Finite Element Analysis (FEA) was used to model viscoelastic effects in the compression of polyurethane (PU) foam. Modelling of the impact compression of foam cubes predicted that a compressed region propagated through the sample, causing step increases in the stress traces. Modelling of head impacts on gymnastic ‘crash’ mats, made of PU chip foam, revealed that the majority, but not all, of th...

SURGICAL TECHNIQUE The bubble mirror technique consists of the stabilization of the anterior chamber by means of a plug made with a combination of conveniently placed air and viscoelastic material. A line arises at interface between the air and viscoelastic where the anterior chamber angle reflected can be seen as in a mirror (bubble mirror). DISCUSSION The viscoelastic-air plug offers three ...

The dynamic response of an initially flat viscoelastic membrane is investigated. The viscoelastic model is described with fractional order derivatives. The membrane is subjected to surface transverse and inplane dynamic loads. The governing equations are three coupled second order nonlinear partial FDEs (fractional differential equations) of hyperbolic type in terms of the displacement componen...

We present a simple model for the adhesive contact of viscoelastic bodies relevant for soft solids. This approach couples the interaction zone creep and the contact zone stress relaxation through a transform of the interaction stresses g(a). We show that g(a), which is proportional to the interaction stress intensity factor, can be extracted from experimentally determined contact variables and ...

In this work, and based on numerical optimization techniques, constitutive parameters for viscoelastic materials are determined using a inverse problem formulation. The optimization methodology is based on experimental results obtained in the frequency domain, for a CFRP-Carbon Fibre Reinforced Polymer, through DMA-Dynamic Mechanical Analysis. The relaxation modulus of viscoelastic materials is...

The propagation of ultrasonic guided waves in viscoelastic isotropic material has been investigated. Based on the plane theory, a numerical model of the guided waves propagating is developed in the frequency domain by employing the SFEM (spectral finite element method). To verify the proposed method, thin bitumen on the steel substrate is examined and compared with the single plate in terms of ...

We study the radial motion of an incompressible viscoelastic spherical shell with a nonconvex strain energy function that models a material that can undergo a phase transition. In addition to the classical Newtonian viscosity for viscoelastic materials, we consider a material with two microstructural coefficients that are supposed to sense local configurational changes that take place during a ...