Stretch–bend-hybrid hierarchical composite pyramidal lattice cores

Structures, Volume 98, April 2013, Pages 153-159, ISSN 0263-8223, http://dx.doi.org/10.1016/j.compstruct.2012.11.004. Stretch–bend-hybrid hierarchical composite pyramidal lattice cores Sha Yin, Linzhi Wu, Steven Nutt 1. Center for Composite Materials, Harbin Institute of Technology, Harbin 150001, China 2. Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-0241, USA *Corresponding authors. Tel.: +86 451 86412549; fax: +86 451 86402739. E-mail addresses: [email protected] (S. Yin), [email protected] (L. Wu). Abstract: Hierarchical composite pyramidal lattice (CPL) cores with foam-core sandwich struts were designed, and two stacking patterns were fabricated and tested in out-of-plane compression. Analytical expressions for five possible failure modes were derived considering not only stretching and bending deformation but also shear deformation of struts. Core shear failure was absent from collapse mechanism maps for both Patterns-I and II CPL cores. Optimized Pattern-I hierarchical CPL cores were more efficient than Pattern-II cores. The following comparison with almost all competing composite sandwich cores revealed that the hierarchical CPL structures here, the assembly of both stretchand bend-dominated constructions, could perform among the most efficient sandwich cores. Meanwhile, the construction concept can also enable multifunctionality by judicious selection of strut core materials without compromising structural efficiency.