Load-bearing characteristics of polyethylene foam: an examination of structural and compression properties.

Cellular foams used in shoe insoles come in a variety of structural configurations differing with respect to cell geometry. The compression of a cellular foam depends on cell reticulation and size. Examination of the compression behavior of closed cell polyethylene foams revealed distinct time-and nontime-related properties that occur during static and cyclic loading. Physical parameters were developed and determined to exactly specify pressure profiles that occur at the plantar interface. Evaluation of an interface material can be made based on peak pressures which are dependent on depth of compression, foam thickness, and physical properties of the foam. Sustained loading damages the mechanical integrity of the cellular structure such that thickness does not completely recover. Therefore, issuing several pairs of thick insoles for daily rotation is recommended for a particular foam.