support tool user guide for pbs blueprint vehicle … · pbs blueprint vehicle design and approval...

SUPPORT TOOL USER GUIDE

FOR

PBS BLUEPRINT VEHICLE DESIGN AND APPROVAL

PRIME-MOVER AND SEMI-TRAILER COMBINATIONS

April 2013

Document Version: v0.1

Software Version: v0.6

Prepared by

Mechanical System Dynamics Pty Ltd

National Transport Commission

Support Tool User Guide for PBS Blueprint Vehicle Design and Approval

Report Prepared by: Mechanical System Dynamics Pty Ltd

CONTENTS

1. INTRODUCTION .................................................................................................. 1

2. INTENDED AUDIENCE ........................................................................................ 1

3. BACKGROUND TO THE TOOL AND SCOPE .................................................... 1

4. OVERVIEW ........................................................................................................... 2

5. TOOL SPECIFICS (WORKSHEETS) ................................................................... 3 5.1 A4_Drawing and Front Overhang Detail ................................................................. 3 5.2 Tool Lines 01 to 14 – Dimensions .......................................................................... 3

5.2.1 Lines 1 to 3 ................................................................................................................ 3 5.2.2 Lines 4a to 5b ............................................................................................................ 4 5.2.3 Lines 6 to 14 .............................................................................................................. 4

5.3 Tool Lines 15 to 23 – Tyres .................................................................................... 4 5.3.1 Lines 15 to 17 ............................................................................................................ 4 5.3.2 Line 18 ....................................................................................................................... 5 5.3.3 Lines 19 to 23 ............................................................................................................ 5

5.4 Tool Lines 24 to 39 – Powertrain ............................................................................ 5 5.4.1 Lines 24 to 35 ............................................................................................................ 5 5.4.2 Lines 36a and 36b ..................................................................................................... 5 5.4.3 Line 37 ....................................................................................................................... 5 5.4.4 Lines 38a and 38b ..................................................................................................... 5 5.4.5 Line 39 ....................................................................................................................... 6

5.5 Tool Lines 40 to 58 – Loads, CGs and Suspensions .............................................. 6 5.5.1 Part A – Axle Group Loads and GCM ....................................................................... 6 5.5.2 Part B – Tare and Sprung Mass CG Heights ............................................................ 6 5.5.3 Part C – Suspension Properties ................................................................................ 6

5.6 Tool Lines 59 to 68 – Semi-trailer Sprung Mass CG Height ................................... 7 5.7 Tool Lines 69 and 70 – Braking Specification ......................................................... 7

6. SUBMIT VEHICLE FOR DESIGN APPROVAL .................................................... 8

7. USER FEEDBACK AND REPORTING DIFFICULTIES ....................................... 8

APPENDIX A – EXAMPLE WORKSHEETS FROM SUPPORT TOOL ...................... 9

Support Tool User Guide for PBS Blueprint Vehicle Design Page 1

1. INTRODUCTION

This User Guide has been prepared to assist users of the spreadsheet-based Support Tool

for PBS 20 m prime mover and semi-trailer Blueprint vehicle design. The tool was

developed as part of a National Transport Commission (NTC) funded project and initiative.

The aim of the project is to make the design of heavy vehicles under the national

Performance-Based Standards (PBS) scheme and formal approvals issued under that

scheme more accessible to a wider segment of the road transport industry at little or no

cost. The tool and associated software is initially available free from the NTC, and later it

is expected to be available together with ongoing support through the National Heavy

Vehicle Regulator (NHVR).

The purpose of the tool is to provide a relatively simple means for users to confirm designs

of 6-axle prime mover and semi-trailer combinations with overall lengths of up to 20 m

operating at axle group loads under General, Concessional and Higher Mass Limits (GML,

CML and HML). The tool can also be used to lodge formal PBS applications, as described

herein, and obtain design approvals.

2. INTENDED AUDIENCE

The tool has been developed to assist users to test vehicle designs and reach a design

outcome that satisfies all of the PBS performance requirements and, ultimately, provides

all of the necessary technical information in a single spreadsheet file to support a formal

PBS application and design approval. It has been assumed that users of the tool will have

some engineering background. It is expected that in some cases a single user will have

sufficient engineering knowledge and access to the required information to perform the

design with little or no outside assistance; others may require engineering support in one or

more areas to complete the design.

