The present paper explores quasi-cleavage processes driven by dislocation pileups against a Dislocation Free Zone (DFZ). The nanoscopic growth of the main crack consists of sequences of nanocrack formation in DFZ and its subsequent linkage with the main crack. Under mode I loading, the equilibrium locations of individual dislocations and the equilibrium number of dislocations are determined by ...

We investigated crack propagation in the drying process of a thin layer of calcium carbonate (CaCO3) paste experimentally. Cracks are induced by uniform desiccation from the top surface of a layer at the approximately same water content for various drying conditions. We found that the crack speed is a nonlinear increasing function of the drying rate at the cracking time although the tensile str...

Modeling of stress corrosion cracking (SCC) is performed using the combination of the finite element method and the symmetric Galerkin boundary element method. The uncracked structural component is represented with finite elements. The crack is simulated using the boundary element method. The superposition principle is employed for combining two solutions. The equilibrium state for the system o...

The development of cracking in concrete structures leads to significant permeability and to durability problems as a result. Approaches to controlling crack development and crack width in concrete structures have been widely debated. Recently, it was recognized that a high-performance fiber-reinforced cement composite (HPFRCC) provides a possible solution to this inherent problem of cracking by...

An elastic analysis is presented for the tensile stretching and bending of a plate containing a surface crack penetrating part-through the thickness, Fig. 1. The treatment is approximate, in that the two-dimensional generalized plane stress and KirchhoffPoisson plate bending theories are employed, with the part-through cracked section represented as a continuous line spring. The spring has both...

SiC/SiC composites are studied for their potential use in the next generation of nuclear reactors. A multiscale approach is under development to construct a predictive modelling of their complex damageable mechanical behaviour due to their heterogeneous microstructure. This paper focuses on the damage characterisation of the composite at the scale of the tow at room temperature, both in terms o...

Deformation in a microcomponent is often constrained by surrounding joined material making the component under mixed loading and multiple stress states. In this study, molecular dynamics (MD) simulation are conducted to probe the effect of stress states on the deformation and fracture of nanocrystalline Cu. Tensile strain is applied on a Cu single crystal, bicrystal and polycrystal respectively...

This paper presents an overview of our recent enhanced 3D extended finite element toolkit for Abaqus (XFA3D) for fatigue damage assessment of welded aluminum structures under block loading. To alleviate the computational burden associated with the insertion and propagation of arbitrary cracks in the presence of a welding induced residual stress field, a nodal enriched displacement field coupled...

The role of foreign-object damage (FOD) and its effect on high-cycle fatigue (HGF) failures in a turbine engine Ti– 6Al–4V alloy is examined in the context of the use of the Kitagawa–Takahashi diagram to describe the limiting conditions for such failures. Experimentally, FOD is simulated by firing 1 and 3.2 mm diameter steel spheres onto the flat specimen surface of tensile fatigue specimens at...

Most transportation infrastructures are exposed to a combination of mechanical and environmental loads. Normal concrete is brittle and tends to crack, resulting in a lack of durability and frequent repair needs. This paper describes an ultra ductile cementitious composite which is highly crack resistant, with a tensile strain capacity over three hundred times that of normal concrete. Apart from...