If you have a sdof system with acceleration applied at the base whose frequency content is far below the resonant frequency, then as a first approximation the base is rigid, the acceleration applied to the base appears at the mass... displacement can be found if needed by integrating that acceleration twice.
Above is one specific example of quasistatic analoysis. In general, it is whenever some aspect of the dynamics of the system is neglected as an approximation.
=====================================
Eng-tips forums: The best place on the web for engineering discussions.
The quasistatic analysis is performed to save time that gives reasonably accepted results. The forces and displacements changes over a long period of time when applied as a quasistatic loading.
These analysis are performed on subsea pipelines to model the affects of waves and currents provided they occur below the lowest natural frequency. When the loads occurs near the natural frequency then full dynamic analysis would then need to be considered.
If you are interested in some "practical " applications of of quasi static analysis you might want to checkout Dr. Ron Fedkiw at Sanford. He is moving into human dynamics, for lack of the proper term.
