Structure Analysis And Optimized Design Of Fully Wrapped Carbon-fiber Reinforced Aluminum Lined Composite Gas Cylinder

With the advantages of a strong bearing capacity,a light weight and a high safety performance,the fully wrapped metal-lined composite gas cylinder has been widely used in many fields.Therefore,it has a significant theoretic meaning and an engineering application value to carry on a mechanical analysis as well as an optimized design to a composite gas cylinder.However,considering the present research situation,it is relatively rare about the study on the stability numerical analysis to a composite gas cylinder.Because the structure of composite gas cylinder is complicated,lots of factors can impact its performance.This paper are mainly studied on the following four aspects:1.The mechanics analysis of filament winding composite gas cylinder.According to the stress features of composite gas cylinder and under the condition of non-losing stability of the liner,a calculation formula is derived in this paper for the minimum bonding strength between the internal liner and the filament wound case to various types of cylinders.The conclusion shows that both the material of internal liner and the length-diameter ratio have a great impact on the stability of the internal liner.And a structural design to filament wound composite cylinders has been conducted on the basis of the grid theory.2.The finite element analysis of the fully-wrapped composite gas cylinder.A parametric finite element model,which has a maximum consistency with the mechanical characteristic of the composite gas cylinder,is established by the software of ANSYS Parametric Design Language(APDL).In this model,considering the impact of autofrettage pressure,various of thickness and angles for the fiber layer of the sealing heads have been implemented.And then the transient dynamic method is used to simulate the pressure loading and unloading processes for the model.An analysis is conducted to the model on different work conditions,and the results indicate that the stress distribution level and the failure mode of the models are complied with the DOT-CFFC Standard.3.The optimization of autofrettage pressure.With the specification referred in the DOT-CFFC Standard and the stress level of composite gas cylinder on different working conditions,the dichotomy method is adopted to define the scope of autofrettage pressure.So the optimization is realized by choosing out the best autofrettage pressure according to the stress distribution of the model under the working pressure.4.The analysis on the autofrettage pressure and the nonlinear of lining material.Based on the above finite element models,the stress impacts on the internal liner and the fiber layer by four different models of composite gas cylinder under the combinations of two types of autofrettage and nonlinear of the internal liner has been discussed.The results show that the autofrettage can effectively reduce the stress level of the internal liner under the working pressure and increase the utilization rate of the fiber layer.However,the autofrettage has no relationship with whether considering the nonlinear of internal lining material or not.Under the work pressure,the nonlinear of internal lining material has no obvious impact on the stress between the internal liner and the fiber layer without the autofrettage.But with the autofrettage,the nonlinear of internal lining material has an obvious influence on the stress of the internal liner,contrarily it has little influence on the stress of the fiber layer.