一个与弹性应变能相协调的脆性横观各向同性材料破坏准则

Failure criterion coordinated with elastic energy for transversely isotropic brittle materials

岩土材料广泛存在于自然界中,在重力沉积作用下表现出明显的横观各向同性。为了更好地研究横观各向同性材料的破坏机制,基于Christensen提出的破坏准则应与弹性应变能函数相协调的思想,推导了横观各向同性材料的弹性应变能,通过应变能的分解和整理,分析了应变能中各项所表示的物理意义,确定了级数展开的基,从而使得应变能函数和材料破坏准则在形式上具有一致性,最终提出了一个适用于脆性横观各向同性材料的破坏准则。该准则由5项能够与弹性应变能相协调的部分组成,仅包含5个独立且物理力学意义清晰的参数。基于常规试验给出了5个独立参数的确定方案。通过与Tsai-Wu准则及已发表的多组试验数据的对比,验证了准则的正确性。

Under natural conditions, geomaterials under gravity usually exhibit transversely isotropic properties. In this study, a new failure criterion for transversely isotropic brittle materials has been developed. The derivation of this failure criterion is driven by the strain energy density, rather than a completely phenomenological approach. So the form of the failure criterion can be coordinated with elastic strain energy density. This coordination explain the terms in the failure criterion as well as those in the elasticity theory. Obtained by series expansion this new failure criterion includes five independent material parameters and five terms which can be coordinated with those of the elastic energy. These material parameters can be determined by corresponding independent test, and are not just fitting parameters. The shapes of the failure surface in the stress space and in the z^-plane of the proposed criterion are compared with Tsai-Wu criterion. Although the derivation of the criterion is totally different, the comparison results show this failure criterion is similar to Tsai-Wu criterion. In addition, this failure criterion can be degenerated into the criterion suggested by Christensen for isotropic materials. Comparisons with three sets of experimental data are compared to illustrate the proposed criterion. the results illustrated the prediction abilitv of the criterion.