{ "title": "Nonlinear and Chaotic Motions for a Shock Absorbing Structure Supported by Nonlinear Springs with Hysteresis Using Fast FEA", "authors": "T. Yamaguchi, Y. Kurosawa, S. Maruyama, K. Tobita, Y. Hirano, K. Yokouchi, K. Kihara, T. Sunaga", "country": null, "institution": null, "volume": "79", "journal": "International Journal of Mechanical and Mechatronics Engineering", "pagesStart": 1562, "pagesEnd": 1574, "ISSN": "1307-6892", "URL": "http:\/\/waset.org\/publications\/16483", "abstract": "

This paper describes dynamic analysis using proposed
\r\nfast finite element method for a shock absorbing structure including a
\r\nsponge. The structure is supported by nonlinear concentrated springs.
\r\nThe restoring force of the spring has cubic nonlinearity and linear
\r\nhysteresis damping. To calculate damping properties for the structures
\r\nincluding elastic body and porous body, displacement vectors as
\r\ncommon unknown variable are solved under coupled condition. Under
\r\nsmall amplitude, we apply asymptotic method to complex eigenvalue
\r\nproblem of this system to obtain modal parameters. And then
\r\nexpressions of modal loss factor are derived approximately. This
\r\napproach was proposed by one of the authors previously. We call this
\r\nmethod as Modal Strain and Kinetic Energy Method (MSKE method).
\r\nFurther, using the modal loss factors, the discretized equations in
\r\nphysical coordinate are transformed into the nonlinear ordinary
\r\ncoupled equations using normal coordinate corresponding to linear
\r\nnatural modes. This transformation yields computation efficiency. As
\r\na numerical example of a shock absorbing structures, we adopt double
\r\nskins with a sponge. The double skins are supported by nonlinear
\r\nconcentrated springs. We clarify influences of amplitude of the input
\r\nforce on nonlinear and chaotic responses.<\/p>\r\n", "references": null, "publisher": "World Academy of Science, Engineering and Technology", "index": "International Science Index 79, 2013" }