Fracture Analysis Of Cracked Plate And Cracks On Bimaterial Interfaces

Since the plate is one of the commonly used structural elements,the analysis of plate members containing through thickness flaws has naturally been a subject of controversy during the past decades. Due to inherent difficulties,despite its practical importance,to our knowledge the subject of plate structures containing crack-like defects and subject to membrane loading and out-of plane loading,special for finite size plate,seems far from being completely resolved.In view of the above-mentioned facts,this thesis presents systematically both linear elastic and elastic-plastic fracture analysis of cracked plate using finite element method ( direct method and J-integral method ),respectively. For the case of LEFM,the main work here is to yield very accurate estimates of the stress intensity factors (SIF) for through-cracked plate,investigate the effect of boundary conditions and loading on the SIF solution for an edge and central cracked finite plate,assess the performance and discuss application skill of several singular isoparametric and transitional elements,etc. It is noticed that,in order to avoid the defect of the classical theory,Reissner's theory which accounts for transverse shear deformations is employed to study cracked plate bending instead of using Kirchhoff's theory. In particular,a path-line-independent J-integral is replaced by a path-domain-independent integral,which not only offers great convenience to program,but also provides effective,available and alternative tool for analysis of any mixed-mode fracture problem and three dimension fracture problem. Similarly,for the case of EPFM,based on incremental-theory plasticity,detailed elastic-plastic analysis of stress state and spread of plastic zone around crack tip in extension is given,and a set ofvaluable conclusions and results are offered.At the same time,a kind of new reliability method is putted forward in this paper,the main idea of this method is that the Rosenblatt transformation is decomposed into mapping transform and orthogonal transform,and then a correlated non-normal random vector is transformed into a independent standard normal vector. This method is used to compare with others,which proves that this method is available.In a word,from the point of view of practical applications,the current mentioned research work could serve as a basis for further study of fracture problem an reliability analysis associated with more complex engineering structures such as stiffened plate and composite micro-structural fracture.