3. BACKGROUND TO THE TOOL AND SCOPE

The tool is the outcome of a process and series of meetings convened and managed by

NTC involving a wide range of stakeholders with a broad range of interests. Stakeholders

included in the process were truck and trailer manufacturers, component suppliers,

transport operators and consultants, trucking associations, road authority representatives,

and regulators.

The aim of these meetings was to establish the key parameters to define the blueprint

design in the most general context in order to satisfy the needs of as much of the industry

as possible. That is, rather than specifying a single set of dimensions, for example, for one

or two designs, a range of dimensions was set that would cover as many possible

applications and vehicle designs. While the initial parameter sets were quite broad, some

constraints had to be imposed on them to make the task tractable. Through consultation

these boundaries were determined to be acceptable for general application of the tool.

Once parameter sets for dimensions, suspensions, tyres, some mass properties and

powertrain were established, they were tested in a large number of designs against the PBS


standards in order to determine what would and what wouldn’t work. The outcome of this

task was a very general and complex formal PBS application that defined the blueprint

vehicle. This went through formal review and approval by the PBS Review Panel (PRP).

It is the formal PBS application that underpins the blueprint vehicle design and the

application in that (complex) form identified a clear need for this Support Tool.

It is important to note that the blueprint vehicle design is not expected to cover all possible

designs but a useful majority. Niche areas will most likely need to be treated separately

through a PBS Assessor. However, with exposure to wider industry and with actual use

and feedback there will most likely be a need for some adjustments to the tool. In the

longer term it is expected that changes in vehicle design and emerging trends will also lead

to the need to occasionally update the tool.

4. OVERVIEW

The Support Tool comprises seven worksheets contained in a single spreadsheet. The

worksheets are labelled as follows:

A4_drawing

Front Overhang Detail

Dimensions

Tyres

Powertrain

CGs, Loads and Suspensions

Sprung Mass CG Height

Braking Specification

The first two worksheets, “A4_drawing” and “Front Overhang Detail”, simply provide

summary drawings showing key dimensions, tyre sizes, axle group loads, semi-trailer

centre-of-mass (CG) height, and front overhang details for the prime mover and semi-

trailer. The purpose of the two drawings worksheets is to simply provide an easy reference

of user selected design values and selected options to assist the formal approval process.

The next four worksheets, namely, “Dimensions”, “Tyres”, “Powertrain” and “CGs, Loads

and Suspensions”, and the last worksheet “Braking Specification”, are the main work areas

for specifying the vehicle. Each of these comprise a combination of pull-down menus for a

selection of numeric values from a preset range and options, spinner buttons for dialling up

desired numeric values, cells for manual entry of numeric values, cells that report

calculated values for information. Assistance to the user is also provided by way of up to

three columns in each worksheet. These columns are headed as “Notes”, “Action

Required” and “Warnings”. Notes lists a short meaningful phrase to help the user, Action

Required simply prompts the user for an action (for example, “select from drop-down list”,

“Enter value”, etc), and Warnings are short messages that appear, usually in bold red type,

alerting the user to a problem with one or more input values.

When all the required data have been entered into a worksheet and there are no warning

messages on that sheet the tool has taken that part of the design to be acceptable. When all

five worksheets have been completed in this way, and there are no warnings on any

worksheet, then the vehicle design as a whole is taken to be an acceptable design. That is,

the vehicle if built is likely to satisfy all of the PBS performance requirements. In this


form the spreadsheet can be submitted (by e-mail) to the NTC/NHVR for processing to

obtain a formal PBS design approval.

The second last worksheet “Sprung Mass CG Height” is available to the user if an

independent value for the semi-trailer sprung-mass CG height is not available. CG height,

which has a major influence on rollover stability, is usually calculated in the normal course

of a vehicle design by manufacturers. For non-manufacturers, this worksheet is intended to

provide an approximate estimate of the CG height using a relatively simple calculation

based on a flat-top semi-trailer carrying a uniform density load.

5. TOOL SPECIFICS (WORKSHEETS)

This section of the User Guide describes each worksheet in detail and provides specific

information on data ranges and data requirements. An example of each worksheet is

presented in Figure A1 to Figure A8 of Appendix A. For convenience and ease of reference

the rows in each worksheet have been labelled with a line number.

