【作者】 刘瑛；

【导师】 李林安；

【作者基本信息】 天津大学 ， 固体力学， 2006， 硕士

【摘要】 泡沫塑料是一种应用广泛的材料,它以塑料为基本成分,含有大量气泡是一种以气体为填料的复合材料。由于它质轻、比强度高、吸收冲击载荷的能力强、隔热和隔音性能好,被广泛应用于农业、建筑、航空、运输、包装等行业,因此它的力学性质受到广泛的关注。本文对泡沫塑料的可压缩的塑性力学性能作了一定的实验及理论分析。第一章介绍了泡沫塑料力学研究的国内外研究背景与主要研究工作,重点突出研究泡沫塑料可压缩的塑性力学性能。第二章介绍了泡沫塑料的结构特点,制作,本身特点及分类等基本知识。第三章介绍了对泡沫塑料进行静态压缩实验。文中介绍了实验装置的设计原则、标定以及测量所需要的国家标准。在三种状况:不同密度、不同加载方式、循环加卸载下做了实验,进行了详细地分析与总结。用实时拍摄记录加载过程,得到泡沫塑料单胞体图片,计算出泊松比。从而更进一步得出泡沫塑料的体积应变与应力的关系,得出与典型塑性理论相矛盾的事实体积在进入塑性变形后为可变的。总结出泡沫塑料弹性模量与密度关系函数。第四章推导出和应力应变曲线及密度有关的本构关系。更改塑性力学全量理论的经典假设,推导出适用于泡沫塑料的全量理论。第五章进行了有限元公式的推导。探讨了对不同孔径的泡沫塑料进行有限元分析计算,观察结果是否和实验相符合。并对泡沫塑料的微观破坏进行有限元模拟。第六章本文的总结与展望提出不足与希望。更多还原

【Abstract】 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.更多还原