Patents by Inventor Lakshman Chandrasekaran
Lakshman Chandrasekaran has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 11198924Abstract: A fibre reinforced polymer (FRP) composite structure incorporates a woven preform containing tows of carbon or other advanced fibres and wires of shape memory alloy (SMA). The SMA wires are capable of absorbing much larger amounts of strain energy than the conventional components of FRP composites and hence enhance the impact resistance of the structure. The woven form incorporates the SMA into the structure in an optimum manner in terms of handling and performance.Type: GrantFiled: October 20, 2005Date of Patent: December 14, 2021Inventors: Lakshman Chandrasekaran, Andrew David Foreman
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Patent number: 8082846Abstract: A munitions casing including an annulus of a shape memory alloy disposed around said casing where the shape memory alloy has been subjected to a combination of mechanical and thermal treatments so as to impart a memory, and a cutter located between the annulus and the casing wherein heating of the shape memory alloy to a predetermined temperature causes said annulus to contract radially inwardly and rupture the said munitions casing.Type: GrantFiled: May 27, 2009Date of Patent: December 27, 2011Assignee: Qinetiq LimitedInventors: John Cook, Lakshman Chandrasekaran
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Publication number: 20100089272Abstract: A munitions casing including an annulus of a shape memory alloy disposed around said casing where the shape memory alloy has been subjected to a combination of mechanical and thermal treatments so as to impart a memory, and a cutter located between the annulus and the casing wherein heating of the shape memory alloy to a predetermined temperature causes said annulus to contract radially inwardly and rupture the said munitions casing.Type: ApplicationFiled: May 27, 2009Publication date: April 15, 2010Inventors: John Cook, Lakshman Chandrasekaran
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Patent number: 7549375Abstract: The invention comprises devices for mitigating the explosive reaction of a munition when it is subject to an external thermal hazard threat. The devices are based on the use of shape memory alloys. In one arrangement there is device which consists of a connector that is at least in part formed from a shape memory alloy, which typically undergoes large dimensional changes when heated or cooled through a particular transition temperature range. The connector in this invention is designed to form a locking engagement, between two components of a munitions casing at one temperature, but when subjected to external heating through the transition temperature range will deform to allow the connector to disengage and thus release the two joined components, allowing any build up of pressure to be released quickly. Advantageously if the co-operative parts of the connector and components are threaded portions, then the locking engagement will be capable of being dismantled during normal servicing of the munition.Type: GrantFiled: August 7, 2003Date of Patent: June 23, 2009Assignee: Qinetiq LimitedInventors: John Cook, Lakshman Chandrasekaran
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Patent number: 7393595Abstract: A composite element comprises:(a) a metal or metal alloy component having an elastic modulus that decreases with increasing temperature in a temperature range; and (b) sufficient amount of a shape memory alloy component having an elastic modulus that shows an increase in elastic modulus with increasing temperature in the said temperature range, such that the elastic modulus of the composite element does not fall substantially as the temperature is increased across the said temperature range. An article comprising such a composite element is suitable for use in high temperature applications, including motor vehicle components.Type: GrantFiled: November 27, 2002Date of Patent: July 1, 2008Assignee: Qinetiq LimitedInventors: Lakshman Chandrasekaran, Alan J Shakesheff
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Publication number: 20070202296Abstract: A fibre reinforced polymer (FRP) composite structure incorporates a woven preform containing tows of carbon or other advanced fibres and wires of shape memory alloy (SMA). The SMA wires are capable of absorbing much larger amounts of strain energy than the conventional components of FRP composites and hence enhance the impact resistance of the structure. The woven form incorporates the SMA into the structure in an optimum manner in terms of handling and performance.Type: ApplicationFiled: October 20, 2005Publication date: August 30, 2007Inventors: Lakshman Chandrasekaran, Andrew Foreman
