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351.
G. Bonnet 《International Journal of Solids and Structures》2009,46(5):1240-1250
Obtaining the Green tensor for the most general orthotropic medium is not generally possible in a closed form because the solution requires the roots of a sextic, often known as Stroh eigenvalues. The paper gives some conditions under which the sextic can be solved in a closed form for any direction within the space. It enables the construction of classes of orthotropic materials for which the Green tensor can be computed in a closed form (closed-form orthotropic or CFO) for any direction within the space. The cases of transversely isotropic, tetragonal and cubic materials are studied as special cases. The comparison between the exact Green function and approximate Green functions obtained from the nearest CFO material (in the sense of four different distances) is finally performed in the case of five examples of elasticity tensors. 相似文献
352.
Overview of Identification Methods of Mechanical Parameters Based on Full-field Measurements 总被引:6,自引:1,他引:5
Stéphane Avril Marc Bonnet Anne-Sophie Bretelle Michel Grédiac François Hild Patrick Ienny Félix Latourte Didier Lemosse Stéphane Pagano Emmanuel Pagnacco Fabrice Pierron 《Experimental Mechanics》2008,48(4):381-402
This article reviews recently developed methods for constitutive parameter identification based on kinematic full-field measurements,
namely the finite element model updating method (FEMU), the constitutive equation gap method (CEGM), the virtual fields method
(VFM), the equilibrium gap method (EGM) and the reciprocity gap method (RGM). Their formulation and underlying principles
are presented and discussed. These identification techniques are then applied to full-field experimental data obtained on
four different experiments, namely (i) a tensile test, (ii) the Brazilian test, (iii) a shear-flexural test, and (iv) a biaxial
test. Test (iv) features a non-uniform damage field, and hence non-uniform equivalent elastic properties, while tests (i),
(ii) and (iii) deal with the identification of uniform anisotropic elastic properties. Tests (ii), (iii) and (iv) involve
non-uniform strain fields in the region of interest.
Working group “Identification” of the French CNRS research network (GDR 2519) “Mesures de champs et identification en Mécanique
des Solides / Full-field Measurements and Identification in Solid Mechanics”. 相似文献
353.
Vivarès D Belloni L Tardieu A Bonneté F 《The European physical journal. E, Soft matter》2002,9(1):15-25
We present the experimental and theoretical background of a method to characterize the protein-protein attractive potential
induced by one of the mostly used crystallizing agents in the protein-field, the poly(ethylene glycol) (PEG). This attractive
interaction is commonly called, in colloid physics, the depletion interaction. Small-Angle X-ray Scattering experiments and
numerical treatments based on liquid-state theories were performed on urate oxidase-PEG mixtures with two different PEGs (3350
Da and 8000 Da). A “two-component” approach was used in which the polymer-polymer, the protein-polymer and the protein-protein
pair potentials were determined. The resulting effective protein-protein potential was characterized. This potential is the
sum of the free-polymer protein-protein potential and of the PEG-induced depletion potential. The depletion potential was
found to be hardly dependent upon the protein concentration but strongly function of the polymer size and concentration. Our
results were also compared with two models, which give an analytic expression for the depletion potential.
Received 29 April 2002
RID="a"
ID="a"Present address: CRMC2-CNRS, Campus de Luminy, case 913, F-13288 Marseille Cedex 09, France; e-mail: vivares@crmc2.univ-mrs.fr
RID="b"
ID="b"e-mail: bonnete@crmc2.univ-mrs.fr
RID="c"
ID="c"Laboratory associated to Universities Aix-Marseille II and III. 相似文献
354.
New experimental techniques to investigate fluid and plasma flows in a non-intrusive way were presented at the EURO-MECH 260 Colloquium held in Poitiers, France, on September 5–7, 1990. A total of 55 participants from 7 countries attended. Five sessions were organized with 29 oral presentations, each session being opened by an invited lecture. The colloquium was closed by a general discussion. 相似文献
355.
We isolate spatial shifts and Wigner delays for reflection at the same interface and demonstrate that they can carry different information. The spatial shifts associated with Wood anomalies on gratings can be either positive or negative, while the corresponding delays are both positive. In the standard case of total reflection at a glass-air interface, a differential two-photon absorption correlation technique allows us to measure for the first time a delay of up to 35 fs in agreement with the associated 10.5 microm spatial shift. The method also allows us to isolate giant Wigner delays. The existence of similar delays in different areas of physics is discussed. 相似文献
356.
Antonopoulos A Bonnet P Botek E Debrun JL Hakim B Herbreteau B Morin-Allory L 《Rapid communications in mass spectrometry : RCM》2003,17(2):122-125
The mechanism of attachment of Na(+) on glucose, methyl-alpha-D-glucose, methyl-beta-D-glucose, 3-O-methylglucose, tetra-O-methylglucose, and also on galactose and methyl-beta-D-galactose, was studied. For this we measured the ion yields for the complex [sugar-Na(+)] formed by ionisation by matrix-assisted laser desorption/ionisation (MALDI) and ionspray. These data were compared with the relative volatilities and hydrophobicities of the sugars, measured by evaporative light scattering and reversed-phase liquid chromatography, respectively. Some formation enthalpies for the complexes [sugar-Na(+)], starting from the sugar and the cation, were obtained by ab initio calculations. No simple correlations could be observed between the ion yields and the parameters studied, so that the cationisation mechanism of the sugars remains unclear. 相似文献
357.
Ackermann KH Adams N Adler C Ahammed Z Ahmad S Allgower C Amsbaugh J Anderson M Anderssen E Arnesen H Arnold L Averichev GS Baldwin A Balewski J Barannikova O Barnby LS Baudot J Beddo M Bekele S Belaga VV Bellwied R Bennett S Bercovitz J Berger J Betts W Bichsel H Bieser F Bland LC Bloomer M Blyth CO Boehm J Bonner BE Bonnet D Bossingham R Botlo M Boucham A Bouillo N Bouvier S Bradley K Brady FP Braithwaite ES Braithwaite W Brandin A Brown RL Brugalette G Byrd C Caines H 《Physical review letters》2001,86(3):402-407
Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at square root(S)NN = 130 GeV using the STAR Time Projection Chamber at the Relativistic Heavy Ion Collider. The elliptic flow signal, v2, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented. 相似文献
358.
Measurement of positive and negative Goos--Hänchen effects for metallic gratings near Wood anomalies
Large Goos-H?nchen effects are isolated for reflection on a metallic grating. These shifts occur in the vicinity of Wood anomalies. Depending on the nature of the anomaly, these displacements are found to be either positive or, contrary to the usual GH effect, clearly negative. Those shifts, associated with forward and backward leaky surface waves, are as large as plus or minus tens of wavelengths for a classic metallic grating. 相似文献
359.
J. Sijbers P. Scheunders N. Bonnet D. Van Dyck E. Raman 《Magnetic resonance imaging》1996,14(10):1157-1163
A procedure is developed to quantify and improve the signal-to-noise ratio (SNR) of magnetic resonance images. The image SNR is quantified using the correlation function of two independent acquisitions of an image. To test the performance of the quantification, SNR measurement data are fitted to theoretically expected curves. The proposed correlation technique is also used to improve the SNR by estimating the amplitude of the signal spectrum. The technique is applied to a set of MR images, and its performance in terms of gain in SNR, contrast-to-noise ratio (CNR), and resolution loss is compared to that of classical noise filters. The SNR as well as the CNR is improved significantly with minor loss of resolution. Finally, it is shown that the correlation technique can be implemented in a highly efficient way in almost any acquisition procedure of a magnetic resonance imaging system. 相似文献
360.