User subroutine for compressive failure of composites
For high strength carbon fiber reinforced polymers, the design criteria are often specified by the compression strength of the composite materials component. This is due to the fact that the compression strength of unidirectional composites is as low as 50 to 60 percent of the tensile strength. One important compressive failure mode in composite is kink-band formation which for a great deal is governed by the waviness of the fibers and the yielding properties of the matrix material.