| The laminated composites have become one of the most important development branches of the damping function structural materials and a hot research topic because of their excellent mechanical properties and damping property. According to the strengthen mechanism of shell material, damping mechanism of laminated composites and preparation technology of ARALL, two novel kinds of multiple laminated composites, fiber/resin/metal laminated composites and foam metal/resin/metal laminated composites, are designed and developed. The fiber/resin/Al alloy laminated composites and foam aluminum/ resin/Al alloy laminated composites are successfully fabricated by heat-squeeze solidifying and forming technique. In the course of preparing, based on many experiments and analyses, a set of excellent processing procedure and parameter optimized is obtained. This ensures that the performance of laminated composites is reliable and stabile.The surface treatment of blasting shot and acid corrosion on the surface of Al alloy and the surface treatment of oxidize and coating with silane coupling agents on the surface of fibers are adopted. The morphology of the interface, bonding state and fracture morphology of the two kinds of laminate composites are observed and analyzed by means of scanning electron microscope (SEM). Results indicate that the bonding state on Al alloy/resin and fiber/resin interfaces is good after surface treating on composite elements. The interface bonding state and strength of Al alloy/resin and fiber/resin interfaces can be improved by the surface treatment on aluminum alloy plate and fiber. The interface bonding mechanism and damaging mechanism of these laminate composites are discussed.The tensile strength, bending strength and impacting toughness of two kinds of laminated composites are tested. Experimental results show that the glass fiber/resin/ Al alloy laminated composites possess good integrated properties, i.e., the tensile strength is 507.4MPa and the bending strength is 348.1MPa under the condition that the fiber content is 30%. Moreover, foam aluminum/ resin/Al alloy laminated composites possess good bending strength (298.7MPa) and outstanding impacting toughness (18.07J·cm-2). The mechanical properties of two kinds of laminated composites accords with the mixing rule of composite materials basically. The reinforcing mechanisms of the fibersand foam aluminum contributed to the laminated composites are analyzed: The high strength of the fiber has guaranteed the fiber/resin/Al alloy laminated composites possess high tensile strength and bending strength. And 'draw-up from matrix' of glass fiber and 'stress-strain platform effect' of aluminum foam make important contribution to impacting toughness of the two kinds of laminated composites.Based on the method of free vibration attenuation, the damping properties of the two kinds of laminated composites are tested. The different contributions from resin, fiber, foam aluminum, laminated structure and interface to damping properties of the laminated composites are researched. The free damping factors of the fiberglass/resin/Al alloy laminated composites, carbon fiber/resin/Al alloy laminated composites and foam aluminum/ resin/Al alloy laminated composites are separately up to 0.332, 0.266 and 0.323, which are much higher than the aluminum alloy base layer (smaller than 0. 004). The damping mechanism of the laminated composites is discussed preliminary. The damping property of laminated composites is made up of the damping of base layer, interface layers and structure surtax damping. The main damping element comes from resin and foam aluminum. The fiber/resin interface and foam aluminum/resin interface offer a large number of interfaces to produce damping effort. Aluminum alloy/resin structure is superimposed with two kinds of laminated composites with different nature. Furthermore, foam aluminum/resin structure like network with adhesiveness offers the structure damping for the laminated composites.
|
PDF Full Text Request