A vast majority of mollusks grow a hard shell for protection. The structure of these shells comprises several levels of hierarchy that increase their strength and their resistance to natural threats. This article focuses on nacreous shells, which are composed of two distinct layers. The outer layer is made of calcite, which is a hard but brittle material, and the inner layer is made of nacre, a...

The present study investigates the failure mechanisms of industrial fiber materials 13 a custom designed fiber cutting performance test bench. The fracture morpholog 14 fibers are examined by scanning electron microscopy. The analysis reveals that fiber cutting can be 15 distinguished according to four distinct stages of fiber failure represented by shearing, cutting, 16 brittle fracture, and t...

We find that the classical failure criteria, i.e., maximum normal stress criterion, Tresca criterion, Mohr-Coulomb criterion, and von Mises criterion, cannot satisfactorily explain the tensile fracture behavior of the bulk metallic glass (BMG) materials. For a better description, we propose an ellipse criterion as a new failure criterion to unify the four classical criteria above and apply it t...

In this paper the influence of microstructure on crack initiation stress and ultimate strength is investigated using results and analysis of 32 triaxial compression tests performed on cylindrical cores of dolomite samples which exhibit a wide range of grain sizes and mosaic textures. All tests were performed at a constant strain rate, under confining pressures between 0 to 40 MPa. The predictiv...

In this work, additional input is provided into the ongoing discussion on the mechanisms, causes and remedies of brittle fracture failures of composite (non-ceramic) insulators. This has been done partially to complement the recently published article on this topic entitled “ IEEE Task Force Report: Brittle Fracture in Non-Ceramic Insulators” [1]. At first, the most important characteristics of...

This study investigates the mechanical behavior of steel fiber-reinforced concrete (SFRC) beams internally reinforced with steel bars and externally bonded with carbon fiber-reinforced polymer (CFRP) sheets fixed by adhesive and hybrid jointing techniques. In particular, attention is paid to the load resistance and failure modes of composite beams. The steel fibers were used to avoiding the rip...

We present an experimentally-based failure criterion for symmetric two-ply plain-weave laminates of carbon-fiber reinforced plastic. The criterion is formulated in terms of six force and moment stress resultants and consists of a set of three inequalities, related to in-plane, bending, and combined in-plane and bending types of failure. All failure parameters in the criterion are measured direc...

Three-dimensional failure analyses of slopes are rather elaborate, and for rock slopes, where the strength is defined by nonlinear envelopes, they particularly intricate. This why many earlier approaches used a linear approximation envelope prior to carrying out stability analysis. avoided in this paper, thanks using parametric form Hoek-Brown criterion. The kinematic approach limit analysis as...

Stress enhancement in the vicinity of brittle cracks makes the macro-scale failure properties extremely sensitive to the micro-scale material disorder. Therefore: (i) Fracturing systems often display a jerky dynamics, socalled crackling noise, with seemingly random sudden energy release spanning over a broad range of scales, reminiscent of earthquakes; (ii) Fracture surfaces exhibit roughness a...