| The hydraulic-powered supports are used to assure the safety and success of the production in modern high-yield and high-efficiency coal mine. To assure the quality of design and manufacture, we need to obtain the stress and strain data under various kinds of operating modes. For the traditional 'simplified model and laboratory strength test' method has shortcomings -such as lack of accuracy, less experimental data, time consuming and so on-, researchers and engineers began using Finite Element Method in the analysis of the support's strengths in recent years. Now, the design of hydraulic support is no longer a process of simple calculations like before; it has stepped into a new stage of leanness and informationization. However, most of their analyses have neglected the effect of welding process. In fact the support often breaks near the welding line, suggesting that the welding process has an evident effect on the strength. So these analyses may have low reliability.In view of the above-mentioned circumstances, based on the heat-transfer theory and thermal-elasto-plastic mechanics as well as the finite element method, this paper analyzed the welding residual stresses on the main roof beam of the support; then analyzed its strength under dangerous working conditions; and finally compared it with analysis which didn't take the residual stresses into account, thus we could see how the residual stresses will affect the strength.This paper will introduce the theory of welding residual stress, the temperature analysis and the residual stress analysis techniques, as well as the related heat-transfer theory and mechanics; study and discuss the analysis strategy of the residual stresses, the simplification of analysis models, the choice of the heat source type, the simulation of heat-treatment, and the method to introduce the residual stresses into the strength analysis; and also discuss the result with theoretical and experimental data; at last, point out the merits and the deficiencies ,as well as the prospect of this field. All theses thing are described in six consequential and logical-orderly chapters. |
