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Simulation Driven Innovation
Process Automation for Static Analysis o
Haridas P.T AGM - CAE
Ashok Leyland Ltd Technical Centre, Velliyoyal Chavadi Chennai – 600 103
Balakrishnan Senior
Ashok Leyland LtdTechnical Centre, VelliyoyalChennai
Abbreviations: CAE (Computer
Command Language), FEA (FiniteRAW (Rear Axle Weight), GVW (Gross Vehicle weight)
Keywords: Chassis, Process automation
In today’s competitive world, the customer expects betterresponsive, adaptive and innovative product development processes. Computer Aided Engineering (CAE) is aids in this. This paper explains the process automation techniques employed fromstatic analysis of truck chassis assembly in CAE. These automations resulted in the reduction of cycle time, elimination of possible mistakes and result variation due to manuaprocessing.
Introduction Frame assemblies of most heavy commercial vehicles are ladder shaped structure with side frame rails interconnected with cross members at critical locations where frame stresses are expected to be higher. These primary load carrying frame sipayload, cab, load body, power trainspare wheel carrier, Air tank, Air cleaner, silencer, Pre-processing and post-processingreduction in pre-processing and postthereby the project duration. Hence, process.
1. Organizing of CAD model. 2. Mid surface extraction and assigning thickness using macro3. Meshing of thin shell components & Automatic bolt creation 4. Renaming of components with specific name with
processing). 5. Renumbering of specific nodes to apply Loads, Boundary conditions & extraction of output.6. Lumped mass creation at respective CG locations using Excel worksheet and macro7. Leaf spring suspension modeling using macro.8. Using solver template file with include files.9. Automatic post processing of results10. Comparison of results between two chassis results
Flow chart for static analysis of truck chass The following flow chart explains the list of activities involved in static analysis of truck chassis assembly and process automations are made in the activity which is filled with "Green" colour.
Process Automation for Static Analysis of Truck Chassis Assembly
Balakrishnan .M Senior Manager-CAE
Ashok Leyland Ltd Technical Centre, Velliyoyal Chavadi Chennai-600103
Shashidhar .D Senior Manager-CAE
Ashok Leyland Ltd Technical Centre, Velliyoyal Chavadi Chennai-600103
(Computer Aided Engineering), CAD (Computer Aided Design),(Finite Element Analysis), CG (Centre of gravity), FAW (Front Axle Weight),
(Gross Vehicle weight), BC (Boundary Condition)
Process automation, Macros, Solver templates, Time reduction
Abstract
In today’s competitive world, the customer expects better products than the existing one. To meet this, there is a need to adopt fast, responsive, adaptive and innovative product development processes. Computer Aided Engineering (CAE) is
This paper explains the process automation techniques employed from pre-processing stage to report generation stage during the static analysis of truck chassis assembly in CAE.
These automations resulted in the reduction of cycle time, elimination of possible mistakes and result variation due to manua
Frame assemblies of most heavy commercial vehicles are ladder shaped structure with side frame rails interconnected with cross members at critical locations where frame stresses are expected to be higher. These primary load carrying frame side members and cross members form an integral structure to support
power train and other chassis mounted components such as fuel tank, battery, Air tank, Air cleaner, silencer, etc.,
processing are major time consuming activities in a chassis analysis. Time and post-processing will help us to reduce the overall analysis duration and
thereby the project duration. Hence, the following improvements are made to automate the
Mid surface extraction and assigning thickness using macro
of thin shell components & Automatic bolt creation using macro enaming of components with specific name with thickness details (for checking FE model and post
Renumbering of specific nodes to apply Loads, Boundary conditions & extraction of output.Lumped mass creation at respective CG locations using Excel worksheet and macro
modeling using macro. Using solver template file with include files. Automatic post processing of results using advanced option in HyperView
between two chassis results using excel macro
Flow chart for static analysis of truck chassis assembly
The following flow chart explains the list of activities involved in static analysis of truck chassis assembly and process automations are made in the activity which is filled with "Green" colour.
