User Defined Time Integrators
FEAP allows for user defined time integrators in a fairly flexible fashion.
Here is a report by Karl Steeger on
implementing the Wilson-theta time
integrator into FEAP. This is a fairly complex scheme and illustrates many
of the issues one must grapple with when adding one's own time integrator.
User Defined Elements
Feap allows one to add ones own elements. Normally these are done
using FORTRAN but it is also possible to do this in C. Here is an
example of a linear viscoelastic element that is
written in C.
Example user element for a Lysmer-Kuhlemeyer damper in 2D Cartessian
as well as axis-symmetric problems when coupled with linear or bi-linear
User Defined Load Curves
Feap allows one to add ones own proportional load curve functions to the
main program. This done through the uprop.f interface. Here
is an example uprop.f that implements a Haversine
Example Input Files:
An example using follower loads and pressure elements:
An example using the LINK command to prestress a component, glue it to another
unstressed one, and then release the system and let it come to equilibrium: