George L. Ball

Alternative Low Cost Roofing Material Candidates Based On Bagasse Filled Composites

Four composite material systems useful for roofing in the tropics were developed which utilize major percentages of bagasse (sugar cane residue) filler, and minor amounts of phenolic or other resin binders. The various materials were actually manufactured in small quantities in three developing countries and trial exposure roofs installed.

Development of a Viscoelastic Composition having Superior Vibration‐Damping Capability

An intensive investigation of polymers, plasticizers, and fillers was conducted with the resulting development of a viscoelastic material that effectively damps 38‐in. steel plating. This vibration damping material exhibits greater than 3% critical damping over two decades of frequency, and a 45°F temperature range, at a one‐third plate‐weight application. At the temperature of maximum efficiency, the material exhibits greater than 9% critical damping over a decade of frequency. The viscoelastic damping material consists of a self‐extinguishing vinyl chloride/vinyl acetate copolymer, and is capable of withstanding both saline water and JP‐4 jet fuel. The application of this material in spaced and constrained damping systems results in the effective damping of steel plate up to 1.75 in. thick. The investigation also demonstrated that three types of fillers are useful in increasing the damping effectiveness of the polymer system: (1) flake, (2) granular, and (3) low‐density granular. The flake filler (e.g.,...

Viscoelastic High‐Damping Materials

An intensive investigation of polymers, polymer systems, and fillers was conducted that provided a material that effectively damps steel‐plating up to 2 in. thick. The damping material exhibited greater than 3% critical damping over two decades of frequency and a 25°C temperature range, at a 13 plate‐weight application. At an optimized temperature, the material exhibited greater than 9% critical damping over a decade of frequency. The damping material significantly reduced vibration and noise when applied to light‐ and moderate‐gauge steels. The investigation also revealed three effects of fillers useful in increasing the damping properties of a polymer system.