The following sections refer to the line numbers specific to each worksheet.

5.1 A4_Drawing and Front Overhang Detail

As described earlier, these two worksheets, “A4_drawing” and “Front Overhang Detail”,

simply provide summary drawings showing key dimensions, tyres, axle group loads, semi-

trailer centre-of-mass (CG) height, and front overhang details for the prime mover and

semi-trailers. The values shown in the drawings are not editable but instantly updated as

changes are made to the design through the other worksheets. An example of each is

presented in Figure A1 and Figure A2 of Appendix A.

5.2 Tool Lines 01 to 14 – Dimensions

5.2.1 Lines 1 to 3

Lines 1 and 2 – The prime mover wheelbase and front plan profile are selected by the user

on Lines 1 and 2, respectively, using the pull-down menu. For a square front profile the

wheelbase range is from 3550 to 5150 mm in 50 mm increments, for a tapered front profile

the wheelbase range is from 3550 to 5200 mm. The square and taper details are shown in

worksheet “Front Overhang Details”. When square is selected the details for square front

is shown, when taper is selected the details for taper are shown.

It is important to note that a dimension increment of 50 mm has been used as agreed with

stakeholders. Where a wheelbase is not an integer multiple of 50 mm then wheelbase

values should be used in the assessment either side of the actual wheelbase. That is, an

actual wheelbase of 3570 mm may require assessments for wheelbase values at 3550 mm

and 3600 mm.

Line 3 – The front overhang dimension is selected in Line 3 using the pull-down menu.

For a square plan profile the overhang range is from 700 to 1650 mm, for a tapered plan

profile the overhang range is from 1300 to 1500 mm.


5.2.2 Lines 4a to 5b

Lines 4a and 4b (Option 1) and Lines 5a and 5b (Option 2) – The allowable semi-trailer S-

dimension and front overhang dimension corresponding to the selected prime mover

wheelbase and front planview detail appear in lines 4a to 5b in two groupings referred to as

Option 1 and Option 2. One or both options may be available depending on choice of

prime mover dimensions and front overhang plan profile detail. If one option only is

available then the other option becomes “not valid” with a message to that effect appearing

in the warnings column.

5.2.3 Lines 6 to 14

Line 6 – In this line one of the two options is selected from the pull-down menu. If one

option only is available then that option must be selected; if two options are available then

either one of the two can be selected. Once an option has been selected the S-dimension

range and forward projection dimensions for that option are available for the semi-trailer.

Line 7 – The S-dimension for the semi-trailer is entered in this line. The value must be

consistent with the option selection in Line 6. Depending on choice of other dimensions

the total semi-trailer wheelbase range available to the user is 9600 to 10500 mm. Values at

the long end of the range will generally only be valid for short wheelbase prime movers

with short front overhang dimensions.

Line 8 – The forward projection dimension for the semi-trailer is entered in this line. The

value must be consistent with the option selected in Line 6.

Line 9 – The coupling lead for the fifth wheel connection is entered in this line. The range

for this parameter is 600 to -100 mm. A positive value denotes a coupling location that is

forward of the centre of the drive axle group.

Line 10 – The rear overhang dimension for the semi-trailer is entered in this line.

Acceptable values are up to the lesser of 4600mm or 45% of the semi-trailer S-dimension.

Lines 11 and 12 – These two lines are for information and show the overall length of the

vehicle and the deck length. The values are automatically updated as other numbers on

this worksheet are changed affecting these two lengths.

Lines 13 and 14 – Axle group spread is defined in these two lines for the drive (tandem)

and semi-trailer (triaxle) axle groups. Acceptable values for the drive axle group are in the

range 1200 to 1600 mm, for the semi-trailer axle group the range is 2000 to 3200 mm.

5.3 Tool Lines 15 to 23 – Tyres

5.3.1 Lines 15 to 17

Lines 15 – Using the pull-down menu select tyre size for the steer axle. Two (2) tyres sizes

are offered, 11R22.5 and 295/80R22.5.

Lines 16 – Using the pull-down menu select tyre size for the drive axles. Two (2) tyres

sizes are offered, 11R22.5 and 295/80R22.5.


Lines 17 – Using the pull-down menu select tyre size for the semi-trailer axles. Six (6)

tyres sizes are offered, 11R22.5, 295/80R22.5, 305/70R22.5, 275/70R22.5, 255/70R22.5

and 265/70R19.5.

