I am currently working on such a problem based on CalculiX: calculating the structural dynamic responses of a flexible plate. One end of the plate is constrained by a spring, while the other end is free to move. A constant force is applied on the plate end, as shown in following figure. My problem is how to handle the spring and what kind of boundary conditions should be applied to end with the spring? Does anyone have ideas about it? Thank you very much!
You can use discrete spring elements for this purpose, CalculiX supports them. One type is spring to ground (SPRING1) which requires just a single node but you could also use a two-node spring and fix one node. Of course, these elements take spring constact as input.
With discrete springs like SPRING1 and SPRINGA connected to a deformable surface or edge, you have to be careful to set the spring constants appropriately for each mesh node to make them behave like a uniformly distributed spring. Quadratic elements should have negative spring constant on some nodes.
You can avoid that by using an orthotropic solid or shell material as the spring and set near-zero stiffness in the directions you don’t want to constrain.
Thank you very much for your valuable advice!!!