University of Dayton

United States of America As Represented by the Secretary of the Air Force

George A Hartman

James R Sebastian

A new extensometer is disclosed that avoids prior art problems of drift and other problems from variations in temperature, humidity and other environmental factors. Two primary extensometer body parts each hold at one end specimen contact rods and at their other ends a displacement measuring sensor, preferably a linear variable differential transformer. A thin hinge area connects the two body parts into a single piece monolithic construction so that relative movement between the two body parts is restricted to a single rotational degree of freedom.

Stable LVDT extensometer

A magnetostrictive actuator is provided comprising an actuator base, a magnetostrictive assembly, an actuator frame, and a flexible disk. The magnetostrictive assembly includes a magnetostrictive element. A first end of the magnetostrictive element is mechanically coupled to the actuator base. A first portion of the actuator frame is mechanically coupled to the actuator base. The flexible disk includes a perimetrical disk portion and a bearing surface portion. The perimetrical disk portion is mechanically coupled to the second frame portion and the bearing surface portion is mechanically coupled to the second magnetostrictive element end portion. The magnetostrictive actuator comprises a magnetostrictive material portion and a plurality of cooling fluid bores formed within the magnetostrictive material portion. Further, the magnetostrictive actuator may comprise an epoxy matrix, a plurality of cooling fluid bores formed within the epoxy matrix, and a plurality of magnetostrictive rods formed within the epoxy matrix.

Magnetostrictive actuator

A mechanical test system is provided comprising a primary actuator arranged so as to create mechanical movement of a first specimen holder along an axis of actuation and an oppositely oriented secondary actuator arranged so as to create mechanical movement of a second specimen holder along the axis of actuation. The magnetostrictive actuator comprises a magnetostrictive assembly including a magnetostrictive element and a flexible disk mechanically coupled to the magnetostrictive element. The magnetostrictive element comprises either a magnetostrictive material portion with a plurality of cooling fluid bores formed within the magnetostrictive material portion or an epoxy matrix with a plurality of cooling fluid bores and a plurality of magnetostrictive rods formed within the epoxy matrix.

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Waynesville, OH, United States of America

George A Hartman