eng Science and Education Publishing Biomedical Science and Engineering 2373-1265 2015-09-08 3 2 30 34 10.12691/bse-3-2-1 BSE2015321 article Tetsuya Kanagawa kanagawa@kz.tsukuba.ac.jp 1 Hisao Taira 2 Department of Engineering Mechanics and Energy, University of Tsukuba, Tsukuba, Japan Department of Education, Hokkaido University of Education, Sapporo Campus, Sapporo, Japan Bending a human joint generates a sound. This paper theoretically tackles the cracking sound generated by the manipulation of human joint such as finger. The Rayleigh-Plesset equation in the classical bubble dynamics is applied to determine the nonlinear oscillations of bubble that generates sound. Comparing the numerical solutions of the Rayleigh-Plesset equation for two types of modeling, i.e., forced- and free-oscillator assumptions for inhomogeneous terms, gives clear difference. http://pubs.sciepub.com/bse/3/2/1/bse-3-2-1.pdf cracking sound joint manipulation bubble dynamics bubble oscillation