1,721,160 research outputs found
Compatible mixed formulations for elastoplastic models
No full textThis review addresses the use of Norplant in women with or atrisk for noninsulin-dependent diabetes mellitus (NIDDM). Background information on NIDDM is given, including pathogenesis, effect on glucose and lipid metabolism, and management. The effect of exogenous estrogen and progestogens on glucose tolerance is briefly discussed. In reviewing the effects of Norplant on glucose metabolism, studies on women with normal glucose tolerance were reviewed, along with the one study of Norplant use in women with a past history of gestational diabetes. Norplant does have a minor effect on glucose metabolism. Studies are contradictory regarding lipid metabolism but most suggest that Norplant does not have a negative effect on the high density lipoprotein/total cholesterol ratio. Factors influencing contraceptive choice are reviewed. Protocols for management of Norplant in women with or at-risk for NIDDM are then presented, followed by a case study and a brief discussion
Finite element modelling of nonlocal beams
No full textBased on a high-order Euler–Bernoulli nonlocal beam theory, a nonlocal finite element method (NFEM) is consistently developed to evaluate the displacement and the bending moment of nanobeams. As a benchmark a simply supported nanobeam under a uniform external load is considered and the numerical solution obtained by means of the proposed NFEM is compared with the exact nonlocal solution obtained by solving a sixth-order differential equation. The comparison shows that the NFEM provides an exact solution of the nonlocal problem, for any value of the internal length parameter, with a coarse mesh. The proposed NFEM does not show pathological behaviours such as mesh dependence, numerical instability or boundary effects. Moreover a cantilever nanobeam subjected to an intermediate applied force is addressed. Contrary to what is reported in the literature, the proposed methodology shows that the nonlocal effects are apparent to both left and right of the application point of the external force
A thermodynamic approach to nonlocal elastoplasticity and related consistent tangent operator
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A new variational theory and a computational algorithm for coupled elastoplastic damage models
No full textA model of elastoplasticity with hardening coupled with ductile damage which allows anisotropic change of the shape of the damage domain is presented. The assumption for the development of the constitutive model consists in assigning the elastic and damage domains and the free energy. The general variational formulation for the elastoplastic model coupled with damage is derived as well as a mixed principle which is useful from the computational standpoint. Accordingly a solution algorithm is then derived and examples are presented
Some Variational Principles for Coupled Thermoelasticity
No full textThe nonlinear thermoelasticity of type II proposed by Green and Naghdi is considered. The thermoelastic structural model is formulated in a quasistatic range, and the related thermoelastic variational formulation in the complete set of state variables is recovered. Hence a consistent framework to derive all the variational formulations with different combinations of the state variables is provided, and a family of mixed variational formulations, with different combinations of state variables, is provided starting from the general variational formulation. A uniqueness condition is provided on the basis of a suitable variational formulation
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