基于激光-介质损伤的三维内裂纹3D-ILC实现

在材料内部制作可用于试验的真实、可控的三维内裂纹,一直是断裂力学中的基础性难题。针对此瓶颈,提出了通过电磁场在试样内部制造等离子体进而制作任意宏观三维内裂纹的全新方法“3D-ILC”,实现了“内科手术式”制作内裂纹而对表面无任何影响。首先综述传统的脆性材料的内裂纹制作方法及不足,然后给出激光-介质损伤的基本原理与3D-ILC实现方法,给出基于3D-ILC技术的单裂纹、随机多裂纹、双X形内裂纹试样实例。通过经典的单轴压缩与巴西圆盘试验,证明3D-ILC在断裂力学三维内裂纹断裂力学研究中的可用性。结果表明：3D-ILC相对于传统方法具有以下优势：①可观测性强;②简便、快速、高效;③裂纹真实;④试样均质度、脆性度高、完整性强;⑤裂纹数量、尺寸可控。3D-ILC的提出,解决了断裂力学百年来在材料内部实现任意可控宏观三维内裂纹这一基本问题,使原本复杂和高门槛的三维内裂纹扩展断裂研究具备“平民化”的特征,对于推动断裂力学中内裂纹及三维问题的研究,具有重要意义。

Embedded cracks in brittle solids induced by laser-medium interaction (3D-ILC)

The research of fracture mechanics is based on physical experiments, which mainly deal with the specimen containing cracks and defaults. Since surface cracks and penetrated cracks are relatively easy to make and observe, the theoretical study on fracture mostly depends on these two kinds of experiments. The embedded cracks actually can largely influence the characteristics of the materials. However, the experiments with embedded cracks have been a tough task because of the difficulty in the manufacturing technique. A new method (3D-ILC) is proposed for making the internal embedded cracks based on the laser-medium damage theory. Firstly, review of the traditional methods for embedded cracks is given. Then the theory of laser-medium damage is proposed. The specimen examples with a single embedded crack, double X-type cracks and multi-cracks are shown. By the axial compressive experiment tests, the feasibility of 3D-ILC is confirmed. Meanwhile, 3D-ILC has the following advantages: easy observation, economy and efficiency, real cracks, high homogeneity, easy control and great reduction of discretization of results, which is very important in experimental research. The proposed 3D-ILC method will provide vast potential for future development of fracture mechanics.