Modelling of crack propagation in layered structures using extended finite element method

Crack propagation in structuresis animportant issue which isengineers and designersshould consider. Modelingcrack propagation in structures and study the behavior ofthis phenomenoncangive a better insight to engineers and designers forselecting the construction’smaterials. Extended finite element method (XFEM) was used successfullyin the past few years for simulating crack initiation and propagation insophisticatedand complexgeometries in elastic fracture mechanics. In this paper,crack propagation in three-point bending beam includinginitial crackwasmodeled based onABAQUSsoftware.The following consequenceswere attained through the study of simulation data. First,theeffectsof young’s modulus and fracture energy on force-displacementcurve atthree-pointbending beam wereinvestigated.It was observed that,by increasing the value of young’s modulus and fracture energy,three-point bendingbeam was showed more loadcarryingagainst initiation. Second,in multi-layer beam, the effect ofyoung’s modulusonforce-displacementcurvewas investigated.In case I (the thin upper layer is harder than the substrate)the value of young’s modulus in substrate was kept constant and the amount of young’s modulus in thin layer was risenin each steprather than the substrate,the peak in force-displacementcurve wasascendedand three-point bendingbeamresistedbetter against crack initiation. Next,similar conditions was consideredin caseII (the thin upper layer is softer than the ubstrate), by decreasingthevalue of young’ modulusin top layer, peak in force-displacementcurve was declined and crack initiation was happened in lower loadingin eachstep.Finally,sensitivity analysisfor thickness of top layerwas conductedand the impactof this parameter was studied.

Keywords:

Extended finite elementmethod(XFEM) , Fracture , Three-pointbending beam , crack propagation