Damping in composite materials through domain wall motion
OwnerGreg P. Carman, Geoff McKnightinventors
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Abstract
The present invention relates to composite materials exhibiting passive domain-wall activated damping, methods for using passive domain-wall activated damping, and processes for producing materials that exhibit passive domain-wall activated damping. One typical embodiment uses a polymer matrix phase and a dispersed particulate phase that exhibits domain wall motion under an applied mechanical load. Materials that exhibit domain wall motion under an applied mechanical load include magnetostrictive, piezoelectric and electrostrictive materials. One specific embodiment used Terfenol-D as the damping phase, aligned by magnetization during curing in a polymer matrix. Other specific embodiments employed PZT-5H and PMN-PT as the damping phase.
Claims21
A composite material comprising:
- a damping phase,
- wherein the damping phase exhibits irreversible domain wall motion when acted on by a mechanical load exceeding a critical stress;
- a matrix phase,
- wherein the damping phase is dispersed within the matrix phase, and
- wherein the damping phase is anisotropically aligned within the matrix phase, and
- wherein the damping phase is less than about 60% by volume of the composite material, and
- wherein the damping phase is greater than 0% by volume of the composite material.
A process of fabricating a composite material, comprising
- mixing less than about 60% by volume damping phase into a matrix phase to form a mixture, wherein the damping phase exhibits irreversible domain wall motion when acted on by a mechanical load exceeding a critical stress;
- forming the mixture into a desired shape;
- applying an electromagnetic field, wherein the damping phase, aligns within the matrix phase;
- and
- solidifying the matrix phase while simultaneously applying the electromagnetic field.
Dependencies are inferred from the claim text.