f Truck Chassis Assembly
Selva Karunakar .S Manager-CAE
Ashok Leyland Ltd Technical Centre, Velliyoyal Chavadi Chennai-600103
CAD (Computer Aided Design), TCL (Tool , FAW (Front Axle Weight),
Time reduction
. To meet this, there is a need to adopt fast, responsive, adaptive and innovative product development processes. Computer Aided Engineering (CAE) is one such a tool, which
processing stage to report generation stage during the
These automations resulted in the reduction of cycle time, elimination of possible mistakes and result variation due to manual post
Frame assemblies of most heavy commercial vehicles are ladder shaped structure with side frame rails interconnected with cross members at critical locations where frame stresses are expected to be higher.
de members and cross members form an integral structure to support components such as fuel tank, battery,
in a chassis analysis. Time will help us to reduce the overall analysis duration and
to automate the chassis analysis
thickness details (for checking FE model and post
Renumbering of specific nodes to apply Loads, Boundary conditions & extraction of output. Lumped mass creation at respective CG locations using Excel worksheet and macro
The following flow chart explains the list of activities involved in static analysis of truck chassis assembly and process automations are made in the activity which is filled with "Green" colour.
Simulation Driven Innovation
Extract mid
NO
Free - Free normal mode analysistemplate
NO
Correct the element connectivity
Lumped mass creation using
Bolt
Re-mesh
Organize the CAD parts with
Renumbering of specific nodes apply Loads &
Extract mid-surface & assign thickness using macro
Meshing using macro
Free normal mode analysis using Solver template files with include files (Mesh data)
Check the quality of the mesh
YES
A
Import CAD model in Hypermesh
A
Lumped mass creation using macro
Start
Is the mesh quality O.K?
Bolt connection using macro
Is the element connectivity
O.K?
YES
Check the element connectivity by viewing the mode shapes in Hyperview
Assign material
Organize the CAD parts with specific name
Renumbering of specific nodes & elements to Loads & BCs and to extract desired output
Check the quality of the mesh
Check the element connectivity by viewing the mode shapes in Hyperview
Simulation Driven Innovation
Calculate FE model mass
NO
forces at ground points for Modify the payload CG location to match the
reaction forces
Adjust missing mass in the payload with the consent
of customer
Apply Loads & BC’s for Vertical_1Gfile with include files (Mesh data file & input variable file)
Suspension modeling using
NO
Calculate FE model mass
YES
Is that matching with
GVW?
Solve for Vertical_1G
YES
Is that matching with FAW & RAW?
Extract the FEA reaction forces at ground points for
Vertical_1G
Compare the FE model mass with GVW
Compare the FEA reaction forces at ground points with FAW & RAW (given in the input sheet)
B
B
Apply Loads & BC’s for Vertical_1G using Solver template file with include files (Mesh data file & input variable file)
Suspension modeling using macro
Compare the FE model mass with GVW
Compare the FEA reaction forces at ground points with FAW & RAW (given in the input sheet)
Simulation Driven Innovation
1. Organizing the CAD model Organizing the CAD model with specific name will help us in checking of FE model and aid in postprocessing. Sample CAD model of chassis assembly
Post processing using
Apply Loads & BC’s cases (
Solve for other load cases
Extract the FEA reaction forces for
Check the reaction forces for Braking, Cornering and Articulation
Comparison of results between two chassis
CAD model with specific name will help us in checking of FE model and aid in postof chassis assembly is shown in Figure 1.
Post processing using "Advanced option" in Hyperview
Report preparation
End
Apply Loads & BC’s for other load cases (Vertical_3G, Braking, and
Cornering & Articulation)
Solve for other load cases using solver template file
Extract the FEA reaction forces for other load cases
Check the reaction forces for Braking, Cornering and Articulation
load case
Comparison of results between two chassis assembly using excel macro
CAD model with specific name will help us in checking of FE model and aid in post-
Simulation Driven Innovation
Figure
2. Mid surface extraction and assigning thickness
This macro extracts the mid surface and assigns thickness
component will look like "MID_COMPOENT
Figure 2:
Figure 1: Sample CAD model of Chassis assembly
Mid surface extraction and assigning thickness using macro
This macro extracts the mid surface and assigns thickness to the components and the name of the
component will look like "MID_COMPOENT-NAME_THICKNESS" as shown in Figure
Figure 2: Mid surface extraction and assigning thickness
and the name of the
ure 2.
