Effects of defects on the tensile strength of rigid polyurethane foamed plastics
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摘要: 针对几种密度的无缺陷和含缺陷的硬质聚氨酯泡沫塑料试件进行了拉伸实验,研究了材料的强度性质,并且探讨了各种缺陷形式对拉伸强度的影响.实验结果表明,材料经长期放置后(约6年)其拉伸强度并未发生明显的变化,且与相对密度的二次幂成正比;此外,发现缺陷形式对聚氨酯泡沫塑料的拉伸强度有明显的影响,且弧形缺陷对材料拉伸强度的影响具有明显的尺寸效应.Abstract: The tensile tests have been done for different densities polyurethane rigid foam (PURF) specimens with and without defects. On the basis of experiments, the strength of PURF is investigated and the effects of defect with different kind and different size on the ultimate strength of PURF are discussed at the same time. The result of experiments shows that the tensile strengths of PURF specimens stored in a long time (about 6 years) have not been changed and they are proportional to the square of relative densities of PURF. It also found that the form of defects has significant effects on the tensile strength of PURF and if the defects of specimens have the shape of an arc, they have significant size effect of defects on their tensile strengths.
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Key words:
- foamed plastics /
- mechanical properties /
- defects /
- tensile test
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