Search results for "Elastic"
showing 10 items of 2162 documents
One-dimensional heterogeneous solids with uncertain elastic modulus in presence of long-range interactions: Interval versus stochastic analysis
2013
The analysis of one-dimensional non-local elastic solids with uncertain Young's modulus is addressed. Non-local effects are represented as long-range central body forces between non-adjacent volume elements. For comparison purpose, the fluctuating elastic modulus of the material is modeled following both a probabilistic and a non-probabilistic approach. To this aim, a novel definition of the interval field concept, able to limit the overestimation affecting ordinary interval analysis, is introduced. Approximate closed-form expressions are derived for the bounds of the interval displacement field as well as for the mean-value and variance of the stochastic response.
New Measurements of the Beam Normal Spin Asymmetries at Large Backward Angles with Hydrogen and Deuterium Targets
2017
International audience; New measurements of the beam normal single spin asymmetry in the electron elastic and quasielastic scattering on the proton and deuteron, respectively, at large backward angles and at ⟨Q2⟩=0.22 (GeV/c)2 and ⟨Q2⟩=0.35 ( GeV/c)2 are reported. The experimentally observed asymmetries are compared with the theoretical calculation of Pasquini and Vanderhaeghen [Phys. Rev. C 70, 045206 (2004).PRVCAN0556-281310.1103/PhysRevC.70.045206]. The agreement of the measurements with the theoretical calculations shows a dominance of the inelastic intermediate excited states of the nucleon, πN and the Δ resonance. The measurements explore a new, important parameter region of the exc…
Stress gradient versus strain gradient constitutive models within elasticity
2014
Abstract A stress gradient elasticity theory is developed which is based on the Eringen method to address nonlocal elasticity by means of differential equations. By suitable thermodynamics arguments (involving the free enthalpy instead of the free internal energy), the restrictions on the related constitutive equations are determined, which include the well-known Eringen stress gradient constitutive equations, as well as the associated (so far uncertain) boundary conditions. The proposed theory exhibits complementary characters with respect to the analogous strain gradient elasticity theory. The associated boundary-value problem is shown to admit a unique solution characterized by a Helling…
Shakedown Analysis by Elastic Simulation
2000
Shakedown analysis of elastic plastic structures is widely credited as a valuable analytical/numerical tool for design purposes. For complex structures and loading conditions, e. g. for fast breeder nuclear reactor plants, full inelastic analysis is rarely performed, practically never within the early stages of the design advancement and the inherent decision process. The essential information therein needed can in fact be obtained, at moderate computational costs, by application of the shakedown methods and rules, at least within some limits related to the present developments of shakedown theory and its applicability to practical engineering problems, see e. g. Ponter et al. (1990), Carte…
The transition from single layer to foliation boudinage: A dynamic modelling approach
2012
Abstract Foliation boudinage is a deflection of foliation in the vicinity of a central discontinuity in foliated rocks, mostly filled with vein material. It shows evidence for brittle deformation and void-opening during ductile flow. We used a two-dimensional visco-elastic spring model based on a discrete element approach to study the dynamic development of foliation boudinage and the behaviour of anisotropic visco-elastic material deformed under pure shear conditions. The anisotropies are set by defining rheological heterogeneities in the models with (1) a single layer in a weaker matrix; (2) multi-layers with different elastic properties and (3) random-distributed “micas”, rows of horizon…
On the hyperporous non-linear elasticity model for fusion-relevant pebble beds
2010
Abstract Packed pebble beds are particular granular systems composed of a large amount of small particles, arranged in irregular lattices and surrounded by a gas filling interstitial spaces. Due to their heterogeneous structure, pebble beds have non-linear and strongly coupled thermal and mechanical behaviours whose constitutive models seem limited, being not suitable for fusion-relevant design-oriented applications. Within the framework of the modelling activities promoted for the lithiated ceramics and beryllium pebble beds foreseen in the Helium-Cooled Pebble Bed breeding blanket concept of DEMO, at the Department of Nuclear Engineering of the University of Palermo (DIN) a thermo-mechani…
Transverse-momentum-dependent Multiplicities of Charged Hadrons in Muon-Deuteron Deep Inelastic Scattering
2017
A semi-inclusive measurement of charged hadron multiplicities in deep inelastic muon scattering off an isoscalar target was performed using data collected by the COMPASS Collaboration at CERN. The following kinematic domain is covered by the data: photon virtuality $Q^{2}>1$ (GeV/$c$)$^2$, invariant mass of the hadronic system $W > 5$ GeV/$c^2$, Bjorken scaling variable in the range $0.003 < x < 0.4$, fraction of the virtual photon energy carried by the hadron in the range $0.2 < z < 0.8$, square of the hadron transverse momentum with respect to the virtual photon direction in the range 0.02 (GeV/$c)^2 < P_{\rm{hT}}^{2} < 3$ (GeV/$c$)$^2$. The multiplicities are pres…
Collisional Raman Linewidths of Nitrogen at High-Temperature (1700-2400 K)
1995
0146-9592; New high-temperature measurements of collisional linewidths of the Roman Q branch of nitrogen have been performed at 1700-2400 K with stimulated Raman spectroscopy in a tungsten filament. We fitted these data together with previous data obtained in the 295-1500-K range to redetermine the parameters of the relaxation models used in coherent anti-Stokes Raman spectroscopy thermometry. The improvement in the accuracy of the temperature measurement has been checked. Semiclassical calculations of linewidths in the 1700-2400-K range agree with the experimental data and have been extended to even higher temperatures.
The one loop gluon emission light cone wave function
2017
Light cone perturbation theory has become an essential tool to calculate cross sections for various small-$x$ dilute-dense processes such as deep inelastic scattering and forward proton-proton and proton-nucleus collisions. Here we set out to do one loop calculations in an explicit helicity basis in the four dimensional helicity scheme. As a first process we calculate light cone wave function for one gluon emission to one-loop order in Hamiltonian perturbation theory on the light front. We regulate ultraviolet divergences with transverse dimensional regularization and soft divergences with using a cut-off on longitudinal momentum. We show that when all the renormalization constants are comb…
Hyaluronic Acid–Silica Nanohybrid Gels
2013
Excessive water sorption and low mechanical properties are a severe drawback in some biomedical applications of hyaluronic acid (HA). A way to improve these properties is here explored through the novel concept of nanohybrid hydrogels consisting of a HA matrix including different amounts of silica-derived species. This inorganic filler phase controls the mechanical and swelling properties of HA cross-linked matrices. Below a 2 wt % of silica in the systems, nanoparticle aggregates of tens of nanometers and silica oligomers are distributed more or less homogeneously throughout the organic matrix, without percolating. This morphology of the silica phase is accompanied by an increased swelling…