5.3.2 Line 18

The vertical stiffness of the softest tyre is entered on this line. The softest tyre must have a

stiffness value of at least 750 N/mm measured at its rated load and at the recommended

inflation pressure.

5.3.3 Lines 19 to 23

The main cornering properties of the tyre with the lowest cornering stiffness are entered on

these lines. Cornering stiffness varies with vertical load so it is necessary to define tyre

characteristics for a range of vertical loads as defined in Lines 20 to 23. The tyres

cornering stiffness measured at zero lateral slip angle must be at least 0.7, 1.4, 2.1 and

2.8 kN/deg at vertical loads of 10, 20, 30 and 40 kN, respectively. These characteristics

are taken at the recommended inflation pressure.

5.4 Tool Lines 24 to 39 – Powertrain

5.4.1 Lines 24 to 35

Engine characteristics are entered in Lines 25 to 35. Engine torque values for engine speed

in the range 1000 to 2000 rpm are required. The worksheet includes a graph of engine

torque and power output versus engine speed, which overlays the engine torque (and

power) characteristics specified by the user and the minimum torque (and power)

requirement. This graph can be used to check if the specified characteristics satisfy the

minimum performance characteristics. Warning will also appear if the specified torque is

below the minimum requirement. Note that only engine torque characteristics are required

from the user and the power curve is derived from the torque curve.

5.4.2 Lines 36a and 36b

These two lines are for information and report peak torque and maximum power from the

user entered values.

5.4.3 Line 37

Use the spinner buttons to enter a value for clutch engagement torque or stall torque if the

transmission has a torque convertor. The range for this parameter is 100 to 1350 Nm.

5.4.4 Lines 38a and 38b

Gear ratio values for the lowest and highest gears are entered in these lines. For the lowest

gear a value not less than 9.16 must be entered, for the highest gear a value in the range

0.73 to 1.00 will be accepted.


5.4.5 Line 39

Use the spinner buttons to enter a value for rear axle ratio. The range is 3.4 to 4.7 for this

parameter.

5.5 Tool Lines 40 to 58 – Loads, CGs and Suspensions

5.5.1 Part A – Axle Group Loads and GCM

Line 40 – Use the pull down menu to select axle group loading from GML, CML and

HML.

Line 41 – If the prime mover qualifies for an extra 0.5 t on the steer axle (compliant Front

Underrun Protection Device, etc) select “yes” from drop-down list.

Lines 42 to 44 – For GML and HML loading, axle group loads for the steer, drive and

semi-trailer are set values, for CML loading the spinner buttons can be used to adjust the

axle group loads.

Line 45 – The calculated value of Gross Combination Mass (GCM) is shown for

information on this line. This is a calculated value which is automatically updated when

the axle group loads are adjusted. GCM cannot be adjusted directly on this line.

5.5.2 Part B – Tare and Sprung Mass CG Heights

Line 46 – Select from the drop-down list the tare mass of the prime mover. The range is

from 7.5 to 12.5 t selectable in 0.5 t increments.

Line 47 – Select from the drop-down list the height of the prime mover’s sprung mass CG.

The range is from 800 to 1250 mm selectable in 50 mm increments. Sprung mass refers to the

portion of the prime mover’s total mass that is supported above the suspension.

Line 48 – Use the spinner buttons to set the height of the semi-trailer’s sprung mass CG.

The range is from 2100 up to 2440 mm set in 10 mm increments. The value set is an “up

to” limit, which means if an acceptable outcome is achieved lower CG height values are

also acceptable. Please note, the value entered in Line 48 is not linked to worksheet

“Sprung Mass CG Height” and the stability analysis is based on the value set in Line 48.

5.5.3 Part C – Suspension Properties

Lines 49 to 51 – Use the spinner buttons to set the total roll stiffness for the steer, drive and

semi-trailer axles. Total roll stiffness comprises roll stiffness due to the springs (air or

leaf) and auxiliary mechanisms from sources such as anti-roll bars, bushings, tie-rods,

locating rods, and “wind-up” of suspension components. Roll stiffness values in the

following ranges are considered:

Steer: 1.0 to 6.0 kNm/deg

Drive: 6.1 to 46.0 kNm/deg/axle

Semi-trailer: 7.7 to 44.9 kNm/deg/axle

Line 52 – This line checks that the ratio of semi-trailer to drive total roll stiffness falls

within an acceptable range and the suspensions are correctly matched. If there is a


mismatch a warning message will appear with advice on whether this ratio should be

increased or decreased.

