A particular class of laminated composites is presented where the stiffness characteristics are isotropic with respect to both in-plane and out-of-plane stiffnesses. The paper presents a determining method for isotropic and orthotropic laminate configurations and shows examples of isotropic laminates consisting of 40 plies. Experimental verifica tion by a tension test and a four-point flexure test has been made on a 40-ply isotropic lam inate. Experimental results of elastic properties show almost isotropic properties.
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