Simulation Driven Innovation
3. Meshing of thin shell components & Automatic bolt creation using macro
This macro will mesh the components with specified mesh
the components where there is a matching hole. Sam
Sample rigid spider and beam element creation is shown in Fi
Figure 4:
Meshing of thin shell components & Automatic bolt creation using macro
This macro will mesh the components with specified meshing criteria and create bolt
the components where there is a matching hole. Sample mesh pattern around the hol
element creation is shown in Figure 4.
Figure 3: Sample mesh pattern around the hole
Figure 4: Sample Rigid spider & Beam element creation
and create bolt connection between
mesh pattern around the hole is shown in Figure 3.
Simulation Driven Innovation
4. Renaming of components with specific name Once the meshing is completed, we model and post processing of results
Conventional Naming
1 FSM
2 Internal Flitch
2 External Flitch
3 Front cross member
5. Renumbering of specific nodes and elements Standard node and element numbers are being employed to apply Loads, Boundary conditions extract desired outputs using solversuspension is shown in Figure 6 and rear suspension is shown in Figure 7.
X-
Y-Axis
FR
ON
T
NODE IDSGround : Spring Seat : Bump stop : Spring Bkt front :Spring Bkt rear :
NODE IDSGround : Spring Seat : Bump stop : Spring Bkt front :Spring Bkt rear :
with specific name
Once the meshing is completed, we have to rename the components with specific of results. Sample component naming format is shown in Figure 5.
Conventional Naming Specific Naming Format
01_FSM_*T 02_Flitch_Int_Front_*T 02_Flitch_Int_Middle_*T 02_Flitch_Int_Rear_*T 02_Flitch_Ext_Middle_*T 02_Flitch_Ext_Rear_*T 03_Front_Xmem_Channel_*T
03_Front_Xmem_Gusset_*T
03_Front_Xmem_Stiffener_*TFigure 5: Specific component naming format
and elements
tandard node and element numbers are being employed to apply Loads, Boundary conditions solver template file. Standard nodes and elements numbering at front
suspension is shown in Figure 6 and rear suspension is shown in Figure 7.
Figure 6: Node numbering at front suspension
-Axis
NODE IDSGround : 1Spring Seat : 101Bump stop : 201Spring Bkt front : 301Spring Bkt rear : 401
FA1_LH FA2_LH
FA1_RH FA2_RH
NODE IDSGround : 2Spring Seat : 102Bump stop : 202Spring Bkt front : 302Spring Bkt rear : 402
NODE IDSGround : 3Spring Seat : 103Bump stop : 203Spring Bkt front : 303Spring Bkt rear : 403
NODE IDSGround : 4Spring Seat : 104Bump stop : 204Spring Bkt front : 304Spring Bkt rear : 404
Power train ( Engine + Gear box)
NODE ID: 1001
Ram point
NODE ID
specific name for checking FE naming format is shown in Figure 5.
Specific Naming Format
_Channel_*T _Gusset_*T _Stiffener_*T
tandard node and element numbers are being employed to apply Loads, Boundary conditions and to Standard nodes and elements numbering at front
Ram point
NODE ID: 1002
Simulation Driven Innovation
RA1_LH
RA1_RH
NODE IDSGround : Spring Seat : Bump stop : Spring Bkt front :Spring Bkt rear :
NODE IDSGround : Spring Seat : Bump stop : Spring Bkt front :Spring Bkt rear :
Figure 7: Node numbering at rear suspension
RA1_LH RA2_LH
RA1_RH RA2_RH
NODE IDSGround : 5Spring Seat : 105Bump stop : 205Spring Bkt front : 305Spring Bkt rear : 405
NODE IDSGround : 7Spring Seat : 107Helper spring mid node : 207Spring Bkt front : 307Spring Bkt rear :407FSM Bump Stop Spring Bottom node1 :FSM Bump Stop Spring Bottom node2 :FSM Bump Stop Spring Bottom node3 :Bump stop node on Axle : 607ELEMENT IDSHelper spring Bush: 2007 (F), 3007 (R)FSM Bump stop Spring1: 5007FSM Bump stop Spring2: 7007FSM Bump stop Spring3: 8007
NODE IDSGround : 6Spring Seat : 106Bump stop : 206Spring Bkt front : 306Spring Bkt rear :406
NODE IDSGround : 8Spring Seat : 108Helper spring mid node : 208Spring Bkt front : 308Spring Bkt rear : 408FSM Bump Stop Spring Bottom node1 :FSM Bump Stop Spring Bottom node2 :FSM Bump Stop Spring Bottom node3 :Bump stop node on Axle : 608ELEMENT IDSHelper spring Bush : 2008 (F), 3008 (R)FSM Bump stop Spring1 : 5008FSM Bump stop Spring2 : 7008FSM Bump stop Spring3 : 8008
Hinge_LH
Hinge_RH
NODE ID: 1003
NODE ID: 1004
:507:707:807
FSM Bump Stop Spring Bottom node1 : 508FSM Bump Stop Spring Bottom node2 : 708FSM Bump Stop Spring Bottom node3 : 808
Simulation Driven Innovation
6. Lumped mass creation at respective CG locations using Excel worksheet and macro
This macro will create lumped mass
after lumped mass creation is shown in Figure 9.
