Title: Directional damage and failure of composite materials under cyclic loading

Authors: Moez Chafra, Yvon Chevalier

Addresses: IPEI EL Manar, Systems and Applied Mechanics Laboratory, Polytechnic School of Tunisia. LASMAP BP 244, 2090 El Mana, Tunisia. ' Laboratory of Engineering of Mechanical Systems and Materials (LEMSMA), Institute Superior of Mechanics of Paris (ISMEP), Vibroacoustic Group, 3, rue F. Hainaut, 93407, Saint Ouen cedex, France

Abstract: Fibre orientation and shape of structure create directional effects that must be taken into account in mechanical behaviour of composite materials. Some orientations are more sensitive to strain and failure. This sensitivity is analysed by considering the feature of loading (direction and type that depend on the sign of stress components). We suggest a model able to identify mechanical properties in various directions by using an iso-strain quadratic surface in the space of stress. And we define a directional damage parameter, which depends on the plastic residual strain and the loading cycles. For failure, we use a quadratic surface similar to Hill criterion, the coefficients of which depend on loading cycles, for each type and direction of loading. Computations are validated on unidirectional glass.

Keywords: composites; behaviour law; anisotropy; failure; cyclic loading; off axes tests; hill criterion; proportional loading; directional damage; mechanical behaviour; fibre orientation; strain; stress.

DOI: 10.1504/IJVD.2005.007227

International Journal of Vehicle Design, 2005 Vol.39 No.1/2, pp.163 - 172

Available online: 24 Jun 2005 *

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