ELASTOMER STRUCTURES, ROCKET MOTORS INCLUDING ELASTOMER STRUCTURES AND METHODS OF FORMING STRUCTURES FROM LAYERED VISCOELASTIC MATERIALS
Methods of forming structures from layered viscoelastic materials are disclosed. In some embodiments, such methods may include covering at least a portion of a first viscoelastic material layer disposed on a substrate with a portion of at least a second viscoelastic material layer and containing a quantity of gas within a space defined between a portion of the substrate, a portion of the first viscoelastic material layer and a portion of the second viscoelastic material layer. The methods may further include forming at least one discrete fluid path between the defined space containing the quantity of gas and the vacuum, and removing at least a portion of the quantity of gas from the defined space through the at least one discrete fluid path. Additionally, elastomer structures comprising at least one void defined therein, the at least one void exhibiting at least a partial vacuum, are disclosed.
1 . A method of forming a structure from layered viscoelastic material, the method comprising:
covering at least a portion of a first viscoelastic material layer disposed on a substrate with a portion of at least a second viscoelastic material layer to form a defined space containing a quantity of gas between a portion of the substrate, a portion of the first viscoelastic material layer and a portion of the at least a second viscoelastic material layer;
forming at least one discrete fluid path between the defined space containing the quantity of gas and a vacuum; and
removing at least a portion of the quantity of gas from the defined space through the at least one discrete fluid path.
2 . The method of claim 1 , further comprising:
covering the first viscoelastic material layer and the at least a second viscoelastic material layer with a flexible membrane; and
forming the vacuum between the flexible membrane and the first viscoelastic material layer and the at least a second viscoelastic material layer.
3 . The method of claim 2 , further comprising positioning a woven fabric between the flexible membrane and the first viscoelastic material layer and the at least a second viscoelastic material layer.
4 . The method of claim 2 , further comprising:
positioning the substrate, the first viscoelastic material layer and the at least a second viscoelastic material layer and the flexible membrane within an autoclave; and
forming a vacuum within the autoclave outside of the flexible membrane.
5 . The method of claim 2 , wherein forming at least one discrete fluid path between the defined space containing the quantity of gas and the vacuum comprises expanding the defined space containing the quantity of gas and separating the first viscoelastic material layer and the at least a second material layer until an opening is created between the defined space containing the quantity of gas and the vacuum.
6 . The method of claim 5 , further comprising containing a sufficient quantity of gas within a defined space with the at least a second viscoelastic material layer to separate the first viscoelastic material layer and the at least a second viscoelastic material layer to form the opening by a gas pressure provided by the contained quantity of gas.
7 . The method of claim 5 , further comprising positioning an edge of the at least a second viscoelastic material layer at a location relative to the defined space containing the quantity of gas that allows a gas pressure provided by the contained quantity of gas to separate the first viscoelastic material layer and the at least a second viscoelastic material layer to form the at least one discrete fluid path.
8 . The method of claim 1 , wherein forming at least one discrete fluid path between the defined space containing the quantity of gas and the vacuum comprises cutting at least one groove into a surface of at least one of the first and the at least a second viscoelastic material layers, the at least one groove extending from the defined space containing the quantity of gas to the vacuum.
9 . The method of claim 1 , wherein forming at least one discrete fluid path between the defined space containing the quantity of gas and the vacuum comprises positioning a gas permeable material between the first and the at least a second viscoelastic material layers to provide a gas permeable path extending from the defined space containing the quantity of gas to the vacuum.
10 . The method of claim 9 , wherein positioning a gas permeable material between the first viscoelastic material layer and the at least a second viscoelastic material layer comprises positioning a fibrous material between the first viscoelastic material layer and the at least a second viscoelastic material layer.
11 . The method of claim 9 , wherein positioning a gas permeable material between the first viscoelastic material layer and the at least a second viscoelastic material layer comprises positioning a powdered material between the first viscoelastic material layer and the at least a second viscoelastic material layer.
12 . The method of claim 9 , wherein positioning a gas permeable material between the first viscoelastic material layer and the at least a second viscoelastic material layer comprises positioning a liquid material between the first viscoelastic material layer and the at least a second viscoelastic material layer.
13 . The method of claim 1 , wherein covering at least a portion of a first viscoelastic material layer with a portion of at least a second viscoelastic material layer comprises covering at least a portion of a first less than fully cured polybenzimidazole fiber reinforced nitrile butadiene rubber sheet with a portion of at least a second less than fully cured polybenzimidazole fiber reinforced nitrile butadiene rubber sheet.
14 . The method of claim 1 , wherein:
the quantity of gas contained within the defined space comprises a quantity of air contained within the defined space; and
forming at least one discrete fluid path between the defined space containing the quantity of gas and the vacuum comprises forming at least one discrete fluid path between the defined space containing the quantity of air and the vacuum; and
removing at least a portion of the quantity of gas from the defined space through the at least one discrete fluid path comprises removing at least a portion of the quantity of air from the defined space through the at least one discrete fluid path.
15 . The method of claim 2 , further comprising applying an isostatic pressure to the flexible membrane, the first viscoelastic material layer and the at least a second viscoelastic material layer.
16 . The method of claim 15 , wherein applying an isostatic pressure comprises applying ambient atmospheric pressure to the flexible membrane, the first viscoelastic material layer and the at least a second viscoelastic material layer.
17 . The method of claim 1 , wherein covering at least a portion of a first viscoelastic material layer disposed on a substrate with a portion of at least a second viscoelastic material layer comprises covering at least a portion of a first viscoelastic material layer, the first viscoelastic material layer disposed on at least a third viscoelastic material layer of a substrate comprising the third viscoelastic material layer, with a portion of at least a second viscoelastic material layer.
18 . A unitary elastomer structure, comprising: at least one void defined therein, the at least one void exhibiting at least a partial vacuum.
19 . The unitary elastomer structure of claim 18 , wherein the unitary elastomer structure is positioned between a heat source and a heat sensitive structure to provide thermal insulation therebetween.
20 . The unitary elastomer structure of claim 19 , wherein the unitary elastomer structure is adhered to a casing of a solid rocket motor between the casing and a solid propellant grain.
21 . The unitary elastomer structure of claim 20 , wherein the unitary elastomer structure comprises polybenzimidazole fiber reinforced nitrile butadiene rubber.
22 . The unitary elastomer structure of claim 20 , wherein the unitary elastomer structure comprises asbestos fiber reinforced nitrile butadiene rubber.
23 . The unitary elastomer structure of claim 18 , wherein the void exhibits a gas pressure of less than about 1 psia.
24 . A solid rocket motor comprising: an insulation layer comprised of a unitary elastomer structure having at least one void defined therein, the at least one void exhibiting at least a partial vacuum.
25 . The solid rocket motor of claim 24 , wherein the insulation layer is adhered to a casing and positioned between the casing and a solid propellant grain.
26 . The solid rocket motor of claim 25 , wherein the unitary elastomer structure comprises polybenzimidazole fiber reinforced nitrile butadiene rubber.
27 . The solid rocket motor of claim 25 , wherein the unitary elastomer structure comprises asbestos fiber reinforced nitrile butadiene rubber.
28 . The solid rocket motor of claim 24 , wherein the at least one void exhibits a gas pressure of less than about 1 psia.