Modified Restoring Force Surface Method for Clearance Identification in Nonlinear Multi-degree-of-freedom Systems

Jie LIU
2016 Journal of Mechanical Engineering  
Abstract:Clearance is ubiquity in the mechanical system. The contact nonlinearities which are caused by the clearance can significantly affect the dynamic response, and eventually degrade the dynamic performance. If the parameter of the clearance nonlinearity can be identified by taking advantage of the equipment dynamic information, the system can be adjusted to control the influence of the clearance nonlinearity. Based on the multi-degree-of-freedom (MDOF) system with clearance, a modified
more » ... ance, a modified method which combines the traditional restoring force surface (RFS) method and the orthogonal projection technology in the matrix row space is proposed to identify the clearance value. For the modified method, the traditional restoring force can be estimated by the excitation force and the acceleration response. The traditional restoring force should be projected on the nonlinearity location. The projection restoring force-displacement curve can be drawn, and the clearance size can be identified by inflection points. The feasibility of the proposed method is verified by the simulation, and the superiority is revealed by the comparison with other methods. The effectiveness of the proposed method is verified by the parameter identification experiments which are conducted on the designed testbed with adjustable clearance. Key words:clearance identification;orthogonal projection;modified restoring force surface 0 前言 * 在机械系统中,由于加工误差、磨损、热效应 以及局部变形的存在,工程结构结合面位置不可避 免地会出现间隙。间隙对机械系统的影响远不止体 * 国家自然科学基金资助项目(51475356)。20150122 收到初稿,20160503 收到修改稿
doi:10.3901/jme.2016.14.001 fatcat:lz2jdhrvgncg5lxtso7jerkbxa