木材Ⅰ/Ⅱ复合型断裂破坏研究进展

A STATE-OF-THE-ART REVIEW OF FAILURE OF WOOD UNDER Ⅰ/Ⅱ MIXED MODE FRACTURE

复合型应力状态是木材断裂破坏的主要受力模式,本文从复合断裂模型和试验方法两个方面回顾了木材复合断裂研究的发展历程.在介绍了木材复合断裂的经验模型和物理模型后,通过一组试验数据进行了这些断裂模型的比较,总结了各自的特点.同时,总结了确定这些模型而进行的各类试验方法,主要是Ⅰ/Ⅱ复合断裂模式,即断裂模式Ⅰ和断裂模式Ⅱ均存在的情况.最后阐述了木材复合断裂研究中的一些问题,并对今后的研究方向提出了建议.

For the design and the safety assessment of wood structures, an adequate knowledge of wood fracture behavior is important. Due to the complexity in its structure, wood is naturally anisotropic in the macroscopic scale, which makes it more difficult to study wood failure based on fracture mechanics than to study isotropic materials. Therefore, only fractures of pure mode I and pure mode II were given a considerable attention.Wood structural members are, however, often subject to the mixed mode fracture in reality, and the mixed mode fracture is now one of hot topics in the fracture studies. This paper gives a literature review on the wood mixed fracture from two aspects： the fracture criterion and the testing method. After an introduction of some empirical and physical models to predict the mixed mode fracture failure of wood, a comparison is made among these models using the test data in the literature. Various test methods are reviewed, with focus on fractures of mode I and mode II combined. Some issues for future studies are highlighted.