316.
[16] Hambali A, Sapuan S, Ismail N, Nukman Y. Application of analytical hierarchy process
in the design concept selection of automotive composite bumper beam during the
conceptual design stage. Sci Resech Essy. 2009;4:198-211.
[17] Marzbanrad J, Alijanpour M, Kiasat M. Design and analysis of an automotive bumper
beam in low-speed frontal crashes. Thin Walled Struct. 2009;47:902-11.
20
[18] Park D, Jang C, Lee S, Heo S, Yim H, Kim M. Optimizing the shape of a bumper beam
section considering pedestrian protection. Int J Automot Technol. 2010;11:489-94.
[19] Johnson W, Walton A. An experimental investigation of the energy dissipation of a
number of car bumpers under quasi-static lateral loads. Int J Impact Eng. 1983;1:301-8.
[20] Zhang Z, Liu S, Tang Z. Design optimization of cross-sectional configuration of rib-
reinforced thin-walled beam. Thin Walled Struct. 2009;47:868-78.
[21] Alghamdi A. Smart frictional impact energy absorber. Int J Crashworthiness.
2000;5:169-78.
[22] AISI. Steel Bumper Systems for Passenger Cars and Light Trucks. Southfield: American
Iron and Steel Institute; 2006.
[23] Schuster PJ. Current trends in bumper design for pedestrian impact. SAE Technical
Paper Series.2006-01-0464.
[24] Choi WJ, Shin DW, Kim NH. Bumper system. Google Patents; 2004.
[25] Miravete A. ICCM/9: Composites Properties and Applications. Zaragoza: Woodhead
Pub Ltd; 1993.
[26] Tan P, Reid S, Harrigan J, Zou Z, Li S. Dynamic compressive strength properties of
aluminium foams. Part II--[] shock'theory and comparison with experimental data and
numerical models. J Mech Phys Solid. 2005;53:2206-30.
[27] Jacob G, Fellers J, Simunovic S, Starbuck J. Energy absorption in polymer composites
for automotive crashworthiness. J Comp Mater. 2002;36:813.
[28] Farley GL. Effect of fiber and matrix maximum strain on the energy absorption of
composite materials. J Comp Mater. 1986;20:322.
[29] Hamada H, Ramakrishna S, Sato H. Effect of fiber orientation on the energy absorption
capability of carbon fiber/PEEK composite tubes. J Comp Mater. 1996;30:947.
[30] Turner T, Warrior N, Robitaille F, Rudd C. The influence of processing variables on the
energy absorption of composite tubes. Composites Part A Appl Sci Manuf.
2005;36:1291-9.
[31] Kim JK, Mai YW. Engineered interfaces in fiber reinforced composites. Oxford:
Elsevier Science Ltd; 1998.
[32] Davoodi M, Sapuan S, Ahmad D, Aidy A, Khalina A, Jonoobi M. Effect of polybutylene
terephthalate (PBT) on impact property improvement of hybrid kenaf/glass epoxy
composite. Mat Lette. 2012;67:5-7.
[33] Davoodi M, Sapuan S, Ahmad D, Aidy A, Khalina A, Jonoobi M. Concept selection of
car bumper beam with developed hybrid bio-composite material. J Mater Des. 2011.
[34] Davoodi M, Sapuan S, Ali A, Ahmad D. Effect of the strengthened ribs in hybrid
toughened kenaf/glass epoxy composite bumper beam. Life Sci J. 2012;9.
[35] Daniel L, Hogg P, Curtis P. The relative effects of through-thickness properties and fibre
orientation on energy absorption by continuous fibre composites. Composites Part B.
1999;30:257-66.
[36] Kurtaran H, Eskandarian A, Marzougui D, Bedewi N. Crashworthiness design
optimization using successive response surface approximations. Comput Mech.
2002;29:409-21.
[37] Johnson W, Reid S. Metallic energy dissipating systems. Appl Mech Rev. 1978;31:277–
88.
