| As a traditional fastening method,bolted connection is widely used in all kinds of mechanical structures,especially in the aerospace fields.The quality of bolted connection structure is very important to the overall performance of mechanical equipment,and has an important impact on the key performance of assembly components,such as stiffness dispersion,structural stability and durability.Aiming at the typical bolted connection structure of aero-engine,the evolution mechanism of joint stiffness considering the non-parallel contact of bolt joint support surface and the influence of other geometric and material characteristics on the joint stiffness of bolted connection structure are proposed.The geometric deviation of the joint surfaces between the bolt and the connected parts are represented as the non-parallel bearing surface of the bolted joint.The simulation models of the two kinds of bolt connection structures under tension and tightening loads are established by using Ansys Workbench.By changing the non-parallel angle between the nut and the connected parts to simulate the effect of accumulated geometric deviation,and decomposing the non-parallel angle to analyze the mechanical properties of the bolt connection structure.The variation law of the joint stiffness caused by the discrete preload of the bolt under non-ideal contact and the influence of geometric characteristics,material properties and friction coefficient on the joint stiffness are revealed.The mapping relationship between the influence factors and the connection stiffness is established.The stiffness of bolted joints is divided into three parts: the stiffness of the joints,the stiffness of the screw and the stiffness of the threaded region.The composition and range of stiffness are analyzed quantitatively.At the same time,the coupling effects of the cross-influence of some variables on the joint stiffness are also explored.In this paper,the stiffness of bolted connection structure are mainly discussed from the aspects of stiffness theory,finite element simulation analysis and bolt stiffness test,which can provide reference for the design of bolted connection structure and the evaluation of service performance. |
