PA07 Process Automation For Static Analysis of Truck ... · PDF fileSimulation Driven...

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


(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


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.


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


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)


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-


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.


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.


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 :


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




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


RA1_LH

RA1_RH



Figure 7: Node numbering at rear suspension

RA1_LH RA2_LH

RA1_RH RA2_RH


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


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.


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


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.


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


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


Figure 14:

Figure 14: Comparison of results - Nomenclature

Figure 15: Comparison of results - Summary


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.

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