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Mechanical and optical properties of Polydimethylsiloxane (PDMS) have been measured and reported for different applications, however, a full analysis and a compendium of its tension and compression moduli behaviour have not been carried out, nor of its refractive index, for several mixture ratios, temperature and curing time. In this work, samples of PDMS were manufactured and tested to know tension and compression moduli and refractive index as a function of fabrication parameters; Minitab ® , Matlab ® 's Least-squares fitting in Curve Fitting Toolbox™ and genetic algorithms were employed to yield functional dependencies to describe PDMS's behavior. The obtained fitting polynomials are shown to have large agreement with experimental data. Finally, a potential application in the design of a gradient index lens for use in artificial vision is presented.

…describe the overall significance of this paper? This paper introduces a novel approach to incorporate the effect of variability in the microstructure to study failure in fiber reinforced composite materials. The uncertainty in the fiber volume fraction is propagated to determine the uncertainty in the failure location and in the strain invariant used to predict the onset of damage.…describe this work to a materials science and engineering professional with no experience in your technical specialty? In general, failure criteria in composite systems are based on a critical magnitude of an effective strain or stress. We present evidence that uncertainty in the fiber volume fraction affects the magnitude of the effective strain in the matrix phase at failure and therefore this uncertainty should be taken into account to predict damage of composite materials. This paper presents a model that determines the range of failure angles in an open hole off-axis specimen and the uncertainty in the critical effective shear strain in the matrix phase at failure due to uncertainties in the fiber volume fraction.

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