Failure of cellular foams under multiaxial loading

• Published in: Composites. Part A, Applied science and manufacturing Applied science and manufacturing, 2002-01, Vol.33 (2), p.163-176
• Main Authors: Gdoutos, E.E, Daniel, I.M, Wang, K.-A
• Format: Article
• Language: English
• Subjects: A. Honeycomb; A. Plates; B. Elasticity; B. Fracture; Cellular foams
• ISSN: 1359-835X; 1878-5840
• DOI: 10.1016/S1359-835X(01)00110-5

A thorough investigation of the mechanical behavior of a closed-cell cellular foam (Divinycell) under multiaxial stress conditions was undertaken. Two types of Divinycell, H100 and H250, with densities of 100 and 250 kg/m 3, respectively, were investigated. The uniaxial tensile, compressive and shear stress–strain curves along the in-plane and the through-the-thickness directions of both materials were obtained. The materials showed quite different stress–strain behavior in tension and compression. The H100 material showed a nearly isotropic behavior, while the H250 material showed orthotropic behavior with a higher stiffness along the through-the-thickness than the in-plane direction. A series of biaxial tests were conducted, including: (i) constrained strip specimens in tension and compression with the strip axis along the through-the-thickness and in-plane directions; (ii) constrained thin-wall ring specimens in compression and torsion; (iii) thin-wall tube specimens in tension and torsion; and (iv) thin-wall tube specimens under axial tension, torsion and internal pressure. From these tests, biaxial strength results in the stress plane of the through-the-thickness and in-plane directions for different values of applied shear were obtained. Failure envelopes were constructed by the Tsai–Wu failure criterion based on the strength values in uniaxial tension, compression and shear. The experimental results were described well by the Tsai–Wu failure criterion.