Plain concrete structures such as dams or retaining walls, as well as rock structures such as tunnels, caverns, excavations, and rock slopes, have commonly been designed by elastic-perfectly plastic analysis in which the tensile yield strength of the material is taken as zero. The paper analyzes the safety of this "notension" design in the light of the finiteness of the tensile strength of conc...

S E On the Fracture Toughness of Advanced Materials A R C H By Maximilien E. Launey, and Robert O. Ritchie* N E W S Few engineering materials are limited by their strength; rather they are limited by their resistance to fracture or fracture toughness. It is not by accident that most critical structures, such as bridges, ships, nuclear pressure vessels and so forth, are manufactured from materia...

Recent studies document linear elastic response of muddy marine sediments to load and deformation on temporal and spatial scales relevant to animal movement, with burrowers making openings for movement in such sediments by fracture. Cracks propagate through linear elastic solids in mode I (opening-mode crack growth) when the stress intensity factor (KI) at the crack tip exceeds the material’s f...

This paper addresses the question of homogenization fracture properties for three-dimensional disordered brittle solids. The effective toughness, identified as minimum elastic energy release rate required to ensure crack growth, is predicted from a semi-analytical framework inspired by both micromechanics and statistical physics, that encompasses decisive influences material disorder mechanisms...

The more common use of instrumentation in impact testing opened up the possibility to apply fracture mechanics testing methods to polymers at moderately high impact rates. Tensile impact testing offers some advantages over the more common three-point bending and compact tension geometries. Most importantly the dynamic effects encountered at (moderately) high impact rates are less significant du...

The present study is devoted to the problem of enhancing fracture toughness of ZrO2 ceramic materials through the formation of composite structure by addition of Al2O3 and NiO particles. In this paper, we analyzed the general and distinguished features of microstructure of both composite materials and its effect on fracture toughness of materials. In this paper, we used the XRD, SEM, and EDS me...

The effect of bleaching on fracture toughness (Kic) of existing composite-dentin interfaces was assessed using the notchless triangular prism (NTP) specimen fracture toughness test. Human molars and premolars (<6 months old) were wet ground on 600 SiC to obtain 4x4x4x4mm triangular prisms with buccal or lingual exposed for bonding. Buccal or lingual dentin surfaces, ground on 600 grit sandpaper...

A probabilistic methodology has been developed for fracture-mechanics analysis of nonlinear cracked structures. The methodology involves nonlinear ®nite element analysis using well-known commercial codes; statistical models for uncertainty in material constitutive law, fracture toughness, and loads; and standard reliability methods for evaluating probabilistic characteristics of elastic±plastic...

Indentation techniques for assessing fracture toughness are attractive due to the simplicity and expediency of experiments, and because they potentially allow the characterization of both local and bulk fracture properties. Unfortunately, rarely have such techniques been proven to give accurate fracture toughness values. This is a concern, as such techniques are seeing increasing usage in the s...