1,355,572 research outputs found
A method for creating a class of triangular C1 finite elements
No full textFinite elements providing a C1 continuous interpolation are useful in the numerical solution of problems where the underlying partial differential equation is of fourth order, such as beam and plate bending and deformation of strain-gradient-dependent materials. Although a few C1 elements have been presented in the literature, their development has largely been heuristic, rather than the result of a rational design to a predetermined set of desirable element properties. Therefore, a general procedure for developing C1 elements with particular desired properties is still lacking.This paper presents a methodology by which C1 elements, such as the TUBA?3 element proposed by Argyris et al., can be constructed. In this method (which, to the best of our knowledge, is the first one of its kind), a class of finite elements is first constructed by requiring a polynomial interpolation and prescribing the geometry, the location of the nodes and the possible types of nodal DOFs. A set of necessary conditions is then imposed to obtain appropriate interpolations. Generic procedures are presented, which determine whether a given potential member of the element class meets the necessary conditions. The behaviour of the resulting elements is checked numerically using a benchmark problem in strain-gradient elasticit
A behavioural framework for fibre reinforced gravel
No full textData for: Ajayi, Olufemi, Le Pen, Louis, Zervos, Antonios and Powrie, William (2016) A behavioural framework for fibre reinforced gravel. Geotechnique, 1-35. (doi:10.1680/jgeot.16.P.023)</span
Stock Market Liquidity and Economic Growth: A Critical Appraisal of the Levine/Zervos Model
No full textLevine and Zervos (1998) presented cross-country econometric evidence showing that, in a sample of 47 countries, stock market liquidity contributed a significant positive influence on GDP growth between 1976-93. We show that the Levine-Zervos results are not robust to alternative specifications because of the incomplete manner in which they control for outliers in their data. We show that when one properly controls for outliers, stock market liquidity no longer exerts any statistically observable influence on GDP growth.
Some finite elements for elasticity with microstructure and gradient elasticity
No full textWe present a general finite element discretisation of Mindlin’s Elasticity with Microstructure. A total of twelve isoparametric elements are developed and presented, six for plane strain conditions and six for the general case of three-dimensional deformation. All elements interpolate both the displacement and microdeformation fields. The minimum order of integration is determined for each element, and they are all shown to pass the single-element test and the patch test. Numerical results for the benchmark problem of one-dimensional deformation show good convergence to the closed-form solution. Thebehaviour of all elements is also examined at the limiting case of vanishing relative deformation, where Elasticity with Microstructure degenerates to Gradient Elasticity. An appropriate parameter selection that enforces this degeneration in an approximate manner is presented, and numerical results are shown to provide good approximation to the respective displacements and strains of a gradient elastic solid
Data set for "Modelling the effects of trafficking and tamping on scaled railway ballast in triaxial tests"
No full textData for the paper Aingaran, S., Le Pen, L., Zervos, A., & Powrie, W. (2018). Modelling the effects of trafficking and tamping on scaled railway ballast in triaxial tests. Transportation Geotechnics.</span
Three-dimensional stress analysis of a wellbore with perforations and a fracture
No full textThis study presents results of large scale 3-D elastic analysis of a wellbore with perforations. Both vertical and horizontal wellbores with perforations at different orientations are considered. The extra stresses imposed by a propped fracture at the unfractured perforations are also evaluated. A propped fracture results in increase of the compressive stress around the perforations which is higher in the perforations closer to the fracture and increases with propped width. The increase of compressive stress is much higher at the top/lower faces of perforations which is already less than the existing compressive stress at the lateral faces of the perforations. The results are also discussed in relation to the problem of hydraulic fracture initiatio
Influence of thermomechanics in the catastrophic collapse of planar landslides
No full textFrictional heating has long been considered a mechanism responsible for the high velocities and long run-out of some large-scale landslides. In this work a landslide model is presented, applicable to large-scale planar landslides occurring in a coherent fashion. The model accounts for temperature rise in the slip zone due to the heat produced by friction, leading to water expansion, thermoplastic collapse of the soil skeleton, and subsequently to an increase of pore-water pressure. The landslide model, comprising equations that describe heat and pore pressure diffusion and the dynamics of the moving mass, is used to analyse the evolution of the Jiufengershan planar landslide as an example. Further, its parameter space is systematically and efficiently explored using a Taguchi parametric analysis in an attempt to quantify dominant parameters. It is shown that the process of sliding is dominated by the softening properties of the material, as expected, but also by the permeability of the slip zone and the thickness of the sliding mass. It is worth noting that the latter two parameters do not enter traditional stability analyses of uniform slope
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