Assignment 6-Frontal Crash Simulation Challenge

AIM

 FOR THE GIVEN FRONTAL CRASH BIW

• CHECK UNIT SYSTEM AND FOLLOW THE RELEVANT AS APPLICABLE.
• CREATE APPROPRIATE INTERFACE, FRICTION AND RECOMMENDED PARAMETERS.
• TO MAKE SURE THAT THERE ARE NO PENETRATIONS AND INTERSECTIONS.
• CORRECTION OF RIGID BODIES IF NEEDED AND CREATION OF RIGID WALL WITH FRICTION AS RECOMMENDED.
• TO COMPARE THE MODEL WEIGHT WITH FULL SCALE NODES MODEL, USE ADDED MASS TO GET TARGET WEIGHT BY CONSIDERING CG RECOMMENDATIONS.
• UPDATING INITIAL VELOCITY AS RECOMMENDED.
• TO USE MODEL CHECKER TO ENSURE GOOD QUALITY.
• TO KEEP THE TIME STEP AT RECOMMENDED VALUES.
• TO RUN THE SIMULATION AT RECOMMENDED VALUES.

PROCEDURE

• UNIT SYSTEM CHECKING WAS DONE BY OPENING THE STARTER FILE @_0000.rad>'right click' OPEN WITH>NOTEPAD.

• APPROPRIATE INTERFACE CREATION WAS DONE USING IN HYPERCRASH @HYPERCRASH (2019)>FILE>IMPORT>RADIOSS>'past link' TAB>'select' OK>LOAD CASE>CONTACT INTERFACE>'right click' CREATE NEW>MULTIUSAGE (TYPE 7)>Istf '4'>Igap '2'>Idel '2'>Inacti '6'>Fric '0.2'>Iform '2'>Slav_id 'right click'>SELECT IN GRAPHICS>ADD ALL NODES>SAVE>Mast_id 'right click'>SELECT IN GRAPHICS>ADD SELECTED PARTS BY BOX 'select all'>SAVE.

• PENETRATION AND INTERSECTION WERE CHECKED @TREE>SELECT/UNSELECT ALL>QUALITY>CHECK INTERSECTION OF TREE SELECTION/MODEL CHECKER>RUN>CLOSE.

• RIGID BODIES WAS CHECKED AND RIGID WALL WAS FORMULATED @LOAD CASE>RIGID WALL>'right click' CREATE NEW>RIGID WALLS>PLANE>D_search '1000'>Slide '2'>fric '0.1'>'select node and input values as advised'>SAVE>CLOSE.

• BEFORE ADDING MASSES, WE NEED TO CHECK COG. CG WAS CHECKED BY @MASSES>BALENCING>SHOW COG POINT>CLOSE. MASS ADDITION WAS DONE @LOAD CASE>ADDED MASS>'right click' CREATE NEW>TYPE 1>TITLE 'rename as needed'>MASS 'enter value as needed'>grnod_ID 'right click'>SELECT IN GRAPHICS>ADD NODES BY BOX SELECTION>SAVE>CLOSE>FILE>EXPORT>RADIOSS>'enter path as needed' OK.

• INITIAL VELOCITY WAS ADDED @HYPERMESH>FILE>IMPORT>SOLVER DECK>'select as needed' FILE>IMPORT>CLOSE>SOLVER>'right click' CREATE>BOUNDRY CONDITIONS>INIVEL>Grnod_id 'right click'>CREATE>ENTITY IDs>NODES>'select all'>PROCEED>CLOSE>Vx,Vy & Vz '15.6464,0,0'>FILE>EXPORT>RADIOSS>'select path as needed' OK.

• TIME STEP WAS CHANGED @HYPERMESH>FILE>IMPORT>SOLVER DECK>'select as needed' FILE>IMPORT>CLOSE>MODEL>CARDS>ENGINE_RUN>Tstop '80'. RUN TIME WAS ALSO MODIFIED @MODEL>CARDS>ENGINE_ANIM_DT>Tfreq '0.3'.

