A high temperature cured self-healing epoxy is demonstrated by incorporating microcapsules of poly (dimethylsiloxane) (PDMS) resin and separate microcapsules containing an organotin catalyst. Healing is triggered by crack propagation through the embedded microcapsules in the epoxy matrix, which releases the healing agents into the crack plane initiating crosslinking reactions. A series of taper...

The effect of loading rate on the plane stress fracture toughness properties of a 3.2-mm thick 2219-T87 aluminum alloy plate was investigated with center-cracked panels. Plane-stress J-resistance curves were generated at a constant displacement rate of 10-6 and 5.7 m s-l. Dynamic fracture testing was performed with a coupled pressure plates technique. Fracture initiation and propagation toughne...

ID No. : FC-168 ABSTRACT Fiber-reinforced self-healing ceramic (shFRC) [1] is considered to be most attractive candidate of next generation structural materials using at high temperature, e.g. turbine blade, exhaust component of car engine etc. The shFRCs consist of three components, which are oxide fiber bundle, oxide matrix and self-healing agent interlayer. As the self-healing is generated a...

Bones are the principal structural components of a skeleton; they play unique roles in the body providing its shape maintenance, protection of internal organs and transmission of forces. Ultimately, their structural integrity is vital for the quality of life. Unfortunately, bones can only sustain loads until a certain limit, beyond which they fail. Understanding a fracture behaviour of bone is ...

The orientation dependence of Charpy toughness has been investigated in API-X80 linepipe steel. The occurrence of delamination and preferential alignment of {100} cleavage planes are found to contribute to the observed anisotropy in Charpy properties. Delamination is also related to the presence of banding in the hot–rolled alloy, and the additional plasticity it entails during the process of f...

Relations between fracture toughness and microstructural details have been calculated for ductile materials based on a dilatational plasticity constitutive model that has recently been proposed. The model generalizes the Gurson model to account for both void growth and coalescence with explicit dependence on void shape and distribution effects. Based on a small scale yielding formulation of cra...

Low fracture toughness of ferroelectric ceramics calls for a reliability concern in the development of smart structures. For ferroelectrics under mechanical and electrical loadings, the intensified stress and electric fields in the vicinity of a crack-like flaw lead to domain reorientation. The switched domains induce incompatible strain near the flaw and consequently change the apparent fractu...

Systematic changes in composition were employed to increase the notch toughness of a variety of Fe-based Bulk Metallic Glasses (BMGs). The Fe50Mn10Mo14Cr4C16B6 BMG possessed very high hardness (e.g. 12GPa) but very low notch toughness (e.g. 5.7MPam) at room temperature, consistent with fracture surface observations of brittle features. Many of the other Fe-BMG variants, created to change the Po...

In situ mechanical testing coupled with imaging using high-energy synchrotron X-ray diffraction or tomography is gaining in popularity as a technique to investigate micrometer and even sub-micrometer deformation and fracture mechanisms in mineralized tissues, such as bone and teeth. However, the role of the irradiation in affecting the nature and properties of the tissue is not always taken int...

‘Curving’ could occur in Mode I brittle fracture and it can be attributed to the constraint. The variation of the apparent fracture toughness with constraint with or without crack curving is investigated. Using a critical opening or hoop stress as the fracture criterion, it is demonstrated that a fracture event can be quantified by two mechanics parameters, i.e. K and A3 for fracture without cu...