Control of Wave Propagation in Periodic Composite Rods Using Shape Memory Inserts

Longitudinal wave propagation is controlled using shape memory inserts placed periodically along rods. The inserts act as sources of impedance mismatch with tunable characteristics. Such characteristics are attributed to the unique behavior of the shape memory alloy whereby the elastic modulus of the inserts can be varied up to three times as the alloy undergoes a phase transformation from martensite to austenite. With such controllable capability, the inserts can introduce the proper impedance mismatch necessary to impede the wave propagation along the rods. An analytical model is presented to study the attenuation capabilities of the composite rods and to determine the influence of the various design parameters of the inserts that can control the width of the pass and stop-bands. The numerical results demonstrate the potential of shape memory alloys in controlling the dynamics of wave propagation in rods. Furthermore, the obtained results provide a guideline for designing inserts that are capable of filtering out selected excitation frequencies through proper adjustment of the geometry of the inserts as well as their activation strategies. [S0739-3717(00)00102-1]

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Control of Wave Propagation in Periodic Composite Rods Using Shape Memory Inserts

10.1115/imece1999-0563 ◽

1999 ◽

Author(s):

M. Ruzzene ◽

A. Baz

Keyword(s):

Wave Propagation ◽

Phase Transformation ◽

Elastic Modulus ◽

Shape Memory Alloy ◽

Shape Memory ◽

Longitudinal Wave ◽

Design Parameters ◽

Impedance Mismatch ◽

Periodic Composite ◽

Longitudinal Wave Propagation

Abstract Longitudinal wave propagation is controlled using shape memory inserts placed periodically along rods. The inserts act as sources of impedance mismatch with tunable characteristics. Such characteristics are attributed to the unique behavior of the shape memory alloy whereby the elastic modulus of the inserts can be varied up to three times as the alloy undergoes a phase transformation from martensite to austenite. With such controllable capability, the inserts can introduce the proper impedance mismatch necessary to impede the wave propagation along the rods. An analytical model is presented to study the attenuation capabilities of the composite rods and to determine the influence of the various design parameters of the inserts that can control the width of the pass and stop-bands. The numerical results demonstrate the potential of shape memory alloys in controlling the dynamics of wave propagation in rods. Furthermore, the obtained results provide a guideline for designing inserts that are capable of filtering out selected excitation frequencies through proper adjustment of the geometry of the inserts as well as their activation strategies.

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Finite Element Simulation of NiTiNb Shape Memory Alloy Pipe-Joint Subjected to Coupled Transformation and Plastic Deformation

Advances in Materials Science and Engineering ◽

10.1155/2020/6895850 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14

Author(s):

Xiang Chen ◽

Bin Chen ◽

Xianghe Peng ◽

Xiaoqing Jin ◽

Ying Ma ◽

...

Keyword(s):

Plastic Deformation ◽

Phase Transformation ◽

Shape Memory Alloy ◽

Shape Memory ◽

High Performance ◽

Coupling Effect ◽

Longitudinal Direction ◽

Design Parameters ◽

Pull Out ◽

Pipe Joint

The assembling process of Ni47Ti44Nb9 alloy pipe joints considering the phase transformation and plasticity was numerically simulated for the first time with a developed constitutive model. The simulated process was based on the experimental material parameters, which were determined with the experimental tensile results of Ni47Ti44Nb9 shape memory alloy (SMA) and steel bars. The results showed that, after assembly, the Mises stress distributed uniformly along the longitudinal direction of the NiTiNb joint, but nonuniformly along the radial direction. The maximum σeq does not appear at the inner wall of the joints due to the coupling effect of the plastic deformation and the recoverable transformation. The contact pressure distributed uniformly along the circumferential direction, but nonuniformly along the longitudinal direction. The sizes of the SMA joint and the pipe should be properly matched to ensure contact during the stage of the rapid reverse phase transformation to obtain stable connection performance. The pull-out force was also computed, and the results were in good agreement with the experimental results. The results obtained can provide available information for the optimization of the design parameters of the high-performance SMA pipe-joint, such as inner diameter and assembly clearance.

