聚氯乙烯复合断裂性能研究

PERFORMANCE STUDY ON MIXED-MODE FRACTURE OF UPVC

  • 摘要: 从弹塑性断裂力学理论出发,进行了硬质聚氯乙烯材料多角度下的Ⅰ/Ⅱ复合断裂试验,研究硬质聚氯乙烯材料复合断裂性能. 利用数字图像相关技术,计算复合裂纹稳定扩展的临界裂纹尖端张开角值(ΨC1),尝试用该值作为一种断裂参数来描述硬质聚氯乙烯材料的断裂韧性. 结果表明:(1) 此材料与常见的金属材料不同,Ⅱ型加载模式下承载能力最大,纯Ⅰ型时承载能力最小;(2) 当裂纹稳定扩展时,ΨC1 值趋于稳定. 故临界裂纹尖端张开角可作为硬质聚氯乙烯材料裂纹稳定扩展的断裂韧性.

     

    Abstract: Based on elastic-plastic fracture mechanics theory, combined with mixed-mode I/II rupture test of UPVC (unplasticised polyvinyl chloride) under multiple loading angles, the composite fracture toughness of UPVC is studied. The critical CTOA (crack-tip-opening angle) (ΨC1) at stable composite crack extension is determined by using the digital correlation image technique, and ΨC1 is used as the fracture toughness parameter to describe the fracture toughness of UPVC. It is shown that: (1) unlike the common metallic materials, the load-carrying capacity of UPVC under mode II loading conditions is the largest, while under mode I loading conditions it is the smallest; (2) the CTOA tends to be stable when the crack extension is steady, so it can be used as the fracture toughness parameter of UPVC.

     

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