Investigations On Compressible Plastic Mechanical Properties Of Foam Plastic

Foam plastic is a commonly used high polymer material. Its general component is palstic air. As it is light, with high specific strength, strong ability to absorb impacting load, heat-insulated and noise- insulated, it has a wide application in aricluture, construction, agitation, transportation, packing and so on. So more and more people place much emphasis on its mechanical properties.This dissertation does some primary investigation into the compressible plastic mechanical properties。In chapter1, the current status of researching requirements and developments of this kind of material are reviewed. It states the investigation background and major content of this dissertation.In chapter2, the basic concepts and knowledge about foam palstics sturcture characteristic, producing and class are discussed.In chapter3, this dissertation introduces the comressible rexperiment. The design of equiment, criterion of experments and calibration of this equipment are detailed represented. Som experiments, diversity loading ways and diversity density and cycle loading, are done in this paper. Using a new and simple method to measure the poisson's ratio. Then, deriving the ralationship of volumetric strain and stress. At last,a conclusion is drawn which is the volum of foam plastic change in plastic deforming.In chapter4, deducing the constitutive equations and rededucing the platic theory about the changing volume.In chapter5, deriving the finite element theory about plastic. Caculating the diversity size foam plastis and simulating the damaged otlooking of foam plastic.The last chapter draws the conclusion of the whole dissertation. The weakness and the applicable range of model is point out, and the prospect of the research is brought forwards.