The stress-free thermal strain corresponding to the temperature rise induced in a target by an incident laser pulse constitutes volume source of ultrasound. In present work, appropriate point-source representation is derived starting from general theorem for sources. A formal solution double (Hankel–Laplace) transform displacement potentials obtained axially symmetric configurations, with lying within or on surface half-space plate. Cagniard-de Hoop technique used invert these transforms....

Two mechanisms are proposed for the limitation of strength in transformation‐toughened zirconia ceramics: that is limited by critical stress to induce tetragonal‐to‐monoclinic phase transformation and inherent R ‐curve behavior these materials limits strength. Experimental evidence support both presented which agrees tolerably well with theoretical predictions. However, larger initial flaws higher toughness experimental results favor argument.

The incorporation of rigid nanoparticles has proven to enhance microcracking resistance in carbon fibre reinforced polymer (CFRP) composites at cryogenic temperatures, enabling CFRP tanks store liquid like hydrogen without requiring liners. Herein, we investigate efficacy low-modulus soft addressing the challenges inherent temperatures. By incorporating a tri-block copolymer (BCP) into an epoxy, nano-structured fillers with average diameter approximately 100 nm are formed. Experimental...

Structural health monitoring systems based on guided waves typically utilise a network of embedded or permanently attached sensors, allowing for the continuous detection damage remote from sensor location. The presence is often diagnosed by analysing residual signals structure after subtracting damage-free reference data. However, variations in environmental and operational conditions such as temperature, humidity, applied thermally-induced stresses affect measured residuals. A previously...

Herein, we report a new method of mitigating cryogenic microcracking in carbon-fibre reinforced-plastics (CFRPs) using negative thermal-expansion nanomaterial, zirconium tungstate (ZrW2O8), to simultaneously reduce the thermal residual stresses and enhance fracture energy epoxy matrix CFRPs. The results show that 1 wt% added ZrW2O8 nanoparticles functionalized by polydopamine can increase material 140%, coefficient expansion 20% and, more importantly, interlaminar resulting CFRP about 100%...

The contribution of volunteers to the success mega sport events is very valuable, as they dedicate their time and skills without financial compensation. Despite undiminished enthusiasm for volunteering at events, grassroots in Europe faces increasing challenges retaining long-term sports clubs. This study aims contribute existing research by examining characteristics motivations with a particular focus on Special Olympics World Games 2023 (SOWG 23). Furthermore, it seeks identify factors...

A consideration of the relevant length scales and time suggests that Mindlin plate theory provides a judicious model for damage detection. systematic investigation this is presented emphasizes its mixed vector-scalar character analogies with 3D elasticity. These lead to use Helmholtz potentials, compact statements reciprocal theorem representation theorem. The response point moment derived using direct source specification, rather than an indirect specification through boundary conditions....

For thin structures, fatigue crack growth rates may vary with the structure's thickness for a given stress intensity factor range. This effect is mainly due to change in nature of plastic deformation when zone size becomes comparable with, or greater than, cross‐sectional thickness. Variations constraint affect both tip blunting behaviour as well closure level. Approximate expressions are constructed based on asymptotic values and numerical results, which shown correlate finite element...

The scattering of plate waves by localized damage or defects that can be modeled as flexural inhomogeneities is examined within the framework Mindlin theory. These are characterized variations in one more four plate-theory parameters: bending stiffness, shear rotary inertia, and transverse inertia. It shown Born approximation for scattered field leads to a analog Fourier diffraction theorem, which relates far-field amplitude spatial transform inhomogeneity variations. application this result...

The enhanced fracture toughness due to stress‐induced transformation can be explained from two viewpoints: (1) the increase attributed need supply a work of transformation, or (2) considered result in internal stresses which oppose crack opening. Experimental results for magnesia‐partially‐stabilized zirconia are presented experimental measures corresponding these viewpoints, namely specific fracture, R , and nominal stress intensity factor, K . It is observed that not equivalent during...

Explicit analytical formulas are derived for the stress intensity factors at tips of a main crack and microcrack two‐dimensional case collinear microcrack. This configuration is used to derive an estimate toughness degradation due microcracks linking up with advancing crack. The implications this theoretical predictions toughening stress‐induced micro‐cracking discussed.

Two basic problems in the theory of transformation toughening are discussed, by using a continuous distribution strain centres to represent inelastic due stress-induced transformation. First, it is shown that two approaches which can be used account for toughening, based on energy and residual stress considerations, do not general lead equivalent measures toughness. An expression crack-extension force derived distinguishes contribution dependent external load from change configuration...