Reliability Design Of Pressure Vessel And Its Application On Solid Rocket Motor Vessel

The basic needs of pressure vessel design is safety and economic. The safe is premise and the economy is aim. The aim of economy may be meeted in the premise of safe. At present, according to the international norm of pressure vessel design the safe coefficient method is main current in either the normal design or the analysis design. Various parameters such as strength of material, size of parts, and loads have been regarded as fixed parameters in the norm. The random changes of the parameters are ignored with the change of various condition and the values of parameters are conservatively selected. So that the sizes of the pressure vessels and the parts designed are larger and the design is not economic. Frequent accidents showed that high safe coefficient and high reliability are not same. Besides, fixed design methods have been using same safety factors for different important pressure vessels. So the conventional fixed design methods are not reasonable. With improving manufacturing technologies of row materials and process equipments as well as controlling methods of using process equipments, reliability design of pressure vessels which regards strength of material, size of parts, and loads as random variables will plays an important role in using pressure vessels. So pressure vessel design using reliability concept is very important.According to the above conditions the reliability calculation formulas of various shells of revolution were conducted in the dissertation. The reliability of the uncontinuous structure of pressure vessels were calculated by Random finite element analysis. And the method was applied to reliability design of solid rocket motor vessel. The main contents are as follows,1. The reliability formulas of cylindrical shells with internal pressure based on the various failure norm as well as various strength theories of same failure norm were conducted by the second moment method. Then they were applied to an engineering case. The reliability design of cylinder vessels with internal pressure was compared with the rule design. And difference of various reliability formulas of cylinder vessels was found. At last selecting reliability formulas regularity vas proposed.2. The reliability formula of spherical shells, and ellipsoidal heads, and dished heads, and conical shells based on the non-moment theory were conducted by using the second moment method. The reliability formula of various based on the plate theory were conducted by using the second moment method.3. The model of an uncontinuous structure of pressure vessel was created by parameter mode of ANSYS software and analyzed by random finite element analysis. Not only the reliability of the structure was calculated, but also the sensitivity of the maximum stress (Von Mises SEQV) and the performance function were analyzed.4. The solid rocket motor metal vessel was analyzed by random finite element. Not only the reliability of the vessel was calculated, but also the sensitivity of the maximum stress (Von Mises SEQV) and the performance function were analyzed in order to provide a reference for optimization design of the structure.5. The reliability safe coefficient of Carbon Fiber Reinforced Plastics solid rocket motor vessel based on the non-moment theory and the net theory was conducted. Eight carbon fiber reinforced plastics (CFRP) pressure vessels were manufactured and the experiments were conducted to obtain the probabilistic distribution of design variables, such as the fiber strength, winding angle, geometric size, burst strength and so on. The fiber thickness was calculated by using the reliability safe coefficient formula.