囊式蓄能器壳体静力强度可靠性分析

文章通过对宁波奉化地区生产的囊式蓄能器的调研,测试了壳体材料35CrMo钢的力学性能、壁厚,对成形壳体进行了爆破压力测试,测试统计结果表明材料的抗拉强度、壁厚负偏差率和爆破压力指标基本符合正态分布规律.按正态分布拟合函数对抗拉强度、壁厚负偏差率和爆破压力进行了可靠性分析.统计分析结果表明抗拉强度的期望值μr为999.9 MPa,标准差σr为33.1 MPa;壁厚负偏差率的期望值μΔt为-0.056,标准差σΔt为0.026;爆破压力的期望值μpb为117.5 MPa,标准差σpb为9.75 MPa.基于上述分布规律及可靠性分析表明,囊式蓄能器壳体静力强度失效概率约在10-10以下.

Reliability Study on Static Intensity of Bladder Type Accumulator Shell

Investigation on the bladder type accumulators produced from Fenghua, Ningbo was conducted. The shell of the accumulators was made of 35CrMo steel. The mechanical property and the thickness of the 35CrMo steel sheet were measured. Blasting test was conducted for the shaped shells. The measured results reveal that the tension strength, the negative deviation ratio of the material and the blasting pressure of the shells nearly follow a normal distribution law. Reliability study on the tension strength, the negative deviation ratio and the blasting pressure was performed according to the normal distribution function. The results illuminat that the mathematical expectation/xr and standard deviation σr are μr = 999.9 MPa, σr = 33. 1 MPa for the tension strength,μ△t = - 0. 056, μ△t = 0. 026 for the negative deviation ratio and μpb = 117.5 MPa,σpb = 9.75MPa for blasting pressure respectively. When loaded with static pressure, the failure probability of the accumulator shell would be less than 10-10.