<title>Negative-stiffness-mechanism vibration isolation systems</title>

Elastic composite with negative stiffness inclusions in antiplane strain

“…Anomalous fluctuations with temperature in the Young's modulus and loss tangent as well as negative Poisson's ratio were further reported in tetragonal BaTiO 3 after ageing under bending (Dong, Stone, & Lakes, 2010). Another experimental evidence was found in sound vibration attenuation and isolation observed in systems with negative stiffness elements (e.g., Park & Luu, 2007;Platus, 1999;Yang et al, 2010). It is seen from the above that the theoretical analysis of materials with negative stiffness inclusions proposed in the literature is based on the simple extension of the conventional elastic (or viscoelastic) solutions to the case of negative moduli.…”

“…In particular, it was suggested that such materials have elevated stiffness, thermal expansion and damping (Jaglinski, Kochmann, Stone, & Lakes, 2007;Lakes, 2001a;Lakes & Drugan, 2002;Wang, 2007;Wang, Ludwigson, & Lakes, 2004;Yap, Lakes, & Carpick, 2008). The list of possible applications includes sound attenuation (e.g., Yang, Dai, Chan, Ma, & Sheng, 2010) and vibration isolation (e.g., Park & Luu, 2007;Platus, 1999) and acoustic negative refraction (e.g., Fang et al, 2006). Applications are envisaged in high sensitivity sensors (through utilisation of postbuckling state of a beam (Samuel, Desai, & Haque, 2005) and actuators based on thermoelastic or piezoelectric coupling and in optimisation of existing technologies in which both stiffness and damping are important (Lakes & Drugan, 2002).…”

Vibration isolation system combining zero-power magnetic suspension with springs

“…The application of negative stiffness to vibration isolation was previously reported by Platus (1999) and Trimboli et al (1994). In their work, a negative spring was used in parallel with a positive spring to lower the stiffness of suspension of the isolation table.…”

An integrated design of quasi-zero stiffness mechanism

“…1) is called a Quasi-zero-stiffness (QZS) characteristic [4,5]. Many vibration isolators have been extensively studied using these QZS characteristics, such as high static loading and low natural frequency [6][7][8][9][10][11][12][13][14][15]. A combination of QZS characteristics and active control showed performance improvement of vibration isolation [16][17][18].…”