CHARACTERIZATION OF ENERGY DISSIPATIVE CUSHIONS MADE OF Ni-Ti SHAPE MEMORY ALLOY

2021 ◽  
Author(s):  
Ahmet Güllü ◽  
Josiah Owusu Danquah ◽  
Savaş Dilibal
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Damping Ratio ◽  
Seismic Energy ◽  
Dissipated Energy ◽  
Residual Drift ◽  
Displacement Capacity ◽  
Earthquake Resistant Design ◽  
Earthquake Resistant ◽  
Metallic Dampers

Abstract Earthquake-resistant design of structures requires dissipating seismic energy by deformations of structural members or additional fuse elements. Owing to its easy-to-produce, plug-and-play, high equivalent damping ratio, and large displacement capacity characteristics, energy dissipative steel cushions were found to be an efficient candidate for this purpose. However, similar to other conventional metallic dampers, residual displacement after a strong shaking is the most notable drawback of the steel cushions. In this work, cushions produced from Ni-Ti shape memory alloy are evaluated numerically by experimentally verified finite element models to assess their impact on the performance of earthquake-resistant structures. Furthermore, a reinforced concrete testing frame is retrofitted with energy dissipative steel and Ni-Ti cushions. Performance of the frames (e.g. dissipated energy by the cushions, hysteretic energy to input energy ratio, maximum drift, and residual drift) with different types of cushions are evaluated by nonlinear response history analyses. The numerical results showed that the steel cushions are effective to reduce peak responses, while Ni-Ti cushions are more favorable to reduce residual drifts and deformations. Hence, a hybrid system, employing the steel and shape memory alloy cushions together, is proposed to reach optimal seismic performance.

Design, analysis, and manufacture of a tension–compression self-centering damper based on energy dissipation of pre-stretched superelastic shape memory alloy wires

2017 ◽  
Vol 28 (15) ◽  
pp. 2129-2139 ◽  
Author(s):  
Amin Alipour ◽  
Mahmoud Kadkhodaei ◽  
Mohsen Safaei
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Damping Ratio ◽  
Dissipated Energy ◽  
Damping Capacity ◽  
Compression Tests ◽  
Mechanical Unloading ◽  
Tension And Compression ◽  
The Individual

Superelastic shape memory alloys dissipate significant amount of energy since they recover large transformation strains upon mechanical unloading. Due to their dissipation properties, shape memory alloys can be effectively employed as dampers. Design, simulation, and fabrication of a newly developed superelastic shape memory alloy damper are discussed in this article. To enhance the stroke and dissipation capacity of the proposed damper, a system is implemented which operates more efficiently than a single shape memory alloy wire. Although shape memory alloy wires can only undergo tension, the new system enables the damper to be loaded in both tension and compression. Two damping groups are employed in this mechanism: one of which is activated during tension and the other is activated during compression of the damper. Each damping group consists of two shape memory alloy wires acting in the opposite directions to increase the damping capacity of the system. The mechanical responses of the individual components as well as the assembled damper are simulated. The predicted performance of the damper is then validated through tension/compression tests on the fabricated sample. Numerical and experimental force–displacement curves are also shown to be in a good agreement. The effect of different parameters on damping ratio and dissipated energy of the presented damper is investigated.

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.

Active Vibration Control of Epoxy Matrix Composite Beams with Embedded Shape Memory Alloy TiNi Fibers

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1744-1749 ◽  
Author(s):  
T. Aoki ◽  
A. Shimamoto
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Vibration Control ◽  
Matrix Composite ◽  
Epoxy Matrix ◽  
Damping Ratio ◽  
Active Vibration Control ◽  
Composite Beams ◽  
Epoxy Matrix Composite ◽  
Active Vibration

In this paper, epoxy matrix composite beams with embedded TiNi (SMA: Shape Memory Alloy) fiber are applied to enhance the strength and fracture toughness of the machinery components. It is also well known that SMA shows the remarkable changes of stiffness and damping ratio between martensite at lower temperature and austenite at high temperature. A shape recovery force is associated with inverse phase transformation of SMA. The effects of heating with current and pre-strain in TiNi fiber of SMA on vibration characteristics are experimentally investigated. The active vibration control is achieved by controlling the current and pre-strain.

scholarly journals Vibrational Analysis of Composite Beam Embedded with Nitinol Shape Memory Alloy Wires

