The bulk modulus and Poisson's ratio of “incompressible” materials

✍ Scribed by P.H. Mott; J.R. Dorgan; C.M. Roland

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 127 KB
• Volume: 312
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1016/j.jsv.2008.01.026

✦ Synopsis

Poisson's ratio, n, is a fundamental parameter characterizing the mechanical behavior of a material. Because the ratio of the bulk to the shear modulus, B/G, becomes infinite when n ¼ 1=2, it is often assumed that the bulk modulus becomes very large as a material approaches ''incompressibility.'' This is incorrect; experimental results for viscoelastic materials show that changes in the bulk modulus are actually negligible as n approaches 1/2. An analysis is performed to clarify the apparent conflict between the classic elastic equations and the experiments. At n ¼ 1=2, the bulk modulus is shown to exhibit a singularity, but this is irrelevant to real materials.