Kobology 0 Report post Posted May 11, 2016 Hello, I am trying to run the Optistruct Tutorial OS 2098 with the MBD excavator arm. The analysis works fine, but optimization unfortunately not. Doing everything like in the tutorial, I get errors you can see in the attached output file. Decreasing h_min in the Load_Collector doesn't help. Like it is recommended in line 1062 in the output. But if i decrease h_min to 1e-14, Iteration 0 is running for hours now. So this could not be the right way to solve the tutorial i guess. Is this the only big error? Or are there others I can solve? Would be great to get this tutorial running, because my goal in optistruct is to optimize one part in a MBD, too. Thanks in Advance! os_2098_error.txt Quote Share this post Link to post Share on other sites
Guest Report post Posted May 13, 2016 Hi, Can you paste the entire error message here? I am unable to open the .out file on my phone Quote Share this post Link to post Share on other sites
Kobology 0 Report post Posted May 13, 2016 Hi, here are all parts where i can find "error". I also change the document type in my first post to a .txt file. ... Time=1.000E+00; Order=1; H=6.568E-13 [Max Phi=1.978E-11] Time=1.000E+00; Order=1; H=1.984E-12 [Max Phi=2.583E-11] Time=1.000E+00; Order=1; H=7.583E-13 [Max Phi=3.173E-11] Time=1.000E+00; Order=1; H=9.607E-13 [Max Phi=3.801E-11] WARNING: Simulation terminated because stepsize has diminished consistently belo ERROR: At time=1.000E+00 the integrator failed to proceed. ----------- Possible Causes ---------------------------------------------------- (1) The integration has become unstable. Tighten (decrease) integr_tol, h_max, or both in Param_Transient can help stabilize the integration. If the simulation contains distinctive phases, use multiple Simulate, each with its own proper integrator parameter setting, to selectively tighten the tolerance during the period where instability is encountered. (2) If the simulation was terminated because stepsize has diminished consistentl below h_min, reduce h_min in Param_Transient to force integration to continue. (3) Non-physical inertia properties, such as mass=100 Kg and Ixx=Iyy=Izz=1 Kg*mm or extremely small inertia on a part with an unconstrained degree of freedom. Make sure the modeling data, in particular the part inertia and the gravity, are specified in proper units consistent with the units given in Param_Unit element. (4) Beam, flexible body goes out of linear range, bushing has large rotation alo more than one axis, curve goes out of its interpolation range, higher-pair joint goes out of the range of U or V, etc. Make sure fundamental modeling assumptions such as rigid contact assumption used in Force_Contact, are not violated. (5) Motion displacement defined using LINSPL, AKISPL in dynamic analysis, or as function of model states (DX, VX etc), as well as forces defined as a function o other forces, can cause hard convergence and integrator failure. Avoid these modeling practices wherever possible. -------------------------------------------------------------------------------- .... ERROR: Error encountered in analysis! Forced termination from API_SendOffCommandSimulate! Error: MBD analysis failed. This error occurs in module "mbddrv". ************************************************************************ FEASIBLE DESIGN (ALL CONSTRAINTS SATISFIED). Delete bootstrap file xxx/excavator_MBD_Topology.OS_dumpfile_scr.bin ************************************************************************ ... *** PROGRAM STOPPED: FATAL ERROR(s) ENCOUNTERED. ***** END OF REPORT ***** For Useful OptiStruct Tips and Tricks, go to the URL:http://www.altairhyperworks.com/tips.aspx ************************************************************************ A fatal error has been detected during input processing: FEASIBLE DESIGN (ALL CONSTRAINTS SATISFIED). ************************************************************************ Quote Share this post Link to post Share on other sites
Kobology 0 Report post Posted May 23, 2016 On 13.5.2016 at 7:02 AM, Prakash Pagadala said: Hi, Can you paste the entire error message here? I am unable to open the .out file on my phone Hi, I upload the file as pdf. But if you really prefer all of the 1200 lines in here. I can do this =) Thanks Regards os_2098_error.pdf Quote Share this post Link to post Share on other sites
Mike 0 Report post Posted April 10, 2017 Did you find the error? How did you solve the problem?? Quote Share this post Link to post Share on other sites
Guest Report post Posted April 10, 2017 Mike, Can you share the .out file? Quote Share this post Link to post Share on other sites