statement of problem: tooth-coloured restorative materials are brittle with the major shortcomings of sensitivity to flaws and defects. although various mechanical properties of resin composites have been studied, no fracture toughness test data for nano-hybrid composites under acidic condition for a long period of time has been published. objectives: to compare the fracture toughness (k ic ) o...

Bone is a composite material with five distinct structural levels: collagen molecules, mineralized collagen fibrils, lamellae, osteon and whole bone. However, most fracture testing methods have been limited to the macroscopic scale and there is a need for advanced characterization methods to assess toughness at the osteon level and below. The goal of this investigation is to present a novel fra...

changes in moisture content and temperature can perturb both stiffness and strength and as such the impact resistance of composite structures. in this paper, the pre-notched basalt fibre reinforced epoxy (bfre) composite specimens are studied under charpy impact loads in order to investigate the changes in impact energy absorption (fracture toughness) with different kinds of aging conditions. t...

Fracture toughness, strength, and elastic modulus of poly(methyl methacrylate) (PMMA)and poly(buty1 methacrylate) (PBMA)-impregnated alumina ceramics were measured as a function of polymer volume fraction, mean polymer particle size, and interfacial bonding between the polymer and ceramic. Fracture toughness was found to increase with increasing polymer volume fraction and decreasing polymer pa...

The proportional relationships between the Charpy absorbed energy (CVN) and the KIC values have been established for a wide variety of steels. Several formulae have been proposed that predict KIC from CVN. The purpose of this study is to investigate, by means of compact testing fracture toughness specimens, the effective role of microstructure for estimation of the fractur...

In mode II interlaminar fracture toughness tests of composite laminates, the evaluated based on linear elastic mechanics deviates from true due to material nonlinearity matrix. this study, an elastoplastic finite-element analysis was performed a new quasi-static test, i.e., doubly end-notched tension (DENT) investigate difference between perceived energy release rate and J-integral. The effect ...

Introduction: The fracture mechanisms of bone tissue have been described as a damage accumulation process, which starts with the initiation and propagation of microcracks. Knowledge of crack initiation and propagation at tissue level (tissue fracture toughness) is critical to understand and prevent bone fractures. Tissue fracture toughness could provide valuable information for defining bone qu...