Regression Analysis On Formula Of Stress Concentration Coeffient And Hoop Stress Of Weld Sphercial Shell Of Welded Hollow Spherical Joints

With the promotion of suspended crane were used in factory building, the faigue problem about space grid design is becoming more and more popular. The welded hollow spherical joints, as a common used form of j oints, has been widely used in the space grid engineering. The reason of fatigue failure is numerous of crack, the location of crack is always the region of stress concentration, so analysis about stress concentration is b ecoming the significant link of the whole research. Moreover, hollow sph ere is always connected wth more than one pipe, acquaintance of knowle dge about regular of sphere surface stress distribution can help caclulation of surface stress superpostion on multipiped hollow spherical joint.Based on the problem of stress concentration coefficient of welded hollow spherical joints and the problem of regular about stress distribution on sphere shell, the paper carried out the following research work:1,Based on the study of pipe—welded hollow spherical joints commonly used in engineering, which meet the specfiction,the paper used ANSYS to simulate diffierernt geometry parmeters types of axial compression welded hollow spherical joints by solid 45 element. and carried out the following conclusions:1) the author used different types of welded hollow spherical joints model to got the rule of the three dimensional stress distribution of sphere shell and stress concentration coefficient;2) the paper used the regression analysis to fit the formula Kt(T), Kt(t), Kt(D)and Kt(d);3) the paper used the multipleregression analysis to gaine the formula of stress concentration coefficient Kt= f(D,d, t, T).4) the paper used the comparatativ stuy to analyze the diference of inner surface stess and outer surface stress, and fit the hoop stress formulaσφ,=f(sinθ).2,based on steel tube-welded hollow sphere connection joints, the author has conducted the static load test research, and gained the following conclusions:1) Though the test data aquistion,the author got the rule of the stress distribution of joints;2) the paper gained the numerical solution of stress concentration.2) the author has carried on the contrast to the theoretical analyses and the test results of stress concentration coefficient, results showed that the theoretical value of test node stress and the measured value exist error, and an analysis of the causes of errors.Through the research and analysis of this paper, it will offer the useful method of fatigue design by hot spot stress amplitude, and give surport to calculate the stress of multipiped welded sphere jonts.