Patents by Inventor Krishnaswamy Ravi-Chandar

Krishnaswamy Ravi-Chandar 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).

  • Patent number: 6581446
    Abstract: A method for determining the adhesion strength of any HVOF-coating/substrate system. This method applies a spherical indentor to the coated part in a loading-unloading cycle. During the loading phase, the substrate deforms plastically. During the unloading phase, the elastic-plastic mismatch between coating and substrate material properties gives rise to a tensile stress normal to the interface. This leads to delamination for a sufficient indentation load. A hybrid numerical-experimental approach calculates the interfacial adhesion. The threshold load for delamination is found experimentally. A finite element model calculates the corresponding adhesion stress for delamination. This method enables the quantitative evaluation of the adhesion for any coating/substrate interface, regardless of bond strength.
    Type: Grant
    Filed: October 11, 2001
    Date of Patent: June 24, 2003
    Assignee: The University of Houston
    Inventors: Loic Deneuville, Kenneth W. White, Krishnaswamy Ravi-Chandar
  • Publication number: 20010011066
    Abstract: The fabrication of superconducting wires and rods having desired and consistent electrical and mechanical properties, in particular those based on Yttrium Barium Copper Oxide (YBCO) and Bismuth Strontium Calcium Copper Oxide (BSCCO), is disclosed. The first fabrication step is to form an extrudable paste by mixing YBCO or BSCCO superconducting powder with a set of organic additives, which include binder, plasticizers lubricant, dispersant, and a solvent. The following additional steps are performed on both YBCO and BSCCO based wires or rods: (i) using a piston extruder to extrude the superconducting wire or rod; (ii) drying the wire or rod to remove the solvent; and (iii) subjecting the wire or rod to a binder burn-out treatment to remove the remaining organic additives. In addition, YBCO wires and rods also require a sintering step, while BSCCO wires and rods also require cold isostatic pressing and heat treatment steps.
    Type: Application
    Filed: January 19, 2001
    Publication date: August 2, 2001
    Applicant: UNIVERSITY OF HOUSTON
    Inventors: Krishnaswamy Ravi-Chandar, Devamanohar Ponnusamy, Kamel Salama
  • Patent number: 6191074
    Abstract: The fabrication of superconducting wires and rods having desired and consistent electrical and mechanical properties, in particular those based on Yttrium Barium Copper Oxide (YBCO) and Bismuth Strontium Calcium Copper Oxide (BSCCO), is disclosed. The first fabrication step is to form an extrudable paste by mixing YBCO or BSCCO superconducting powder with a set of organic additives, which include binder, plasticizer, lubricant, dispersant, and a solvent. The following additional steps are performed on both YBCO and BSCCO based wires or rods: (i) using a piston extruder to extrude the superconducting wire or rod; (ii) drying the wire or rod to remove the solvent; and (iii) subjecting the wire or rod to a binder burn-out treatment to remove the remaining organic additives. In addition, YBCO wires and rods also require a sintering step, while BSCCO wires and rods also require cold isostatic pressing and heat treatment steps.
    Type: Grant
    Filed: April 2, 1997
    Date of Patent: February 20, 2001
    Assignee: University of Houston
    Inventors: Krishnaswamy Ravi-Chandar, Devamanohar Ponnusamy, Kamel Salama
  • Patent number: 5656574
    Abstract: The fabrication of superconducting wires and rods having desired and consistent electrical and mechanical properties, in particular those based on Yttrium Barium Copper Oxide (YBCO) and Bismuth Strontium Calcium Copper Oxide (BSCCO), is disclosed. The first fabrication step is to form an extrudable paste by mixing YBCO or BSCCO superconducting powder with a set of organic additives, which include binder, plasticizer, lubricant, dispersant, and a solvent. The following additional steps are performed on both YBCO and BSCCO based wires or rods: (i) using a piston extruder to extrude the superconducting wire or rod; (ii) drying the wire or rod to remove the solvent; and (iii) subjecting the wire or rod to a binder burn-out treatment to remove the remaining organic additives. In addition, YBCO wires and rods also require a sintering step, while BSCCO wires and rods also require cold isostatic pressing and heat treatment steps.
    Type: Grant
    Filed: January 13, 1995
    Date of Patent: August 12, 1997
    Assignee: University of Houston
    Inventors: Krishnaswamy Ravi-Chandar, Devamanohar Ponnusamy, Kamel Salama