Assignment 7-Side Pole Crash Simulation Challenge

AIM

 FOR THE GIVEN NEON SIDE 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.
• TO CREATE A RIGID POLE WITH A FRICTION OF 0.1 AS PER THE FMVSS 214 STANDARDS.
• TO COMPARE THE MODEL WEIGHT WITH REFERENCE MODEL, USE ADDED MASS TO GET TARGET WEIGHT BY CONSIDERING CG RANGE.
• 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 @HYPERMESH (2019)>FILE>IMPORT>SOLVER DECK>'select as needed' IMPORT>CLOSE>MODEL>'right click' CREATE>CONTACT>CARD IMAGE 'TYPE 7'>Istf '4'>Igap '2'>Idel '2'>Stmin '1'>Inacti '6'>Fric '0.2'>Iform '2'>Gapmin '0.5'>Iform '2'>Grnod_id (S) 'dropdown'>COMPONENTS>SELECT ALL>OK>Surf_id (M) 'dropdown'>COMPONENTS>SELECT ALL>OK.

 

• PENETRATION AND INTERSECTION WERE CHECKED @TOOLS>PENETRATION CHECK>ENTITY TYPE 'GROUPS/COMPONENTS'>SELECTION 'select as needed'>CHECK>CLOSE.

 

• RWALL WAS FORMULATED WITH THE HELP OF A REFERENCE NODE @GEOM>TEMP NODE>NODES 'select as needed'>ADD>RETURN>TOOLS>TRANSLATE>Y AXIS>MAGNITUDE '20'>NODES 'select node'>NODES>DUPLICATE>TRANSLATE + '6 points'>RETURN>GEOM>NODES>XYZ>'select node and note points' RETURN. RWALL FORMATION @SOLVER>'right click' CREATE>RWALL>CYL>XM, YM & ZM 'input values as needed'>NORMAL '0,0,1'>SLIDE '2'>Dsearch '1000'>FRIC '0.1'>Diameter '234'>grnod_ID1 'right click'>CREATE>ENTITY IDs>NODES>'select all'>PROCEED>CLOSE>FILE>EXPORT>SOLVER DECK>'select as needed' EXPORT>CLOSE.

• BEFORE ADDING MASSES, WE NEED TO CHECK COG. CG WAS CHECKED BY @HYPERCRASH (2019)>FILE>IMPORT>RADIOSS>'past link' TAB>'select' OK>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.

 

• INITIAL VELOCITY WAS ADDED @LOAD CASE>INITIAL VELOCITY>'right click' CREATE NEW>Vy '8.94'>Gnod_id 'right click'>SELECT IN GRAPHICS>ADD ALL NODES>SAVE>CLOSE>FILE>EXPORT>SOLVER DECK>'select as needed' EXPORT>CLOSE.

 

• TIME STEP WAS CHANGED @HYPERMESH (2019)>FILE>IMPORT>SOLVER DECK>'select as needed' IMPORT>CLOSE>MODEL>CARDS>ENGINE_RUN>Tstop '80'. RUN TIME WAS ALSO MODIFIED @MODEL>CARDS>ENGINE_ANIM_DT>Tfreq '0.5'.

 

 

• OUTPUT REQUEST METHODS

AS PER THE GIVEN NODE, SECTIONAL FORCE WAS CALCULATED @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.

 

INTRUSIONS ON THE B-PILLAR, HINGE PILLAR AND FUEL TANK WAS DEPLOYED @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'.

PEAK VELOCITY WILL BE MONITORED USING @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 'select node 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'>

RESULTS

• VON-MISSES STRESS WAS ANALYSED USING @HYPERVIEW>LOAD FILE 'select .h3d'>OPEN>APPLY>CONTOUR>RESULT TYPE 'Von Misses'>AVERAGING TYPE 'Simple'>APPLY.

HERE WE CAN SAY THAT THE STRESS DISTRIBUTION IS QUITE GOOD, B-PILLAR STRESS IS INDUCED MORE AS IT TAKE THE IMPACT FIRST. THEN THE SAME IS TRANSFERED TO THE CROSS-MEMBERS. THE IMPACT IS GETTING TRANSFERED FIRST TO THE BOTTOM CROSS-MEMBER THEN TO THE REST OF THE PARTS. THIS CANNOT BE COMPLETELY COMPARED WITH A VEHICLE FULLY EQUIPED WITH COMPONENTS.

• MASS AND ENERGY ERROR WERE ANALYSED @OPEN '0001.out'>OPEN WITH>NOTEPAD.

THERE WERE NO MASS AND ENERGY ERRORS IN THIS SIMULATION, -2.2% IS THE ENERGY ERROR WHICH IS LINEARLY INCREASING SHOWN WHICH IS ACCEPTABLE. THUS WE CAN CONCLUDE FOR NO ERRORS.

