有机玻璃裂纹扩展双参量驱动力模型

Model of Two-parameter Driving Force for Fatigue Crack Growth of PMMA

测定了定向有机玻璃YB-DM-11在应力比R=-0.4,0.1和0.4下的中部区和加速扩展区的裂纹扩展速率。将适用于金属材料的双参量裂纹扩展驱动力模型K*=(Km ax)α(ΔK+)1-α引入到有机玻璃裂纹扩展行为研究。对于有机玻璃,双参量裂纹扩展驱动力模型中的相关参数α并非定值,是与应力比、断裂韧度、应力场强度因子和裂纹扩展速率趋于无穷大时双参量动力模型中相关参数αb有关的函数。在一定应力比范围内,得到基于双参量动力模型的疲劳裂纹扩展速率通用表达式,能很好地表征不同应力比下的疲劳裂纹扩展行为,表明了应力比对有机玻璃疲劳裂纹扩展速率中部区和加速区的影响。

The fatigue crack propagation rate of YB-DM-11 PMMA in intermediate and accelerated regions was measured with the R-ratio of-0.4,0.1,and 0.4.The two-parameter driving force model,K＊=（Kmax）α（ΔK＋）1-α,which apply to metal materials,was introduced to describe the crack propagation behavior of PMMA.For PMMA,the parameter α is not a fixed value but a function is related to stress ratio,fracture toughness,stress intensity factor and α1,which is calculated while the crack propagation rate is tending to infinity.To R=-0.4— 0.4,the common crack propagation rate equation based on the two-parameter driving force model was obtained,and was used to explain the fatigue crack propagation behavior under different stress ratios,and predicted the fatigue crack propagation rate of PMMA in intermediate and accelerated regions was effected by the stress ratios.