2018 ◽  
Vol 7 (3.4) ◽  
pp. 143
Author(s):  
Omer Muwafaq Mohmmed Ali ◽  
Rawaa Hamid Mohammed Al-Kalali ◽  
Ethar Mohamed Mahdi Mubarak
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Frequency Response ◽  
Response Curve ◽  
Natural Frequencies ◽  
Damping Ratio ◽  
Vibrational Analysis ◽  
Laminated Composite ◽  
Vibration Modes ◽  
Frequency Response Curve

In this paper, laminated composite materials were hybridized with fibers (E-glass) and shape memory alloy wires which considered a smart material. The effect of changing frequency on the (acceleration- frequency) response curve, the damping ratio of the vibration modes, the natural frequencies of the vibration mode, the effect of shape memory alloy wires number on the damping characteristics were studied. Hand lay-up technique was used to prepare the specimens, epoxy resin type was used as a matrix reinforced by fiber, E-glass. The specimens were manufactured by stacking 2 layers of fibers. Shape memory alloy, type Nitinol (nickel-titanium) having a diameter (1 and 2mm), was used to manufacture the specimens by embedding (1,2 and 3) wires into epoxy. Experimentally, the acceleration- frequency response curve was plotted for the vibration modes, this curve was used to measure the natural frequencies of the vibration modes and calculate the damping ratio of the vibration modes. ANSYS 15- APDL was used to determine the mode shape and find the natural frequencies of the vibration modes then compared with the experimental results. The results illustrated that, for all specimens increasing the natural frequency leads to decreasing the damping ratio. Increasing the number of shape memory alloy wires leads to increase the values of the damping ratio of the vibration modes and the natural frequencies of the vibration modes at room temperature. 

scholarly journals Comparison of Bending Fatigue of NiTi and CuAlMn Shape Memory Alloy Bars

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Haoyu Huang ◽  
Yuan-Zhi Zhu ◽  
Wen-Shao Chang
Keyword(s):  
Fatigue Life ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Damping Ratio ◽  
Strain Curve ◽  
Fatigue Properties ◽  
Functional Fatigue ◽  
Cyclic Bending ◽  
Structural Fatigue ◽  
Secant Stiffness

The behaviour under cyclic bending and in particular the fatigue properties of shape memory alloy (SMA) bars are important for civil engineering applications. In this paper, structural and functional fatigue is studied for both NiTi- and copper-based shape memory alloys. The results are presented from cyclic bending tests on 7 mm diameter NiTi and 12 mm diameter CuAlMn SMA bars targeted at 100,000 cycles. During the tests, dynamic loading at 1 Hz, 5 Hz, and 8 Hz was applied for different strain levels (0.5%, 1%, 2%, and 6%). The stress-strain curve, damping ratio, and secant stiffness were analysed for material characterisation, and the evolution of these parameters was studied to assess functional fatigue. The fatigue life is extended dramatically when the strain is below 1%, and the structural fatigue life of CuAlMn is shown to be better than that of NiTi and to depend on the loading rate. However, decay in stiffness can be found in the CuAlMn SMA, which is considered to be caused particularly by its long grain boundary.

scholarly journals SEISMIC WAVEGUIDE OF METAMATERIALS

2012 ◽  
Vol 26 (17) ◽  
pp. 1250105 ◽  
Author(s):  
SANG-HOON KIM ◽  
MUKUNDA P. DAS
Keyword(s):  
Cylindrical Shell ◽  
Seismic Wave ◽  
Stop Band ◽  
Seismic Energy ◽  
New Method ◽  
Acoustic Metamaterials ◽  
Frequency Range ◽  
Helmholtz Resonators ◽  
Earthquake Resistant Design ◽  
Earthquake Resistant

We developed a new method of an earthquake-resistant design to support conventional aseismic system using acoustic metamaterials. The device is an attenuator of a seismic wave that reduces the amplitude of the wave exponentially. Constructing a cylindrical shell-type waveguide composed of many Helmholtz resonators that creates a stop-band for the seismic frequency range, we convert the seismic wave into an attenuated one without touching the building that we want to protect. It is a mechanical way to convert the seismic energy into sound and heat.

Damage as a measure for earthquake-resistant design of masonry structures: Slovenian experienceThis article is one of a selection of papers published in this Special Issue on Masonry.

