Guided waves are generally considered as a powerful approach for crack detection in structures,which are commonly investigated using the finite element method(FEM).However,the traditional FEM has many disadvantages in...Guided waves are generally considered as a powerful approach for crack detection in structures,which are commonly investigated using the finite element method(FEM).However,the traditional FEM has many disadvantages in solving wave propagation due to the strict requirement of mesh density.To tackle this issue,this paper proposes an efficient time-domain spectral finite element method(SFEM)to analyze wave propagation in cracked structures,in which the breathing crack is modeled by definiiig the spectral gap element.Moreover,novel orthogonal polynomials and Gauss-Lobatto-Legendre quadrature rules are adopted to construct the spectral element.Meanwhile,a separable hard contact is utilized to simulate the breathing behavior.Finally,a comparison of the numerical results between the FEM and the SFEM is conducted to demonstrate the high efficiency and accuracy of the proposed method.Based on the developed SFEM,the nonlinear features of waves and influence of the incident mode are also studied in detail,which provides a helpful guide for a physical understanding of the wave propagation behavior in structures with breathing cracks.展开更多
为了提升采煤机运行安全性与稳定性,以MG300-700-AWD型采煤机为研究对象,通过有限元法对采煤机平滑靴与中部槽接触碰撞特性进行了研究。研究发现,中部槽安装间隙量与高度差是影响平滑靴接触碰撞特性的重要因素,随着安装间隙量与高度差...为了提升采煤机运行安全性与稳定性,以MG300-700-AWD型采煤机为研究对象,通过有限元法对采煤机平滑靴与中部槽接触碰撞特性进行了研究。研究发现,中部槽安装间隙量与高度差是影响平滑靴接触碰撞特性的重要因素,随着安装间隙量与高度差的提高,平滑靴碰撞特性应力升高,当安装间隙量超过30 mm,平滑靴产生的接触力会超过ZG25CrMn Ni Mo许用应力的222.67 MPa,增加平滑靴碰撞损伤的危险。采煤机运行过程中应注重安装间隙量与高度差的控制,通过实践应用验证了模拟分析结果的合理性,将安装间隙量与高度差控制在较低水平范围内,可保证整个采煤机稳定运行,有利于煤矿开采工作更好地开展。展开更多
基金the National Natural Sclenee Foundation of China(Grant No.51704222)China Pastdoctoral Science Foundation(Grant No.2018M633570)Fundamental Research Funds for the Cemtal Unveritiee(Grant No.3102017090004).
文摘Guided waves are generally considered as a powerful approach for crack detection in structures,which are commonly investigated using the finite element method(FEM).However,the traditional FEM has many disadvantages in solving wave propagation due to the strict requirement of mesh density.To tackle this issue,this paper proposes an efficient time-domain spectral finite element method(SFEM)to analyze wave propagation in cracked structures,in which the breathing crack is modeled by definiiig the spectral gap element.Moreover,novel orthogonal polynomials and Gauss-Lobatto-Legendre quadrature rules are adopted to construct the spectral element.Meanwhile,a separable hard contact is utilized to simulate the breathing behavior.Finally,a comparison of the numerical results between the FEM and the SFEM is conducted to demonstrate the high efficiency and accuracy of the proposed method.Based on the developed SFEM,the nonlinear features of waves and influence of the incident mode are also studied in detail,which provides a helpful guide for a physical understanding of the wave propagation behavior in structures with breathing cracks.
文摘为了提升采煤机运行安全性与稳定性,以MG300-700-AWD型采煤机为研究对象,通过有限元法对采煤机平滑靴与中部槽接触碰撞特性进行了研究。研究发现,中部槽安装间隙量与高度差是影响平滑靴接触碰撞特性的重要因素,随着安装间隙量与高度差的提高,平滑靴碰撞特性应力升高,当安装间隙量超过30 mm,平滑靴产生的接触力会超过ZG25CrMn Ni Mo许用应力的222.67 MPa,增加平滑靴碰撞损伤的危险。采煤机运行过程中应注重安装间隙量与高度差的控制,通过实践应用验证了模拟分析结果的合理性,将安装间隙量与高度差控制在较低水平范围内,可保证整个采煤机稳定运行,有利于煤矿开采工作更好地开展。
