This paper describes the crack sensing performance of a wireless and passive smart-skin sensor designed as a folded patch antenna. When strain/deformation occurs on the patch antenna, the antenna’s electrical length changes and its electromagnetic resonance frequency also changes accordingly. An inexpensive off-the-shelf radiofrequency identification (RFID) chip is adopted in the sensor design ...

Deformation twinning at the tip of a straight crack or notch is analyzed using a phase-field method that seeks equilibrium twin morphologies via direct minimization of a free energy functional. For isotropic solids, the tendency to twin under mode I or mode II loading is found to depend weakly on Poisson’s ratio and elastic nonlinearity and strongly on surface energy and twinning shear (i.e. ei...

Link slabs designed for macroscopically crack free concrete bridge decks system were experimentally tested. The property requirements of the link slab material were considered. Special focus was placed on the fatigue and durability performance. Introduction of a ductile Engineered Cementitious Composite (ECC) material is proposed for its ability to control crack width and to exhibit high ductil...

In this work, the plastic deformation mechanisms responsible for mechanical properties and fracture toughness in nanotwinned (NT) magnesium is studied by molecular dynamics (MD) simulation. The influence of twin boundary (TBs) spacing and crack position on deformation behaviors are investigated. The microstructure evolution at the crack tip are not exactly the same for the left edge crack (LEC)...

*Correspondence: Daniel Bonamy, Laboratoire SPHYNX, Service de Physique de l’État Condensé, DSM, Institut Rayonnement Matière de Saclay, CEA Saclay, CNRS URA 2464, Batiment 772, Orme des Merisiers, F-91191 Gif sur Yvette Cedex, France e-mail: [email protected] We analyze the intermittent dynamics of cracks in heterogeneous brittle materials and the roughness of the resulting fracture surface...

A growing interest in designing high-alumina MgO-bonded refractory castables has been identified recent years due to the magnesia ability react: (i) with water at initial processing stages of these materials (inducing precipitation brucite phase) or (ii) alumina, giving rise situ MgAl2O4 generation high temperatures. Nevertheless, despite great potential caustic be used as a binder such systems...

The crack growth resistance of human dentin was characterized as a function of relative distance from the DEJ and the corresponding microstructure. Compact tension specimens were prepared from the coronal dentin of caries-free 3rd molars. The specimens were sectioned from either the outer, middle or inner dentin. Stable crack extension was achieved under Mode I quasi-static loading, with the cr...

various concentrations of copper are embedded into silica matrix to xerogel form using copper source - cu(no3)2∙3h2o. the xerogel samples are prepared by hydrolysis and condensation of tetraethyl orthosilicate (teos) by the sol-gel method  and with determination of new molar ratio of components h2o/teos to be 6.2. in this investigation, the necessary amount of trihydrated copper nitrate is adde...

OBJECTIVE To analyze the evolution of drug use among treated crack cocaine users. METHODS A cohort originally comprising 131 crack addicts admitted to a detoxification unit in the city of São Paulo, Southeastern Brazil, between 1992 and 1994 were followed up on three occasions: 1995-96, 1998-99, and 2005-06. Variables investigated included demographical data, risky sexual behaviors, intake pa...

A complete investigation on the free vibration and stability analysis of beams made of functionally graded materials (FGMs) containing open edge cracks utilizing four beam theories, Euler-Bernoulli, Rayleigh, shear and Timoshenko, is performed in this research. It is assumed that the material properties vary along the beam thickness exponentially and the cracked beam is modeled as two segments ...