- "Welsch, Gerhard E." (x)
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Show moreBackground of the invention: Cellular materials can be made to combine high strength to weight ratio, elastic resilience and energy absorbing properties. They are attractive for lightweight structures, packaging and insulating purposes. Nature provides an abundance of examples in wood, leaves, cork, bone and many other organically built structures that display a wealth of intricate and ingenious shapes, forms and designs. Bone and its growth response to stresses is an example of the versatility and of the adaptability of cell structures to mechanical requirements. Manmade cellular materials have found many applications because it is possible to tailor the properties for a variety of purposes, such as for packaging, insulating, or structural purposes. Open cell structures such as foamed polymers constitute perhaps the most widely used manmade cell materials. Significant developments have also been made in the fabrication of cell materials from metals, glass, ceramics and graphite. Honeycomb structures may be considered as cell structures with designed architecture. They find use in structural applications such as for lightweight aircraft components. A variety of methods exist for producing cell structures of less well defined design. Such are the foaming methods. Metallic foams are well suited for a variety of applications including impact energy absorbers, silencers, filters, heaters, heat exchangers and structural parts, but more cost effective competitive materials are generally used. Open metal foams were investigated by Ford Motor Company in the early 1970's, but they have not yet found significant use in motor vehicles. One reason for this may be that such foams can be easily crushed in compression due to buckling and plastic collapse of relatively thin cell walls. The inventors presented their analysis of closed cell metal composites in their published article, M. Ozgur, R. L. Mullen and G. Welsch, "Analysis of Closed Cell Metal Composites" Acta Mater., Vol. 44, No. 5, pp. 2115-2126 (.COPYRGT.1996). They also presented the results of finite modelling of pressurized closed all composites in M. Ozgur, R. L. Mullen, G. Welsch, "Finite Element Modelling of Internally Pressurized Closed Cell Composites" International Journal for Numerical Methods in Engineering, Vol. 39, pp. 3715-3730 (.COPYRGT.1996). Closed cell metal composites offer advantages over open cell metal foams. An object of this invention is to provide an artificial closed cell metal composite having desirable strength as well as damping or elastic properties. Depending upon the materials used in forming the closed cell metal composites, the resulting bodies can be compatibly adapted for use in a variety of applications ranging from biomedical prostheses to automotive brake disks, various castings and to structural parts.
http://www.google.com/patents?vid=USPAT6709739
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Show moreBackground of the invention: The present invention relates to the capacitor arts. It finds particular application in conjunction with titanium, aluminum, tantalum and other metal sponges or particles in the form of thin layers for providing capacitor anodes and cathodes of high surface area, and will be described with particular reference thereto. The invention is also applicable to a variety of applications in which a high accessible surface area to volume ratio is desired. Electrical devices, such as power supplies, switching regulators, motor control-regulators, computer electronics, audio amplifiers, surge protectors, and resistance spot welders often require substantial bursts of energy in their operation. Capacitors are energy storage devices that are commonly used to supply these energy bursts by storing energy in a circuit and delivering the energy upon timed demand. Typically, capacitors consist of two electrically conducting plates, referred to as the anode and the cathode, which are separated by a dielectric film. In order to obtain a high capacitance, a large dielectric surface area is used, across which the electrical charge is stored. The capacitance, C of a capacitor is determined by the formula: C [ Farads ] = Q [ coulombs ] V [ volts ] ( 1 )where Q is the electrical charge and V is the voltage between the plates. Capacitance is proportional to the charge-carrying area of the facing plates, A, and is inversely proportional to the gap width, X, so that C [ Farads ] = ( ɛ · ɛ 0 [ F / m ] ) A [ m 2 ] X [ m ] ( 2 )
where (∈·∈0) is a proportionality constant, ∈0 is the permittivity of vacuum (value=8.85 · 10−12 Farad/m), and ∈ is the relative permittivity or dielectric constant for a dielectric substance. High capacitance capacitors should have a large area, A, and a thin dielectric film with a high dielectric constant. Commercial capacitors attain large surface areas by one of two methods. The first method uses a large area of thin foil as the anode and cathode. See, e.g., U.S. Pat. No. 3,410,766. The foil is either rolled or stacked in layers. In the second method, a fine powder is sintered to form a single slug with many open pores, giving the structure a large surface area. See, e.g., U.S. Pat. No. 4,041,359. Both these methods require considerable processing to obtain the desired large surface area. In addition, the sintering method results in many of the pores being fully enclosed and thus inaccessible to the dielectric. To be effective as an energy storage device, a capacitor should have a high energy density.
http://www.google.com/patents?vid=USPAT6914769
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Show moreThis application claims the benefit of Provisional Application Ser. No. 60/003,512, filed Sep. 7, 1995. Background: Cellular materials can be made to combine high strength to weight ratio, elastic resilience and energy absorbing properties. They are attractive for lightweight structures, packaging and insulating purposes. Nature provides an abundance of examples in wood, leaves, cork, bone and many other organically built structures that display a wealth of intricate and ingenious shapes, forms and designs. Bone and its growth response to stresses is an example of the versatility and of the adaptability of cell structures to mechanical requirements. Manmade cellular materials have found many applications because it is possible to tailor the properties for a variety of purposes, such as for packaging, insulating, or structural purposes. Open cell structures such as foamed polymers constitute perhaps the most widely used manmade cell materials. Significant developments have also been made in the fabrication of cell materials from metals, glass, ceramics and graphite. Honeycomb structures may be considered as cell structures with designed architecture. They find use in structural applications such as for lightweight aircraft components. A variety of methods exist for producing cell structures of less well defined design. Such are the foaming methods. Metallic foams are well suited for a variety of applications including impact energy absorbers, silencers, filters, heaters, heat exchangers and structural parts, but more cost effective competitive materials are generally used. Open metal foams were investigated by Ford Motor Company in the early 1970's, but they have not yet found significant use in motor vehicles. One reason for this may be that such foams can be easily crushed in compression due to buckling and plastic collapse of relatively thin cell walls. Closed cell metal composites offer advantages over open cell metal foams. An object of this invention is to provide an artificial closed cell metal composite having desirable strength as well as damping or elastic properties. Depending upon the materials used in forming the closed cell metal composites, the resulting bodies can be compatibly adapted for use in a variety of applications ranging from biomedical prostheses to automotive brake disks, various castings and to structural parts. Brief description of the invention: A closed cell metal composite material comprises a plurality of closed structural metal cells that are joined together into an aggregate arrangement. Each cell encapsulates a fluid or fluid-like filler therein in order to provide strength and damping characteristics to the material. Fluid or fluid-like materials may be gases, liquids, powders and solids of relatively low elastic or plastic deformation strength in relation to the cell wall material. The aggregate arrangements of cells serve to provide crush resistance in compression. The cells are at least one nanometer in size.
http://www.google.com/patents?vid=USPAT5890268
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