Machine Learning Enhanced Dynamic Response Modelling of Superelastic Shape Memory Alloy Wires

Superelastic shape memory alloy (SMA) wires exhibit superb hysteretic energy dissipation and deformation capabilities. Therefore, they are increasingly used for the vibration control of civil engineering structures. The efficient design of SMA-based control devices requires accurate material models. However, the thermodynamically coupled SMA behavior is highly sensitive to strain rate. For an accurate modelling of the material behavior, a wide range of parameters needs to be determined by experiments, where the identification of thermodynamic parameters is particularly challenging due to required technical instruments and expert knowledge. For an efficient identification of thermodynamic parameters, this study proposes a machine-learning-based approach, which was specifically designed considering the dynamic SMA behavior. For this purpose, a feedforward artificial neural network (ANN) architecture was developed. For the generation of training data, a macroscopic constitutive SMA model was adapted considering strain rate effects. After training, the ANN can identify the searched model parameters from cyclic tensile stress–strain tests. The proposed approach is applied on superelastic SMA wires and validated by experiments.

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Evaluation of Bodner-Partom Model Parameters at High Strain Rate

Journal of Engineering Materials and Technology ◽

10.1115/1.3225845 ◽

1986 ◽

Vol 108 (1) ◽

pp. 75-80 ◽

Cited By ~ 21

Author(s):

A. M. Rajendran ◽

S. J. Bless ◽

D. S. Dawicke

Keyword(s):

High Strain Rate ◽

Strain Rate ◽

High Strain ◽

Material Behavior ◽

Model Parameters ◽

Plate Impact ◽

Plane Plate ◽

Wide Range ◽

Split Hopkinson ◽

Stress States

The objective of this paper is to model the high strain rate material behavior of metals using Bodner-Partom visco-plastic constitutive model. A unique algorithm has been developed to evaluate the model parameters from the split Hopkinson Bar and plane plate impact tests data. The model parameters were successfully determined for the 6061-T6 aluminum, 1020 steel, and HY 100 steel. Using the evaluated model parameters, the test data obtained from an unusually wide range of stress states for these three metals were successfully modeled.

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A Review Of Utilizing Shape Memory Alloy In Structural Safety

AIUB Journal of Science and Engineering (AJSE) ◽

10.53799/ajse.v19i3.111 ◽

2020 ◽

Vol 19 (3) ◽

pp. 116-125

Author(s):

Abul Hasnat ◽

Safkat Tajwar Ahmed ◽

Hafiz Ahmed

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Smart Materials ◽

Large Scale ◽

Civil Engineering ◽

Structural Safety ◽

Damping Capacity ◽

Engineering Structures ◽

Structural Deterioration ◽

Wide Range

Abstract- The advancement of material technology has paved the way for smart materials to emerge in the civil engineering sector. These smart materials possess the potential to encounter structural deterioration. Therefore, proper attention should be provided to smart materials regarding both research and application. Shape memory alloy (SMA) is a unique smart material that demonstrates growing applicability in numerous sectors. Recently, a lot of emphasis is being given to SMA research with a view to utilizing SMA in civil engineering structures. SMAs have some special properties such as high damping capacity, self-centering mechanism, two-way memory, self-adaptability etc. for which they can be used to make various types of structural control devices. An integrated assessment of the fundamental properties of SMAs, based on the existing data is presented by this paper in a concise and graphical manner. This paper also discusses the possibility of implementing SMAs in a wide range of civil engineering application, therefore motivating the large scale development of smart structures.

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Mechanical Consequences of Dynamically Loaded NiTi Wires under Typical Actuator Conditions in Rehabilitation and Neuroscience

Journal of Functional Biomaterials ◽

10.3390/jfb12010004 ◽

2021 ◽

Vol 12 (1) ◽

pp. 4

Author(s):

