Abstract:

The stress strain characteristics and strain rate effect of PUR foamed plastics are investigated by tensile experiments for three kinds of densities. In the meantime, in order to determine the tensile failure mechanism of foamed plastics, microscopic tensile tests were conducted in the observing room of a scanning electronic microscopy. The tensile failure mechanism of foamed plastics is discussed on the basis of observing the deformation and failure course of cells on the surface of a tensile specimen and the SEM analysis of fracture surface of tensile specimens. Finally, the tensile constitutive relation is fitted by the numerical method according to the tensile stress strain curves of PUR foamed plastics, which agrees well with the experimental curves.

Key words: foamed plastics, tensile failure, constitutive relation