For composite structure, fracture toughness is a dominant parameter when using cohesive laws to predict the nominal strength. In the present study the compact tension test is performed on composites structures and is simulated using FEM. The process of fracture takes places in two sequential stages, crack initiation and crack propagation. The critical energy release rate is determined using the...

Silk fibres from silkworm cocoons have lower strength than spider silk and have received less attention as a source of high-performance fibres. In this work, we have used an innovative procedure to eliminate the flaws gradually of a single fibre specimen by retesting the unbroken portion of the fibre, after each fracture test. This was done multiple times so that the final test may provide the ...

Fish scales from modern teleost fish are high-performance materials made of cross-plies of collagen type I fibrils reinforced with hydroxyapatite. Recent studies on this material have demonstrated the remarkable performance of this material in tension and against sharp puncture. Although it is known that teleost fish scales are extremely tough, actual measurements of fracture toughness have so ...

Endovascular stents made of the superelastic nickel-titanium alloy Nitinol are subjected in service to tens of millions of loading cycles and even "single-event" overloads, both of which can potentially result in fracture and/or complete failure of the device. A fracture-mechanics-based methodology can provide a means to quantify relevant material parameters critical to the design against such ...

OBJECTIVE To investigate the reinforcing effect of short E-glass fibre fillers on fracture related mechanical properties of dental composite resin with a semi-interpenetrating polymer network (IPN) polymer matrix. METHODS Experimental short fibre composite (FC) resin was prepared by mixing 22.5 wt% of short E-glass fibres, 22.5 wt% of IPN-resin and 55 wt% of silane treated silica fillers usin...

Geopolymers are known as high strength and durable construction materials but have a brittle fracture. In practice, this results in a sudden collapse at ultimate load, without any chance of preventing the breakdown of parts or of withstanding the stress for some time. Glass fiber usage as a total anisotropic shape acting as a compact structure component should hinder the fracture mechanism. The...

The use of high performance composite materials provides a substantial performance improvement for microrobotics. Such materials have great benefits over common MEMs materials such as better fracture toughness and fatigue properties than semiconductors, and higher stiffness to weight ratios than most metals. Composite structures yield remarkable improvements in microrobotic links and joints, as...

the use of methods employed for estimating the strength and toughness of composites reduces the trial-and-error in their design. the strength of interface between reinforcement and matrix and the effective surface of pulled-out particles have great influences on toughness and strength of these composites. in this study, a model was proposed to estimate the interface strength and matrix strength...

The mode II initiation fracture toughness of wood was measured by the three-point bend endnotched flexure (3ENF) test for various crack lengths, and the dependence of toughness on the crack length was analyzed by the four conventional methods of data reduction : elementary beam theory, Williams end correction method, and two compliance calibration methods. In addition to these methods, the comp...