Search results for "Elastic"
showing 10 items of 2162 documents
Health monitoring of high performance composite pressure vessels,
2018
International audience; The most important form of damage in carbon fiber reinforced composite pressure vessels is the failure of the fibers however the rate of fiber failure is controlled by the viscoelastic nature of the matrix, which determines overall in-service lifetimes. This type of damage is very different from that encountered with metal pressure vessels and requires a detailed understanding in order to ensure reliability. Innovative proof testing methods based on these processes are necessary. The damage processes and the means of quantifying them are discussed. Their reliability under pressure over periods of decades is analyzed. Intrinsic safety factors linked directly to the pr…
12C + 12C large angle elastic scattering at 240 MeV
2010
Abstract The measurement of the differential cross sections of the 12C + 12C and the 13C + 12C elastic scattering are carried out at the 12C energy 240 MeV and the 13C energy 250 MeV to solve some interpretation problem of the 12C + 12C scattering data. Is it possible that the 1st Airy minimum in 12C + 12C scattering data is missing? Our analysis shows that the positions of the 1st Airy minima obtained in former measurements are confirmed.
A Non-Local Two Dimensional Foundation Model
2012
Classical foundation models such as the Pasternak and the Reissner models have been recently reformulated within the framework of non-local mechanics, by using the gradient theory of elasticity. To contribute to the research effort in this field, this paper presents a two-dimensional foundation model built by using a mechanically based non-local elasticity theory, recently proposed by the authors. The foundation is thought of as an ensemble of soil column elements resting on an elastic base. It is assumed that each column element is acted upon by a local Winkler-like reaction force exerted by the elastic base, by contact shear forces and volume forces due, respectively, to adjacent and non-…
Complex Potential Function in Elasticity Theory: shear and torsion solution through line integrals
2012
Aim of this paper is to introduce a basis formulation framed into complex analysis valid to solve shear and torsion problems. Solution, in terms of a complex function related to the complete tangential stress field, may be evaluated performing line integrals only. This basis formulation framed into elasticity problems may be a useful support for a boundary method to verify the accuracy of an approximation of function solution. The numerical applications stress the latter point and show the validity of these formulas since exact solutions may be reached for sections where the exact solution is known.
Solution strategies for 1D elastic continuum with long-range interactions: Smooth and fractional decay
2010
Abstract An elastic continuum model with long-range forces is addressed in this study within the context of approximate analytical methods. Such a model stems from a mechanically-based approach to non-local theory where long-range central forces are introduced between non-adjacent volume elements. Specifically, long-range forces depend on the relative displacement, on the volume product between interacting elements and they are proportional to a proper, material-dependent, distance-decaying function. Smooth-decay functions lead to integro-differential governing equations whereas hypersingular, fractional-decay functions lead to a fractional differential governing equation of Marchaud type. …
Bending stress fields in composite laminate beams by a boundary integral formulation
1999
Abstract The elasticity of a composite laminate under bending loads is approached through a boundary integral formulation and solved by the boundary element method. The integral equations governing the behaviour of each layer within the laminate, are deduced using the reciprocity theorem. Exact analytical singular solutions of the generalized orthotropic elasticity, i.e. the fundamental solutions of the problem, are employed as the kernels of the integral equation. The formulation does not make any assumption as to the nature of the elastic response and it allows consideration of general section geometries and stacking sequences. The solution is obtained through the enforcement of the inter…
A four-node MITC finite element for magneto-electro-elastic multilayered plates
2013
An isoparametric four-node finite element for multilayered magneto-electro-elastic plates analysis is presented. It is based on an equivalent single-layer model, which assumes the first order shear deformation theory and quasi-static behavior for the electric and magnetic fields. First, the electro-magnetic state of the plate is determined in terms of the mechanical primary variables, namely the generalized displacements, by solving the strong form of the magneto-electric governing equations coupled with the electro-magnetic interface continuity conditions and the external boundary conditions. In turn, this result is used into the layers constitutive law to infer the equivalent single-layer…
A finite element formulation for large deflection of multilayered magneto-electro-elastic plates
2014
An original finite element formulation for the analysis of large deflections in magneto-electro-elastic multilayered plates is presented. The formulation is based on an equivalent single-layer model in which first order shear deformation theory with von Karman strains and quasi-static behavior for the electric and magnetic fields are assumed. To obtain the plate model, the electro-magnetic state is firstly determined and condensed to the mechanical primary variables, namely the generalized displacements. In turn, this result is used to obtain laminate effective stiffness coefficients that allow to express the plate mechanical stress resultants in terms of the generalized displacements and a…
Impact of hydrothermal ageing on the thermal stability, morphology and viscoelastic performance of PLA/sisal biocomposites
2016
The influence of the combined exposure to water and temperature on the behaviour of polylactide/sisal biocomposites coupled with maleic acid anhydride was assessed through accelerated hydrothermal ageing. The biocomposites were immersed in water at temperatures from 65 to 85 °C, between the glass transition and cold crystallisation of the PLA matrix. The results showed that the most influent factor for water absorption was the percentage of fibres, followed by the presence of coupling agent, whereas the effect of the temperature was not significant. Deep assessment was devoted to biocomposites subjected to hydrothermal ageing at 85 °C, since it represents the extreme degrading condition. Th…
An integral framework for computational thermo-elastic homogenization of polycrystalline materials
2023
A grain scale framework for thermo-elastic analysis and computational homogenization of polycrystalline materials is proposed. The morphology of crystal aggregates is represented employing Voronoi tessellations, which retain the main statistical features of polycrystalline materials. The behaviour of the individual grains is modelled starting from an integral representation for anisotropic thermo-elasticity, which is numerically addressed through a dual reciprocity boundary element method. The integrity of the aggregate is enforced through suitable intergranular thermo-elastic continuity conditions. By virtue of the features of the underlying formulation, the polycrystalline thermo-elastic …