摘要
针对３种密度的聚氨酯泡沫塑料进行了拉伸实验．通过无缺口试件确定了３种密度泡沫塑料的拉伸断裂强度，而利用有缺口试件确定了这些材料的拉伸断裂韧性为了研究高密度泡沫塑料的拉伸断裂机制，还对破坏后试件进行了扫描电镜分析．此外，还简要讨论了泡沫塑料拉伸断裂力学性能的理论预测问题。
As one kind of structural material, it is indispensable to undergo tensile loading in use for high--density foam plastics. So, it is an important work to investigate its tensile fracture properties and to determine its tensile fracture strength as well as the fracture toughness for engineering applications. In this paper, the tensile experiments have been done for the polyurethane rigid foam plastics of three different densities. Their tensile fracture strength and fracture toughness were determined by specimens without and with a notch, respectively. In order to investigate the tensile fracture mechanism, the SEM analyses have been conducted for the broken specimens. In addition, the theoretical prediction for fracture toughness of polyurethane rigid foam plastics is also discussed in this paper. Finally, the following conclusions can be drawn: 1) The Young's modulus and tensile fracture strength of polyurethane rigid foam plastics increase with its density. 2) The fracture toughness of polyurethane rigid foam plastics also increases with its density. 3) It is shown by SEM analyses that the cell failure of foam plastics generally originates from the edge of penetrating holes on the cell wall and its breaking basically belongs to one kind of britle fracture. 4) The fracture toughness of polyurethane rigid foam plastics has a direct bearing on the cell size of it. 5) The micro-defects (or voids) exert a larger effect on the practical strength of foam plastics, but they hardly affect its fracture toughness.
出处
《力学学报》
EI
CSCD
北大核心
2000年第5期627-632,共6页
Chinese Journal of Theoretical and Applied Mechanics
基金
国家自然科学基金!(19672005)
国防科技预研基金&&
关键词
泡沫塑料
力学性能
强度
断裂韧性
电镜分析
聚氨酯
foam plastics, mechanical properties, strength, fracture toughness, SEM analyses
