Magnetostrictive vibration damper and energy harvester for rotating machinery

2017

Smart Mater. Struct.

Self Cite

The performance of magnetostrictive materials, especially those with high initial magnetic permeability and associated low magnetic reluctance, is sensitive to not just the amount of magnetic bias but also how the bias is applied. Terfenol-D and Galfenol have been characterized under constant magnetic field and constant magnetomotive force, which require active control. The application of a magnetic flux bias utilizing permanent magnets allows for robust magnetostrictive systems that require no active control. However, this biasing configuration has not been thoroughly investigated. This study presents flux density versus stress major loops of Terfenol-D and Galfenol at various magnetic flux biases. A new piezomagnetic coefficient d 33 f is defined as the locally-averaged slope of flux density versus stress. Considering the materials alone, the maximum d 33 f is 18.42 T GPa −1 and 19.53 T GPa −1 for Terfenol-D and Galfenol, respectively. Compared with the peak piezomagnetic coefficient d 33 * measured under controlled magnetic fields, the piezomagnetic coefficient d 33 f is 26% and 74% smaller for Terfenol-D and Galfenol, respectively. This study shows that adding parallel magnetic flux paths to lowreluctance magnetostrictive components can partially compensate for the performance loss. With a low carbon steel flux path in parallel to the Galfenol specimen, the maximum d 33 f increased to 28.33 T GPa −1 corresponding to a 45% improvement compared with the case without a flux path. Due to its low magnetic permeability, Terfenol-D does not benefit from the addition of a parallel flux path.

Section: Galfenol-with Flux Pathmentioning

confidence: 63%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Magnetic flux biasing of magnetostrictive sensors

2017

Smart Mater. Struct.

Self Cite

“…Compared with similar shunted dampers based on piezoelectric materials [15], magnetostrictive materials are able to provide a higher loss factor. Due to the mechanical robustness, high stiffness, and large damping capacity of Galfenol, Denget al [74] recently developed a ring-shaped damper which can be mounted inside gear body and dissipate gear meshing vibrations before they propagate and induce structure-borne noise. The semi-active vibration control devices mentioned above can also be self-sustained, since part of the electrical energy on the shunted circuit can be scavenged [95,96].…”

Section: Semi-active Controlmentioning

confidence: 99%

“…The damping capacity of magnetostrictive materials is usually described by the loss factor η in previous studies [15,74]. The value of η is calculated from strain versus stress curves as tan , 9…”

Section: Passive Controlmentioning

confidence: 99%

Review of magnetostrictive materials for structural vibration control

2018

Smart Mater. Struct.

Self Cite

Excessive vibrations in civil and mechanical systems can cause structural damage or detrimental noise. Structural vibrations can be mitigated either by attenuating energy from vibration sources or isolating external disturbance from target structures. Magnetostrictive materials coupling mechanical and magnetic energies have provided innovative solutions to vibration control challenges. Depending on the system's tunability and power consumption, the existing vibration control strategies are categorized into active, passive, and semi-active types. This article first summarizes the unique properties of magnetostrictive materials that lead to compact and reliable vibration control strategies. Several magnetostrictive vibration control mechanisms together with their performance are then studied using lumped parameter models. Finally, this article reviews the current state of vibration control applications utilizing magnetostrictive materials, especially Terfenol-D and Galfenol.

Magnetostrictive Devices

Wiley Encyclopedia of Electrical and Electronics Engineering

Calkins

et al. 2016

Magnetostrictive materials exhibit coupling between magnetic and mechanical energies. This bidirectional energy exchange can be employed for actuation, sensing, and energy harvesting. All ferromagnetic materials exhibit the magnetostrictive effect, but only certain iron–rare earth alloys, iron–gallium alloys, amorphous metals, and iron‐ aluminum alloys exhibit sufficiently high magnetostriction for commercial use. Because the magnetostrictive effect is an intrinsic material property that is robust against external factors such as stress and cyclic fatigue, magnetostrictive devices are suitable for harsh environments. This article provides an overview ofmagnetostrictivematerials and devices, particularly focused on Metglas, Terfenol‐D, and Galfenol. Various transducer topologies are presented and discussed, along with quantification of performance metrics and experimental aspects related to understanding and harnessing the intrinsic nonlinearities of magnetostrictive materials. Selected modeling approaches considering both constitutive material behavior and system response are presented.