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Publication number: 20060054046Abstract: The invention comprises devices for mitigating the explosive reaction of a munition when it is subject to an external thermal hazard threat. The devices are based on the use of shape memory alloys. In one arrangement there is device which consists of a connector that is at least in part formed from a shape memory alloy, which typically undergoes large dimensional changes when heated or cooled through a particular transition temperature range. The connector in this invention is designed to form a locking engagement, between two components of a munitions casing at one temperature, but when subjected to external heating through the transition temperature range will deform to allow the connector to disengage and thus release the two joined components, allowing any build up of pressure to be released quickly. Advantageously if the co-operative parts of the connector and components are threaded portions, then the locking engagement will be capable of being dismantled during normal servicing of the munition.Type: ApplicationFiled: August 7, 2003Publication date: March 16, 2006Applicant: QinetiQ LimitedInventors: John Cook, Lakshman Chandrasekaran
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Publication number: 20050067059Abstract: A composite element comprises:(a) a metal or metal alloy component having an elastic modulus that decreases with increasing temperature in a temperature range; and (b) sufficient amount of a shape memory alloy component having an elastic modulus that shows an increase in elastic modulus with increasing temperature in the said temperature range, such that the elastic modulus of the composite element does not fall substantially as the temperature is increased across the said temperature range. An article comprising such a composite element is suitable for use in high temperature applications, including motor vehicle components.Type: ApplicationFiled: November 27, 2002Publication date: March 31, 2005Inventors: Lakshman Chandrasekaran, Alan Shakesheff
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Patent number: 6865791Abstract: A method of generating force between a structure and an additional member, particularly for reinforcing an existing structure so that an additional member can share existing load. Pre-cooled or pre-heated shims of shape memory alloy (SMA) are inserted between the additional member and the existing structure, or between different sub-units of the additional member, or between the additional member and shoes fixed for this purpose to the existing structure. On subsequent warming or cooling the SMA shims expand to apply compressive forces to the portions of the structure, additional member or shoe(s) with which they are in contact on their opposite sides. Further compressive, tensile, flexural or torsional forces will be developed within other parts of the structure and additional member as a result of the shim expansion depending on the particular arrangement.Type: GrantFiled: May 8, 2001Date of Patent: March 15, 2005Assignee: Qinetiq LimitedInventors: John Cook, Lakshman Chandrasekaran
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Publication number: 20030126828Abstract: A method of reinforcing a structure with an additional member, said additional member comprising one or more sub-units comprising the steps of: (a) inserting pre-cooled or pre-heated shims (6) of shape memory alloy between said member (4, 8) and said structure (2, 3) or between at least two of said sub-units; (b) allowing said shims to expand on subsequent cooing or warming so as to force said member into compression or tension against said structure, simultaneously driving an adjacent portion of said structure into tension or compression.Type: ApplicationFiled: November 5, 2002Publication date: July 10, 2003Inventors: John Cook, Lakshman Chandrasekaran
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Patent number: 6129951Abstract: A physical vapour deposition apparatus for pre-coating fibres of a reinforcement material with a predetermined thickness of matrix metal prior to consolidation to yield a metal matrix composite material comprises: at least one evaporation crucible; a heater for heating a charge of metal in the at least one evaporation crucible to a temperature at which an appreciable vapour pressure is generated and a flux of metal vapour is evolved; a powered take-up device for drawing the reinforcement through the apparatus, and a guide mechanism for guiding the reinforcement repeatedly through the vapour flux, and to effect twisting of the reinforcement about its longitudinal axis after each successive pass through the vapour flux by an amount which is a fraction of 180.degree.. The guide mechanism comprises a pair of multi-pass transfer rollers each having a multiplicity of concentric fibre-receiving grooves formed on its surface.Type: GrantFiled: September 1, 1998Date of Patent: October 10, 2000Assignee: The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kindgom of Great Britain and Northern IrelandInventors: Charles M. Ward-Close, Lakshman Chandrasekaran