1,721,333 research outputs found
Estimates of the post-shakedown response of hardening structures by means of simplified computations
No full textA simplified procedure, aiming at the estimate of the post-shakedown response of elastic-plastic structures under varying external actions, is proposed in the paper. A single step, holonomic elastic-plastic analysis is performed under fictitious loads obtained by replacing the actual, variable, elastic stress response with its envelope. Such a solution is usually a reasonable estimate of the actual response and permits a comparatively stringent bracketing from below and above of some particular functions of the plastic strains actually developed. Often these functions are closely related to quantities of direct engineering relevance, thus stressing the practical interest of the proposed procedure
REFINED FINITE ELEMENT MODEL FOR THE ANALYSIS OF ELASTIC - PLASTIC FRAMES.
No full textA finite element model for the elastic-plastic analysis of plane frames is proposed. The formulation is based on the independent modelling of the displacement and plastic strain fields; the latter is modelled both over the cross-section and along the element length as function of a finite number of parameters, which are considered as an extra set of independent variables, in addition to nodal displacements. It is shown that the model can be formulated in such a way that not only compatibility and elasticity, but also equilibrium (in the sense of beam theory), are fully complied with and only the plastic portion of the constitutive relationship is approximately fulfilled, even if, in principle, to any desired level of accuracy. The model produces accurate results, including a detailed representation of the spreading of plastic zones, with a fairly limited number of elements
Collapse of Thick Cylinders under Radial Pressure and Axial Load
No full textThis paper provides the theoretical collapse loads of thick, long cylindrical shells subject to pressure and axial forces. Tubes are made of isotropic, perfectly plastic von Mises’ material. Axial strains are assumed to be constant but possibly different from zero, so that
elongation is permitted. This assumption, together with axial symmetry and the isochoric nature of plastic flow, unambiguously defines the set of possible collapse mechanisms,and collapse loads are computed on this basis. Results are contrasted to those presently
available, based on thin-shell assumptions. Comparison shows that differences are of engineering significance, well worth considering for thick tubes, such as those envisaged in some nuclear power plant applications
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Interaction domains for steel beam-columns in fire conditions
No full textA parametric study on the interaction curves for steel beam-columns in fire conditions is performed. The study is based on a trilinear idealization of the uniaxial stress-strain relation for steel at elevated temperature and aims at assessing the influence of the slope of the hardening branch, on which results are strongly dependent. A refined and numerically efficient elastic-plastic beam element model is employed to analyse different load conditions and temperature distributions. Results for uniform temperature are systematic enough to permit fairly general analytical approximations, which might be useful also in the presence of temperature variations along the element length only. Thermal gradients through the cross-section are also considered
- …
