The Research Of The Safety Performamce For Bladder Type Accumulators

The accumulators is an essential component of the hydraulic system, affects the system’s performance. Because of the simple structure, reliable performance, low energy consumption, convenient inspection and repair, the bladder type accumulator has been used widely. As the bladder type accumulator always work in the alternating load caused by pressure, its shell, support ring and valve body, will usually occur fatigue damage. It is necessary to research on its safety.This paper uses the finite element method to calculate stress and fatigue analysis of the entire shell, the support ring, the valve body and other key components of the bladder type accumulators. Make the statistical analysis of mechanical properties of materials, the burst test and statistical analysis of the shell thickness negative deviation. At the same time, the fatigue test of long period of the bladder type accumulators is carried out, and the fatigue properties parameters of the materials were measured.Throughout this paper, the following results are obtained:(1) Through the calculation of the stress and fatigue analysis of the entire shell, the support ring, the valve body and other key components of bladder type accumulators, the characteristics of the stress distribution of the entire shell, the support ring, the valve body and other key components of bladder type accumulators was obtained. The key point of bladder accumulator for fatigue strength checking was confirmed by the real test.(2) Through the Common condition investigation of bladder type accumulators, statistical analysis of mechanical properties of materials, the shell burst test and analysis of the static strength reliability, the basic information of the current security situation of bladder type accumulators was obtained. After analysis, we propose that the producers and tester should pay attention to the material impact absorption work in the current production situations. As the shell have high static strength and reliability, we can improve the toughness of materials through adjusting the material hardening and tempering process to reduce the tensile strength of material.(3) The low cycle fatigue properties of35CrMo,40Cr steel at room temperature (25℃) were measured through the experiment, gives fatigue design curve of two kinds of steel at room temperature (25℃), provides the fatigue design basis for the accumulators that made of this materials. At the same time, the experiment provides data and suggestions for the existing national standards GB/T20663-2006"Bladder type accumulators " in its next revision.(4) Through the fatigue test, the life parameters of the entire shell, the support ring and the valve body of bladder type accumulators that under the4-41MPa and3-31.5MPa fatigue cyclic pressure were obtained. Through the whole accumulator and shell fatigue test and finite element simulation, the shell of the bladder type accumulators can be used in a long period under the conditions of the alternating pressure to0.5P, while the valve body and a supporting ring cannot be used in a long period, need further improvement...