Strength Analysis Of Large-scale Hydraulic Support Roof Timber

Hydraulic support is the main mining automation equipment in China, and the roof timber is the main structural parts of hydraulic support. Because formulas of mechanics of materials is commonly used in the design of the strength of hydraulic support, the stress distribution can not be got in detail, and the influence of the weld on the stress can not be investigated. ZY8640/24/50 hydraulic support roof timber is simulated by finite element method in the article. The difference from the common numerical simulation of hydraulic support is that the model of the roof timber is include the weld, so this calculating model can more realistically reflect the real working conditions and stress distribution. According to finite element results, the stress of the roof timber is evaluated, and a comprehensive stress concentration factor of weld and a estimating formula of weld average stress are proposed.First, the calculating methods of the roof timber weld are discussed. The T-shaped welded joint model is simulated in the multi-condition by using finite element method. Basing on calculated results, a comprehensive stress concentration factor of weld and a estimating formula of weld average stress are proposed.The strength of two kinds of roof timber A and B with weld are analyzed in three working condition by finite element method, and the weld stress are investigated. According to the calculated results, the strength of the roof timber are checked and the evaluation proposals are put forward. It can be seen that the stress in most region of the roof timber of the main structure is lower than 460MPa, so the strength in most regions of the main structure and the weld of the roof timber have certain amount of surplus. Adopted measures of local strengthen, the strength level of the base material can be lowered, thereby, production cost is reduced.Basing on the calculated results of the roof timber A, the average stress of the weld of the roof timber B is estimated by the estimating formula of weld average stress. Through comparing and analyzing the results of finite element results and estimated results of the roof timber B weld average stress, the comprehensive stress concentration factor of weld and the estimating formula of weld average stress are verified numerically. The results show that the estimated results are in good agreement with the finite element results and the maximum discrepancy is 6.35% which can meet the design requirements. A new way of thinking of hydraulic support design is proposed, which can shorten product development cycles and save product research fundings.