• OUTPUT REQUEST METHODS

AS PER THE GIVEN NODE, SECTIONAL FORCE WAS CALCULATED @HYPERMESH>FILE>IMPORT>SOLVER DECK>'select as needed' FILE>IMPORT>CLOSE>SOLVER>'right click'>CREATE>FRAME>MOV>NODE (ORIGIN NODE) 'select as needed'>NODE (Z-AXIS) 'select as needed'>NODE (YZ-PLANE) 'select as needed'>CREATE>RETURN>SOLVER>'right click'>CREATE>SECT>SECT>'select' N1,N2 & N3>detltaT '0.1'>alpha '1.67'>Iframe '12'>Frame_ID 'select as needed'>grshel_id 'right click'>CREATE>ENTITY ID>ELEMENTS>'select as needed' PROCEED.

ACCELEROMETER WAS PLACED AT BOTH SIDES @HYPERMESH>SOLVER>'right click'>CREATE>ACCEL>node_ID 'select as needed'>PROCEED>Fcut '1.65'.

INTRUSIONS ON THE DASH WALL @HYPERMESH>SOLVER>'right click'>CREATE>SKEW>MOV>NODE (ORIGIN NODE) 'select as needed'>NODE (Z-AXIS) 'select as needed'>NODE (YZ-PLANE) 'select as needed'>CREATE>MODEL>OUTPUT BLOCK 'right click'>CREATE>ENTITY IDs>NODES>BY ID 'enter as needed'>Iskew 'select as needed'.

CREATING OUTPUT REQUEST FROM SOLVER BROWSER @HYPERMESH>MODEL>OUTPUT BLOCK 'right click'>CREATE>ENTITY IDs>SELECT TYPE 'select as needed'.

MODEL CHECKER WAS DEPLOYED @HYPERMESH>TOOLS>MODEL CHECKER>RADIOSSBLOCK>'right click at area' RUN.

MODEL RUN WAS DONE @HYPERMESH>FILE>IMPORT>SOLVER DECK>'select as needed' FILE>IMPORT>CLOSE>ANALYSIS>RADIOSS>INPUT FILE 'select/rename as needed'>RADIOSS>RETURN.

RESULTS

•  ENERGY ERROR AND MASS ERROR WERE CHECKED BY OPENING THE ENGINE OUT FILE @_0001.out>'right click' OPEN WITH>NOTEPAD.

ENERGY ERROR IS NEGATIVE IT MEANS SOME ENERGY IS DISSIPATED, SAME HAS BEEN LINEARLY INCREASING UPTO -2.4% AND IS ACCEPTABLE.

MASS ERROR IS ZERO, WHICH IS ALSO ACCEPTABLE.

• GLOBAL VARIABLE GRAPHS WERE ANALYSED @HYPERWORKS>DATA FILE 'select as needed'>Y TYPE 'Global Variables'>Y REQUEST 'Internal/Kinetic/Contact/Hourglass/TE-Total Energy'>Y COMPONENT 'MAG'>APPLY.

AS PER THE LAW OF CONSERVATION OF ENERGY, KINETIC ENERGY IS ABSORBED AND CONVERTED INTO INTERNAL ENERGY DUE TO CRUSHING. MAXIMUM INTERNAL ENERGY NOTED @22493KN/mm AND MAXIMUM KINETIC ENERGY NOTED @85414KN/mm. CONTACT ENERGY IS THE OPPOSITE ENERGY CREATED BY THE RIGID-WALL TO WITHSTAND PENETRATION, REACTION FORCE IS DEVELOPED TO AVOID PENETRATION THUS WE CAN SEE A SMALL INCREASE IN CONTACT ENERGY AND MAXIMUM VALUE NOTED @1978KN/mm. TOTAL ENERGY SEEMS ALMOST CONSTANT AND IS ACCEPTABLE.