Umut D. Çakmak ◽

Zoltán Major ◽

Michael Fischlschweiger

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Storage Modulus ◽

Loss Factor ◽

Empirical Relation ◽

Material Behavior ◽

Chemical Compositions ◽

Loading Frequency ◽

Frequency Dependency ◽

Controlled Conditions

In the field of rehabilitation and neuroscience, shape memory alloys play a crucial role as lightweight actuators. Devices are exploiting the shape memory effect by transforming heat into mechanical work. In rehabilitation applications, dynamic loading of the respective device occurs, which in turn influences the mechanical consequences of the phase transforming alloy. Hence in this work, dynamic thermomechanical material behavior of temperature-triggered phase transforming NiTi shape memory alloy (SMA) wires with different chemical compositions and geometries was experimentally investigated. Storage modulus and mechanical loss factor of NiTi alloys at different temperatures and loading frequencies were analyzed under force-controlled conditions. Counterintuitive storage modulus- and loss factor-dependent trends regarding the loading frequency dependency of the mechanical properties on the materials’ composition and geometry were, hence, obtained. It was revealed that loss factors showed a pronounced loading frequency dependency, whereas the storage modulus was not affected. It was shown that force-controlled conditions led to a lower storage modulus than expected. Furthermore, it turned out that a simple empirical relation could capture the characteristic temperature dependency of the storage modulus, which is an important input relation for modeling the rehabilitation device behavior under different dynamic and temperature loading conditions, taking directly into account the material behavior of the shape memory alloy.

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Functional behaviour of TiNi shape memory alloy after high strain rate deformation

Materials Science and Technology ◽

10.1080/02670836.2021.1958466 ◽

2021 ◽

pp. 1-11

Author(s):

Eugeny Ostropiko ◽

Alexandr Yu Konstantinov

Keyword(s):

Shape Memory Alloy ◽

High Strain Rate ◽

Strain Rate ◽

Shape Memory ◽

High Strain ◽

High Strain Rate Deformation

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Rate-Dependent Damping Capacity of NiTi Shape Memory Alloy

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.172-174.37 ◽

2011 ◽

Vol 172-174 ◽

pp. 37-42 ◽

Cited By ~ 2

Author(s):

Yong Jun He ◽

Qing Ping Sun

Keyword(s):

Shape Memory Alloy ◽

Strain Rate ◽

Shape Memory ◽

Strain Curve ◽

Tensile Loading ◽

Niti Shape Memory Alloy ◽

Damping Capacity ◽

Environmental Condition ◽

Mechanical Coupling ◽

Rate Dependent

High damping capacity is one of the prominent properties of NiTi shape memory alloy (SMA), having applications in many engineering devices to reduce unwanted vibrations. Recent experiments demonstrated that, the hysteresis loop of the stress-strain curve of a NiTi strip/wire under a tensile loading-unloading cycle changed non-monotonically with the loading rate, i.e., a maximum damping capacity was obtained at an intermediate strain rate (ε.critical). This rate dependence is due to the coupling between the temperature dependence of material’s transformation stresses, latent-heat release/absorption in the forward/reverse phase transition and the associated heat exchange between the specimen and the environment. In this paper, a simple analytical model was developed to quantify these thermo-mechanical coupling effects on the damping capacity of the NiTi strips/wires under the tensile loading-unloading cycle. We found that, besides the material thermal/mechanical properties and specimen geometry, environmental condition also affects the damping capacity; and the critical strain rate ε.criticalfor achieving a maximum damping capacity can be changed by varying the environmental condition. The theoretical predictions agree quantitatively with the experiments.

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Comparing different block propagation modelling approaches using the Platrock simulation platform

10.5194/egusphere-egu21-10619 ◽

2021 ◽

Author(s):

Vincent Acary ◽

Franck Bourrier ◽

David Toe ◽

Francois Kneib

Keyword(s):

Expert Knowledge ◽

Material Point ◽

Model Parameters ◽

Propagation Models ◽

Rockfall Hazard ◽

Wide Range ◽

Natural Terrain ◽

Block Propagation ◽

Propagation Modelling ◽

Modelling Approaches

Block propagation models are routinely used for the quantitative assessment of rockfall hazard. In these models, one of the major di&#64259;culties is the development of physically consistent and &#64257;eld applicable approaches to model the interaction between the block and the natural terrain. For most of propagation models, a thorough calibration of the input parameters is not available over the wide range of configurations encountered in practice. Consequently, the parameters choice is strongly depending on expert knowledge. In addition, most of models exhibit substantial sensitivity to some parameters, i.e. small changes of these parameters entail large differences in the simulation results.The trajectory analysis platform Platrock, freely available upon request (contact: [email protected]), allows performing 2D and 3D simulations using both material point rebound models and models, based on non-smooth mechanics, that explicitly account for block shape. This platform provides several simulation tools for detailed analyses of block propagation on study sites.The possibilities of the predictive capabilities of different block propagation modelling approaches integrated into the Platrock platform have been assessed on a well-documented study site, where a benchmark of propagation models has been done in the context of C2ROP research project. This analysis emphasized the capacities of trajectory analyses to traduce block propagation but also demonstrated their substantial sensitivity to model parameters. The results from these simulations cannot be relevantly interpreted if they are not accompanied with calibration proofs, sensitivity analysis, and detailed interpretation of the results from the expert in charge of the study.

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