Computer Simulation of Nonlinear Thermoelastic Behavior of a Joint in Machine Tool Structure and its Effect on Thermal Deformation

Analysis of a computer simulated case study of the nonlinear thermoelastic behavior of the joint between the column and the knee in a milling machine is presented. Significance of this behavior on the thermal deformation of contacting structural elements is evaluated. Computer simulation is performed by applying the approach based on recognition of interactions taking place at the joint. Through successive iterations, a convergence to the state of equilibrium is reached. Convergence is verified on a simplified model. The results indicate the significance of considering the behavior of the joint in predicting the thermal deformation, as the effect of this behavior extends throughout the structural elements. For the case under study, deformation of the structure differs noticeably from that without considering interactions at the joint. Distribution of the contact pressure, thermal contact conductance and heat flux along the joint indicate high degree of nonuniformity, which is responsible for the effect the joint has on the thermal deformation. Convergence to the state of equilibrium is reached in an oscillatory manner, as shown by the deformation of the knee. The simulated case is treated under the steady state conditions, however the approach can be extended to the transient state as well.