Lines 53 to 55 – Use the spinner buttons to set the suspension roll steer coefficients for the

steer, drive and semi-trailer axles. Roll steer values in the following ranges are considered:

Steer: -0.1 to 0.1 deg/deg

Drive: -0.1 to 0.25 deg/deg

Semi-trailer: -0.1 to 0.25 deg/deg

Lines 56 to 58 – Use the spinner buttons to set the suspension relative roll centre heights

(measured above the axle) for the steer, drive and semi-trailer axles. Roll centre height

values in the following ranges are considered:

Steer: -100 to 200 mm

Drive: -100 to 400 mm

Semi-trailer: -100 to 400 mm

5.6 Tool Lines 59 to 68 – Semi-trailer Sprung Mass CG Height

Line 59 – Use the spinner button to set the tare weight of the semi-trailer. The range for

tare weight is 2.5 to 11.25 t.

Line 60 – Use the spinner button to set the king-pin load of the laden semi-trailer. The

range for this load is 5.5 to 15.5 t.

Line 61 – In order to calculate the CG height of the semi-trailer sprung mass, the user must

specify the mass of the unsprung components, comprising complete axle assemblies (axles,

suspension, brake assemblies, wheels, etc.). Use the spinner button to set the unsprung

weight of a single (one) complete axle assembly. The range for axle unsprung weight is

750 to 1250 kg.

Lines 62 and 63 – Use the spinner buttons to set the floor/deck height and load height. The

range for floor/deck height is from 750 to 1750 mm, the range for overall load height is

from 2600 to 4600 mm.

Lines 64 to 67 – The values presented in these lines are for information and comprise the

Aggregate Trailer Mass (ATM), which is the sum of the kingpin load and the axle group

load, load mass (ATM less the tare), payload volume and payload density. The calculation

assumes uniform density over an assumed rectangular prism load shape.

Line 68 – This value is a simple estimate of the semi-trailer sprung mass CG height. This

value is not used in the stability calculations but is compared to the value set in worksheet

“Loads, CGs and Suspensions” which is used in the stability calculations. If the simple

estimate of the semi-trailer sprung mass CG height (Line 68) is greater than the set value

(Line 48) then a warning message is issued.

5.7 Tool Lines 69 and 70 – Braking Specification

Select the relevant option from the drop-down list for the prime mover and semi-trailer.


6. SUBMIT VEHICLE DESIGN FOR APPROVAL

When the five worksheets labelled “Dimensions”, “Tyres”, “Powertrain”, “CGs, Loads

and Suspensions” and “Braking Specification”, have been completed and there are no

warnings on any of these worksheets then the vehicle design as a whole is taken to be an

acceptable design. That is, the vehicle if built is likely to satisfy all of the PBS

performance requirements.

In this form the spreadsheet can be submitted (by e-mail) to the NHVR at the address

shown below prior to commencing the vehicle build:

Les Bruzsa

PBS Administrator

National Heavy Vehicle Regulator

L9 / 515 St Pauls Terrace

Fortitude Valley QLD 4005

p: (07) 3309 8599

f: (07) 3309 8777

e: [email protected]

Upon confirmation from the NHVR, vehicle build can be commenced. Built vehicles must

be certified by an authorised PBS Certifier and submitted to the NHVR for a Final

(Vehicle) Approval.

7. USER FEEDBACK AND REPORTING DIFFICULTIES

User feedback and reporting of any difficulties is welcome and should be directed to the

NTC/NHVR at the address shown the previous section.

mailto:[email protected]


APPENDIX A – EXAMPLE WORKSHEETS FROM SUPPORT TOOL


Figure A1 - Worksheet “A4_drawing”


Figure A2 - Worksheet “Front Overhang Details”


Figure A3 - Worksheet “Dimensions”


Figure A4 - Worksheet “Tyres”


Figure A5 - Worksheet “Powertrain”


Figure A6 - Worksheet “Loads, CGs and Suspensions”


Figure A7 - Worksheet “Sprung Mass CG Height”


Figure A8 - Worksheet “Braking Specification”

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