空孔-裂纹偏置方式对PMMA冲击断裂动态行为的影响

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振动与冲击 ›› 2018, Vol. 37 ›› Issue (20) : 122-128.

论文

杨仁树1,2，陈程1，赵勇1，丁晨曦1，苏洪1，郑昌达1

作者信息 +

Influence of the void-crack offset method on the dynamic behavior of PMMA during impact fracture#br#

YANG Renshu1,2，CHEN Cheng1，ZHAO Yong1，DING Chenxi1，SU Hong1，ZHENG Changda1

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文章历史 +

摘要

为研究空孔-裂纹偏置方式对材料冲击断裂行为的影响，以有机玻璃（PMMA）为实验材料，采用动态焦散线实验方法开展了冲击加载的三点弯实验研究。结果表明：在冲击载荷作用下，空孔与预制裂纹相对偏置位置影响裂纹的起裂方向以及裂纹与空孔的贯通。预制裂纹偏置情况下，裂纹起裂时KIId<0，起裂方向指向空孔；空孔对运动裂纹的作用效应是吸引，裂纹扩展路径呈抛物线型，并与空孔贯通，在空孔上端裂纹会再次起裂。空孔偏置条件下，裂纹起裂时KIId>0，起裂方向背离空孔；空孔对运动裂纹的作用效应是先排斥后吸引再排斥，裂纹扩展路径呈S型，裂纹未与空孔贯通。当运动裂纹与空孔贯通后，裂纹发生止裂，从时间尺度上延迟了试件的破坏，但当裂纹由空孔上边界处二次起裂后，裂纹扩展速度、动态应力强度因子均相应提高，进而会加剧试件的破坏。

Abstract

In order to study the influence of the void-crack offset method on the impact-fracture behavior of materials, PMMA was used as the experimental material.The dynamic caustic experiment method was used to study the three-point bending of impact loading.The results show that: under the impact load, the relative offset position of the hole and the prefabricated crack affects the crack initiation direction and the crack and void penetration.In the case of prefabricated crack offsetting, at the time of crack initiation, KdⅡ<0 and the direction of the fracture points to the empty hole; the hole has an attractive effect on the running crack, crack propagation path is parabolic, crack and hole coalesce, the crack will be initial again at the top of the hole.Under the condition of hole offsetting, KdⅡ>0 and crack initiation direction away from the hole; the role of hole on the propagating crack is attractive firstly, then repulsive and attractive finally, crack propagation path is S-type, crack and hole are not through.When the running crack and the empty hole penetrate, crack arrest will delay the destruction of the specimen on a time scale.But after the second crack initiation at the upper boundary of the hole, crack propagation velocity and dynamic stress intensity factor are increased accordingly, which will exacerbate the destruction of the specimen.

导出引用

杨仁树1,2，陈程1，赵勇1，丁晨曦1，苏洪1，郑昌达1. 空孔-裂纹偏置方式对PMMA冲击断裂动态行为的影响[J]. 振动与冲击, 2018, 37(20): 122-128

YANG Renshu1,2，CHEN Cheng1，ZHAO Yong1，DING Chenxi1，SU Hong1，ZHENG Changda1. Influence of the void-crack offset method on the dynamic behavior of PMMA during impact fracture#br#[J]. Journal of Vibration and Shock, 2018, 37(20): 122-128

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