STEPS TO USE THE MACRO
1) Enter X, Y, Z coordinates of reference point in r
2) Enter the description of each aggregate
3) Enter mass of each aggregate (in Tonnes) in column C
4) Enter X, Y, Z coordinates (in mm) of the aggregates in respective
5) Press button "Run“. A new
6) Execute C:\CGmass.tcl in HM
Figure 8:
creation at respective CG locations using Excel worksheet and macro
This macro will create lumped mass of Payload and other aggregates at respective CG locations.
wn in Figure 9.
tes of reference point in respective cells as shown in Figure
e description of each aggregate in Column B
Enter mass of each aggregate (in Tonnes) in column C
coordinates (in mm) of the aggregates in respective cells.
Press button "Run“. A new *.tcl file will be created in C drive (C:\CGmass.tcl)
CGmass.tcl in HM to create lumped masses and corresponding tags
Figure 8: Lumped mass creation data from inputs
Figure 9: FE model after lumped mass creation
creation at respective CG locations using Excel worksheet and macro
at respective CG locations. FE model
espective cells as shown in Figure 8.
CGmass.tcl)
and corresponding tags.
Simulation Driven Innovation
7. Leaf spring suspension modeling using macro
This macro will create beam element representation model after leaf spring modeling using
7. Leaf spring suspension modeling using macro
beam element representation of leaf springs with shackle at specified locationsmodel after leaf spring modeling using macro is shown in Figure 11.
Figure 10: Inputs for Leaf spring modeling
Figure 11: FE model after Leaf spring modeling
springs with shackle at specified locations. FE
Simulation Driven Innovation
8. Using solver template file with include files Solver template will help the analyst to apply loads, boundary conditions and (Displacements, Stress, SPC forces, MPC forces, BUSH element forces, etc.,)reduce mistakes due to manual application of loads & BC's and also reduces FE model review time.
9. Automatic post processing of results This option will help the analyst to post process the desired resultsexplained below
1. Click the icon “Contours” to view the stress and displacements.2. Select “Stress [t]” and “vonMises3. Select the “Elements” or “Components4. Click “Apply”. 5. Select “Query Results” to extract
8. Using solver template file with include files
olver template will help the analyst to apply loads, boundary conditions and to extract (Displacements, Stress, SPC forces, MPC forces, BUSH element forces, etc.,). Using the template files will reduce mistakes due to manual application of loads & BC's and also reduces FE model review time.
Figure 12: Portion of sample solver template file
9. Automatic post processing of results using advanced option in HyperView
This option will help the analyst to post process the desired results. Steps for advanced post processing are
” to view the stress and displacements. vonMises” options under Result type to view the vonMises stress results.
Components” under selection icon.
” to extract the plots in h3D format
to extract desired outputs Using the template files will
reduce mistakes due to manual application of loads & BC's and also reduces FE model review time.
. Steps for advanced post processing are
” options under Result type to view the vonMises stress results.
Simulation Driven Innovation
On Clicking “Query Results” option, the following window will open. Click the “
The html file will be having component wise results with a hyperlink to respective h3D files for all the loading conditions. Sample view of html file which comes out of the above mentioned postshown in Figure 13.
” option, the following window will open. Click the “Advanced
The html file will be having component wise results with a hyperlink to respective h3D files for all the loading Sample view of html file which comes out of the above mentioned post
Advanced” option
The html file will be having component wise results with a hyperlink to respective h3D files for all the loading Sample view of html file which comes out of the above mentioned post-processing option is
Simulation Driven Innovation
10. Comparison of results between two chassis results using excel macro Steps to be followed to compare the results between two frames using Excel spreadsheet macrofollows.
