scholarly journals Active Adjustment of Surface Accuracy for a Large Cable-Net Structure by Shape Memory Alloy

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2619
Author(s):  
Xiangjun Jiang ◽  
Fengqun Pan ◽  
Yesen Fan ◽  
Jingli Du ◽  
Mingbo Zhu ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
High Surface ◽  
Element Model ◽  
Optimization Method ◽  
Space Environment ◽  
Antenna Structure ◽  
Adjustment Procedure ◽  
Surface Accuracy ◽  
Parabolic Reflectors

The high surface accuracy design of a cable-net antenna structure under the disturbance of the extremely harsh space environment requires the antenna to have good in-orbit adjustment ability for surface accuracy. A shape memory cable-net (SMC) structure is proposed in this paper and believed to be able to improve the in-orbit surface accuracy of the cable-net antenna. Firstly, the incremental stiffness equation of a one-dimensional bar element of the shape memory alloy (SMA) to express the relationship between the force, temperature and deformation was effectively constructed. Secondly, the finite element model of the SMC antenna structure incorporated the incremental stiffness equation of a SMA was established. Thirdly, a shape active adjustment procedure of surface accuracy based on the optimization method was presented. Finally, a numerical example of the shape memory cable net structure applied to the parabolic reflectors of space antennas was analyzed.

Shape memory alloy sensory particles for damage detection: Experiments, analysis, and design studies

2017 ◽  
Vol 17 (4) ◽  
pp. 777-814 ◽  
Author(s):  
Brent R Bielefeldt ◽  
Jacob D Hochhalter ◽  
Darren J Hartl
Keyword(s):  
Finite Element ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Structural Damage ◽  
Structural Integrity ◽  
Fatigue Cracks ◽  
Element Model ◽  
Optimization Method ◽  
Sensory Response ◽  
Analysis And Design

Developing novel techniques for monitoring structural integrity has become an important area of research in the aerospace community. One new technique exploits the stress-induced phase transformation behavior in shape memory alloy particles embedded in a structure. By monitoring changes in the mechanical and/or electromagnetic behavior of such particles, the formation or propagation of fatigue cracks in the vicinity of these particles can be detected. This work demonstrates sensory particle response to local structural damage using finite element modeling for the first time. Using an optimization method to minimize the difference between experimentally measured strain and simulated results, a good approximation of sensory particle properties can be determined and the strong sensory response of the transforming particle demonstrated. To illustrate an application of this method, a multi-scale finite element model of sensory particles embedded in the root rib of an aircraft wing is then considered. In particular, this unique model utilizes substructure modeling to maintain computational efficiency while relating globally applied loads to local structural response, allowing for the consideration of predicted particle response to crack propagation during wing loading. The effect of particle position relative to the crack tip on particle sensory response is assessed. Finally, this work demonstrates how sensory particles can be used to approximate the location of structural damage by interpolating a stress field based on the responses of multiple sensory particles in the vicinity of a propagating crack.

Steerable Unidirectional Wave Emission From a Single Piezoelectric Transducer Using a Shape Memory Alloy Composite Metasurface

2020 ◽  
Author(s):  
Yihao Song ◽  
Yanfeng Shen
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Excitation Frequency ◽  
Element Model ◽  
Martensite Phase ◽  
Guided Wave ◽  
Ultrasonic Waves ◽  
Unit Cell ◽  
Wave Radiation ◽  
Wave Emission

Abstract Structural Health Monitoring (SHM) and Nondestructive Evaluation (NDE) systems generally adopt piezoelectric transducers which emit omnidirectional wave fields. The achievement of directionality of guided wave generation will benefit the structural sensing purpose, which allows better detection and localization of the damage sites. In this study, a type of metamaterial ultrasonic radar is proposed for the steerable unidirectional wave manipulation. It contains a circular array of unit cells stuck in an aluminum plate which are delicately arranged in a circular fashion. Each unit cell is composed of a shape memory alloy substrate and a lead stub. The controllable bandgap of such metamaterial system can be achieved due to the stiffness change of nitinol between its martensite phase and austenite phase under a thermal load. This research starts with a Finite Element Model (FEM) of the unit cell to compute its frequency-wavenumber domain dispersion characteristics, demonstrating the adjustable bandgap feature. Then, numerical modeling of the metamaterial radar is performed by shifting the bandgap of one sector of the metasurface away from the excitation frequency. The modeling results demonstrate that the martensite phase metasurface area forms a bandgap region where guided wave energy cannot penetrate, while the bandgap of the austenite sector shifts away from the excitation frequency, opening up a transmission path for the ultrasonic waves. By rotating the austenite sector, the metamaterial structure can work like a wave emission radar, realizing of the steerable unidirectional wave radiation with a single transducer. Such an active metasurface possesses great application potential in future SHM and NDE systems.

