Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics最新文献

From kinematic observations by granularity in whiting light mode based on a technique of digital speckle images correlation, the behaviour in tension of a reactive powders concrete is studied. The measures show several localisation areas of the deformation fields and the role of the fibres in the transmission of the stresses in the neighbourhood of a damaged area.

The aim of the Note is to describe the physical phenomenon of the excitation of modal waves, such as Lamb waves, in anisotropic media by a monochromatic incident beam, and to explain the deviation of the modal wave beam so created. Using a stationary phase approach, the modal wave beam is found to be deviated in the direction normal to the modal slowness curve. Due to the anisotropy, this direction is no longer in the sagittal plane.

Local particle volume fraction measurements in two-phase flows are rare. Generally, the concentration is supposed to be spatially homogeneous in the sedimentation flows fundamental experiments. This is far to be realistic in regimes different from Stokes' regime, particularly near the walls. This paper compares two methods of evaluation of the volume fraction in a three-dimensional two-phase flow.

The two-dimensional sloshing problem is considered in a half-plane covered by a rigid dock with two symmetric gaps. It is proved that the antisymmetric (symmetric) sloshing eigenvalues are monotonically decreasing (increasing) functions of spacing between gaps and formulae for their derivatives are obtained.

This Note presents a computational technique for simulating friction-induced wear in a tribology experiment on a plan/plan, ring-on-disc contact configuration. The boundary element method results in modest computing times and facilitates the mesh modifications used for tracking the wear profile evolution. A typical wear simulation result is presented and discussed.

The classical virial theorem, applied to particles without internal structure, is used to make a direct statistical estimation of a fluid pressure avoiding a thermodynamical potential derivation. Generalising this theorem to structured media leads to a direct statistical estimation of the stress tensor.

Stress Corrosion Cracking (SCC) phenomenon is characterised by initiation and propagation of surface cracks frequently multiple. In order to model the mechanical behaviour of such materials we propose, as for composites, the use of homogenization techniques. Two materials are considered, first one corresponding to the cracked external volume and the second to the internal safe material. The cracked volume is considered as a two phase material, i.e., elastic matrix containing elliptical voids. The overall behaviour of the equivalent material is obtained applying the usual homogenization rules. Comparison between simulations and experimental results is done.

Quadratic approximants [5] are used to increase the range of validity of a vectorial series. We present an application in the framework of the asymptotic numerical method [1].

An original measurement technique based on Rayleigh scattering (Collective Light Scattering) was used in the flow conditions of a normal Mach 2.85 shock wave/homogeneous turbulence interaction. The experimental investigation was limited to the region just downstream of the shock. A non-dimensional attenuation law for the evanescent acoustic waves was found using CLS measurements. This law is significantly different from the one predicted by the Linear Interaction Analysis. However, it was confirmed by hot-wire measurements for which quite severe assumptions were used.

Extending the previous work by Chambon et al. [2] to the finite deformation regime, a local second gradient theory of plasticity for isotropic materials with microstructure is developed based on the multiplicative decomposition of the deformation gradient, the additive decomposition of the second deformation gradient and the principle of maximum dissipation.