Characterisation and modelling of behaviour of a shape memory alloys

Sahli, Mohamed; Necib, Brahim

doi:10.1007/s00170-013-5416-9

Cited by 10 publications

(10 citation statements)

References 16 publications

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“…Two other phases are possible, R-Phase for NiTiFe, NiTiAl, and aged or heat-treated NiTi alloys, as well as the B19 phase for NiTiCu alloys [10]. These phases are unstable and transitional, with their occurrence highly dependent on alloy chemistry and thermomechanical histories [11]. These phases are not discussed further in this as they are not observed experimentally for the material studied.…”

Section: Phases and Crystal Structurementioning

confidence: 99%

“…SMA thermomechanical characterization is an active field of research and development as discussed by Hartl et al [10], with methodologies as abundant as modelling approaches. The two-step basic approach is clear and often performed as in [11,[36][37][38]. First, differential scanning calorimetry (DSC) is used to measure thermal behaviour, for which the relevant standard is ASTM F2004-17 [39].…”

Section: Sma Thermomechanical Characterizationmentioning

confidence: 99%

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Thermomechanical characterization of functionally stabilized nickel-titanium-copper shape memory alloy

Iyer

Hubert

2022

Eng. Res. Express

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Shape memory alloy hybrid composites have promise in realizing the 21st century goal of morphing structures. There is considerable work to be done in the development of characterization and modeling techniques for these materials. The proposed characterization methodology adapts existing standards to include previously omitted factors required for the numerical modelling of shape memory alloys and their integration into end-use applications. A nickel-titanium-copper (NiTiCu) shape memory alloy is characterized using these methods and then numerically modelled. Samples’ mechanical behaviour is shown to stabilize after 43 cycles of mechanical loading. Thermomechanical properties measured before and after stabilization are shown to vary inconsistently by up to 72%, demonstrating the need for stabilization for accurate thermomechanical characterizations and consistency in end-use applications. Physical experiments are numerically replicated in Abaqus\Standard using the measured properties. Sufficient correlation is shown for the design of shape memory alloy hybrid composites. The result of this work is a comprehensive thermomechanical characterization approach for shape memory alloys which can be used to develop morphing SMA hybrid composite structures.

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Section: Phases and Crystal Structurementioning

confidence: 99%

Section: Sma Thermomechanical Characterizationmentioning

confidence: 99%

Thermomechanical characterization of functionally stabilized nickel-titanium-copper shape memory alloy

Iyer

Hubert

2022

Eng. Res. Express

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“…The SMA wire specimen can also be heated and cooled in an environmental air chamber (Iyer and Hubert, 2022; Prahlad and Chopra, 2003; Sahli and Necib, 2014). However, the thermal coupling between air and wire is relatively weak.…”

Section: Introductionmentioning

confidence: 99%

Thermomechanical characterization of phase transformation surfaces for thin SMA wires

Kazi

Hauber

Honold

2023

Journal of Intelligent Material Systems and Structures

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The phase transformation of thermal shape memory alloys (SMAs) can be described by surfaces in a temperature-stress-strain space. A novel experimental technique for the thermomechanical characterization of thin SMA wires allows to scan these surfaces with high resolution. Each experimental run uses a sequence of experimental conditions to traverse the phase transformation surfaces on a different path from “full martensite” to “full austenite” and vice versa. At all times, stress and strain are kept within the limits specified for the use of the SMA wire in actuators. The wire is heated externally through a silicon oil bath, which ensures a controlled and homogeneous temperature of the specimen. The experimental setup is designed to minimize the impact of the large oil temperature variations on measurement results. Experimental results are shown for both mechanical contraction and electrical resistance, each of which forms consistent surfaces for the phase transformation. Measurements for external heating in the oil bath are compared to electrical heating in air.

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“…There are pyrotechnic and non-pyrotechnic separation devices [5,6]. Pyrotechnic devices, such as explosive bolts, pyrotechnic segmented nuts, steel-ball locks, and pin-puller devices, etc., rely on the combustion energy of explosives to actuate separations [7][8][9][10].Non-pyrotechnic devices are classified by actuator types, such as pneumatic, electromagnetic, and pre-pressure spring actuators [7,11,12]. Pyrotechnic devices are light-weight and have simple mechanical structures [9,10], but they can cause strong shocks.…”

Section: Introductionmentioning

confidence: 99%

Modelling and experimental study on dynamics of a gas-driven split nut device

Jiang

Wang

Zhang³

et al. 2022

Preprint

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Separation devices are widely used in satellites and rockets, where mechanical properties of the devices have significant influences on connection and separation behaviors. Compared to a pyrotechnically actuated separation device, a gas-driven separation device employs preloads, instead of explosions, to actuate separation of the aircrafts, which has advantages of reusability and low impacts. Dynamic modeling of the gas-driven separation device can be used to optimize its separation behaviors, where flexibility is considered since preloads stored in deformations play important roles in separations. Complex interactions of interfaces occur during the separation process in a short time, which raises issues of convergence and computational time when a finite element method is in use. In this work, a simplified model of a gas-driven separation device is firstly developed, where flexibility is introduced only on the interfaces of components and their bodies are still rigid. The LZB multi-point method is applied to deal with repeated impacts of the interfaces in the separation process, and a variable-constraint technique is established to rebuild contact-point pairs when contact areas vary. Simulations of the dynamic model describe detailed interactions of the separation process. Results illustrate that the separation time decreases when the preload increases, and the decreasing rate gets lower due to reactions of split nuts. A test bench of the gas-driven separation device is developed, by which experimental results validate that the proposed dynamic model can accurately predict the separation time and speeds at different preloads.

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Characterisation and modelling of behaviour of a shape memory alloys

Cited by 10 publications

References 16 publications

Thermomechanical characterization of functionally stabilized nickel-titanium-copper shape memory alloy

Thermomechanical characterization of functionally stabilized nickel-titanium-copper shape memory alloy

Thermomechanical characterization of phase transformation surfaces for thin SMA wires

Modelling and experimental study on dynamics of a gas-driven split nut device

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