The toughness enhancement due to domain switching near a steadily growing crack in a ferroelastic material is analyzed. The constitutive response of the material is taken to be characteristic of a polycrystalline sample assembled from randomly oriented tetragonal single crystal grains. The constitutive law accounts for the strain saturation, asymmetry in tension versus compression, Bauschinger ...

As our title implies, we consider materials failure at the fundamental level of atomic bond breaking and motion. Using computational molecular dynamics, scalable parallel computers and visualization, we are studying the failure of notched solids under tension using in excess of 108 atoms. In rapid brittle fracture, two of the most intriguing features are the roughening of a crack’s surface with...

It is an effective way to improve the flexural behavior of reinforced concrete (RC) members by externally bonded carbon fiber reinforcement polymer (CFRP) laminates on the soffit of the members. However, there is little investigation on flexural performance of RC beam flexurally strengthened by side-bonded FRP laminates. To investigate the flexural behavior of RC beams side-bonded CFRP laminate...

The majority of fracture mechanics studies on the toughness of bone have been performed under tensile loading. However, it has recently been shown that the toughness of human cortical bone in the transverse (breaking) orientation is actually much lower in shear (mode II) than in tension (mode I); a fact that is physiologically relevant as in vivo bone is invariably loaded multiaxially. Since bo...

Inspections play an essential role in the damage tolerance approach to control fatigue damage. In this paper a method is presented to optimize the cost-effectiveness of inspection scheduling for single and multiple inspections during the expected lifetime. Detailed results are given for a surface-breaking crack of depth a in a cyclic tension field. The original crack depth is treated as a rando...

This paper describes a combined fracture–plastic model for concrete. Tension is handled by a fracture model, based on the classical orthotropic smeared crack formulation and the crack band approach. It employs the Rankine failure criterion, exponential softening, and it can be used as a rotated or a fixed crack model. The plasticity model for concrete in compression is based on the Menétrey–Wil...

In reinforced concrete elements, tension-stiffening strongly influences deflections and crack-widths at the serviceability limit, plastic hinge rotation ultimate limit. Modeling has shown impact of limit to be particularly important when failure is governed by reinforcement rupture, which been common in ultra-high performance fiber (UHPFRC) elements. It further known that magnitude crack openin...

Channeling cracks in low-k dielectrics have been observed to be a key reliability issue for advanced interconnects. The constraint effect of surrounding materials including stacked buffer layers has been studied. This paper analyzes the effect of interfacial delamination on the fracture condition of brittle thin films on elastic substrates. It is found that stable delamination along with the gr...

Metal nanolaminate coatings are introduced as a new approach in post-weld treatment methods. A Cu/Ni coating is electrodeposited from single citrate bath onto butt-welded tension-tension fatigue specimen. The consists of Ni base layer and 160 alternating Cu layers. specimen tested with stress range close to the yield strength This first study reveals surprisingly high lifetime extensions welded...

INTRODUCTION C/C composites have been used for aerospace application due to their excellent properties such as low density, high heat resistance in inert gas atmosphere, high specific strength and etc. Since C/C composites have relatively higher fracture resistance than other CMCs, this material can also be used as structural components with high reliability. The fatigue properties are also imp...