Inertial force effects complicate the determination of the mode I interlaminar fracture toughness under high loading rates in composites. Although using a quasi-static analysis is a common approach, it is not always valid. A time-based threshold criterion is proposed to determine when dynamic effects might be neglected during the analysis of a high loading rate Double Cantilever Beam test. The criterion compares a transition time, time after which inertia effects can be neglected, versus the time for the initiation of fracture propagation. Three different methods are considered for the transition time. Good agreement is found when comparing the expressions with numerical simulations. It is also demonstrated that the transition time is affected by the velocity profile. The proposed criterion and approach to determine the transition time are useful tools to define when a quasi-static data-reduction scheme can be used.

惯性力效应使复合材料在高加载速率下层间断裂韧度I的测定复杂化。尽管使用准静态分析是一种常见方法，但它并不总是有效的。提出了基于时间的阈值准则，以确定在高加载速率双悬臂梁测试的分析过程中何时可以忽略动态影响。该标准将过渡时间（可以忽略惯性影响的时间）与开始裂缝扩展的时间进行比较。考虑三种不同的过渡时间方法。将表达式与数值模拟进行比较时，发现很好的一致性。还证明了过渡时间受速度曲线影响。