[38] Beardmore P, Johnson C. The potential for composites in structural automotive
applications. Compos Sci Technol. 1986;26:251-81.
[39] Johnson W. The elements of crashworthiness: Scope and actuality. Proceedings of the
Institution of Mechanical Engineers. 1990;204:255-73.
[40] Davoodi MM, Sapuan SM, Yunus R. Development of fiber reinforced epoxy composite
energy absorber for automotive bumper system. J Polym Mater. 2008;25:15-21.
21
[41] Lu G, Yu T. Energy absorption of structures and materials: Woodhead Pub.; 2003.
[42] MehrCamPars. GMT bumper beam of Samand. 2003.
[43] Hearn EJ. Mechanics of materials: an introduction to the mechanics of elastic and plastic
deformation of solids and structural materials: Butterworth-Heinemann; 1997.
[44] Isaksson E, Jonsén P, Sundin K, Oldenburg M. Correlation of vehicle crash model
parameters to car properties in low-speed collisions: a design of experiments approach.
Int J Crashworthiness. 2010;15:241-9.
[45] Fu Y, Chuang CH, Li G, Yang R. Reliability-based design optimization of a vehicle
exhaust system. SAE transactions. 2004;113:507-18.
[46] Baccouche R, Mahmood H, Madasamy C, Wagner D. Lightweight bumper for
automobiles. 2007.
[47] Al-Ashaab A, Rodriguez K, Molina A, Cardenas M, Aca J, Saeed M, et al. Internet-
based collaborative design for an injection-moulding system. Conc Eng. 2003;11:289.
[48] Haque E, Bassett W, Lewis T. I-Section automotive bumper formed from mineral-filled
glass mat thermoplastic (GMT) composite. 2001.
[49] Brydson JA. Plastics Materials. New Delhi: Butterworth-Heinemann; 1999.
[50] Kim. K, Won S. Effect of structural variables on automotive body bumper impact beam.
Int J Automot Technol. 2008;9:713-7.
[51] Stewart R, Osterman A, Jalbert D. Vehicle and bumper beam combination. Google
Patents; 1992.
[52] Stewart R, Osterman A, Jalbert D, Nulty J. Vehicle bumper beam. Google Patents; 1994.
[53] Sharpe N, Vendrig R, Houtzager K. Improved design for frontal protection. TNO
Automotive. 2001.
[54] Mallick PK. Fiber-reinforced composites: materials, manufacturing, and design. Boca
Raton: CRC Press; 2008.
[55] Edwards K. Strategic substitution of new materials for old: Applications in automotive
product development. J Mater Des. 2004;25:529-33.
[56] Deng YM, Edwards K. The role of materials identification and selection in engineering
design. J Mater Des. 2007;28:131-9.
[57] Ashby. MF. Materials Selection in Mechanical Design. Oxford: Butterworth-
Heinemann; 2005.
[58] Sapuan SM. A computer Aided Material Selection for Design of Automotive Safety
Critical Components with Novel Materials. Malay J Comput Sci. 1999;12: 37-46.
[59] Lampman S. Materials selection and design: ASM International; 1997.
[60] Mitchell BS. An introduction to materials engineering and science for chemical and
materials engineers. Hoboken: John Wiley; 2004.
[61] Sapuan. A computer-aided-material selection for design of automotive safety critical
components with novel materials. Malay J Comput Sci. 1999;12:37-46.
[62] Sapuan, Jacob MSD, Mustaph F, Ismail N. A prototype knowledge-based system for
material selection of ceramic matrix composites of automotive engine components. J
Mater Des. 2002;23:701–8.
[63] Ullman DG. The Mechanical Design Process. New York: McGraw-Hill Higher
Education; 2009.
[64] Kroll E, Condoor SS, Jansson DG. Innovative conceptual design: theory and application
of parameter analysis. Cambridge: Cambridge University Press; 2001.
