粉末冶金材料断裂韧性的动态算法
Dynamic Algorithm of Fracture Toughness of Powder Metallurgy
史平安
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作者单位：中国工程物理研究院总体工程研究所
中文关键字：微裂纹，断裂韧性，动态规划法
英文关键字：Micro-crack, Fracture toughness, Dynamic programming
中文摘要：加工过程中材料内部会形成很多微裂纹，而微裂纹的分布和取向将直接影响到材料的断裂韧性。为考察粉末冶金材料细观结构特征对于宏观裂纹扩展机制的影响，本文通过引入等效表面能密度概念,建立了含微裂纹材料的断裂韧性的计算方法，并利用动态规划算法研究了微裂纹的分布和取向对材料断裂韧性的影响。同时，根据不同取向微裂纹的统计分布规律，给出了材料断裂韧性和微裂纹标量密度之间关系的解析表达式。通过计算结果与相关文献数据的比较，结果吻合较好。
英文摘要：Many micro-cracks exist in the inner structure during contour machining processes, and their existing had a big affect on fracture toughness. In order to find how the meco-structure character of powder metallurgy influences the crack propagation, a new method for the effective fracture toughness of a micro-cracked body is derived by considering the micro-cracked solid as an effective medium and introducing the concept of effective surface energy density. And the effect of distribution and orientation of micro-cracks on fracture toughness of the materials are quantitatively investigated with dynamic programming algorithm, the functional relation between fracture toughness and Scalar density is obtained according to the statistical laws of crack orientation. The computing results are very close to the conclusion drawn by Ortiz, which verifies the precision of the method.