scholarly journals Mechanical Analysis of Shape Memory Alloy Beams under Asymmetric Bending

2020 ◽  
Vol 38 (4) ◽  
pp. 881-888
Author(s):  
Jingning Yang ◽  
Yongxiang Wang ◽  
Liansheng Ma
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Phase Boundary ◽  
Cross Section ◽  
Neutral Axis ◽  
Asymmetry Coefficient ◽  
Concentrated Load ◽  
Tension Compression Asymmetry ◽  
Asymmetric Bending ◽  
Shaped Cross Section

Based on the bending theory of beams, combining with the constitutive relationship of shape memory alloy materials, the asymmetric bending of shape memory alloy beams under concentrated load was studied. Considering tension-compression asymmetry on both sides of the tension and compression in the process of bending, tension-compression asymmetry coefficient was introduced, by using the step-by-step method. The stress distribution, neutral axis displacement, curvature and phase boundary of the beam sections of the I-shaped cross-section shape memory alloy beam were analyzed. The results show that under the same load, the maximum offset of the neutral axis displacement increases with the increase of tension-compression asymmetry coefficient. Under the same tension-compression asymmetry coefficient, the displacement and curvature of the neutral axis increased with the increase of load; as tension-compression asymmetry coefficient increased, the proportion of mixed phase increased gradually, the proportion of martensite phase decreased, and the asymmetry of phase boundary became more obvious. Under the same conditions, the rectangular section is more suitable. The cross section of I shaped cross section was prone to occur phase transformation.

Response of Composite Beams to an Internal Actuator Force

1992 ◽  
Vol 114 (3) ◽  
pp. 343-348 ◽  
Author(s):  
Z. Chaudhry ◽  
C. A. Rogers
Keyword(s):  
Composite Materials ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Compressive Force ◽  
Internal Force ◽  
Composite Beams ◽  
Neutral Axis ◽  
Engineering Structures ◽  
Shape Memory Alloy Actuator ◽  
Cantilevered Beam

Shape memory alloy hybrid composite materials have demonstrated numerous control capabilities. One such capability is the controlled bending of structures. In this paper the response of a cantilevered beam to an internal actuator is examined. The modeling of the compressive force exerted by the induced strain of the actuator on the beam is discussed. The results obtained from treating the force as an external follower force are presented. The response to an internal force such as exerted by an internal shape memory alloy actuator is quite different from that produced by loads due to sources external to the beam. Contrary to normal expectations such an internal force although compressive does not produce any buckling tendencies or any other instabilities in the beam. This principle which is already in use in the design of civil engineering structures is discussed in detail. If the actuators are embedded off of the neutral axis, then due to the eccentricity the beam bends, but again without any buckling tendency. The experimental results obtained for this configuration are also presented.

Damping capacity in pseudo-elastic and ferro-elastic shape memory alloy-reinforced hybrid composite beam

2019 ◽  
Vol 38 (10) ◽  
pp. 467-477 ◽  
Author(s):  
Yahya Bayat ◽  
Hamid EkhteraeiToussi
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Composite Beam ◽  
Volume Fraction ◽  
Hysteresis Loops ◽  
Beam Theory ◽  
Material Model ◽  
Resonance Phenomenon ◽  
Damping Capacity ◽  
Concentrated Load

Reinforcing a composite beam with shape memory alloy wires may have several benefits such as reduction of buckling risks or elimination of unwanted oscillations. In this paper, the vibration damping of a typical shape memory alloy-reinforced composite or hybrid beam is explored. To formulate the thermo-mechanical behavior of embedded shape memory alloy wires, three-dimensional Panico–Brinson model is employed and tailored to one-dimensional model. This material model can simulate pseudo-elastic and ferro-elastic forms of martensite transformations which occurs in cyclic loadings. Besides, unlike the former studies which rely on classical beam theories, the first-order shear deformation beam theory is used to obtain more accurate estimations of shape memory alloy-wire hysteresis loops and their decaying characteristics. In order to explore the effects of a transient concentrated load applied in the middle of a beam, the governing equations are developed and discretized by differential quadrature–integral quadrature combined method. Incremental time marching solution of the problem is accomplished using the Newmark technique. Results are assessed by comparing with available literature. Considering different types of boundary conditions, the influence of pseudo-elastic and ferro-elastic hysteresis loops on the material damping effects, shape memory alloy volume fraction, and resonance phenomenon is studied in detail.

