LARGE DEFORMATIONS AT THIN PLANE DISKS BENDING UNDER UNIFORM DISTRIBUTED LOADS, CONSIDERING THE MEMBRANE STRESSES PART I - GENERAL THEORETICAL CONSIDERATIONS ON LARGE DEFORMATIONS

RADU GHEORGHE^{*}, COMÄNESCU IOANA^{**} *TRANSILVANIA UNIVERSITY OF BRASOV, DEPT. OF STRENGTH OF MATERIALS,B-DUL EROILOR 29, TEL.0268474761, E-MAIL: RNGH@UNITBV.RO **TRANSILVANIA UNIVERSITY OF BRASOV, DEPT. OF MECHANICS, B-DUL EROILOR 29, TEL.0268413000/169, E-MAIL: IOANACOM@UNITBV.RO

The present paper deals with the state of stress and deformation at thin circular plates subjected to symmetrical axial loading. The loading is a bending owing to the uniform distributed loads which act perpendicular to the mean surface of the plate, simultaneous with a membrane load (loads acting in the mean plane of the plate). This type of problem is solved by help of equations which result from the equilibrium of a plate`s element and from the boundary and continuity conditions of the mean surface of the plate. One considers the following two cases: - the membrane stresses are small comparatively to the bending stresses; in this case the calculus is precise enough if we take into account only the mean plane extensions which will be superposed over the effects given by the transversal bending stress q; - the membrane stresses are considerable and can not be neglected; in this case, second order calculus is required.