DEFORMATION AND ENERGY-ABSORPTION OF POLYMER FOAMS AS A FUNCTION OF 2-D INDENTER AND ABSORBER GEOMETRIES

Two-dimensional indenters (flat plate and cylinder) were used to compress rectangular and trapezoidal foam energy absorbers as a function of polymer, foam density, and thickness. An increased deformation volume formed when the indenter contact area was less than the foam absorber area, resulting in both increased energy absorption and stress transmitted to the indenter (i.e., ''load spreading''). The deformation volume was trapezoidal, not prismatic, and was characterized by the indenter geometry, dimensions, and foam thickness. Conservative energy absorber design can be achieved by using ''energy absorption diagrams'' that account for the indenter (i.e., product) and absorber geometry and degree of load spreading.