In recent years, the bio-refining industry has developed a number of cyclic molecules with unique attributes derived from renewable carbohydrate feedstocks. Isosorbide is one such compound that has a distinctive fused bicyclic ring system that provides a scaffold for the development of novel bio-based resin systems. We synthesized isosorbide-methacrylate (IM) by the direct esterification of isosorbide using highly reactive species such as methacryloyl chloride or methacrylic anhydride and a base catalyst. IM is a low viscosity (157 cP) cross-linking resin that free radically reacts to form a thermoset polymer with extent of cure at 85%. The resulting polymer has a T g greater than 240 C and main degradation temperature of $400 C. Mechanical test results showed that IM had a modulus of $4 GPa and strength of 85 MPa. These thermal and mechanical properties show that IM has a significantly higher temperature operating window than any known vinyl ester resin and has similar performance to expensive high temperature epoxy resins. As such, this material has good potential for use in composite applications where a moderate to high temperature free radical cured polymer matrix is needed.
This paper presents an analysis of the vibroacoustic response of a finite, simply supported rectangular plate covered by a layer of decoupling material and immersed in a heavy fluid. An exact formulation using the three-dimensional theory of elasticity for the decoupling material is derived for this problem, thereby extending previous studies that were limited to infinite plates. The paper details the constitutive equations of the problem and the analytical method of solution. Numerical results show that shear waves in the decoupling material generally have little influence on the sound radiation in the heavy fluid. Comparisons with a locally reacting model of the decoupling material and with the simple model of House [Proc. I.O.A. 13(3), 166-173 (1991)] are also presented.
The vibroacoustic behavior of an elastic, simply supported rectangular plate covered by a locally reacting decoupling layer supporting thickness deformation is presented. The model simulates the vibration and acoustic response of the system immersed in water and subjected to a point force disturbance. A simplified version of the theory is derived in the limiting case of a large decoupling (low mechanical impedance of the layer/high frequency). An appropriate vibratory indicator, representative of the acoustic attenuation provided by the decoupling treatment, and independent of the structure dimensions, is also investigated from the perspective of small-scale laboratory characterization.
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