The expElement command is used to construct experimental elements that represent specimens such as trusses, beams, columns, braces, springs, walls, and other parts of a structure that are physically tested in a laboratory. Analogous to an analytical element, the experimental element acts within the host finite element analysis software, but represents a physical portion of a model instead of a numerical one. Like the analytical element the basic functionality of an experimental element is to provide the mass, damping, and stiffness matrices as well as the residual force vector for a given deformation state. The experimental element is thus responsible for transforming prescribed boundary conditions from the global coordinate system of the FE-model into the local or basic element coordinate system that is best suited for testing. Additionally, it needs to provide inverse transformations for the measured response quantities, such as displacements, velocities, accelerations and forces, from the element coordinate system back to the global coordinate system of the FE-model.
The type of element created and the additional arguments required depends on the $eleType provided in the command.
The following commands contain information about $eleType and the $args required for each of the available element types:
The valid queries to any experimental element when creating an element recorder are documented in the Notes section for each element.