Mechanical Characteristics Analysis And Optimal Design Of Metal Diaphragm

As the core component of the metal diaphragm tank,the metal diaphragm is prone to the defects like wrinkle,eccentricity and cracking during the overturning process,which cause the overturning failure.The overturning characteristics of the metal diaphragm directly affect the operation of the entire tank.Due to complex configuration and many geometric parameters,there isn't a set of mature standards for the diaphragm design at present.Therefore,it's very necessary to do systematical research on the overturning law and failure cause to provide technical support for the design of tank diaphragm.In this paper,the metal diaphragm is taken as the research object,and the overturning characteristic and optimum design are focused on.The main work and achievements are as follows.Aiming at the disadvantage of poor convergence in existing method,the dynamic explicit simulation method is proposed for the simulation of diaphragm overturning.The result of dynamic explicit simulation is verified by comparison with the result of arc length method which is based on quasi-static analysis and the experimental result.The effect of inflation speed on the differential pressure cure and eccentricity degree during the overturning process is studied using the proposed method.The proposed method solves the convergence problem existed in the present method,so it provides an important simulation way for the design of metal diaphragm.The method to design the geometry parameter of cone-bar diaphragm,ellipse-bar diaphragm and spherical diaphragm under a certain volume of tank is proposed.And the accuracy of the method is verified by the simulation result.Under a certain volume of tank,the influence of bar angle,arc segment and radius of the diaphragm on the overturning effect is researched.Aiming at the overturning failure problem,the change regulation of the buckling load and reason of the failure during overturning is explored by buckling analysis.The influence of geometric parameters on the cone-bar diaphragm overturning effect are studied by the method of range analysis.And the variables of multi-objective optimization design is determined refer to the range analysis result.A RBF approximate model of diaphragm overturning is established,and the genetic algorithm is used to optimize the model.The overturning effect is greatly improved after optimization,so the feasibility of the method in diaphragm optimization design is verified.The modeling method of tank filled with liquid propellant is proposed,and the finite element model of tank under different working condition is established.Using the established model,the effects of propellant consumption on the dynamic of the diaphragm are studied by modal analysis and random response analysis.