Fluid and Matrix Components of Polyurethane Foam Behavior Under Cyclic Compression

Semi-rigid polyurethane foam specimens were compressed to 25, 50, or 75 percent strain at nominal strain rates of 0.14/s, 1.4/s or 14/s for up to 100 cycles. The loads carried by the fluid and matrix phases of the foam were determined over these deformation histories using an experimental method recently developed by the authors. The fluid phase contributed significantly to the first-cycle stress of specimens compressed to 50 or 75 percent strain. During subsequent cycles, the fluid component decreased more quickly than the matrix component and became negligible by 100 cycles.