一种基于应变梯度监测Ⅰ型裂纹的方法

A STRAIN GRADIENT BASED METHOD OF MONITORING MODE-I CRACK

基于线弹性断裂力学中I型裂纹的欧文解答,解析推导了在单向拉伸作用下无限大平板中I型裂纹尖端应变梯度场,建立了应变梯度与裂纹扩展之间的关联;基于挠曲电效应建立了电极化强度与应变梯度之间的力电耦合关系,提出了一种利用应变梯度传感器监测I型裂纹的方法,获知裂纹尖端坐标和裂纹扩展长度.本研究拟为应用应变梯度传感器对工程结构中裂纹扩展的实时监测提供初步的理论依据及方法.挠曲电感应技术在结构健康监测领域前景广阔.

The strain gradient field in the neighborhood of a Mode-I crack in an infinite plate under uniaxial tension is formulated based on the solution put forward by Irwin in the linear elastic fracture mechanics,and the relation between the strain gradient and the crack extension is established. Flexoelectric relationship between the electric polarization and the strain gradient is also presented, and a method of Mode-I crack monitoring to obtain the coordinates of the crack tip and the length of the crack extension using strain gradient sensors is proposed. This study provides some necessary theoretical preparations for implementing the strain gradient sensors, by which the crack extension in engineering structures can be monitored in a real-time manner.Flexoelectricity sensing technology has broad prospects in the field of structural health monitoring.