本文選題：模態(tài)修改　切入點：等效載荷　出處：《東北大學》2014年碩士論文

【摘要】：梁被廣泛應用于大型機械設備和橋梁建筑等重要的生產(chǎn)生活設施當中,研究其不同故障機理,以保障生產(chǎn)生活安全和可靠運行,進而保障國民經(jīng)濟的穩(wěn)定健康發(fā)展和人民財產(chǎn)安全,具有重要意義。因此,能準確快速的識別裂紋的種類、位置和深度,做到及早發(fā)現(xiàn)與處理,是十分有必要的。在針對于基于等效載荷方法中模態(tài)修改問題所涉及的自由度匹配問題,文中提出了按不同自由度將特征矩陣統(tǒng)一進行分塊組合,并舍棄對結果影響較小的自由度所對應的塊,解決了理論與實驗的對應問題；在模態(tài)修改方法方面,采用靈敏度方法與優(yōu)化方法相結合,通過靈敏度值確定修改目標,解決了效率低的問題,同時,采用迭代尋優(yōu)方法以保證結果的可靠性。提出了張開裂紋梁的故障仿真方法和故障診斷方法。運用基于等效載荷的故障診斷方法,根據(jù)監(jiān)測的動力學響應,計算出實際的等效載荷(剩余位移),然后在故障空間中搜尋對應的最佳理論等效載荷(剩余位移),最終實現(xiàn)準確快速地診斷出設備的故障。通過理論和實驗的雙重驗證,成功的確定了裂紋位置與深度,證明了該方法的準確性和可靠性。針對于呼吸裂紋的仿真方面,充分考慮了呼吸效應的非線性,采用的余弦開關函數(shù)來計算出帶有時間序列的特征矩陣求解等效載荷以完成故障診斷,合理的簡化了非線性問題復雜性。同時,在理論與實驗兩方面,識別了裂紋的位置與深度,驗證基于等效載荷方法在呼吸裂紋故障中的實用性。通過在實驗和理論仿真兩方面進行分析,驗證了基于等效載荷的故障診斷方法的有效性,不但能精確的識別出裂紋所在的位置,而且也能基本識別出裂紋的深度,充分證實了該方法的有效性、準確性和穩(wěn)定性,也揭示了其在相關領域的進一步潛在應用可能。
[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.
【學位授予單位】：東北大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TU312.1

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