2007 ◽  
Vol 34 (11) ◽  
pp. 1403-1412 ◽  
Author(s):  
Miha Tomaževič
Keyword(s):  
Lateral Displacement ◽  
Reduction Factor ◽  
Shaking Table ◽  
Eurocode 8 ◽  
Masonry Buildings ◽  
Limit States ◽  
Masonry Construction ◽  
Displacement Capacity ◽  
Earthquake Resistant Design ◽  
Earthquake Resistant

The results of lateral resistance tests of masonry walls and shaking table tests of a number of models of masonry buildings of various structural configurations, built with various materials in different construction systems, have been analyzed to find a correlation between the occurrence of different grades of damage to structural elements, characteristic limit states, and lateral displacement capacity. On the basis of correlation between acceptable level of damage and displacement capacity, it has been shown that the range of elastic force reduction factor values used to determine the design seismic loads for different masonry construction systems proposed by the recently adopted European standard Eurocode 8 EN-1998-1 for earthquake resistant design are adequate. By using the recommended design values, satisfactory performance of the masonry buildings that have been analyzed may be expected when subjected to design intensity earthquakes with respect to both the no-collapse and damage-limitation requirements.

Nonlinear dynamics of earthquake-resistant structures using shape memory alloy composites

2020 ◽  
Vol 31 (5) ◽  
pp. 771-787 ◽  
Author(s):  
Lucas L Vignoli ◽  
Marcelo A Savi ◽  
Sami El-Borgi
Keyword(s):  
Energy Dissipation ◽  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Volume Fraction ◽  
Kinematic Hardening ◽  
Frame Structure ◽  
Earthquake Resistant ◽  
Earthquake Resistant Structures ◽  
Residual Strains

Earthquake-resistant structures have been widely investigated in order to produce safe buildings designed to resist seismic activities. The remarkable properties of shape memory alloys, especially pseudoelastic effect, can be exploited in order to promote the essential energy dissipation necessary for earthquake-resistant structures. In this regard, shape memory alloy composite is an idea that can make this application feasible, using shape memory alloy fibers embedded in a matrix. This article investigates the use of shape memory alloy composites in a one-story frame structure subjected to earthquakes. Different kinds of composites are analyzed, comparing the influence of matrix type. Both linear elastic matrix and elastoplastic matrix with isotropic and kinematic hardening are investigated. Results indicate the great energy dissipation capability of shape memory alloy composites. A parametric analysis allows one to conclude that the maximum shape memory alloy volume fraction is not the optimum design condition for none of the cases studied, highlighting the necessity of a proper composite design. Despite the elastoplastic behavior of matrix also dissipates a considerable amount of energy, the associated residual strains are not desirable, showing the advantage of the use of shape memory alloys.

Rocking isolation of bridge pier using shape memory alloy

2021 ◽  
Vol 16 (2-3) ◽  
pp. 85-103
Author(s):  
Rajesh R. Rele ◽  
Ranjan Balmukund ◽  
Stergios A. Mitoulis ◽  
Subhamoy Bhattacharya
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Lateral Displacement ◽  
Plastic Hinge ◽  
Time History ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Isolation Technique ◽  
Residual Drift ◽  
Dynamic Time

The conventional design philosophy of bridges allows damage in the pier through yielding. A fuse-like action is achieved if the bridge piers are designed to develop substantial inelastic deformations when subjected to earthquake excitations. Such a design can avoid collapse of the bridge but not damage. The damage is the plastic hinge formation formed at location of maximum moments and stresses that can lead to permanent lateral displacement which can impair traffic flow and cause time consuming repairs. Rocking can act as a form of isolation by means of foundation uplifting which act as a mechanical fuse, limiting the forces transferred to the base of the structure. In this context, this paper proposes a novel resilient controlled rocking bridge pier foundation, which uses elastomeric pads incorporated beneath the footing of the bridge piers and external restrainer in the form of shape memory alloy bar (SMA). The rocking mechanism is achieved by restricting the horizontal movement of footing by providing stoppers at all sides of footing. The pads are designed to remain elastic without allowing their shearing. The pier, the footing and the elastomeric pads are assumed to be supported on firm rigid concrete sub base resting on hard rock. By performing nonlinear dynamic time history analysis in the traffic direction of the bridge, the proposed pier with the novel resilient foundation is compared against a fixed-based pier and classical rocking pier (CC). The proposed pier rocking on elastomeric pads and external restrainer (CP+SMA) has good re-centering capability during earthquakes with negligible residual drift and footing uplift. In this new rocking isolation technique, the forces in the piers are also reduced and thus leading to reduced construction cost with enhanced post-earthquake serviceability.

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