Contact characteristic analysis of bolted joint on machine tools considering temperature effect

Bolt connection is widely used in mechanical equipment and has a significant effect on the mechanical properties of the whole structure. Due to the difference in thermal expansion coefficient of bolt rod and the connect structures, the thermal deformation of bolt rod and connect structures caused by temperature change will change the bolt preload, thus affecting the contact characteristics of the contact surface and the dynamic characteristics of the whole structure. This paper studied the influence of temperature on the contact characteristics of bolted structures based on finite element analysis. The iron material which widely used in machine tools is taken as an example and the contact characteristics of connecting plate thickness, bolt diameter, bolt preload coupling with temperature are studied. The contact characteristics parameter database of bolts was constructed by Kriging interpolation method. The results show that when the thickness of the connecting plate is small, the influence of temperature change on the contact characteristics is not significant. While the change of the contact area and contact pressure will be significantly increased by temperature change when the thickness of the connecting plate increases to a certain value. The temperature change will affect the size of contact area and the average contact pressure when the preload is small, while this influence is not obvious when the preload increases to a certain value.