• SECTIONAL FORCES WERE ANALYSED USING @HYPERWORKS>DATA FILE 'select as needed'>Y TYPE 'section', Y REQUEST, Y COMPONENT 'select as needed'>APPLY.

ABOVE ARE THE FORCES EXPERIENCED BY THE LEFT AND RIGHT SHOT-GUN PART FOR THE CRASH, MAXIMUM AT LEFT @4.6KN/mm AND MINIMUM AT RIGHT @5.8KN/mm. THE FORCE PROPOGATION THROUGH BOTH THE RAILS ARE DIFFERENT AS THE AMOUNT OF DEFORMATIONS EXPERIENCED ARE NOT SAME.

RAILS TRANSMITTE THE FORCE TO THE BACK OF THE CAR, RH A PILLAR TRANSMITTES MORE FOR THAN THE LH A PILLAR. MAXIMUM FOR RH @2.7KN/mm AND MAXIMUM FOR LH @1.2KN/mm.

THIS PART IS DIRECTLY CONNECTED TO THE FRONTAL CRASH BAR AREA, ENERGY IS TRANSMITTED TO THE REST OF THE BODY VIA THIS PART. WE CAN SEE A NOTABLE ENERGY SPIKE INITIALLY, MAXIMUM @RH 7.4KN/mm AND MAXIMUM @LH 5.2KN/mm.

• ACCELEROMETER WERE ANALYSED USING @HYPERWORKS>DATA FILE 'select as needed'>Y TYPE 'section', Y REQUEST, Y COMPONENT 'select as needed'>APPLY.

ACCELEROMETERS WERE PLACED AT B-PILLAR BOTTOM SIDE, GRAPH IS VERY JERKY AND THIS MIGHT BE DUE TO THE VIBRATIONS DEVELOPED DURING CRASH. VALUES ARE CONSTANT BEFORE HITTING THE VEHICLE AND CHANGES SUDDENLY NON-LINEARLY AFTER CRASH. MAXIMUM @RH 6.8mm/ms² AND MAXIMUM @LH 4.7mm/ms².

• INTRUSIONS WERE ANALYSED USING @HYPERWORKS>DATA FILE 'select as needed'>Y TYPE 'Node/intrusion', Y REQUEST, Y COMPONENT 'select as needed'>APPLY.

INTRUSION SHOWS THE DISPLACEMENT OF THE NODES FROM THE FIXED POINT, HERE A NOTABLE VALUE INCREMENT CAN BE SEEN. THIS MIGHT BE DUE TO THE MISSING OF ENGINE COMPONENTS. MAXIMUM @RH 950mm AND MAXIMUM @LH 870mm.

•  VON-MISES

CONCLUSION

• PROJECT FILE GIVEN WAS 2020 VERSION SUPPORT, WAS CHANGED TO 2019 BY STARTER FILE EDITING.
• THE FRONTAL CRASH SIMULATION WERE DONE AND NOTED WITH ALL ENERGY PLOTS AS REQUIRED.
• MOST OF THE PROCEDURES WERE DONE USING HYPERCRASH AND REST WERE DONE USING HYPERMESH.
• SIMULATION WERE DONE USING CHASSIS FRAME ONLY BUT NOT WITH OTHER COMPONENTS, SO NOTABLE DIFFERENCE CAN BE SEEN.
• GRAPHICAL FORCE RESULTS WERE PLOTTED AT A PILLAR, SHOTGUN, INSIDE FENDER AND INSIDE FRAME.
• GRAPHICAL RESULTS WERE PLOTTED AND ANALYSED, RH SIDE ENERGY TRANSFER ARE MORE COMPARED TO THE LH SIDE.
• INSIDE INTRUSION POINTS DISPLACEMENT WERE NOTED DUE TO MISSING ENGINE COMPONENTS.
• VARIOUS ERRORS AND ABNORMALITIES WERE OBSERVED FOR THIS CHALLENGE COMPLETION, UNDERSTOOD HOW TO RECTIFY AND FIX ERRORS.