Silicon carbide (SiC) is one of the advanced engineered ceramic materials designed to operate in extreme environments. One of the main reasons for the choice of this material is due to its excellent electrical, mechanical or optical properties that benefit the semiconductor, MEMS and optoelectronic industry respectively. Manufacturing this material is extremely challenging due to its high hardn...

OBJECTIVES This study evaluated the impact and flexural strength and analyzed the fracture behavior of acrylic resins. METHODS Eighteen rectangular specimens were fabricated of Lucitone 550, QC 20 (both unreinforced acrylic resins), Impact 1500 (extra strength impact), Impact 2000 (high impact) according to the manufacturers' instructions. The impact strength was evaluated in notched specimen...

Residual stress present in coupons used for fracture testing will influence the experimental determination of fracture toughness. Triaxial residual stress (e.g., due to welding) can alter both the driving force for fracture and the crack-tip constraint at a specified load, so that the apparent toughness of a coupon depends on the residual stress present. In this paper, we employ a micromechanic...

A traction-displacement relationship that may be embedded into a cohesive zone model for microscale problems of intergranular fracture is extracted from atomistic molecular-dynamics simulations. A molecular-dynamics model for crack propagation under steady-state conditions is developed to analyze intergranular fracture along a flat Σ99 [1 1 0] symmetric tilt grain boundary in aluminum. Under hy...

We have demonstrated the ability to perform a ductile material removal operation, via single-point diamond turning, on single-crystal silicon carbide (6H). To our knowledge, this is the first reported work on the ductile machining of single-crystal silicon carbide (SiC). SiC experiences a ductile-to-brittle transition similar to other nominally brittle materials such as silicon, germanium, and ...

the premature breakage in some four cylinder diesel engine crankshafts was reported. all crankshafts were failed from the same region. failures had occurred in the first crankpin, the nearest crankpin to the flywheel. dynamic analysis and finite element modelling were carried out to determine the state of stress in the crankshaft. fem results revealed that the first crankpin fillet is the most ...

Recent developments in fracture dynamics include the discovery of elastic waves which propagate along moving crack fronts in three-dimensional solids, and the identification of possible sources of the roughening and low terminal speeds of tensile cracks in brittle amorphous solids. Those topics are discussed briefly here.