[65] Pahl G, Beitz W, Feldhusen J. Engineering Design: A Systematic Approach. London:
Springer 2007.
[66] Hsu W, Woon IMY. Current research in the conceptual design of mechanical products.
Comput Aided Des. 1998;30:377-89.
22
[67] Ashby M, Shercliff H, Cebon D. Materials: engineering, science, processing and design.
Burlington: Butterworth-Heinemann; 2009.
[68] Davies G. Materials for automobile bodies. Burlington: Butterworth-Heinemann; 2003.
[69] Kutz M. Mechanical Engineers‘ Handbook, 1986. John Wiley, New York.
[70] Backman BF. Composite structures, design, safety and innovation. Oxford: Elsevier;
2005.
[71] Dieter GE. Engineering Design: A Materials and Processing Approach. New York:
McGraw-Hill; 2000.
[72] Wang L, Shen W, Xie H, Neelamkavil J, Pardasani A. Collaborative conceptual design--
state of the art and future trends. Comput Aided Des. 2002;34:981-96.
[73] Surhone LM, Tennoe MT, Henssonow SF. Product Design Specification: VDM Verlag
Dr. Mueller AG & Co. Kg; 2010.
[74] Cars P. US Departement of Transportation National Highway Traffic Safety
Administration. 1989.
[75] United Nations Agreement. Uniform provisions concerning the approval of vehicles with
regards to their front and rear protective devices (bumpers, etc.). E.C.E.; 1994.
[76] Canadian Motor Vehicle Safety Regulations (CMVSR). Motor Vehicle Safety
Regulations (C.R.C., c. 1038) Bumpers 2009.
[77] Pugh. S. Total Design. Cornwall: Addison-Wesley 1994.
[78] Xiao A, Park S, Freiheit T. A comparison of concept selection in concept scoring and
axiomatic design methods. 2007.
[79] Huthwaite B. Manufacturing competitiveness and quality by design. 4th International
Conference Product Design for Manufacture and assembly. Stockholm,Sweden1989.
[80] Hsu W, Woon I. Current research in the conceptual design of mechanical products.
Comput Aided Des. 1998;30:377-89.
[81] Qiu S, Fok S, Chen C, Xu S. Conceptual design using evolution strategy. Int J Adv Man
Techol. 2002;20:683-91.
[82] Fung R, Chen Y, Tang J. A quality-engineering-based approach for conceptual product
design. Int J Adv Man Techol. 2007;32:1064-73.
[83] Keinonen T, Takala R. Product Concept Design: A Review of the Conceptual Design of
Products in Industry. New York: Springer 2006.
[84] Edwards K. Selecting materials for optimum use in engineering components. J Mater
Des. 2005;26:469-73.
[85] Hsiao S. Fuzzy logic based decision model for product design. Int J Ind Ergon.
1998;21:103-16.
[86] Saaty T. The analytic hierarchy process: planning, priority setting, resource allocation.
New York: Mc.GrawHill; 1980.
[87] Hwang. C, Yoon K. Multiple Attribute Decision Making: Methods and Applications: A
State-of-the-Art Survey. New York: Springer; 1981.
[88] Shih H, Shyur H, Lee E. An extension of TOPSIS for group decision making. Math
Comput Modell. 2007;45:801-13.
[89] Edwards K. Towards more strategic product design for manufacture and assembly:
priorities for concurrent engineering. J Mater Des. 2002;23:651-6.
[90] Petroski H. Design paradigms: case histories of error and judgment in engineering.
Cambridge: Cambridge University Press; 1994.
[91] Drozda TJ. Tool and manufacturing engineers handbook: a reference book for
manufacturing engineers, managers, and technicians. Material and part handling in
manufacturing: One SME Drive; 1998.
[92] Chanda M, Roy SK. Plastics Fundamentals, Properties, and Testing. Boca Raton,: CRC
Press; 2008.
