WS13 -1 NAS105, Workshop 13, May 2005 WORKSHOP 13 TRANSIENT DYNAMIC ANALYSIS OF A CAR GOING OVER A BUMP

WS13 -2 NAS105, Workshop 13, May 2005

WS13 -3 NAS105, Workshop 13, May 2005 Tasks n Apply a time varying enforced y-disp at the front suspension point (node 7238) to simulate the bump in the road. n Create the Dynamic Load (TLOAD1) from above n Input the time stepping (TSTEP) data for analyzing for a total duration of 0.5 sec. (Note: The Lowest fundamental frequency is 3.23 Hz) n Input the Case Control to run the job as a Direct Transient Response Analysis n Ignore any damping n Create a graph of the displacement over time at various locations (e.g. Nodes 7858, 8640, 8798)

WS13 -4 NAS105, Workshop 13, May 2005 Problem Files n Required Files: workshop13. dat : Model of the car car.dat: Include file referenced by above n Solution Files: ws13s.bdf : Proposed Solution

WS13 -5 NAS105, Workshop 13, May 2005 DIRECT TRANSIENT ANALYSIS OF A CAR CHASSIS n Problem Description (cont.) Time Dependent Enforce Displacement (Node 7238) Pin Constraint to simulate contact with road (Nodes 1869, 7239)

WS13 -6 NAS105, Workshop 13, May 2005 Profile of a Road Bump

WS13 -7 NAS105, Workshop 13, May 2005 Disp History Plot Locations Node 8640 Node 7858 Node 8798

WS13 -8 NAS105, Workshop 13, May 2005 Input Deck $Workshop 13 $ File: workshop13. dat $ $Uses Include File, car.dat $ SOL 109 CEND TITLE = Direct Transient Dynamic Analysis of a car going over a bump SUBCASE 1 SUBTITLE=Car hitting a bump on a road TSTEP = SPC = DLOAD = DISPLACEMENT(SORT2,REAL)=ALL ACCELERATION(SORT2,REAL)=ALL SPCFORCES(SORT2,REAL)=ALL BEGIN BULK include 'car.dat' $ $Workshop 13 $ File: workshop13. dat $ $Uses Include File, car.dat $ SOL 109 CEND TITLE = Direct Transient Dynamic Analysis of a car going over a bump SUBCASE 1 SUBTITLE=Car hitting a bump on a road TSTEP = SPC = DLOAD = DISPLACEMENT(SORT2,REAL)=ALL ACCELERATION(SORT2,REAL)=ALL SPCFORCES(SORT2,REAL)=ALL BEGIN BULK include 'car.dat' $

WS13 -9 NAS105, Workshop 13, May 2005 Input Deck (ctd.) PARAM, POST, 0 PARAM, AUTOSPC, YES PARAM, PRTMAXIM, YES $ $ Enforced Disp., at the pin_left_front_suspension SPCD, 2, 7238, 2, 1. SPC1, 1, 123, 7238 $Create Dynamic Load from the Enforce Disp TLOAD1, $ Bump Profile TABLED1, 1, 0., 0.,.1, 0.,.12,.99,.125, 1., $,.13,.99,.15, 0.,.16, 0., ENDT $ Time stepping Scheme TSTEP, ENDDATA PARAM, POST, 0 PARAM, AUTOSPC, YES PARAM, PRTMAXIM, YES $ $ Enforced Disp., at the pin_left_front_suspension SPCD, 2, 7238, 2, 1. SPC1, 1, 123, 7238 $Create Dynamic Load from the Enforce Disp TLOAD1, $ Bump Profile TABLED1, 1, 0., 0.,.1, 0.,.12,.99,.125, 1., $,.13,.99,.15, 0.,.16, 0., ENDT $ Time stepping Scheme TSTEP, ENDDATA

WS NAS105, Workshop 13, May 2005 Z-Disp. History Plot

WS NAS105, Workshop 13, May 2005 X-Disp. History Plot

WS NAS105, Workshop 13, May 2005 Y-Disp. History Plot

WS NAS105, Workshop 13, May 2005 Additional Tasks n Rerun the analysis, using the following: Modal Transient Method, Time step of 0.002, and 6 % structural damping (at 100Hz)

WS NAS105, Workshop 13, May 2005