MULTIAXIAL STRESS STUDIES ON RIGID POLYURETHANE FOAM

摘要

Thin-walled tubes of rigid polyurethane foam, at 5 lb/ft3 and 4 lb/ft3 nominal den¬sities, were subjected to combined stresses. A universal test machine ap¬plied the axial tensile or compressive stress;an independent pressurization sys¬tem supplied the internal pressure to the specimen. Changes in diameter, length, and wall thickness were measured at room temperature and at -50°F. Failure envelopes in 2-dimensional stress space were obtained for the two densities at room temperature and for the greater density at -50°F. For the wall thickness range investigated (0.15 ≤ t ≤ 0.25) no effect on the failure envelope was observed. Material constants were obtained in terms of orthotropic elastic theory (at 5 lb/ft3 and room temperature) to describe the material in terms of structure.