基于裂纹诱导弦挠度的Timoshenko梁裂纹无损检测

发布时间：2018-01-16 17:20

本文关键词：基于裂纹诱导弦挠度的Timoshenko梁裂纹无损检测　出处：《工程力学》2016年12期 　论文类型：期刊论文

【摘要】：研究了基于Timoshenko梁静态挠度识别梁中裂纹位置及损伤程度的计算方法。首先,将梁开闭裂纹等效为单向旋转弹簧,利用Delta函数和Heaviside函数,得到了具有任意开闭裂纹数目梁的等效抗弯刚度,求得了开闭裂纹Timoshenko梁弯曲变形的显式闭合通解,给出了闭合通解待定常数的迭代求解方法。其次,建立了裂纹诱导弦挠度函数,证明了在裂纹处裂纹诱导弦挠度曲线斜率存在突变,为裂纹位置识别提供了理论依据。在此基础上,给出了裂纹等效旋转弹簧刚度的近似计算公式。最后,通过数值试验,将所建立的方法分别应用于裂纹位置及损伤程度已知的简支和固支Timosheoko梁裂纹位置识别和损伤程度计算,结果表明该文建立的裂纹损伤识别方法不仅具有一般的适用性,而且具有较高的精度和可靠性。
[Abstract]:Based on the static deflection of Timoshenko beam, the calculation method of the crack location and damage degree in the beam is studied. Firstly, the open and close crack of the beam is equivalent to a unidirectional rotating spring. By using Delta function and Heaviside function, the equivalent bending stiffness of beams with arbitrary number of open and close cracks is obtained. The explicit closed general solution of the bending deformation of the Timoshenko beam with open and closed cracks is obtained. The iterative solution of the undetermined constant of the closed general solution is given. Secondly, the deflection function of the crack induced chord is established. It is proved that there is a sudden change in the slope of the crack induced chord deflection curve at the crack, which provides a theoretical basis for the identification of the crack position. On this basis, an approximate formula for calculating the stiffness of the crack equivalent rotation spring is given. Through numerical experiments, the proposed method is applied to the identification of crack location and the calculation of damage degree of simply supported and clamped Timosheoko beams with known crack location and damage degree respectively. The results show that the proposed method not only has general applicability, but also has high accuracy and reliability.
【作者单位】：上海大学土木工程系;
【分类号】：TU317
【正文快照】： 工程中对各类梁构件完整性和可靠性的评估需求使得梁损伤识别理论及方法成为近十几年来土木工程和机械工程等领域的关注课题,并得到了广泛深入的研究[1 3]。通常,梁的损伤关联于梁构件材料性能的退化或裂纹的出现,且通过梁弯曲刚度为损伤变量的函数来表示[4 6]。结构损伤识

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