Hysteretic behavior of precast segmental bridge piers with superelastic shape memory alloy bars

2010 ◽  
Vol 32 (10) ◽  
pp. 3394-3403 ◽  
Author(s):  
Hwasung Roh ◽  
Andrei M. Reinhorn
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Hysteretic Behavior ◽  
Bridge Piers ◽  
Segmental Bridge

Seismic Performance of Concrete Bridge Piers Reinforced with Hybrid Shape Memory Alloy (SMA) and Steel Bars

2019 ◽  
Vol 14 (01) ◽  
pp. 2050001
Author(s):  
Jize Mao ◽  
Daoguang Jia ◽  
Zailin Yang ◽  
Nailiang Xiang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Seismic Performance ◽  
Residual Deformation ◽  
Steel Reinforcement ◽  
Bridge Piers ◽  
Dissipated Energy ◽  
Concrete Bridge ◽  
Loss Of Function ◽  
Hybrid Reinforcement

Lack of corrosion resistance and post-earthquake resilience will inevitably result in a considerable loss of function for concrete bridge piers with conventional steel reinforcement. As an alternative to steel reinforcement, shape memory alloy (SMA)-based reinforcing bars are emerging for improving the seismic performance of concrete bridge piers. This paper presents an assessment of concrete bridge piers with different reinforcement alternatives, namely steel reinforcement, steel-SMA hybrid reinforcement and SMA reinforcement. The bridge piers with different reinforcements are designed having a same lateral resistance, or in other words, the flexural capacities of plastic hinges are designed equal. Based on this, numerical studies are conducted to investigate the relative performance of different bridge piers under seismic loadings. Seismic responses in terms of the maximum drift, residual drift as well as dissipated energy are obtained and compared. The results show that all the three cases with different reinforcements exhibit similar maximum drifts for different earthquake magnitudes. The SMA-reinforced bridge pier has the smallest post-earthquake residual displacement and dissipated energy, whereas the steel-reinforced pier shows the opposite responses. The steel-SMA hybrid reinforcement can achieve a reasonable balance between the residual deformation and energy dissipation.

Experimental characterization and control of a magnetic shape memory alloy actuator using the modified generalized rate-dependent Prandtl–Ishlinskii hysteresis model

2018 ◽  
Vol 232 (5) ◽  
pp. 506-518 ◽  
Author(s):  
Saeid Shakiba ◽  
Mohammad Reza Zakerzadeh ◽  
Moosa Ayati
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Excitation Frequency ◽  
Hysteresis Loops ◽  
Experimental Results ◽  
Hysteretic Behavior ◽  
Magnetic Shape Memory ◽  
Shape Memory Alloy Actuator ◽  
Rate Dependent ◽  
Magnetic Shape Memory Alloy

In this article, two models are used, namely rate-independent and rate-dependent generalized Prandtl–Ishlinskii, to characterize a magnetic shape memory alloy actuator. The results show that the rate-independent model cannot consider the effect of input excitation frequency, while the rate-dependent model omits this drawback by defining a time-dependent operator. For the first time, the effects of excitation frequency on the hysteretic behavior of magnetic shape memory alloy actuator are investigated. In this study, five excitation voltages with different frequencies in the range of 0.05–0.4 Hz are utilized as inputs to the magnetic shape memory alloy actuator and the displacement outputs are measured. Experimental results indicate that, with increasing the excitation frequency, the size of the hysteresis loops changes. Since the generalized rate-dependent Prandtl–Ishlinskii model cannot consider the asymmetric hysteresis loops, in the developed model, a tangent hyperbolic function is applied as an envelope function in order to improve the capability of the model in characterizing the asymmetric behavior of magnetic shape memory alloy actuator. The parameters of both rate-dependent and rate-independent models are identified by genetic algorithm optimization. The results reveal that the rate-independent form is not capable of accurately describing the hysteretic behavior of magnetic shape memory alloy actuator for different input frequencies. Simulation and experimental results also demonstrate the proficiency of the developed model for precise characterization of the saturated rate-dependent hysteresis loops of magnetic shape memory alloy actuator. In addition, the proposed model is utilized for determining a proper range for controller coefficients during controller design.

Rocking bridge piers equipped with shape memory alloy (SMA) washer springs

2020 ◽  
Vol 214 ◽  
pp. 110651 ◽  
Author(s):  
Cheng Fang ◽  
Dong Liang ◽  
Yue Zheng ◽  
Michael C.H. Yam ◽  
Ruiqin Sun
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Bridge Piers

A uniaxial constitutive model for NiTi shape memory alloy bars considering the effect of residual strain

2019 ◽  
Vol 30 (8) ◽  
pp. 1163-1177
Author(s):  
Canjun Li ◽  
Zhen Zhou ◽  
Yazhi Zhu
Keyword(s):  
Shape Memory Alloy ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Residual Strain ◽  
Hysteretic Behavior ◽  
Niti Shape Memory Alloy ◽  
Strain Effect ◽  
Proposed Model ◽  
Residual Strains

