Abstract:

Revolute joints and sliding joints are essential mechanical elements connecting moving parts of machineries. When implementing the whole machine/global modeling, the connection joints and their local detailed geometric features are usually simplified in order to improve the computational efficiency and avoid convergence difficulties. These kinds of simplification strategies may lead to the problem that the accurate stress in the vicinity of the simplified local regions could not be obtained from the analysis of the global model. In such cases, subsequent sub-modeling analyses are usually employed to obtain the accurate stress results in these regions. Simplification of the local features in the model may sometimes result in significant changes in stiffness of these local regions. When traditional interpolated displacement type of boundary conditions are used to indirectly apply loading to the sub-model, the actual loading added to the sub-model boundary could be much different to the loading derived from the global model due to the stiffness error of the global model. In contrast to applying the displacement boundary condition, a method of directly implementing forces to the sub-model cut-boundaries has been proposed in this paper. These forces applied to the cut-boundaries could be obtained from the analysis results of the global model. Numerical analysis results have shown that the newly proposed sub-modeling technique can load the model more accurately than the traditional sub-model method and the analysis accuracy is not sensitive to the degree of simplification of the global model. The predicted stress results for a telescopic boom of a truck-mounted crane have also been validated by experimental results.