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总览 评价 麻鸳鸳 , 张振亚 , 周风华 * ( 宁波大学冲击与安全工程教育部重点实验室,宁波 315211; ) 摘要: 本文采用实验方法观察偏心起裂裂纹在固支预拉伸加载的PMMA带板内的弯曲传播现象,并定量分析偏心距离和荷载幅值对裂纹动态传播行为的影响。研究
麻鸳鸳, 张振亚, 周风华*
(
宁波大学冲击与安全工程教育部重点实验室,宁波 315211; )
摘要:
本文采用实验方法观察偏心起裂裂纹在固支预拉伸加载的PMMA带板内的弯曲传播现象,并定量分析偏心距离和荷载幅值对裂纹动态传播行为的影响。研究表明:偏心裂纹在传播过程中向中心弯曲;裂纹的弯曲行为与偏心位置相关;低预加载荷不改变偏心裂纹路径,高预加载荷会导致裂纹分叉;如果同时启动双裂纹,在实验所能达到的范围内,双裂纹中只有一条裂纹能够传播,其行为与单偏心裂纹一致。采用含内聚力单元的动态有限元程序较好地模拟了实验现象。
关键词:
动态裂纹传播;偏心裂纹;脆性PMMA板;裂纹弯曲
Yuanyuan Ma, Zhenya Zhang, Fenghua Zhou*
(
Moe Key Laboratory of Impact and Safety Engineering,Ningbo University,Ningbo 315211; )
Abstract:
In this paper we studied experimentally the high speed propagation and curving behavior of a crack in a pre-tensile loaded brittle PMMA plate. The crack was initiated off-axially in the edge of the plate. Once initiated, the crack propagates and curved toward the middle line of the plate. The curved path of the crack is strongly dependent on the initiation site, and seems uninfluenced by the preloading level unless the load is very high causing crack to branch. If two edge cracks were initiated simultaneously, only one will propagate to cause specimen break into two pieces. The experimentally observed phenomenon have been well simulated using a FEM code incorporated with cohesive fracture elements.
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