This work investigates the torque sensing capabilities for Galfenol. A static test and rotating static test are
performed on a single crystal and a rolled polycrystal Galfenol patch. The rotating static test demonstrates
Galfenol's noncontact use. Both the static and rotating static tests show a linear response for the Galfenol
This work investigates the optimal topology for harvesting energy using a micro cantilever. The objective is to
maximize the amount of power output of a micro cantilever composed of an elastic and piezoelectric layer. Both
layers are discretized using finite elements. The optimal topologies show large gains in power output over the
This paper investigates the optimal topology of an actively controlled piezoelectric actuator bonded to an
elastic cantilever beam under steady-state harmonic loading. The actuator is discretized using finite
elements, and control is applied to the actuator based on the sensor's degrees of freedom using proportional
control. This study investigates the optimal distribution of actuator material for one and five layers of finite
elements. The optimized actuator topology shows substantial improvement over initial piezoelectric
topologies and over traditional actuator placement.
The objective of this research is to determine the optimal topology of a piezoelectric actuator on an elastic base beam undergoing harmonic excitation. The piezoelectric actuator is modeled using finite elements. This preliminary research provides insight into the potential of optimized piezoelectric actuators. Results from topology optimization show that significant improvements in vibration amplitude reduction are possible by optimizing the actuator damping layer topology.
Topology optimization has been successfully used for improving vibration damping in constrained layer damping structures with viscoelastic materials. Reinforcing carbon nanotubes in a polymer matrix greatly influences the mechanical properties of the polymer. Such nanotube-reinforced polymers (NRP) can be used to further enhance the damping properties of the constrained layer structures. The effects of nanotube inclusions on the damping properties of polymers and applicability of NRP for damping in structures have been studied previously. The inclusion of nanotubes into a polymer matrix provides new design variables in the topology optimization studies on such structures. The aim of this research is to determine the optimal topology and the optimal constituent make-up of the constrained NRP layer, where the volume fraction of the nanotubes in the constrained layer is optimized to maximize the system loss factor.
Of the many methods available for achieving effective vibration damping, adding viscoelastic lamina constrained by a stiff elastic materials is an inexpensive, space efficient means for achieving significant damping levels. Recently, the desire to apportion this material in a way that will take the greatest advantage of its dissipative characteristics has led to studies in optimization1-7. The aim of this research is to determine the optimal shape of a constrained viscoelastic layer on an elastic beam used for vibration damping by means of topology optimization and to experimentally verify these results. The optimization objective is to maximize the system loss factor for the first resonance frequency of the base beam. All previous optimal design studies on viscoelastic lamina have been size or shape optimization studies assuming a certain topology for the damping treatment (with the exception of Lumsdaine8 and Lumsdaine and Pai9, of which this work is an extension). In this study, this assumption is relaxed, allowing an optimal topology to emerge. The loss factor is computed using the Modified Modal Strain Energy Method10 in the optimization process. It is observed that a novel topology emerges from the optimized result. From this computational result, a topology is interpreted that can be reasonably manufactured, and this topology is custom fabricated to experimentally validate the computational result. The experimental results show that significant improvement in damping performance, over 300%, is obtained by optimizing the constrained damping layer topology.