Dynamic simulation of seat suspension system with virtual prototyping technology

As known, one of main causes that which induce many damages of machinery, equipment is undesirable vibrations. Particularly, vibrations that occur in low frequency regions (<5Hz) are almost harmful and dangerous to human health and activity researched by (Paddan, 2002). Thus, suspensions are widely used to lengthen the service life of the machinery, equipment as well as to provide more comfortable and safe condition for human in vehicle. Commonly, a linear system (conventional system), which is widely used for isolating unwanted vibrations, consists of a linear stiffness spring, K, in parallel to a damper, C in (Thorby, 2008) and (Graham Kelly, 2002). The performance of vibration isolation can be only effective when the excitation frequency is greater than 2 times the natural frequency of the system. This limitation confines a conventional system to attenuate vibration in low frequency band. One of strategies for extending isolation ability to low frequency domain is to reduce the stiffness of the system. However, a reduction in stiffness results in a low load bearing capacity and an excessive static deformation of the system. This could cause many difficulties for designing a traditional system. Currently, there are many researchers, engineers and scholars who have suggested solutions to reduce the resonance frequency such as a highly deformed elastic structure working as a nonlinear spring is used to support a static load as presented by (Chnin et al., 2005), (Plaut et al., 2008), (Virgin et al., 2003) and (Winterflood et al., 2002) or another structure that is also based on the elastic model with extreme geometric nonlinearity is studied by (Santillan et al., 2005) and (Virgin et al., 2008). The purpose of elastic structures is to reduce the resonance frequency. However, these structures easily lose stability when the stiffness of the elastic elements is low. In order to overcome the dichotomy between load bearing capacity and reduction in stiffness, in recent years, quasi-zero stiffness (QZS) vibration isolation systems have been studied and developed by (Carrella et al, 2007, 2008 and 2012), (Hao et al., 2015) and (Kovacic et al, 2008). These systems are also referred to as high-static low-dynamic Dynamic simulation of seat suspension system with virtual prototyping technology