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The R-Phase Transformation in the Ti-Ni Shape Memory Alloy and its Application

MRS Proceedings ◽

10.1557/proc-459-345 ◽

1996 ◽

Vol 459 ◽

Cited By ~ 8

Author(s):

I. Ohkata ◽

H. Tamura

Keyword(s):

Phase Transformation ◽

Shape Memory Alloy ◽

Shape Memory ◽

Cold Water ◽

Design Parameters ◽

Cyclic Performance ◽

Long Cycle Life ◽

Material Characteristics ◽

Linear Characteristic ◽

New Type

ABSTRACTWe discuss a comprehensive design approach of Ti-Ni alloy coil springs and introduce a new application of the R-phase transformation. In order to attain high cyclic performance, one must understand the two relationships between design parameters and material characteristics and between material characteristics and cyclic performance. Metallurgical parameters and coil spring dimensions play an important role as design parameters in the former relationship. High cyclic performance of an actuator is closely related to the suppression of the monoclinic martensite. Transformation temperatures and their stress dependence is of primary importance as material characteristics in the latter relationship. A thermostatic mixing valve, which is the latest application of the R-phase transformation in Japan is then discussed as a new type of a shape memory alloy actuator. The R-phase transformation is employed to achieve not only a long cycle life but a linear operation with the set temperature to continuously control the mixing ratio of hot and cold water. This is achieved by changing the total length of the two-way actuator in a linear manner with the set temperature. The linear characteristic is satisfied between 35–50°C by optimizing thermomechanical treatment and the dimensions of Ti-Ni and biasing coil springs.

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PHASE TRANSFORMATION TEMPERATURE CONTROL OF WELD METAL OF LASER WELDED TiNi SHAPE MEMORY ALLOY JOINT

ACTA METALLURGICA SINICA ◽

10.3724/sp.j.1037.2012.00482 ◽

2013 ◽

Vol 49 (2) ◽

pp. 199 ◽

Cited By ~ 1

Author(s):

Chenggong YANG ◽

Jiguo SHAN ◽

Jialie REN

Keyword(s):

Phase Transformation ◽

Shape Memory Alloy ◽

Weld Metal ◽

Shape Memory ◽

Temperature Control ◽

Transformation Temperature ◽

Phase Transformation Temperature

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Effect and identification of parametric distributed uncertainties in longitudinal wave propagation

Applied Mathematical Modelling ◽

10.1016/j.apm.2021.05.018 ◽

2021 ◽

Author(s):

M.R. Machado ◽

J.M.C. Dos Santos

Keyword(s):

Wave Propagation ◽

Longitudinal Wave ◽

Longitudinal Wave Propagation

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Experimental and Numerical Analysis of the Mechanical Properties of a Pretreated Shape Memory Alloy Wire in a Self-Centering Steel Brace

Processes ◽

10.3390/pr9010080 ◽

2021 ◽

Vol 9 (1) ◽

pp. 80

Author(s):

Bo Zhang ◽

Sizhi Zeng ◽

Fenghua Tang ◽

Shujun Hu ◽

Qiang Zhou ◽

...

Keyword(s):

Mechanical Properties ◽

Elastic Modulus ◽

Energy Dissipation ◽

Shape Memory Alloy ◽

Shape Memory ◽

Loading Rate ◽

Effective Elastic Modulus ◽

Maximum Energy ◽

Numerical Results ◽

Energy Dissipation Capacity

As a stimulus-sensitive material, the difference in composition, fabrication process, and influencing factors will have a great effect on the mechanical properties of a superelastic Ni-Ti shape memory alloy (SMA) wire, so the seismic performance of the self-centering steel brace with SMA wires may not be accurately obtained. In this paper, the cyclic tensile tests of a kind of SMA wire with a 1 mm diameter and special element composition were tested under multi-working conditions, which were pretreated by first tensioning to the 0.06 strain amplitude for 40 cycles, so the mechanical properties of the pretreated SMA wires can be simulated in detail. The accuracy of the numerical results with the improved model of Graesser’s theory was verified by a comparison to the experimental results. The experimental results show that the number of cycles has no significant effect on the mechanical properties of SMA wires after a certain number of cyclic tensile training. With the loading rate increasing, the pinch effect of the hysteresis curves will be enlarged, while the effective elastic modulus and slope of the transformation stresses in the process of loading and unloading are also increased, and the maximum energy dissipation capacity of the SMA wires appears at a loading rate of 0.675 mm/s. Moreover, with the initial strain increasing, the slope of the transformation stresses in the process of loading is increased, while the effective elastic modulus and slope of the transformation stresses in the process of unloading are decreased, and the maximum energy dissipation capacity appears at the initial strain of 0.0075. In addition, a good agreement between the test and numerical results is obtained by comparing with the hysteresis curves and energy dissipation values, so the numerical model is useful to predict the stress–strain relations at different stages. The test and numerical results will also provide a basis for the design of corresponding self-centering steel dampers.

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