23
[93] Brown RP. Handbook of polymer testing: physical methods. Shropshire: Rapra
Technology Limited; 1999.
[94] Huang S, Yang J, Fredriksson R. Performance analysis of a bumper–pedestrian contact
sensor system by using finite element models. Int J Crashworthiness. 2008;13:149-57.
[95] Research council for automotive repair (RCAR). RCAR Bumper Test. Research council
for automotive repair; 2010.
[96] Matthew C. Motor Vehicle Safety Regulations. Minister of Justice; 2009.
[97] Lawrence G, Hardy B, Carroll J, Donaldson W, Visviskis C, Peel D. A study on the
feasibility of measures relating to the protection of pedestrians and other vulnerable
road users. Transportation Research Library. 2004.
[98] David Benedict. Human Factor Issues of Driving Assistance Systems. 2007.
[99] Gladwell M. Big and bad: How the SUV ran over automotive safety. The New
Yorker,2004,January 12. p. 28-33.
[100] Huda MS, Drzal LT, Mohanty AK, Misra M. Effect of fiber surface-treatments on the
properties of laminated biocomposites from poly (lactic acid)(PLA) and kenaf fibers.
Compos Sci Technol. 2008;68:424-32.
[101] Soden JA, Stewart GFJ. Natural fibre composites with 3D woven reinforcement for
new application areas. J Biobased Mater Bio. 2010;4:139-47.
[102] Joffe R, Wallström L, Berglund L. Natural fiber composites based on flax –matrix
effects. International scientific colloquium: modelling for saving resources. Riga2001.
[103] Ho M, Wang H, Lee JH, Ho C, Lau K, Leng J, et al. Critical factors on manufacturing
processes of natural fibre composites. Composites Part B. 2011.
[104] NHTSA. Frontal collision warning systems. National Highway Traffic Safety
Administration2009.
[105] Madhavan R, Messina ER, Albus JS. Intelligent vehicle systems: a 4D/RCS approach:
Nova Science Publishers; 2006.
Fig. 1. Common Bumper systems
Fig. 2. Pedestrian, low impact and crash impact system
Fig. 3. GMT bumper beam of Samand
Material Selection in Bumper Beam Design Process
Conceptu
al Desig
n
Embodim
ent Desig
n
Detail
Design
Product Design Specification (See Fig.5)
Screening the Constraints (Function, structure, material properties, geometry, process)
Ranking Materials(propertiesl, geometry, process, cost, environmental impact)
Selecting All Possible Materials
Analyzing appointed materials(Failure, mechanical ,environmental, feasibility, cost, maintenance)
Finalize bill of material (BOM) (FEA, DEA, DEM, dimensions, specification, roughness, tolerances)
Product
Realiz
ation
Selecting materials for whole subset(geometry, size, assembly, maintenance, cost, environmental)
Fig. 4. Material selection in bumper beam design process
Fig. 5. Bumper beam design process flowchart
Bumper Beam PDS
Per
form
ance
Dis
po
sal
Reusable disposal
Easy & fast instalation
Inst
alat
ion
Easy dis-assemble
Minimum Weight
Easy Carry & fit to BIW
Fast & Less Investment
Minimum product cost
Impactable without damage
Mat
eria
ls
Saf
ety
Recycable,Available,Light,Strong
Compatible with environmental condition
Low impact & crust test
Design Material Manufacturing
En
vir
on
men
t
Siz
e
Mai
nte
nan
ce
Pro
cess
Co
st
Wei
gh
t
Fig. 6. Product design specification of bumper beam
Fig. 7. Pedestrian ‘leg-form’ injury criteria
Fig. 8. Automotive intelligent pre-collision system
> The process of new bumper beam development for passenger car is discussed.
> A new bumper system has been added to the previous developed bumper systems. > The flow chart of design and analysis of bumper beam is shown.
> Different analysis for developing new bumper beam before production is discussed.
> The process of material selection in bumper beam is discussed.