A study of dynamic behavior of the autoclaved aerated concrete

This work presents an experimental study on the dynamic behavior of autoclaved aerated concrete. The paper reports a series of tests with a Hopkinson Pressure Bar [Hopkinson B., Phil. Trans. Royal Soc. London, A 213. (1913), pp. 437 and Davies R.M., Phil. Trans. Royal Soc. London, A240 (1948), pp. 375.] applied to the direct impact technique [Klepaczko J.R., Advanced experimental techniques in materials testing, Ch.6 in New Experimental Methods in Material Dynamics and Impact, eds. W.K.Nowacki and J.R.Klepaczko, IFTR, Warsaw, (2002), pp. 223.]. Several strain rates were applied varying from quasi-static to impact between 1.4×102 s−1 to 103 s−1. Two states of the aerated concrete were tested, that is dry and saturated with water. In general, an increase of strain rate causes an increase of the critical failure stress for such materials. In the quasi-static range and up to certain critical impact velocity VC the autoclaved aerated concrete shows a positive strain rate sensitivity However, when a critical impact velocity VC is reached a very specific behavior is observed, that is the cell structure is pulverized near the plane of impact. This effect is completely new

Etude du comportement mécanique du béton cellulaire autoclaveé : influence de la vitesse de déformation

Ce travail pre'sente une e'tude expe'rimentale du comportement me'canique du be'ton cellulaire autoclave'. L'e'tude a port6 essentiellement sur me sine d'essais dcaniques en compression quasi statique ir diyirentes vitesses de d6formation variables entre 10-4 s-1 et 10 s-' et ir deux e'tats dae'rents (e'tat sec et Ctat sature' d'eau). En ge'ne'ral, l'augmentation a2 la vitesse de diformation donne une augmentation de la contrainte critique du be'ton cellulaire autoclavk Le be'ton cellulaire autoclave' pre'sente une sensibilite' ir la vitesse de de'formation positive. La valeur du module d'e'lasticite' est proche de la valeur stMdard (1.5 GPa) pour un be'ton cellulaire autoclave' de masse volwnique &ale ir 500- 550 kg I m

Combined and synergic effect of algerian natural fibres and biopolymers on the reinforcement of extruded raw earth

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Loss Behavior of Viscoelastic Sandwich Structures: a Statistical-Continuum Multi-Scale Approach

This work presents a multi-scale model of viscoelastic constrained layer damping treatments for vibrating plates/beams. The approach integrates a finite element (FE) model of macro-scale vibrations and a statistical-continuum homogenization model to include effects of micro-scale structure and properties. The statistical-continuum homogenization model makes the micro- to macro-scale transition to approximate the effective behavior of the heterogeneous core by using n-point probability functions. A simple sound transmission model is used to show the effect of material microstructure on the sound transmission loss of the sandwich structure. The damping behavior resulting from the presence of voids and negative stiffness regions in the core material is modeled. This study clearly shows that, it is of high interest to research either material structures or processing techniques which lead to negative stiffness behavior. The results also poignantly show that the proposed multi-scale model yields insight on heterogeneous material behavior leading to increased damping properties and ultimately enhances the ability to design sandwich beam/plates