Gm Global Technolgoy Operations, Inc.

University of Michigan

Michigan State University

Dynalloy, Inc.

John Andrew Shaw

Nancy L Johnson

Alan L Browne

Paul W Alexander

Nilesh D Mankame

Christopher Burton Churchill

Guillermo A Herrera

Andrew C Keefe

David S Grummon

Geoffrey P McKnight

Xiujie Gao

Richard J Skurkis

Jeffrey W Brown

Chandra S Namuduri

Paul Edward Krajewski

Christopher Paul Henry

Robin Stevenson

Sanjeev Manubhai Naik

John C Ulicny

William R Rodgers

Diann Brei

Jonathan E Luntz

Jan Henning Aase

Pablo D Zavattieri

Kenneth A Strom

James Ryan Yates

Wayne Brown

Anupam Pathak

Benjamin Reedlunn

Ravindra Brammajyosula

An energy harvesting system for converting thermal energy to mechanical energy includes a heat engine that operates using a shape memory alloy active material. The shape memory alloy member may be in thermal communication with a hot region at a first temperature and a cold region at a second temperature lower than the first temperature. The shape memory alloy material may be configured to selectively change crystallographic phase between martensite to austenite and thereby one of contract and expand in response to the first and second temperatures. A thermal conduction element may be in direct contact with the SMA material, where the thermal conduction element is configured to receive thermal energy from the hot region and to transfer a portion of the received thermal energy to the SMA material through conduction.

Energy harvesting system

A heat engine includes a first rotatable pulley and a second rotatable pulley spaced from the first rotatable pulley. A shape memory alloy (SMA) element is disposed about respective portions of the pulleys at an SMA pulley ratio. The SMA element includes a first wire, a second wire, and a matrix joining the first wire and the second wire. The first wire and the second wire are in contact with the pulleys, but the matrix is not in contact with the pulleys. A timing cable is disposed about respective portions of the pulleys at a timing pulley ratio, which is different than the SMA pulley ratio. The SMA element converts a thermal energy gradient between the hot region and the cold region into mechanical energy.

Shape memory alloy heat engines and energy harvesting systems

A shape memory alloy (SMA) heat engine includes a first rotatable pulley, a second rotatable pulley, and an SMA material disposed about the first and second rotatable pulleys and between a hot region and a cold region. A method of starting and operating the SMA heat engine includes detecting a thermal energy gradient between the hot region and the cold region using a controller, decoupling an electrical generator from one of the first and second rotatable pulleys, monitoring a speed of the SMA material about the first and second rotatable pulleys, and re-engaging the driven component if the monitored speed of the SMA material exceeds a threshold. The SMA material may selectively change crystallographic phase between martensite and austenite and between the hot region and the cold region to convert the thermal gradient into mechanical energy.

Method of starting and operating a shape memory alloy heat engine

This invention discloses a method, using pure niobium as a transient liquid reactive braze material, for fabrication of cellular or honeycomb structures, wire space-frames or other sparse builtup structures or discrete articles using Nitinol (near-equiatomic titanium-nickel alloy) and related shape-memory and superelastic alloys. Nitinol shape memory alloys (SMAs), acquired in a form such as corrugated sheet, discrete tubes or wires, may be joined together using the newly discovered joining technique. Pure niobium when brought into contact with nitinol at elevated temperature, liquefies at temperatures below the melting point and flows readily into capillary spaces between the elements to be joined, thus forming a strong joint.

Manufacture of shape-memory alloy cellular materials and structures by transient-liquid reactive joining

An apparatus for and method of conditioning a thermally activated shape memory alloy wire for use in an application, wherein the apparatus includes an adjustable hard-stop and the preferred method includes pre-determining a minimum activating current, allowable strain, and a loading magnitude and form based on the wire configuration and application, and further includes applying a double-exponential model to determine a final recoverable strain over fewer cycles.

Apparatus for and method of conditioning shape memory alloy wire

A cable adapted for use as an actuator, adaptive structural member, or damper, includes a plurality of longitudinally inter-engaged and cooperatively functioning shape memory alloy wires.

Shape memory alloy cables

This invention discloses a method, using pure niobium as a transient liquid reactive braze material, for fabrication of cellular or honeycomb structures, wire space-frames or other sparse builtup structures or discrete articles using Nitinol (near equiatomic titanium-nickel alloy) and related shape-memory and superelastic alloys. Nitinol shape memory alloys (SMAs), acquired in a form such as corrugated sheet, discrete tubes or wires, may be joined together using the newly discovered technique. Pure niobium when brought into contact with Nitinol at elevated temperature, liquefies at temperatures below the melting point and flows readily into capillary spaces between the elements to be joined, thus forming a strong joint. A series of diagrams of the interface at various stages of brazing is illustrated by FIG.

Manufacture of shape memory alloy cellular materials and structures by transient-liquid reactive joining

Growing community of inventors

Dexter, MI, United States of America

John Andrew Shaw