Thermomechanical Modelling and Experimental Testing of a Shape Memory Alloy Hybrid Composite Plate

2008 ◽  
Vol 59 ◽  
pp. 41-46 ◽  
Author(s):  
Federica Daghia ◽  
Gabriella Faiella ◽  
Vincenza Antonucci ◽  
Michele Giordano
Keyword(s):  
Finite Element ◽  
Shape Memory Alloy ◽  
Finite Element Model ◽  
Shape Memory ◽  
Functional Properties ◽  
Hybrid Composite ◽  
Experimental Testing ◽  
Element Model ◽  
Electrical Heating ◽  
Simultaneous Generation

Shape memory alloys (SMA) exhibit functional properties associated with the shape memory effect, responsible of the SMA shape recovery after a cycle of deforming-heating and of a simultaneous generation of mechanical work. Composite systems incorporating SMA wires have the ability to actively change shape and other structural characteristics. The functional properties of such adaptive composites are related to the martensitic transformation in the SMA elements and to the constraining behaviour that the composite matrix has on the SMA wires. In this work the behaviour of a shape memory alloy hybrid composite (SMAHC) is numerically and experimentally investigated. A plate was fabricated using prestrained SMA wires embedded in an epoxy resin pre preg glass fibres composite system. Upon calorimetric and mechanical material characterization, a finite element model was used in order to predict the structural behaviour of the SMAHC. In the experimental tests, the plate was clamped at one side and actuated via electrical heating. Temperature and displacement data were collected and compared with the prediction of the finite element model. The results show that the model is able to capture the shape change in the actuation region, although a thorough description of the SMAHC behaviour requires further modelling work, including the simulation of the SMA loading history during composite manufacturing.

Development of a shape memory alloy multiple-point injector for chemotherapy

2005 ◽  
Vol 219 (3) ◽  
pp. 213-217 ◽  
Author(s):  
W Xu ◽  
T G Frank ◽  
A Cuschieri
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Direct Injection ◽  
Element Model ◽  
Multiple Point ◽  
Linear Elastic ◽  
Outer Needle ◽  
Non Linear ◽  
Deformation Force ◽  
Medical Needle

A medical needle is described that allows injection to take place at multiple sites through a single stab wound. This is achieved by extruding multiple, thin, and curved internal needles from a larger, straight, outer needle. The development and finite element modelling of the shape memory alloy (SMA) inner needles is presented in this paper. A non-linear elastic element model was used in this process to allow for the non-linear properties of the alloy and the large deformations that occur. The model provided maximum strain values and penetration forces for the inner needles. The deformation force on the tip of the needle was measured against displacement to confirm the predicted penetration force. Applications for the device include the treatment of liver cancer by direct injection of alcohol into the tumours.

Modeling of Artificial Aurelia aurita Bell Deformation

2011 ◽  
Vol 45 (4) ◽  
pp. 165-180 ◽  
Author(s):  
Keyur B. Joshi ◽  
Alex Villanueva ◽  
Colin F. Smith ◽  
Shashank Priya
Keyword(s):  
Finite Element ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Transient Behavior ◽  
Element Model ◽  
Aurelia Aurita ◽  
Thermal Coefficient ◽  
Power Cycle ◽  
Element Simulation ◽  
The Difference

AbstractRecently, there has been significant interest in developing underwater vehicles inspired by jellyfish. One of these notable efforts includes the artificial Aurelia aurita (Robojelly). The artificial A. aurita is able to swim with similar proficiency to the A. aurita species of jellyfish even though its deformation profile does not completely match the natural animal. In order to overcome this problem, we provide a systematic finite element model (FEM) to simulate the transient behavior of the artificial A. aurita vehicle utilizing bio-inspired shape memory alloy composite (BISMAC) actuators. The finite element simulation model accurately captures the hyperelastic behavior of EcoFlex (Shore hardness-0010) room temperature vulcanizing silicone by invoking a three-parameter Mooney-Rivlin model. Furthermore, the FEM incorporates experimental temperature transformation curves of shape memory alloy wires by introducing negative thermal coefficient of expansion and considers the effect of gravity and fluid buoyancy forces to accurately predict the transient deformation of the vehicle. The actual power cycle used to drive artificial A. aurita vehicle was used in the model. The overall profile error between FEM and the vehicle profile is mainly due to the difference in initial relaxed profiles.

