initial cracks occur in high strength concrete sleepers for various reasons, such as shrinkage and wrong curing and long lifetime of over 50 years of sleepers. these cracks may lead to complete failure of the structure. in order to more accurately design the sleepers, fracture mechanics (not strength of materials) should be incorporated. in order to achieve this purpose, it is important to fore...

The industrially-important WC-Co composite materials provide a useful, albeit complicated materials system for understanding the combined influences on hardness and strength properties of the constituent WC particle strengths, the particle sizes, their contiguities, and of Co binder hardness and mean free paths, and in total, the volume fraction of constituents. A connection is made here betwee...

The marginal fracture toughness of several types of composite resins was determined by means of the rattler test. Microparticle-filled resins showed significantly higher marginal fracture toughness than conventional composites. Posterior restorative composites were intermediate between MFRs and conventional composites. Amalgams were inferior to restorative resins. These data correspond with the...

The fracture behaviour of polymers is strongly affected by the addition of rigid particles. Several features of the particles have a decisive influence on the values of the fracture toughness: shape and size, chemical nature, surface nature, concentration by volume, and orientation. Among those of thermoplastic matrix, polypropylene (PP) composites are the most industrially employed for many di...

Interest in natural fiber polymer composite has increased worldwide due to their low cost, low density and good thermal resistivity. Sisal fiber is used as reinforced in mat form and epoxy as matrix in this composite. In present work, thermogravimetric analysis and fracture behavior of composites were studied. The percentage mass loss and physical changes of composite was observed through furna...

Many composites fail by fracture events, such as fiber breaks or matrix cracks, rather than by continuous crack growth. Conventional fracture mechanics deals with predicting crack growth. This paper suggests that conventional fracture mechanics can be extended to predict fracture events by using finite fracture mechanics. In finite fracture mechanics, the next fracture event is assumed to occur...

Al2O3 ceramic reinforced with 4-wt% multiwalled carbon nanotube (CNT) is plasma sprayed for improving the fracture toughness of the nanocomposite coating. Two different methodologies of CNT addition have been adopted in the powder feedstock to assist CNT dispersion in the nano-Al2O3 matrix. First, spray-dried nano-Al2O3 agglomerates are blended with 4 wt% CNT as powder-feedstock, which is subse...

The fracture toughness of snow in shear is one of the most relevant parameters when studying the mechanics of snow slab avalanche release. Double-cantilever snow beams were loaded asymmetrically to determine K(IIc). If crack surfaces touch under applied pressure, the fracture toughness in shear of snow (rho=247 kg m(-3)) is K(IIc)=680+/-60 Pa m(1/2). Screening of the stress intensity at the cra...

The objective of the work was to investigate statistical analysis of fracture toughness of the glass fiber reinforced composites at different stacking sequences, strain rate and crack length. The glass reinforced vinylester composites prepared by hand layup technique with stacking sequences of 0/90, 45/-45 and chopped strand orientations. 3point bending for fracture toughness test for various n...

page 62 Abstract: A fiber pullout test for examining controlled interfaces in fiber reinforced polymers has been designed and demonstrated. This test has been utilized in determining interfacial fracture toughness for sapphire/epoxy single fiber composite specimens. Some of these specimens incorporated a self-assembled monolayer at the sapphire/ epoxy interface as a means of adhesion control—th...