An Estimation of Joint Strength by Using Fe-Based Shape Memory Alloy Subjected to Bending Deformation at Various Deformation Rate

2014 ◽  
Vol 626 ◽  
pp. 228-233 ◽  
Author(s):  
Kazuki Fujita ◽  
Keizo Nishikori ◽  
Takeshi Iwamoto
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Deformation Rate ◽  
Bending Strength ◽  
Rate Sensitivity ◽  
Force Balance ◽  
Bending Test ◽  
Structural Members ◽  
Bending Deformation ◽  
Three Point Bending

In various kinds of shape memory alloy (SMA), Fe-based SMA (Fe-SMA) shows smaller shape memory effect compared with the other SMAs. However, Fe-SMA shows huge advantages on the excellent formability, machinability, etc. Moreover, its production cost is cheaper than other SMAs; therefore, the alloy is attempted to be applied to structural members such as joints and dampers. Since bending deformation at higher deformation rate is generated in the members, especially the joints, due to impact force such as earthquake or wind, a clarification on the bending strength of the joints at various deformation rate is strongly required. In this study, at first, it is attempted that the bending strength and its rate sensitivity of the joints which consist of Fe-based SMA are experimentally estimated by the three-point bending test at various deformation rate. Then, the force balance equation is challenged to be derived to predict the bending strength.

Effect of Deflection Rate on Bending Deformation Behavior of Fe-Based Shape Memory Alloy

2014 ◽  
Vol 566 ◽  
pp. 116-121
Author(s):  
Keizo Nishikori ◽  
Takeshi Iwamoto
Keyword(s):  
Shape Memory ◽  
Static Loading ◽  
Deformation Behavior ◽  
Rate Sensitivity ◽  
Bending Test ◽  
Bending Deformation ◽  
Three Point Bending ◽  
Positive Rate ◽  
The Impact ◽  
Deflection Rate

In this study, three-point bending test is conducted at various deformation rate by using a thin plate of Fe-based alloy. The rate sensitivity of its bending deformation during loading and shape memory effect by heating after unloading are investigated experimentally. The results obtained are summarized as bellows. (1) In the case where the quasi-static loading was applied, the positive rate sensitivity, which means the stress level increases with increasing the deflection rate, can be observed slightly. (2) It is hard to observe that recovery of deflection by SME depends on deflection rate under quasi-static loading. (3) In the case where the impact loading was applied, the positive rate sensitivity can be observed clearly.

Development of Fe-Mn-Si-Cr Shape Memory Alloy Fiber Reinforced Plaster-Based Smart Composites

2005 ◽  
Vol 475-479 ◽  
pp. 2063-2066 ◽  
Author(s):  
Teppei Wakatsuki ◽  
Yoshimi Watanabe ◽  
Hiroshi Okada
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Tensile Strain ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Three Point Bending ◽  
Smart Composites ◽  
Fiber Holder

In previous studies, it has been found that the shape memory effect of the embedded straight and wavy shape memory alloy (SMA) fibers enhance the strength and energy absorption prior to fracture of the composite, where the embedded SMA fibers shrink due to their shape memory effect. In the case of wavy fiber reinforced composites, the SMA fibers were subjected to pre-tensile strain using fiber holder with rotatable rollers to maintain the constant periodicity and amplitude of wavy fibers. In this study, on the other hand, the wavy SMA fibers were subjected to pre-tensile strain without using fiber holder, and therefore, periodicity and amplitude of wavy fibers were varied during the deformation. Then the wavy SMA fiber reinforced smart composite is fabricated. For the mechanical property characterization, three-point bending test is performed for the specimens.

