The notion of replicating the unique fracture resistance of natural composites in synthetic materials has generated much interest but has yielded few real technological advances. Here we demonstrate how using ice-templated structures, the concept of hierarchical design can be applied to conventional compounds such as alumina and poly(methyl methacrylate) (PMMA) to make bulk hybrid materials tha...

The increasing need in the mechanical testing of sub-sized samples motivated the present study focused on the effect of the size of samples. Sometimes, attempts are made, due to economic reasons, to replace testing of the fracture toughness by a cheaper testing of notch toughness. Several empirical relations, pertaining to relations between fracture toughness and energy consumption in impact te...

To gain insight into the large toughness variability observed between metallic glasses (MGs), we examine the origin of fracture toughness through bending experiments and molecular dynamics (MD) simulations for two binary MGs: Pd82Si18 and Cu46Zr54 The bending experiments show that Pd82Si18 is considerably tougher than Cu46Zr54, and the higher toughness of Pd82Si18 is attributed to an ability to...

this study was carried out to determine the effect of seed growing regions and loading speed on some mechanical properties of castor seed. these properties are used to design and improve related machines such as expeller that are used for extraction of oil from castor seed. mechanical properties of castor seed were expressed in terms of rupture force and energy, bio-yield force, apparent modulu...

A model is proposed, which predicts the toughness of 7000 series aluminium alloys in a variety of situations, including two alloy compositions, different quench rates from the solution treatment temperature and ageing states from underaged to overaged. The model is derived in three steps. The energy dissipated by transgranular fracture is first calculated, using a simplified cohesive zone appro...

This investigation compared four conventional vehicle armour materials for performance under blast loading. The parameters measured were resistance to deformation, mechanical toughness and metallurgical microstructure. It was found that two of these, the M steel and A steel, showed the least deformation and M steel showed better shock energy absorption. B steel had high toughness but showed sig...

Charpy V-notch impact testing is widely used in the toughness assessment of large forged components, e.g. the pressure vessel for pressurised water reactors m). At low temperature, A508 C1.3 nuclear pressure vessel steel fails by cleavage fracture. The results reported here are part of both an experimental program and numerical investigations which aim at the establishment of a non-empirical re...

An assessment is made here of the role played by the micropolar continuum theory on the cracked Brazilian disc test used for determining rock fracture toughness. By analytically solving the corresponding mixed boundary-value problems and employing singular-perturbation arguments, we provide closed-form expressions for the energy release rate and the corresponding stress-intensity factors for bo...

A new novel test method, associated analysis, and experimental procedures are developed to investigate the toughness of the facesheet-to-core interface of a sandwich material at cryogenic temperatures. The test method is designed to simulate the failure mode associated with facesheet debonding from high levels of gas pressure in the sandwich core. The effects of specimen orientation are conside...

In this paper, self-similar solutions for a fractional thin film equation governing hydraulic fractures are constructed. One of the boundary conditions, which accounts for the energy required to break the rock, involves the toughness coefficient K ≥ 0. Mathematically, this condition plays the same role as the contact angle condition in the thin film equation. We consider two situations: The zer...