基于等效载荷方法的梁裂纹检测与分析

发布时间：2018-03-28 22:08

本文选题：模态修改　切入点：等效载荷　出处：《东北大学》2014年硕士论文

【摘要】：梁被广泛应用于大型机械设备和桥梁建筑等重要的生产生活设施当中,研究其不同故障机理,以保障生产生活安全和可靠运行,进而保障国民经济的稳定健康发展和人民财产安全,具有重要意义。因此,能准确快速的识别裂纹的种类、位置和深度,做到及早发现与处理,是十分有必要的。在针对于基于等效载荷方法中模态修改问题所涉及的自由度匹配问题,文中提出了按不同自由度将特征矩阵统一进行分块组合,并舍弃对结果影响较小的自由度所对应的块,解决了理论与实验的对应问题；在模态修改方法方面,采用灵敏度方法与优化方法相结合,通过灵敏度值确定修改目标,解决了效率低的问题,同时,采用迭代寻优方法以保证结果的可靠性。提出了张开裂纹梁的故障仿真方法和故障诊断方法。运用基于等效载荷的故障诊断方法,根据监测的动力学响应,计算出实际的等效载荷(剩余位移),然后在故障空间中搜寻对应的最佳理论等效载荷(剩余位移),最终实现准确快速地诊断出设备的故障。通过理论和实验的双重验证,成功的确定了裂纹位置与深度,证明了该方法的准确性和可靠性。针对于呼吸裂纹的仿真方面,充分考虑了呼吸效应的非线性,采用的余弦开关函数来计算出带有时间序列的特征矩阵求解等效载荷以完成故障诊断,合理的简化了非线性问题复杂性。同时,在理论与实验两方面,识别了裂纹的位置与深度,验证基于等效载荷方法在呼吸裂纹故障中的实用性。通过在实验和理论仿真两方面进行分析,验证了基于等效载荷的故障诊断方法的有效性,不但能精确的识别出裂纹所在的位置,而且也能基本识别出裂纹的深度,充分证实了该方法的有效性、准确性和稳定性,也揭示了其在相关领域的进一步潜在应用可能。
[Abstract]:Beams are widely used in important production and living facilities, such as large-scale mechanical equipment and bridge buildings, to study their different failure mechanisms in order to ensure safe and reliable operation of production and life. Thus, it is of great significance to ensure the stable and healthy development of the national economy and the safety of the people's property. Therefore, we can accurately and quickly identify the type, location and depth of cracks, so as to detect and deal with them as early as possible. Aiming at the matching problem of the degree of freedom involved in the modal modification problem based on equivalent load method, this paper proposes to combine the characteristic matrix into blocks according to different degrees of freedom. The corresponding block of degree of freedom, which has less influence on the result, is abandoned, and the corresponding problem between theory and experiment is solved. In the aspect of modal modification, the sensitivity method is combined with the optimization method, and the modification target is determined by the sensitivity value. The problem of low efficiency is solved. At the same time, iterative optimization method is adopted to ensure the reliability of the result. A fault simulation method and fault diagnosis method for open crack beam are proposed. The fault diagnosis method based on equivalent load is used. Based on the dynamic response of the monitoring, The actual equivalent load (residual displacement) is calculated, and the corresponding optimal theoretical equivalent load (residual displacement) is searched in the fault space. Finally, the fault of the equipment can be diagnosed accurately and quickly. The location and depth of the crack are determined successfully, and the accuracy and reliability of the method are proved. In view of the simulation of the respiratory crack, the nonlinearity of the respiration effect is fully considered. The cosine switching function is used to calculate the characteristic matrix with time series to solve the equivalent load to complete the fault diagnosis, which simplifies the complexity of the nonlinear problem reasonably. At the same time, in both theoretical and experimental aspects, The location and depth of the crack are identified, and the practicability of the method based on equivalent load in respiratory crack fault is verified. The effectiveness of the fault diagnosis method based on equivalent load is verified by the analysis of experiment and theoretical simulation. Not only the location of the crack can be accurately identified, but also the depth of the crack can be basically recognized, which fully proves the validity, accuracy and stability of the method, and also reveals the potential application of the method in related fields.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU312.1

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