The dynamic behaviour in the audible frequency range of a magneto-sensitive silicone rubber was investigated experimentally. It was subjected to a constant shear deformation at varying frequencies and to an externally-applied magnetic field. In this manner, three characteristics inherent to the material were observed, i.e. viscoelasticity, magnetic sensitivity and amplitude dependence. The viscoelastic behaviour was found largely to resemble that of ordinary rubber. The influence of the magnetic field grew with decreasing strain, inducing a stiffness change surpassing 100% for very small amplitudes. As amplitudes in structures and air were normally small in the audible frequency range, this effect was highly relevant. Finally, unlike conventional rubber, magneto-sensitive rubber exhibited a strong amplitude dependence even for the smallest strains. 14 refs.

The selection of constitutive models for elastomers used as image carriers in printing processes is discussed. The validity of a general first-invariant model, fitted from one uniaxial loading case and describing deformation during other loading cases, was investigated. The fitting of the parameters of the Ogden law to the data of uniaxial tests of several silicone rubbers was also studied. For each soft silicone rubber, a set of Ogden parameters describing the uniaxial compression set was found. 7 refs.

The calibration of constitutive models is based on the solution of an optimisation problem, where parameter values are sought such that optimal correspondence between measured and simulated response is achieved. The calibration problem is solved in this study using a recently-proposed strategy, which has the advantage that discretisation errors induced in the simulated response, leading to errors in the optimal parameter values, are relatively straightforward to estimate. It is also possible to estimate how sensitive the obtained solution is to uncertainties in the experimental data for silicone rubber. 11 refs.

A statistical hyper-visco-elasto-plastic model comprising seven characteristic parameters was developed. To identify these parameters from material behaviour, a series of experimental tests was conducted at controlled temperatures (-55C to +70C). The tests were carried out on a double-shearing test-piece composed of a silicone elastomer filled with silica and subjected to triangular cyclic loading (at various deformation rates and various amplitudes) and in a relaxation test at various levels of deformation. Comparison of the model with experimental validation tests performed under multiharmonic loading showed that the model represented the data over a relatively wide range of frequencies and a large field of deformation. 11 refs.

Various recycled PTFE powders were compounded with silicone rubber and the mechanical properties, including TS, EB, tear strength and hardness, of silicone rubber/PTFE composite were evaluated. The effects of surface treatment of recycled PTFE and the addition of fluorosilicone rubber as a compatibiliser were also investigated. SEM observations confirmed that, after addition of fluorosilicone rubber, improvement of the interfacial adhesion between the dispersed phase and the polymer matrix occurred. 5 refs.