The Mechanism And Simulation Research On Thermal Deformation Of Mechanical Parts

As the need for precision increases, thermal influences tend to become dominant. The research on the theory and application technology of mechanical parts thermal deformation is beneficial to minimize the impact of temperature, which has important scientific and practical engineering value. Supported by the National Natural Science Foundation of China (No.51175142) and Major Program of National Natural Science Foundation of China (No.51490660/51490661), the mechanism and accurate simulation of thermal deformation of mechanical parts is systematically studied in this paper. The main work of this paper is as follows.Firstly, the objective existence of dissimilarity of mechanical part thermal deformation is demonstrated from the view of mechanism. The atomic model of cube aluminum material at microscopic level was built and solved by using the molecular statics theory and algorithms. The objective existence and formation mechanism of dissimilarity of mechanical part thermal deformation are demonstrated, which makes up defect of demonstrating it only by macroscopic experiment and perfects the mechanical parts thermal deformation theoretical foundation.Secondly, an accurate simulation method of thermal deformation based on theory of conversion of thermal into mechanic is proposed for simulation implementation of thermal deformation at macroscopic level. To make up the defect that the dissimilarity characteristics of thermal deformation is ignored in traditional simulation algorithm and CAE software, the theory of conversion of thermal into mechanic is proposed, which equates thermal deformation of the part with force deformation. In this method, the effect of material properties, temperature and boundary constraints of shape on thermal deformation were taken into account fully. The simulation and measurement experiments of thermal deformation of hollow cylinder parts were carried out. Simulation results consistent with the experimental results very well and validates the rationality of our theory and simulation method.Thirdly, the thermal robust structure design concept is proposed and applied. The influences of temperature and force on the fit of hole and shaft part are taken into account fully and compensated in the dimensions and tolerances design of hollow and shaft parts to guarantee machinery and equipment meeting the design accuracy and optimum performance under working conditions, which is called the optimal thermal robust structure design of hole part and shaft part in this paper. According to this concept, dimensions and tolerances of the pump plunger and barrel are designed to avoid stuck, while obtaining optimal work efficiency.