General Twin Shearing Hydrostatical Stress Fracture Criterion And Experimental Investigation Of Structural Steel

In many situations,structural steel did not over load when brittle fracture occurred. Destroy usually was magnitude which all engineering areas demand avoiding.Theory of metal intensity and study of damnification mechanism and rupture mechanism can not solve this question of brittle fracture.There are great significance and value of engineering application to create affective fracture criterion on combination of micro and macro mechanism.War industry,mechanism and aviation have the same explanation to the problem of brittle fracture.The study will extend to some other areas which was elicited by fracture problem.This will be a comprehensive subject which refer to many sciences including material mechanism,damifacation mechanism,rupture mechanism,elastic mechanism and so on.Damage model strongly depends on stress condition.Experiment reveals that fracture ductility decreases as the stress triaxiality increases.Material whose stress triaxiality is a little higher tends to brittle fracture.From the angle of stress condition, high stress triaxiality led by strong restriction is the critical factor which leads to the material brittle fracture.To study rupture mechanism and fracture design of metal, fracture tests and numerical simulations were performed on ten structural steel tubes with circular holes and ten notched bars.Results of numerical analysis tallied with the tests.Experimental results supplied objective evidence to investigate rupture mechanism and fracture design theory of structural steel.General twin shearing hydrostatical stress fracture criterion was advanced by research on fracture of structural steel in this paper.The fracture criterion successfully predicts the fracture of the tests which include notched bars tests,structural steel tubes with circular holes and notched plates tests.The criterion is convenient to apply in the field of engineering.It is a pity that this criterion was only applied in the scope ofσ_m＞0.Therefore I should achieve a lot to modify this fracture criterion in future.General twin shearing hydrostatical stress fracture criterion which is available was advanced by the study about structural steel.This fracture criterion will popularize to other areas to solve practical engineering problems.Of course,many difficulties will appear in view of referring so many subjects.