• ENERGY ERRORS WERE PLOTTED USING @HYPERGRAPH>DATA FILE 'select T01 file'>APPLY>X TYPE 'Time'>Y TYPE 'Global Variables'>Y REQUEST 'Internal/Kinetic/Contact/Hourglass/TE Energy'>Y Component 'MAG'>APPLY.

HERE THE KINETIC ENERGY ALMOST DECREASES UPON THE IMPACT AND THE SAME IS ABSORBED AS INTERNAL ENERGY, THUS TOTAL ENERGY REMAINS THE SAME. HOURGLASS AND CONTACT ENERGY ARE NEGLIGIBLE SINCE WE ARE USING QEPH ELEMENT FORMULATION.

• RIGID WALL FORCES WERE ANALYSED @HYPERGRAPH>DATA FILE 'select T01 file'>APPLY>X TYPE 'Time'>Y TYPE 'Rwall'>Y REQUEST '1 rigidwall1'>Y Component 'total resultant force'>APPLY.

WE CAN SEE A SUDDEN SPIKE FROM INITIAL STAGE ITSELF AS AS NO SPACE WAS MADE BETWEEN THE RIGID WALL AND VEHICLE CHASSIS. MAXIMUM VELOCITY RECORED WERE 45 MM/MS. SUDDEN SPIKE CAN BE SEEN BETWEEN 30-50MS BECAUSE OF THE CHASIS DESIGN RESTRICTION.

• TWO SECTIONAL FORCES WERE ANALYSED @HYPERGRAPH>DATA FILE 'select T01 file'>APPLY>X TYPE 'Time'>Y TYPE 'Cross Sections'>Y REQUEST '1/2 crossections1/2'>Y Component 'total resultant force'>APPLY.

CROSS-SECTION 2 EXPERIENCES THE MAXIMUM FORCE AS THE FORCE IS FIRST TRANSFERED TO THE MIDDLE CROSS-SECTION AFTER THE B-PILLAR IMPACT. THE NEXT CROSS-SECTION 1 EXPERIENCES MUCH LESSER IMPACT FORCE AS COMPARED TO THE CROSS-SECTION 2.

• NODE INTRUSIONS DISTANCE WERE ANALYSED @HYPERGRAPH>DATA FILE 'select T01 file'>APPLY>X TYPE 'Time'>Y TYPE 'Node Hinge-Pillar/Fuel Tank/BPillar'>Y REQUEST 'select node as needed'>Y Component 'DISP-Resultant Displacement'>APPLY.

HINGE PILLAR MOVES 620MM, FUEL TANK MOVEMENT 441MM AND B-PILLAR MOVES 188MM. AS B-PILLAR HITS FIRST SO MOVEMENT EXPERIENCED IS LESS. HINGE PILLAR MOVES MORE AS COMPARED TO THE B-PILLAR. FUEL TANK MOVEMENT IS CONSIDERABLY NOTED AS THERE ARE OTHER MORE COMPONENTS WHICH CAN GIVE STIFFNESS TO THE WHOLE CHASIS.

• PEAK VELOCITY NODE WERE ANALYSED @HYPERGRAPH>DATA FILE 'select T01 file'>APPLY>X TYPE 'Time'>Y TYPE 'Peak_Velocity'>Y REQUEST 'select node as needed'>Y Component 'VEL-Resultant Velocity'>APPLY.

PEAK VELOCITY WAS MEASURED AS 8.9 BY THE FIRST IMPACT OF B-PILLAR. IT IS REDUCED AS THE IMPACT ENERGY IS TRANSFERED TO OTHER CONNECTED MEMBERS.

CONCLUSION

• THE GIVEN MODEL WAS SIMULATED FOR SIDE CRASH AND OUTPUT RESULTS WERE ANALYSED. BOTH HYPERMESH AND HYPERCRASH WAS USED FOR MODEL PREPRATION. PEAK VELOCITY AND INTRUSION VALUES WERE ALSO MEASURED. BY PLOTTING THE ENERGY GRAPHS AND ERRORS, MAXIMUM FORCE IMPACT WAS EXPERIENCED BY THE B-PILLAR; HOWEVER LESSER FORCES ARE EXPERIENCED BY HINGE PILLAR AND FUEL TANK AREA. B-PILLAR CAN BE MADE MORE STRONGER BY ADDING SUPPORT BEAM UNDERNEATH AND ABOVE THE CABIN AREA. INTRUSIONS RECORDED FOR B-PILLAR WERE MUCH LOWER THAN THE SAME RECORDED FOR HINGE AND FUEL TANK AREA. UNDERSTANDING THE RATE OF DEFORMATION AND ENERGY CURVES, MORE SAFETY CAN BE IMPLEMENTED FOR THE CABIN AREA BY USING IMPROVED MATERIAL PROPERTIES AND EXTRA IMPACT RESISTING SECTIONAL MEMBERS.