The Ultimate Load Of Thin-walled Cylindrical Shells Containing Cracks Under Combined Fracture-buckling Failure

With the rapid development of various industrial technologies such as modern architecture,thin-walled steel components are widely used in practical projects due to their characteristics of energy saving,material saving,environmental protection and good comprehensive benefits.However,there will always be cracks in the actual processing and use,and cracks are the most common defects in most members.Under the influence of external loads and other factors,cracks will further expand,resulting in component fracture,leading to a significant reduction in ultimate bearing capacity,and even directly endangering the safety of relevant structures.And because the section size of thin-walled steel members is obviously larger than the wall thickness,there are obvious problems in the stability of thin-walled steel members.However,the influence of cracks on the ultimate bearing capacity of thin-walled members is rarely studied when the stability of thin-walled members is studied.At present,a key topic in the field of engineering application and structural design is to study the ultimate bearing capacity and fracture mechanical properties of cracked members,which is also the theoretical basis of safety assessment and design.In this paper,the possible failure modes and ultimate loads of thin-walled cylindrical shells with cracks under three load modes of axial tension,axial compression and bias are analyzed.Based on J integral theory,the finite element method is used to solve the stress intensity factor at the crack tip under axial tensile load,and K criterion is used to judge whether the crack is extended and damaged,and the ultimate load of the thin-walled cylindrical shell containing the crack is determined by the criterion.Under axial load,the ultimate load of thin-walled cylindrical shell with crack under buckling failure is calculated,the influence of relative crack length and equivalent length to fineness ratio is analyzed,and the approximate formula of ultimate load of thin-walled cylindrical shell with crack under axial pressure is obtained by fitting the simulated data.The critical ultimate load of thin-walled cylindrical shell with crack under eccentric load is solved,and the failure mode when the ultimate load is generated is analyzed.The results show that these factors greatly influence the critical ultimate load and interact with each other.