Failure behavior of composite materials in general and particulate composites in particular is intimately linked to interactions between a matrix crack and a second phase inclusion. In this work, surface deformations are optically mapped in the vicinity of a crack–inclusion pair using moiré interferometry. Edge cracked epoxy beams, each with a symmetrically positioned cylindrical glass inclusio...

This paper presents the fracture analyses conducted on the FAA/NASA stiffened and unstiffened panels using the STAGS (STructural Analysis of General Shells) code with the critical crack-tip-opening angle (CTOA) fracture criterion. The STAGS code with the “plane-strain” core option was used in all analyses. Previous analyses of wide, flat panels have shown that the high-constraint conditions aro...

Autonomous crack healing in concrete is obtained when encapsulated healing agent is embedded into the material. Cracking damage in concrete elements ruptures the capsules and activates the healing process by healing agent release. Previously, the strength and stiffness recovery as well as the sealing efficiency after autonomous crack repair was well established. However, the mechanisms that tri...

An understanding of the fatigue and fracture behavior of hard tissues (e.g., bone and tissues of the human tooth) is critical to the maintenance of physical and oral health. Recent studies suggest that there are a number of mechanisms contributing to crack extension and crack arrest in these materials, and that they appear to be a function of moisture and age of the tissue. An understanding of ...

This paper discusses the modeling of residual stresses in fracture problems. Historically, residual stress effects in fracture have focused on the crack driving force, so that solely opening mode residual stresses are assumed to influence fracture. However, residual stresses can effect all components of stress at the crack-tip, and can thereby alter crack-tip constraint and influence material t...

In this work, a new approach is developed for dynamic analysis of a composite beam with an interplay crack, in which a physically impossible interpenetration of the crack faces is prevented by imposing a special constraint, leading to taking account of a force of contact interaction of the crack faces and to nonlinearity of the formulated boundary value problem. Longitudinal force resultants in...

Final failure of laminated composite structures is preceded by different damage mechanisms involving fracture initiation and propagation. Fracture in a composite laminate can appear either between two plies or within a lamina. In the first case, interlaminar fracture or delamination, the crack causes separation of two adjacent plies and will mainly involve matrix failure or matrix-to-fibre debo...

Fatigue precracked specimens of three titanium alloys (6Al-4V, ELI, and Timetal 5111) were dynamically loaded in a drop weight tower system while the dynamic fracture toughness was inferred using Coherent Gradient Sensing, crack opening displacement, or strain gage methods. A comparison of the initiation toughness of the three materials as a function of loading rate and specimen thickness is made.

Despite decades of study, the atomic-scale mechanisms of fatigue crack growth remain elusive. Here we use the coupled atomistic–discrete dislocation method, a multiscale simulation method, to examine the influence of dislocation glide resistance on near-threshold fatigue crack growth in an aluminum alloy. The simulations indicate that the threshold increases with an increase in dislocation glid...