The Stress Analysis Of Damage Autofrettage In Ultra-high Pressure Vessel

Ultra-high pressure vessel is the widespread application equipment in modern industrial and scientific research. In order to increase its carrying capacity and extend its fatigue life, it need to be autofrettaged. Residual stress calculation is the key of autofrettage, and it is very important to calculate the autofrettage residual stress in determination fatigue life, but the research isn't still resolved because of complex mechanical behavior of using ultra-high pressure. The paper introduces the calculation model of autofrettage residual stress on ultra-high pressure vessel, on summarizing the development of ultra-high pressure vessel and present situation of autofrettage. The paper puts forward the damage autofrettage model based on damage theory, by excellence and disadvantage of ideal elastic-plastic model of elastic- plastic theory,unload power law hardness model,two-way power law hardness model,two-way linear hardness model. The paper establishes damage autofrettage model of ultra-high pressure vessel tube, based on material damage constitutive equation, from thermodynamically basis of damage theory and damage variable. Though analysis strengths and boundary condition of autofrettage tube, the stress distribution of damage zone and elastic zone,critical load of damage autofrettage and damage autofrettage press are obtained, moreover, damage autofrettage stress distribution is obtained based on unloading law. The experiment method for measuring the damage variable is researched. Because its stress-strain relationship doesn't obey linear relationship, we can use Laser moiréinterferometry and Tensile test method to measure damage variable on theory experiment by Elastic constants method of measuring damage variable. This can be offer method for measuring damage variable. The regularity of damage variable with radius is researched by experiment data. The function relation of damage variable containing parameters is obtained. The paper validates the damage autofrettage residual stress model, compares calculated residual stress with else models, validates the veracity of damage autofrettage residual stress model.