| The composite wound shell structure with metal liner had been widely employed in aeronautics, astronautics industry, naval applications, civil structures, and automotive industry. Such as high-pressure vessels, submersibles, ship hulls, bridges, columns, decking and tubes. The wound fabrication of thermoset composite unavoidably undergoes winding, cure and autofrettage process. The stress fields of all these processes are analyzed by numerical simulation in this paper. Furthermore, in designing, one must pay attention to understand its failure mechanism of fracture and/or damage which are generated by low velocity impact by foreign objects during the manufacturing process and/or in the service life, inevitably. So Damage characteristic of composite filament wound vessel with metal liner under low velocity impact is investigated in this paper. And the main contents of this paper are:(l)The thermal parameter method combined with the real - fictitious finite element analysis strategy is developed to simulate the auto-balance stress fields induced by fiber winding pre-tension. And an iterative scheme to establish equal tension state in the wound layers is proposed.(2) Based on the cure kinetic theory and heat transfer theory, a finite element method of Newton-Raphson format is employed to calculate the distributions of temperature and residual stress during the cure process. And the damage status of structures is predicted by using Chang-Chang damage criterion.(3) In order to clearly understand the characteristics and distribution of the process-induced stresses fields especially for inter-laminar stress field of neighboring layers, an analysis of the process-induced stress is conducted on the basis of a systematic Hamiltonian thermo-elasticity theory in conjunction with semi-analytical finite element method. The set of first order ordinary differential vector equation is solved by the precise integration method. Then from numerical results for a typical example of process-induced stress analysis for a composite wound vessel with a metal liner, it is clear that the process-induced thermo-stress fields involve complex variations of gradient and multi-peak values at different stages during the curing process. It is the reason for pre-failure damage of such composite winding layers that results in a reduction of their load carrying capacity.(4) An elastic-plastic finite element method is used to calculate the distributions of residual stress and deformation of the metal liner during autofrettage process after winding. From a typical numerical example, it can be confirmed that the load carrying capacity of the pressure vessel could be improvedby using sound winding autofrettage processes.(5) In accordance with low velocity impact kinetic theory and corresponding damage criterion for the composite laminated structures, a 3-D incompatible finite element method is employed to investigate the impact mechanical behavior of the composite filament cylindrical vessel with metal liner with and without internal pressure and predict their damage distributions during and after impact. A modified Hertzian contact law is used to calculate the contact force between the impact body and impacted cylindrical vessel and a direct integral scheme-Newmark method is applied in time domain during impact analysis process. From the numerical results of a typical vessel, it is clear, with the same kinetic energy, that the impact damage extent for composite filament wound vessel with internal pressure is more server than that without internal pressure under low velocity impact case.(6) The software named WOUNDUSE is programmed to analyze the all stress fields of filament wound composite structure during molding process and service periods.The method and numerical conclusions provided in this paper should be of great value to engineers dealing with composite wound structures.Finally, all works in this paper are summarized and some further investigation contents are also proposed.
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