1. Open the excel spreadsheet for comparing the results between two2. Update the name of vehicle1 and vehicle2 in the “Nomenclature” tab3. Enter the number of load cases to be compared.4. Open the html file of Vehicle5. Open the html file of Vehicle6. Go to “Nomenclature” sheet and execu
consolidated and summary results
Figure 13: Sample view of results HTML file
10. Comparison of results between two chassis results using excel macro
to compare the results between two frames using Excel spreadsheet macro
Open the excel spreadsheet for comparing the results between two frames as shown in Update the name of vehicle1 and vehicle2 in the “Nomenclature” tab
the number of load cases to be compared. Open the html file of Vehicle-1,copy all the contents and paste it in “VEH1_RES” sheet Open the html file of Vehicle-2,copy all the contents and paste it in “VEH2_RES” sheet .
sheet and execute "Vehicle 1","Vehicle 2" and "Summary" macros to get the consolidated and summary results as shown in Figure 15.
to compare the results between two frames using Excel spreadsheet macro is as
frames as shown in Figure 14.
the contents and paste it in “VEH1_RES” sheet . the contents and paste it in “VEH2_RES” sheet . te "Vehicle 1","Vehicle 2" and "Summary" macros to get the
Simulation Driven Innovation
Figure 14:
Figure 14: Comparison of results - Nomenclature
Figure 15: Comparison of results - Summary
Simulation Driven Innovation
Benefits Summary Pre-processing time reduction and elimination of manual errors using macros Extraction of mid surface and assigning Meshing of thin shell components ( Automatic bolt creation (Time Lumped mass creation at respective CG Leaf spring suspension modeling (Time Pre-processing technical review (Time Solver template file (Time reduction: Post-processing and comparison of results Challenges
• Time reduction in overall Chassis analysis without compromising on the quality of results• Standardization of component names, analysis deck and output requests • Comparison of results between
Conclusions Major time consuming activity in chassis analysis process has been us to reduce the overall analysis duration has been deployed horizontally across all the Truck chadesigner to carry out many iterations and
The authors thank the management of Ashok Leyland, Headopportunity to present the work reported in this paper. Ashok Leyland Technical centre for their continuous support in ex
• Hyper Mesh User Manual, Altair Engineering
• Practical Programming in TCL and TK, Brent Welch
reduction and elimination of manual errors using macros Extraction of mid surface and assigning thickness (Time reduction: 4 hrs to 10 min)
components (Time reduction: 56 hrs to 24 hrs) Automatic bolt creation (Time reduction: 8 hrs to 15 min) Lumped mass creation at respective CG locations (Time reduction: 2 hrs to 5 min)Leaf spring suspension modeling (Time reduction: 10 hrs to 30 min)
processing technical review (Time reduction: 8 hrs to 3 hour)
reduction: 4 hrs to 5 min)
processing and comparison of results using macros (Time reduction: 16 hrs to 3 hour)
Time reduction in overall Chassis analysis without compromising on the quality of resultsStandardization of component names, analysis deck and output requests Comparison of results between two chassis assemblies with hyperlink to result plots.
consuming activity in chassis analysis process has been automated using macros which helped the overall analysis duration by 70%. Macros created during this process automation exercise
has been deployed horizontally across all the Truck chassis analysis carried out in AL,ner to carry out many iterations and to get consistent results.
ACKNOWLEDGEMENTS
ment of Ashok Leyland, Head-CAE and ALTAIR foropportunity to present the work reported in this paper. The authors also thank our CAE team members at Ashok Leyland Technical centre for their continuous support in executing this process automation
REFERENCES , Altair Engineering
Practical Programming in TCL and TK, Brent Welch
4 hrs to 10 min)
2 hrs to 5 min)
16 hrs to 3 hour)
Time reduction in overall Chassis analysis without compromising on the quality of results
two chassis assemblies with hyperlink to result plots.
automated using macros which helped . Macros created during this process automation exercise
ssis analysis carried out in AL, which has helped the
ALTAIR for having provided our CAE team members at
ecuting this process automation.