Structure Strength And Damage Analysis Of Gun Barrel

In order to study the influence of high-temperature, high-pressure and high-speed explosive gas on rapid-firing gun barrel stress when shooting, analysis on the residual stress variation law and the plastic deformation of non-autofrettage barrel and autofrettage barrel in the process of continuous emission is conducted under the pressure of powder gases and thermal stress; based on heat influence playing an important role on barrel strength, and interlayer cooling is an effective way of barrel cooling, analysis on cooling characteristic of this type cooling barrel is conducted under continuous emission; due to repeated heat impact on barrel, crack and part-through slot appeared, analysis on barrel with defeat is conducted. Based on finite element method, every part is researched in the paper using finite element software ANSYS. The primary work and remarks of the paper are as follows:(1)Taking a small caliber rapid firing gun barrel as research object, established the finite element model. The direct coupling method was employed as a solving strategy to simulate the residual stress in the process of continuous emission first, cooling, and continuous emission, cooling under the pressure of powder gases and thermal stress. The conclusion is that the reason why residual stress change, the variation law of residual stress. The repeated changing of plastic strain and residual stress in the inner wall is harmful to the stable of inner wall, puts forward measures to reduce the change of residual stress.(2)Taking a small caliber gun barrel as research object, established the three-dimensional finite element model of interlayer cooling barrel. Use the software of ANSYS module—FLOTRAN to analyze the heat transfer problems of the interlayer cooling based on fluid-structure coupling method, and then analyze the thermal stress of interlayer cooling barrel using indirect method. With air cooling compared, interlayer cooling barrel can reduce the cooling time greatly, so that the time interval of cooling in shooting criterions can be reduced; Increased velocity of cooling liquid would not improve cooling obviously when the velocity exceeds a certain value; interlayer cooling barrel could reduce barrel thermal stress in the process of cooling. This numerical simulation method deal with the fluid-solid boundary conditions for the boundary conditions within, better able to simulate the process of cooling barrel, provides a numerical calculation method for the barrel cooling design. (3)Establish the three-dimensional finite element model of gun barrel with spheroidicity part-through slot, introduced three high efficiency methods to analyze plastic limit load of non-autofrettage and autofrettage barrel. The relation between defect size and limit load is represented through results. It is proved that autofrettage have no or very little effect on increasing limit load of thick-wall cylinder. The method using FE software has advantage to analysis limit load of various structures with complex load.(4)Establish the three-dimensional finite element models of gun barrel with inner axial crack and radial crack individually. The stress intensity factors of non-autofrettage and autofrettage barrel with different size cracks are calculated under static inner pressure. The conclusion is that the bigger the crack size is, the bigger stress intensity factor is; autofrettage could effectively increase the ability of barrel against rupture, the increase to radial crack is less than to axial crack; the barrel with axial crack is more danger than with radial crack.