A shape factor based ultrasonic measurement method for determination of bolt preload
A shape factor based ultrasonic measurement method for determination of bolt preload
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DOI：
10.1016/j.ndteint.2019.102210
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发表时间：
2020-04-01
影响因子：
4.2
通讯作者：
Xu, Xiaoyu
中科院分区：
文献类型：
--
作者：
Pan, Qinxue;Pan, Ruipeng;Xu, Xiaoyu
现有的超声波检测模型由于螺栓有效受力区域轴向应力分布不均匀，无法准确测量螺栓预紧力;由于螺栓有效受力长度等关键参数难以确定，无法快速完成检测系数的标定。为了消除轴向应力分布不均匀对测量的影响，实现检测系数的快速准确标定，进一步提高螺栓预紧力的测量精度，提出了形状因子的概念和确定方法。基于形状因子，采用纵波和横波相结合的方法，建立了测量装配过程中螺栓预紧力的数学模型，避免了测量环境温度的需要。通过对螺栓连接的静力学仿真，得到了形状系数的计算方法。通过有限元模拟和实验标定相结合的方法，得到了45#钢的材料因子和温度因子以及M20和M16螺栓的形状因子。实验表明，该方法的相对误差在5%以内，满足工程应用的要求。
The existing ultrasonic testing models cannot accurately measure bolt preload due to the non-uniform distribution of axial stress in the effective stressed region of bolt and cannot rapidly complete the calibration of detection coefficients due to the difficulty to determine the key parameters such as effective stressed length. In order to eliminate the impact of non-uniform distribution of axial stress on the measurement, realize rapid and accurate calibration of detection coefficients and further improve the measurement accuracy of bolt preload, the concept and determination method of shape factor are proposed. Based on the shape factor, a combination of longitudinal and transverse waves is adopted to establish a mathematical model for measuring the preload applied to a bolt during assembly, avoiding the need to measure ambient temperature. The calculation method of shape factor is obtained by statics simulation of a bolted joint. Through the combination of finite element simulation and experimental calibration, the material factors and temperature factors of 45# steel as well as the shape factors of M20 and M16 bolts are obtained. The experiments show that the relative error of this method is within 5%, which meets the requirements of engineering applications.