Physical Parameters Characterization Research Of Mechanical Joint Interface On Thermo-mechanical Coupled Loads

Joint interface characteristics are of great importance to the whole machine tool dynamicbehavior. Traditionally, study of mechanical joint interfaces were mainly focused onmechanical behavior or thermal behavior separately, while in fact, they couple tightly. Now,there lacks sufficient physical parameters characterization research of mechanical jointinterfaces on coupled loads of force and heat. In this dissertation, a new modeling methodconsidering the coupled effect is presented. The main content is as follows:First, based on heat transfer mechanism, thermal parameter characterization onmechanical joint interfaces is studied. Two rough surfaces do not contact completely. Theactual contact area is much smaller than the apparent area, so there are thermal contactresistance (TCR) on mechanical joint interfaces. Fractal models of constriction resistance,bulk resistance and other resistances are modeled respectively.Then, joint interface physical parameter characterization is finished, combined with thepast study on mechanical behavior modeling and thermal characteristics research in thisdissertation. By adopting virtual material layer method, thermal and mechanical coupledcontact behaviors are transformed into material properties. Compared with weak coupling,strong coupling’s advantage is analyzed in mathematical principles.Finally, the strong coupled model is verified on a specimen and high-speed electricspindle on computer numerical control (CNC) machining center. From comparison betweenexperiment data and simulation results of the specimen under differ load conditions, thestrong coupled model’s validity is proved. The effect of thermal load to mechanical behaviorand the effect of mechanical load to thermal behavior are reflected. This new coupled modelis more accurate than traditional coupled model. The dissertation’s result may be useful to theprecise model of whole machine tools.