Super-elastic shape memory alloys are widely used in structural engineering fields due to their encouraging super-elasticity and energy dissipation capability. Large-size shape memory alloy bars often present significant residual strains after unloading, which emphasizes the necessity of developing a residual strain effect–coupled constitutive model to predict well the performance of shape memory alloy–based structures. First, this article experimentally studies the hysteretic behavior of NiTi shape memory alloy bars under quasi-static loading conditions and investigates the effects of cyclic numbers and strain amplitudes on residual strain. Second, a concept of cumulative transformation strain is preliminarily introduced into a phenomenological Lagoudas model. A uniaxial constitutive model for shape memory alloy bars including the residual strain is proposed. By using OpenSees platform, numerical simulations of shape memory alloy bars are conducted—the results of which indicate that the proposed model can accurately capture the hysteretic behavior of shape memory alloys. The predicted residual strains show a good agreement to experimental results, which demonstrates the desirable efficiency of the proposed model.

Design of Shape Memory Alloy Damper for Base Isolated Structure

1997 ◽  
Author(s):  
Krzysztof Wilde ◽  
Paolo Gardoni ◽  
Yozo Fujino ◽  
Stefano Besseghini
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Base Isolation ◽  
Hysteretic Behavior ◽  
Isolation System ◽  
Rubber Bearing ◽  
Laminated Rubber Bearing ◽  
Base Isolation System ◽  
Rubber Bearings ◽  
Smart Base Isolation

Abstract Base isolation provides a very effective passive method of protecting the structure from the hazards of earthquakes. The proposed isolation system combines the laminated rubber bearing with the device made of shape memory alloy (SMA). The smart base isolation uses hysteretic behavior of SMA to increase the structural damping of the structure and utilizes the different responses of the SMA at different levels of strain to control the displacements of the base isolation system at various excitation levels. The performance of the smart base isolation is compared with the performance of isolation by laminated rubber bearings to assess the benefits of additional SMA damper for isolation of three story building.

A Multi-Channel Power Controller for Actuation and Control of Multiple SMA Actuators

2009 ◽  
Author(s):  
Rohan Hangekar ◽  
Stefan Seelecke
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Electric Power ◽  
Position Control ◽  
Electronic Device ◽  
Hysteretic Behavior ◽  
Graphic User Interface ◽  
Channel Power ◽  
Power Controller ◽  
Sma Actuators

This paper presents a multi-channel electronic power controller device for Shape Memory Alloy (SMA) actuators. The use of shape memory alloy wires as actuators has been proposed in numerous novel applications such as Smart Inhaler System [1], BAT Micro Air Vehicle [2], etc. These systems have multiple SMA wires for actuation of their mechanisms. The SMA wires can be actuated by controlling the joule heating or the electric power in that wire. This paper describes the development of a multi-channel power device that can control multiple SMA actuators simultaneously. The device presented herewith utilizes a Field Programmable Gate Array (FPGA) board and a custom built electronic device to independently and simultaneously control electric power in three different SMA actuators. The controller adapts to the non linear and hysteretic behavior of the resistance of the SMA actuators and adjusts the pulse width modulated voltage across them to maintain the desired value of power. The controller uses the resistance measurement of the SMA actuators as feedback. With the help of modeling efforts to relate resistance to strain, it is envisioned that feedback position control of these actuators can be implemented without the necessity of a sensor. The device is tested with graphic user interface which enables a user to control various parameters during operation of this device and to monitor the results. The design and implementation of this device is detailed in this paper along with its performance charts. The results relate the input power, observed actuation strokes and measured resistances in the SMA actuators under various conditions. A relevant discussion on implementing position control in Smart Inhaler System using this device is also presented.

Reinforcement Learning for Control of a Shape Memory Alloy Based Self-Folding Sheet

2015 ◽  
Author(s):  
Peyman Moghadas ◽  
Richard Malak ◽  
Darren Hartl
Keyword(s):  
Reinforcement Learning ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Laminate Plate ◽  
Reduced Order Model ◽  
Hysteretic Behavior ◽  
Order Model ◽  
Control Policies ◽  
Reduced Order ◽  
Highly Nonlinear

Origami-inspired engineering provides engineers with new means for creating complicated three-dimensional structures through use of folding and fold-like operations. Motivated by the vision of origami engineering, we have created and modeled a reconfigurable self-folding sheet based on a laminate structure of shape memory alloy (SMA) surrounding a layer of elastomer. Folding behavior is achieved by activating an SMA layer through localized heating. In prior work, we demonstrated localized control of such a sheet using PID and On/Off type feedback controllers. The implementation of these control strategies requires several workarounds to deal with the highly nonlinear and hysteretic behavior of the SMA-based laminate sheet. In the current work, we use a reinforcement learning algorithm to learn control policies that better handle these aspects of the sheet behavior. We perform learning on a reduced order model of the sheet developed based on classical laminate plate theory. This significantly reduces computational costs compared to more complicated finite element modeling options. We demonstrate the effectiveness of the learned control policies in several folding scenarios on the reduced order model. Our results show that reinforcement learning can be a useful tool in feedback control of SMA-based structures.

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