You can do a quasi-static analysis the old way by running a regular explicit simulation, invoking time- and/or mass-scaling as necessary to crank out the results in a reasonable timeframe, but this approach can be tricky. You have to keep an eye on the kinetic energy in the system as you want to minimize the inertial effects. Basically, the kinetic energy should remain small relative to the internal energy. (By time-scaling, I mean applying the load more quickly than in the quasi-static experiment in order to reduce the simulation time.) See the file “mass_scaling” for more on mass-scaling.
Or, you can try an implicit, static analysis using v. 960 of LS-DYNA. See the commands
*CONTROL_IMPLICIT_... and Appendix M in the 950 User’s Manual. There are examples of implicit analysis on our user ftp site in the ls-dyna/example directory.
Initializing to a prescribed geometry
If you do a regular dynamic relaxation run to get to the initialized state, a file of prescribed displacements and rotations will automatically be written at the conclusion of the DR phase.
*CONTROL_DYNAMIC_RELAXATIONand include m = filename on the execution line where filename is the file created in step 1. Before the transient run begins, LS-DYNA will automatically run a precusor analysis of 100 timesteps wherein the nodse are displaced according to the data in filename.
revised 7/21/03 jpd 7/2004