Establishment and Verification of Nonlinear Bolt Head Connection Stiffness Theoretical Model Based on Levenberg-Marquardt Method

Although some scholars have established the calculation method of bolt head connection characteristics, the method contains fewer influence factors; the calculation accuracy is not high, and the general applicability is limited. Based on the Levenberg Marquardt optimization algorithms, a more accurate calculation model of bolt head connection stiffness is proposed in this article. The model includes many parameters such as bolt head thickness, equivalent diameter, bolt diameter, thickness of connected parts, elastic modulus of bolt and elastic modulus of connected parts. Through the finite-element verification and comparison with the results of the Fears Alkatan method, the calculation results of the bolt head connection stiffness calculation model in this article are effective and accurate, which provides a universal calculation model for calculating the bolt head connection stiffness of various parameters, and fills the shortage of inaccurate calculation of the current theoretical model of bolt head stiffness.