background: the main purpose of this study was to determine the relationship between serum vitamin d and the status of bone mineral density in patients with low-energy hip and distal radius fracture. methods: this retrospective case-control study was performed between january 2013 and january 2014. participants aged 55 years or older were divided to case group including 85 patients with low-ene...

in this paper, the mean value of strain energy density criterion has been used to predict the critical fracture load in specimens with u-shaped notch under bending loads. an equation for calculation of averaged strain energy density in this zone has been presented. bending loads under mode i have been considered. two cases have been studied: 1) the control volume only includes the semicircular ...

The fracture mechanics examines the development and expansion of cracks in solids and how they affect the deformation of materials. The stress intensity factors at the tip of the crack and the critical stress intensity factors or fracture toughness of materials are considered in the relevant criteria. There are three main modes of applying forces to a crack including the tensile mode, shear mod...

an epoxy resin was modified by silica nanoparticles and cured with an anhydride. the particles with different batches of 12, 20, and 40 nm sizes were each distributed into the epoxy resin ultrasonically. electron microscopy images showed that the silica particles were well dispersed throughout the resin. tensile test results showed that young’s modulus and tensile strength increased with the vo...

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...

this study was conducted in order to evaluate the effects of long term ageing on toughness andresilient modulus of asphalt concrete mixtures containing electric arc and basic oxygen furnacesteel slags. after initial evaluation of the properties of steel slags using x-ray diffraction andscanning electric microscope, eleven sets of laboratory mixtures were prepared. each set wastreated replacing ...

In this paper a new method to determine the fracture properties and strain energy release rate for Carbon- Polyester composite has been introduced.  Fracture characteristics such as critical stress intensity factor and critical strain energy release rate for mode I, mode II and mixed mode loading were determined using Arcan type specimen. 130 layers of carbon fiber polyester woven composite wit...

An investigation into the mixed mode fracture of steel fiber reinforced concrete (SFRC)beams with one percent volume fraction of steel fiber is presented. A series of notched beams withdifferent notch depths and locations are tested under three-point bending. The test results for apparentfracture toughness, crack trajectories, and fracture energy are presented. The crack paths for SFRCand plain...

The role that plastic-frictional energy dissipation in the fracture process zone plays in the workof-fracture method for measuring the fracture energy of concrete or other quasibrittle materials is analyzed, and a possible improvement of this method is proposed. It is shown that by measuring the unloading compliance at a sufficient number of states on the post-peak descending load-deflection cu...

Delamination fracture of a two-dimensional functionally graded multilayered four-point bending beam that exhibits non-linear behaviour of the material is analyzed. The fracture is studied analytically in terms of the strain energy release rate. The beam under consideration has an arbitrary number of layers. Each layer has individual thickness and material properties. A delamination crack is loc...