基于裂纹诱导挠度的悬臂梁裂纹静力损伤识别

发布时间：2018-06-19 02:20

本文选题：悬臂梁 + 等效扭转弹簧　；参考：《力学季刊》2017年02期

【摘要】：将梁横向裂纹等效为内部扭转弹簧,利用广义Delta函数和Heaviside函数,首先给出了悬臂Euler-Bernoulli裂纹梁静力弯曲的解析解,证明了裂纹诱导挠度函数是分段线性函数,且在裂纹处其斜率发生突变,为梁横向裂纹位置的确定提供了理论依据.利用裂纹处裂纹诱导挠度函数斜率的改变,给出了裂纹等效扭转弹簧柔度的计算公式,从而实现了梁横向裂纹损伤程度的识别.其次,给出了根据裂纹梁挠度测量值逼近裂纹诱导挠度函数及确定裂纹位置和裂纹损伤程度的数值方法.最后,通过两个数值算例验证了本文所建立的悬臂梁横向裂纹损伤识别方法的适用性和可靠性,考察了梁裂纹深度和挠度测量噪声等对损伤识别的影响,结果表明横向裂纹位置和裂纹等效扭转弹簧柔度识别误差随挠度测量误差增大和裂纹深度减小而增大,但仍在可接受的范围内,故该裂纹损伤识别方法在工程实际中具有一定的应用性.
[Abstract]:The transverse crack of the beam is equivalent to an internal torsion spring. Using the generalized Delta function and the Heaviside function, the analytic solution of the static bending of a cantilever Euler-Bernoulli crack beam is first given. It is proved that the crack induced deflection function is a piecewise linear function, and the slope of the crack occurs abrupt. It provides a theory for the determination of the transverse crack position of the beam. Based on the change of the slope of the crack induced deflection function at the crack, the formula of the equivalent torsion spring flexibility of the crack is given, and the damage degree of the transverse crack of the beam is identified. Secondly, the numerical formula to approximate the crack induced deflection function according to the measurement value of the crack beam deflection and to determine the position of the crack and the degree of the crack damage are given. In the end, two numerical examples are used to verify the applicability and reliability of the method for the identification of the transverse crack damage of the cantilever beam, and the effect of the crack depth and the deflection measurement noise on the damage identification is investigated. The results show that the lateral crack position and the flexibility recognition error of the equivalent torsion spring are increased with the deflection measurement error. The crack depth of large sum increases but is still within acceptable range, so the method of crack damage identification has certain application in engineering practice.
【作者单位】：上海大学土木工程系;
【分类号】：O346.1

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