Applying the new experimental midpoint concept on strain energy density for fracture assessment of composite materials

A mixed-mode I/II fracture criterion for predicting the response of composite materials is proposed. This derived based on a comprehensive study and consideration physics onset. The phenomenon that causes various damage mechanisms at vicinity crack tip examined. It elucidated stress distribution ought to be defined using reinforcement isotropic solid (RIS) state. new criterion, which called Improved Strain Energy Density with Mid-point (ISEDM), includes effect process zone (FPZ) T-stress, remarkably affect process, particularly, when mode II dominant. Substituting strain energy density in pure I midpoint creative idea employed proposing this criterion. Because effects FPZ are minimal, change fitting point limit curve (FLC) from KIc critical intensity factors (CSIF’s) makes it possible consider more accurately. In ISEDM behavior depends mechanical properties CSIF’s midpoint. Crack initiation angle considered along minimum I/II. RIS theory used as an applicable modeling orthotropic paper valid reliable extracted. addition, changing mid-point experimental data without estimating toughening zone, extracted higher accuracy. FLC’s comparison available prove anticipates well. Finding KIIc analytical method valuable achievement. article, can predicted appropriate accuracy, only by