Hisao Kikugawa

Effect of Long-Term Formalin Preservation on the Bending Properties and Fracture Toughness of Bovine Compact Bone

To precisely determine the mechanical properties of a bone, the effects of the preservation method on its mechanical properties need to be minimized. It seems likely that prolonged exposure to formalin (formaldehyde solution) will have some affect the mechanical properties of bone. This study investigated the effect of the formalin fixation method on the bending properties and fracture toughness of bovine cortical bone after short-term and relatively long-term preservation. To determine the elements and the quantities eluted from bone into formalin solution (the preservation medium), qualitative and quantitative analyses were performed by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Formalin fixation augments the bending stiffness of the cortical bone while diminishing its fracture toughness. As the bending strength diminishes concurrently with removal of Ca2+, this implies that inorganic components of bone contribute to its bending strength.

Postbuckling Stability Analysis of Composite Laminated Flat Plates with Initial Deflection under Biaxial Compression

Postbuckling Stability Analysis of Composite Laminated Flat Plates with Initial Deflection under Biaxial Compression Keiichi Nemoto1, Hirakazu Kasuya2, Hisao Kikugawa3 and Tooru Kohiga4, 1Department of Aerospace Engineering, The Yokohama Rubber Co., Ltd., Hiratsuka 2548601 2Department of Prime Mover Engineering, School of Engineering, Tokai University, Hiratsuka 2591292 3Department of Biomedical Engineering, School of Engineering, Tokai University, Hiratsuka 2591292 4Course of Mechanical Engineering, Graduate School of Engineering, Tokai University, Hiratsuka 2591292

Dynamic Behavior of Partially Liquid-Filled Thin Cylindrical Shells.

This report describes the dynamic behavior of partially liquid-filled thin cylindrical shells which are subjected to vertical excitation. In case too much liquid is contained, the structure is often damaged. The exciting acceleration, the surface deformation and the generated sound, as dynamic behavior of the shell made of a Lummiror polyester sheet, are treated experimentally. The acceleration and the deformation vary with discontinuity as if the transition phenomena occurred. The transition is caused in the lower frequency region at the longer cylinder effective length, that is, with the increased liquid potential head. The frequency response of the shell wall is observed as several spectra which change due to transition. The acoustic spectra of sound generated from the shell depend on the wall response. There are correlations between both characteristics. Therefore, the response condition of the shell wall can be predicted by the acoustic spectrum.