Tension - Compression Asymmetry in Co49Ni21Ga30 High-Temperature Shape Memory Alloy Single Crystals

2013 ◽  
Vol 738-739 ◽  
pp. 82-86 ◽  
Author(s):  
Thomas Niendorf ◽  
Jayaram Dadda ◽  
Jan Lackmann ◽  
James A. Monroe ◽  
Ibrahim Karaman ◽  
...  
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Stress State ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Single Crystals ◽  
Stress Level ◽  
Elevated Temperatures ◽  
Stress States ◽  
Tension Compression Asymmetry

This paper reports on the tension-compression asymmetry of [001]-oriented Co49Ni21Ga30 single crystals at elevated temperatures. Maximum strains of -4.8 % and 8.6 % in compression and tension, respectively, were found. A linear Clausius-Clapeyron relationship was observed for both stress-states where the smaller slope in tension resulted in a significant increase of the phase transformation temperatures with stress, which reached 180 °C under a constant stress level of 150 MPa. In addition, the material demonstrated a large pseudoelastic temperature range of about 300 °C under both stress state conditions. The results in this study unequivocally indicate the potential of these alloys for applications where elevated temperatures and stress levels prevail.

Study on YAG Laser Welding Process of Fe-Mn-Si Shape Memory Alloy

2010 ◽  
Vol 37-38 ◽  
pp. 1364-1367 ◽  
Author(s):  
Chao Yu Zhou ◽  
Cheng Xin Lin ◽  
Lin Lin Liu
Keyword(s):  
Tensile Strength ◽  
Shape Memory Alloy ◽  
Laser Welding ◽  
Shape Memory ◽  
Cross Section ◽  
Welded Joint ◽  
Processing Parameters ◽  
Welding Seam ◽  
Yag Laser ◽  
Optimal Processing

In this study, 1mm thick Fe-Mn-Si shape memory alloy was welded by both sides using YAG laser welding. In a certain range of parameters, the optimal processing parameters for the maximum tensile strength are current 100 A, pulse frequency 3 Hz and pulse width 15 ms by orthogonal experiment. With the optimal processing parameters, the tensile strength of the welded joint can achieve 94% of base material,and the fracture appears in the center of welding seam and the surface morphology of welding seam is good. The influence of processing parameters on tensile strength of weld joint is directly embodied in cross-section of the welding seam morphology. In the laser welding, the tensile strength of nonpenetration in seam and hourglass shape welded joint is generally poor, and the perfect welded joint has conditions such as wide welding seam, deep penetration, weld pool filling and “non-hollow”. Most importantly, the central area in cross-section of the welding seam is the widest.

Shape memory behavior and tension–compression asymmetry of a FeNiCoAlTa single-crystalline shape memory alloy

2012 ◽  
Vol 60 (5) ◽  
pp. 2186-2195 ◽  
Author(s):  
J. Ma ◽  
B. Kockar ◽  
A. Evirgen ◽  
I. Karaman ◽  
Z.P. Luo ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Single Crystalline ◽  
Shape Memory Behavior ◽  
Tension Compression Asymmetry

Effect of constitutive model parameters on the aeroelastic behavior of an airfoil with shape memory alloy springs

2016 ◽  
Vol 24 (6) ◽  
pp. 1065-1085 ◽  
Author(s):  
Vagner Candido de Sousa ◽  
Carlos De Marqui Junior ◽  
Mohammad H Elahinia
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Pure Shear ◽  
Degree Of Freedom ◽  
Model Parameters ◽  
Cross Sectional ◽  
Helical Springs ◽  
Flutter Boundary ◽  
Tension Compression Asymmetry ◽  
Two Degree Of Freedom

The effects of the pseudoelastic hysteresis of shape memory alloy springs on the aeroelastic behavior of a typical airfoil section are numerically investigated for six different sets of alloy constitutive properties. A two-degree-of-freedom (namely, plunge and pitch) typical section is modeled. Shape memory alloy helical springs are considered in the pitch degree-of-freedom based on classical phenomenological models modified by the pure shear assumption. Tension–compression asymmetry and nonhomogeneous distributions of shear strain, shear stress and martensitic fraction in the cross-sectional area of the coiled shape memory alloy wire are considered. A linear model is used to determine the unsteady aerodynamic loads. Attractive alloy characteristics, which can enhance the aeroelastic behavior of the typical section at the flutter boundary and at the post-flutter regime, are identified and discussed in detail.

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