Fabrication and Property of W/Tininb Shape Memory Alloy Laminated Composite

2015 ◽  
Vol 815 ◽  
pp. 211-216 ◽  
Author(s):  
Yang Shao ◽  
Da Qiang Jiang ◽  
Fang Min Guo ◽  
Ya Dong Ru ◽  
Xiao Wei Hu ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Laminated Composite ◽  
Strain Curve ◽  
Alloy Layer ◽  
Bending Test ◽  
Damping Capacity ◽  
Hot Press ◽  
Transformation Behavior ◽  
Three Point Bending

W/TiNiNb shape memory alloy laminated composites were fabricated by vacuum hot press, forging and rolling. The microstructure, transformation behavior, mechanical behavior and damping capacity of the laminated composite were investigated by SEM, DSC, DMA and bending test, respectively. The results showed that the W layer and the TiNiNb shape memory alloy layer in the composite was about 15 μm and 5 μm, respectively. The TiNiNb alloy in the composite exhibited the reversible martensite transformation. The composite also had high damping capacity (tanδ=0.03). The three-point bending test showed various plateaus in the stress–strain curve due to delamination processes, which are suitable for enhancing the fracture toughness of the laminates. The flexure strength of the laminated composite was 1260 MPa.

Cold Bending a Ni-Ti Shape Memory Alloy Wire

2015 ◽  
Vol 661 ◽  
pp. 98-104 ◽  
Author(s):  
Kuang-Jau Fann ◽  
Pao Min Huang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Room Temperature ◽  
Aging Treatment ◽  
Treatment Temperature ◽  
Bending Test ◽  
Solution Treatment Temperature

Because of being in possession of shape memory effect and superelasticity, Ni-Ti shape memory alloys have earned more intense gaze on the next generation applications. Conventionally, Ni-Ti shape memory alloys are manufactured by hot forming and constraint aging, which need a capital-intensive investment. To have a cost benefit getting rid of plenty of die sets, this study is aimed to form Ni-Ti shape memory alloys at room temperature and to age them at elevated temperature without any die sets. In this study, starting with solution treatments at various temperatures, which served as annealing process, Ni-rich Ni-Ti shape memory alloy wires were bent by V-shaped punches in different curvatures at room temperature. Subsequently, the wires were aged at different temperatures to have shape memory effect. As a result, springback was found after withdrawing the bending punch and further after the aging treatment as well. A higher solution treatment temperature or a smaller bending radius leads to a smaller springback, while a higher aging treatment temperature made a larger springback. This springback may be compensated by bending the wires in further larger curvatures to keep the shape accuracy as designed. To explore the shape memory effect, a reverse bending test was performed. It shows that all bent wires after aging had a shape recovery rate above 96.3% on average.

Experimental Study on Temperature External-Characteristics of Ni-Mn-Ga Shape Memory Alloy

2011 ◽  
Vol 311-313 ◽  
pp. 1232-1236 ◽  
Author(s):  
Yong Zhi Cai
Keyword(s):  
Experimental Study ◽  
Critical Temperature ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Temperature Effect ◽  
Deformation Rate ◽  
Variable Temperature ◽  
Temperature Characteristics ◽  
The Relationship ◽  
External Characteristics

Temperature characteristics are essential to reasonable application of Ni-Mn-Ga alloy. This paper reports an experiment equipment which is used as the research of variable temperature effect. The relationship between deformation rate and temperature is studied. Dynamic and static experiments are done. The results show that critical temperature is around 40°C. It can be predicted that thermo-elasticity and magnetically-controlled characteristics will disappear with the increase of temperature.

The Bending Strength of Brittle Materials and the Characteristics of the Elastic Wave Signal by Vickers Indentation

2004 ◽  
Vol 261-263 ◽  
pp. 1635-1640 ◽  
Author(s):  
Seok Hwan Ahn ◽  
Ki Woo Nam ◽  
Kotoji Ando
Keyword(s):  
Elastic Wave ◽  
Room Temperature ◽  
Bending Strength ◽  
Brittle Materials ◽  
Bending Test ◽  
Vickers Indentation ◽  
Three Point Bending ◽  
Wave Signal ◽  
Wave Detector ◽  
Fracture Wave

Four kinds of brittle materials were used to evaluate the bending strength under three-point bending and the characteristics of the elastic wave signal by Vickers indentation. The bending test was carried out under room temperature and high temperature. A crack was made at the tension side of the specimen with a Vickers indenter to investigate fracture strength. Fracture wave detector was used to evaluate characteristics of waveform and frequency of the elastic wave signal.

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