A two-dimensional Saint-Venant principle for second-order linear elliptic equations

Knowles

1981

This paper establishes a principle of Saint-Venant type associated with finite anti-plane shear of a cylinder whose cross-section is a semi-infinite strip. The long sides of the strip are traction-free, and the short side carries an arbitrarily distributed shear traction. At the infinity in the strip, the deformation is prescribed to be one of simple shear, and the associated shear stress is uniform. The analysis is based on the fully nonlinear theory of finite elastostatics and is carried out for a special class of homogeneous, isotropic incompressible materials. It is shown that, along the parallel sides of the strip, the nonvanishing component of shear stress differs from its average value (taken across the strip) by an exponentially decaying function of the distance from the end. A lower bound is given for the rate of decay.

Section: (Ii) Linearizationmentioning

confidence: 99%

The effect of nonlinearity on a principle of Saint-Venant type

Knowles

1981

Upper and lower bounds for the shear stress in the Saint-Venant theory of flexure

Wheeler

1976

Upper and lower bounds are derived for the shear stress as it is determined by Saint-Venant's theory of flexure, and used to establish the asymptotic character of the classical Strength of Materials formula in the limit of vanishing thickness. RI~,SUMI~On d6rive des limites sup6rieures et inf6rieures des contraintes tangentielles suivant la th6orie de la flexion de Saint-Venant, que l'on utilise aux fins d'6tablir le caract6re asymptotique de la formule de la R6sistance des Mat6riaux darts le cas limite d'une 6paisseur extr~mement petite.

Maximum principles and pointwise error estimates for torsion of shells of revolution

Wheeler

1977

Self Cite

This paper is concerned with the question of assessing the quality of approximate thin shell solutions for the problem of axisymmetric torsion of elastic shells of revolution, an issue previously considered by Ho and Knowles [1]. In both works, the objective is to obtain pointwise estimates, based on the threedimensional theory of elasticity, for the errors involved in using an approximate shell theory.The mathematical problem is that of obtaining explicit pointwise gradient estimates for the solutions of homogeneous and nonhomogeneous second-order uniformly elliptic equations, an issue of interest beyond the present context. In contrast to arguments using energy inequalities, here we apply a technique based on maximum principles for such equations.The particular examples of cylindrical, spherical and conical shells of revolution are discussed in detail. In the former two cases, it is shown that the shell theory solution is in fact an exact elasticity solution in the Saint-Venant sense. Asymptotic error estimates for general shells of revolution are also given. RI~SUMIEL'6tude qi-dessous traite de la qualit6 de l'approximation des coques minces appliquEe aux probl~mes de torsion asym6trique des coques 61astiques de r6volution, probl6me d6j~ consid6r6 par Ho et Knowles [1].L'objectif des deux 6tudes est d'6valuer en chaque point, par la th6orie de l'61asticit6 en trois dimensions, les erreurs cons6quentes h l'utilisation de la th6orie de l'approximation des coques.Le probl~me math6matique consiste h obtenir une estimation explicite en chaque point des gradients pour les solutions d'6quations elliptiques uniformes du deuxi~me ordre, homog~nes et non-homog6nes, probl~me d'un inter& qui d6passe le pr6sent contexte. Nous utilisons ici une technique bas6e sur le principe du maximum pour de telles 6quations, par contraste avec les raissonnements utilisant des in6galit6s 6nerg6tiques.Les exemples particuliers des coques de r6volution cylindriques, sph6riques et coniques sont discut6s en d6tail. Dans les deux premiers cas, nous montrons que la solution par la th6orie des coques est en fait une solution exacte dans le sens de Saint-Venant. Des estimations asymptotiques des erreurs dans le cas de coques de r6volution plus g6n6rales sont 6galement donn6es.