Some new considerations concerning the Rayleigh‐wave velocity in auxetic materials

Abstract

The Rayleigh wave velocity is examined in isotropic and non‐isotropic auxetic (negative Poisson's ratio) solids. A novel approximation of the Rayleigh wave speed c versus the Poisson's ratio of an isotropic solid is derived using the concept of ellipticity. The Rayleigh wave propagation is investigated also for anisotropic incompressible solids, such as thick composite balanced symmetric cross‐ply laminates, exhibiting through‐the‐thickness negative Poisson's ratio. The results show increased wave speed for auxetic laminate configurations, as well as increased sensitivity of the wave speed in the cross‐ply regions corresponding to NPR values. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Wave motion in auxetic solids

“…To observe the variation of α for the whole range of the Poisson's ratio, values of α have been obtained for −1 ≤ ν ≤ 0.5, as shown in Fig. .…”

“…Ratio of c 3 / c 2 for −1 ≤ ν ≤ 0.5 (adapted from Vinh and Malischewsky , and Scarpa and Malischewsky ).…”

“…Due to some uniqueness of dynamic stress propagation as compared to static and quasi‐static stress, it is worth investigating the wave motion in auxetic materials in comparison to conventional solids. The dynamic behavior of auxetic materials and structures has been investigated by Chen and Lakes , Scarpa et al , Trzupek et al , Koenders , Malischewsky and Tuan , Maruszewski et al , Kolat et al , and Hou et al . Lipsett and Beltzer considered the effect of Poisson's ratio on Rayleigh and Lamb waves.…”

Acoustic properties of auxetic foams

“…The wave propagation properties of auxetic materials have been studied from theoretical [4] and numerical/experimental perspectives in composite materials [5] and deterministic cellular structures [6]. In 1994, Howell et al [7] measured the acoustic absorption of NPR foams.…”

Vibro-Acoustic Properties of Auxetic Open Cell Foam: Model and Experimental Results

“…Since the publication of that seminal paper,awide range of materials featuring the NPR effect has been produced, from long fibre composites to honeycombs and microporous polymers [2]. The wave propagation properties of auxetics have been studied from at heoretical [3] and numerical/experimental perspective in deterministic cellular structures [4] and composite materials [5]. In 1994, Howell, Prendergarst and Hansen measured the acoustic absorption of transformed NPR foams [6].…”