To find the weak link of the structural stiffness is important to improve machine tool stiffness. However, how to overcome the static deformation with difficulty acquisition is a difficult problem in machine tool structure. The article takes the cantilever beam structure as a numerical example, the weak link is modeled as EA reduction in stiffness. Thorough finite element simulations are performed to assess the robustness and limitations of the method in several scenarios with single and multiple weaknesses. The sensors are used to acquire the acceleration data, the structural modal parameters are obtained by the singular value decomposition technique, and the dynamic characteristics are systematically reconstructed by using the modal state-space method to obtain static stiffness. Then, an identification method proposed by measured data and reconstructed data to identify the weak link of stiffness of the cantilever structure. Furthermore, the comparison of numerical and experimental results validate the correctness and effectiveness of this method. The research has certain practical engineering value and provides an accurate guidance for the optimization of machine tool stiffness.

寻找结构刚度的薄弱环节对于提高机床刚度具有重要意义。然而，如何克服难以获取的静态变形是机床结构中的难题。文章以悬臂梁结构为例，将薄弱环节建模为EA刚度折减。进行彻底的有限元模拟，以评估该方法在具有单个和多个弱点的几种情况下的稳健性和局限性。利用传感器获取加速度数据，通过奇异值分解技术获得结构模态参数，并利用模态状态空间方法系统地重构动态特性以获得静刚度。然后，提出了一种利用实测数据和重构数据识别悬臂结构刚度薄弱环节的识别方法。此外，数值与实验结果的比较验证了该方法的正确性和有效性。该研究具有一定的实用工程价值，为机床刚度优化提供准确指导。