Nonlinear two-dimensional finite element model for transient and damping analysis of cylindrical sandwich panels with pseudoelastic shape memory alloy composite face sheets

2017 ◽  
Vol 21 (1) ◽  
pp. 19-76 ◽  
Author(s):  
Maryam Khanjani ◽  
Mahmoud Shakeri ◽  
Mojtaba Sadighi
Keyword(s):  
Finite Element ◽  
Phase Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Volume Fraction ◽  
Element Model ◽  
Martensite Phase ◽  
Governing Equations ◽  
Time Step ◽  
Composite Face

A new nonlinear finite element model is proposed for the dynamic analysis of cylindrical sandwich panels with shape memory alloy hybrid composite face sheets and flexible core. In order to present a realistic transient vibration analysis, all the material complexities arising from the instantaneous and spatial martensite phase transformation of the shape memory alloy wires are taken into consideration. The one-dimensional constitutive equation proposed by Boyd and Lagoudas is used for modeling the pseudoelastic behavior of the shape memory alloy wires. Since the martensite volume fraction at each point depends on the stress at that point, the phase transformation kinetic equations and the governing equations are coupled together. Therefore, at each time step, an iterative method should be used to solve the highly nonlinear equations. Moreover, considering that the stress resultants generated by the martensite phase transformation in the wires are path-dependent values, an incremental method is used to estimate the increment of the stress resultants at each time step. The governing equations are derived based on the energy method and Newmark time integration method is used to solve the discretized finite element equations. Finally, several numerical examples are presented to examine the effect of various parameters such as intensity of applied pressure load, operating temperature, location of shape memory alloy wires, volume fraction of the shape memory alloy wires, and also boundary conditions upon the loss factor for panels with different aspect ratios.

Enhanced Design of Microgripper Using Double Actuators of Shape Memory Alloy Wires

2014 ◽  
Author(s):  
Qais Khasawneh ◽  
Mohammad A. Jaradat ◽  
Ahmad Alshorman
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Software Package ◽  
Element Model ◽  
Ansys Software ◽  
Micro Gripper ◽  
Sma Actuator ◽  
Main Material

In this paper, new design of micro-gripper with shape memory alloy (SMA) actuator is presented. Double SMA actuators were used to enhance the performance of the micro-gripper by using hinge mechanisms; the little displacement of the SMA wire is converted into larger displacement of the tips of the micro-gripper. Stainless steel (St 304) was used as a main material of the gripper structure. Shape memory alloy (Ni-Ti) wires were used as actuators. Finite element model analysis (FEA) using ANSYS software package was used to simulate displacement and stress analysis on the micro gripper. Finally a comparison between the enhanced design and the initial one showed better results in terms of increasing the gripper stroke and reducing the stress on the gripper joints.

scholarly journals Study on Interference Connection Based on Shape Recovery of NiTiNb Shape Memory Alloy

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2328
Author(s):  
Haojie Niu ◽  
Yubin Sun ◽  
Chengxin Lin ◽  
Yutang Zou
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Element Model ◽  
Interference Fit ◽  
Pull Out ◽  
Hole Wall ◽  
Element Simulation ◽  
Change Trend

Interference connection is an effective method for improving the fatigue life of bolt connections. In this paper, a new method of interference connection was designed based on the shape memory effect of shape memory alloy. Using the method of numerical simulation, a finite element model was established to analyze the stress–strain rule of the bolt and the hole wall under different interference fit sizes. The results show that the stress concentration is formed at the orifice of the connecting plate. When the interference fit size is less than 1%, the connection hole has elastic deformation. When the interference fit size is 1.5%, the hole wall has plastic deformation. When the interference fit size is 2.5%, the maximum stress on the connecting plate is close to the tensile limit of the material. If the interference fit size continues to increase, the strength of the connection structure will be damaged. The connection experiments with different interference fit size were designed, and the interference force was calculated by the pull-out force. The experimental results were compared with the numerical simulation results. The change trend of the interference force with the interference fit size is consistent, which verifies the rationality of the finite element simulation.

Experimental Characterization and Modelling Validation of Shape Memory Alloy Negator Springs

2013 ◽  
Author(s):  
Andrea Spaggiari ◽  
Eugenio Dragoni ◽  
Ausonio Tuissi
Keyword(s):  
Finite Element ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Analytical Model ◽  
Element Model ◽  
Design Tool ◽  
Experimental Characterization ◽  
Finite Element Software ◽  
Spiral Spring ◽  
Force Displacement

This paper is aimed at the experimental characterization and modelling validation of shape memory alloy (SMA) negator springs. A Negator spring is a spiral spring made of strip of metal wound on the flat with an inherent curvature such that, in repose, each coil wraps tightly on its inner neighbour. The main feature of a Negator springs is the nearly-constant force displacement behaviour in the unwinding of the strip. Moreover the stroke is very long, theoretically infinite as it depends only on the length of the initial strip. A Negator spring made in SMA is built and experimentally tested to demonstrate the feasibility of this actuator. The shape memory Negator spring behaviour is predicted both with an analytical model and with a a finite element software. In both cases the material is modelled as elastic in austenitic range while an exponential continuum law is used to describe the martensitic behaviour. The experimental results confirms the applicability of this kind of geometry to the shape memory alloy actuators and the analytical model is confirmed to be a powerful design tool to dimension and predict the spring behaviour both in martensitic and austenitic range, as well as the finite element model developed.

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