ADM703b, Workshop 3, February 2013 Copyright© 2013 MSC.Software Corporation WS3 - 1 WORKSHOP 3 INCLUDE DAMPING: THE EFFECT ON RESULTS

ADM703b, Workshop 3, February 2013 Copyright© 2013 MSC.Software Corporation WS3 - 2

ADM703b, Workshop 3, February 2013 Copyright© 2013 MSC.Software Corporation WS3 - 3 Workshop Objectives –Investigate the effect of Damping and Solver integrator settings for a simple crane model. Software Version – Adams 2013 Files Required –1_crane.cmd –2_load_macro.cmd –3_Create_Measure_CPU.cmd –4_Large_Damping01_Solver_Setting_and_Run.cmd –5_Small_Damping0001_Solver_Setting_and_Run.cmd

ADM703b, Workshop 3, February 2013 Copyright© 2013 MSC.Software Corporation WS3 - 4 Getting Started Load the model, investigate and run a scripted simulation: 1.Load the model named 1_crane.cmd 2.Investigate the model and note that: a.There is one boom discrete flexible part and one rope discrete flexible part. b.Both the boom and the rope are made up of sequences of BEAM and PART elements. c.Fixed joints that connects ground-boom, boom-rope and rope-spool d.SFORCE is acting on spool, which is active during STATIC simulation and deactivated just after STATIC simulation e.MOTION having function step5(time, 1, 0d, 3, 10d) is specified that define the rotation of the boom from 1sec to 3sec. f.Simulation Script: static_letgo

ADM703b, Workshop 3, February 2013 Copyright© 2013 MSC.Software Corporation WS3 - 5 Getting Started (Cont.) 3.Load a macro file that will help when changing the BEAM damping: a.Press the F2 key in Adams/View to import the command file 2_load_macro.cmd. This creates a new macro in Adams/View for looping through BEAM elements and altering the damping. b.Test the macro on the Adams/View Command line (F3) for the 'rope' element using the command: change_beam_damping beam_prefix = "*rope*" damping = 0.01 c.This will update the Damping Ratio in the beam elements associated with the rope. 4.Run a simulation using the simulation script static_letgo. This simply finds static when an imbalance force is active, then lets the spool swing in dynamics. A motion on the boom becomes active at t = 1.

ADM703b, Workshop 3, February 2013 Copyright© 2013 MSC.Software Corporation WS3 - 6 General Setup Use below setting for testing effects of damping on results and simulation time: Solver Settings: a.Select External as Executable b.Select Display under Category and Select Yes for Show Messages to see Solver output in View c.Select Output under Category and Select Yes for Save Files Note: You don't require setting Save Files to Yes for external solver - default Adams as a file prefix will be used. Set it and enter meaningful File Prefix to store analyses and model dataset with different name. e.Select Dynamics under Category: Select Integrator as GSTIFF, Formulation as SI2, Corrector as Original, Error = 1.0E-3 f.Load file (F2) 3_Create_Measure_CPU.cmd to create REQUEST that measures CPU time

ADM703b, Workshop 3, February 2013 Copyright© 2013 MSC.Software Corporation WS3 - 7 Test with large damping in ‘rope’: (Damping = 0.01) Run six simulations by changing error tolerance and integrator formulation for damping = 0.01 in the rope: 1.GSTIFF, SI2, Original, Error = 1.0E-3 File Prefix: 01dam_01_gstiff_SI2_Original_Err1e3 2.GSTIFF, SI2, Modified Corrector, Error = 1.0E-3 File Prefix: 02dam_01_gstiff_SI2_ModCorrector_Err1e3 3.GSTIFF, SI2, Original, Error = 1.0E-4 File Prefix: 03dam_01_gstiff_SI2_Original_Err1e4 4.GSTIFF, SI2, Modified Corrector, Error = 1.0E-4 File Prefix: 04dam_01_gstiff_SI2_ModCorrector_Err1e4 5.GSTIFF, I3, Original, Error = 1.0E-4 File Prefix: 05dam_01_gstiff_I3_Original_Err1e4 6.GSTIFF, I3, Modified Corrector, Error = 1.0E-4 File Prefix: 06dam_01_gstiff_I3_ModCorrector_Err1e4 7.Load file (F2) 4_Large_Damping01_Solver_Setting_and_Run.cmd to run all above simulations and store results in View/Postprocessor

ADM703b, Workshop 3, February 2013 Copyright© 2013 MSC.Software Corporation WS3 - 8 Test with small damping in ‘rope’: (Damping = ) Run six simulations by changing error tolerance and integrator formulation for damping = in the rope: 1.GSTIFF, SI2, Original, Error = 1.0E-3 File Prefix: 01dam_0001_gstiff_SI2_Original_Err1e3 2.GSTIFF, SI2, Modified Corrector, Error = 1.0E-3 File Prefix: 02dam_0001_gstiff_SI2_ModCorrector_Err1e3 3.GSTIFF, SI2, Original, Error = 1.0E-4 File Prefix: 03dam_0001_gstiff_SI2_Original_Err1e4 4.GSTIFF, SI2, Modified Corrector, Error = 1.0E-4 File Prefix: 04dam_0001_gstiff_SI2_ModCorrector_Err1e4 5.GSTIFF, I3, Original, Error = 1.0E-4 File Prefix: 05dam_0001_gstiff_I3_Original_Err1e4 6.GSTIFF, I3, Modified Corrector, Error = 1.0E-4 File Prefix: 06dam_0001_gstiff_I3_ModCorrector_Err1e4 7.Load file (F2) 5_Small_Damping0001_Solver_Setting_and_Run.cmd to run all above simulations and store results in View/Postprocessor

ADM703b, Workshop 3, February 2013 Copyright© 2013 MSC.Software Corporation WS3 - 9 Observations: 1.Consider the results where damping = and err = 1e-4: Here I3 is way faster than SI2 formulation (5 seconds vs 6 minutes - on 32 bit Intel ® Core i5 CPU 2.40GHz, 1.17GHz, 3.24 GB of RAM) –For the comparison above, compare (from the.msg files) the integration order reported as well as the Function Evaluations / Steps Taken ratio for I3 vs. SI2. (example: i3 = 2.66, si2 = 2.82). –Compare the integration order: I3 stays at order=1 throughout the simulation whereas SI2 gets all the way up to order=5.

ADM703b, Workshop 3, February 2013 Copyright© 2013 MSC.Software Corporation WS Observations (Cont.): 2.Note that the amount of damping in the rope has a massive effect on the simulation speed. Obviously the problems are different, but the generalization that: "massively increasing damping in the rope (from 1e-4 to 1e-2) does not vastly influence the gross motion of the spool, but the simulation time differences are drastic.