Reliability and degradation analysis of smart material actuators

Heß, Philipp; Bracke, Stefan

doi:10.3850/978-981-11-2724-3_0541-cd

Cited by 2 publications

(14 citation statements)

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“…eingesetzt. Eine weitere Anwendung The material behavior relies on the martensitic phase transformation (Elahinia (2016), Heß and Bracke (2019), Heß and Bracke (2018), Hinz et al (2018), Lagoudas (2008) and Rao et al (2015)). Figure 1 (a) shows a stressstrain-temperature diagram of a typical SMA.…”

Section: Shape Memory Effectmentioning

confidence: 99%

“…A linear strain recovery (D) is achieved by unloading the SMA. Exceeding both, the austenite start (E) and finish (F) temperature, by heating the SMA (which can be achieved by thermal energy or electric heating), the material transforms back to austenite and the strain recovery is complete (A) (Elahinia (2016), Heß and Bracke (2019), Heß and Bracke (2018) and Lagoudas (2008)).…”

Section: Shape Memory Effectmentioning

confidence: 99%

“…Actual shape memory applications are thermal and electrical valves, release or actuating mechanisms and auto-focus systems of smartphone cameras (Heß and Bracke (2018) and Hinz et al (2018) and Janocha (2010)). According to Elahinia (2016), Heß and Bracke (2019), Heß and Bracke (2018) and van Humbeeck (2001), the nickel titanium alloy with a ratio of 50:50 is the most common one, which is used for more than 90% of the actual commercial applications.…”

Section: Shape Memory Effectmentioning

confidence: 99%

“…Cyclic loading (without pauses) can be a possible accelerated test procedure, which can be used to reduce the required testing time (Nelson (2004) and Meeker (1998)). In case of shape memory actuators a replicable determination of the fatigue behavior, degradation, reliability and service life is not possible due to the lack of standardized test programs including test rigs and test plans (Heß and Bracke (2019)). Despite those major issues, many smart actuators have been developed and tested for varoius applications.…”

Section: Introductionmentioning

confidence: 99%

“…Despite those major issues, many smart actuators have been developed and tested for varoius applications. According to Elahinia (2016), Heß and Bracke (2018), Heß and Bracke (2019), Hinz et al (2018), Janocha (2010) and Lagoudas (2008) smart material alloys are used in various aerospace, automotive, biomedical, civil and electrical engineering as well as mechanical applications.…”

Section: Introductionmentioning

confidence: 99%

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Smart material actuators as a contributor for IoT-based smart applications and systems: Analyzing prototype and process measurement data of shape memory actuators for reliability and risk prognosis

Heß

Bracke

2020

JAMDSM

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In times of smart products and systems, the Internet of Things (IoT) plays an increasingly important role. IoT combines the digital world (internet) with the physical world (sensors, actuators, robots, smartphones, connected cars etc.). The autonomous operation and remote control of smart systems (e.g. smart home, production hall or line) requires efficient and specially reliable actuators and control mechanisms. Shape memory actuators are particularly suitable for this application due to their properties as they are lightweight, small, energy-efficient and can also be used as sensors at the same time. Many shape memory actuators have been developed for various applications over the past years. Despite great interest, there are no standardized test programs available. The complexity of the shape memory technology is a major challenge in testing fatigue and degradation behavior of components to determine reliability. This article presents fatigue test results of a laboratory test rig of a case study for a shape memory actuator, including all boundary conditions and test requirements. The measurement data consists of different parameters e.g. the stroke of the actuator, the electrical voltage and current (to activate the actuator) as well as the ambient temperature. Since the study comprises only a few prototypes, parametric methods are not suitable for a comprehensive evaluation, therefore parameter-free methods are used as well. The analysis regarding the description of dependencies between the recorded signals and the detection of degradation of the shape memory actuators is discussed in detail. The main objective is the development of a prognosis algorithm in order to be able to predict the failure behaviour of the actuators at an early stage. The methodical approach includes various methods and procedures, which are applied in a logical order. The statistical analytics used in this study are focusing on nonparametric significance tests, such as the Levene's test and the u-test by Wilcoxon and Mann-Whitney. Further methods are the correlation analysis and the regression analysis as well as multivariate 3D-plots. The fundamentals of shape memory alloys, as well as the used statistical nonparametric methods, are described briefly. Finally, the realization (application of the analysis methods) based on the real test rig data of a case study consisting of 18 actuators is shown and discussed in detail.

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Section: Shape Memory Effectmentioning

confidence: 99%

Section: Shape Memory Effectmentioning

confidence: 99%

Section: Shape Memory Effectmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Smart material actuators as a contributor for IoT-based smart applications and systems: Analyzing prototype and process measurement data of shape memory actuators for reliability and risk prognosis

Heß

Bracke

2020

JAMDSM

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The Development and Verification of a Simulation Model of Shape-Memory Alloy Wires for Strain Prediction

et al. 2022

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One of the greatest challenges in the design of shape-memory elements (mostly binary Nickel-Titanium wires) is to ensure that the required travel (stroke) is achieved, as this is subject to variation due to various influencing factors. One way of predicting the stroke is to use a suitable energy model. In the past, for example, a model was developed by Oelschläger with which the stroke can be calculated on the basis of the electrical energy. However, so far no model takes into account the change of the phase transformation temperature. In this study, the model of Oelschläger is extended and verified to consider the degradation behavior over the whole lifetime. For this purpose, fatigue tests of 52 wires (2 different load scenarios) were performed. Based on these tests and the application of statistical methods (distribution models, goodnes-of-fit tests etc.), a target model was developed for each load scenario, which is used to verify the extended energy model. The energy model was applied to wires of both load scenarios to simulate the stroke progression. The verification of the extended simulation model shows that it is possible to simulate the longterm behavior of the stroke for one of the two load scenarios. The second load scenario shows deviations between the target model and the simulation, which is due to problems in the area of measurement equipment, convection, and temperature distribution in the wire. Nevertheless, a decisive modeling approach could be developed, which can be used to consider the long-term behavior of the phase transformation temperature of wires in simulations.

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Reliability and degradation analysis of smart material actuators

Cited by 2 publications

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Smart material actuators as a contributor for IoT-based smart applications and systems: Analyzing prototype and process measurement data of shape memory actuators for reliability and risk prognosis

Smart material actuators as a contributor for IoT-based smart applications and systems: Analyzing prototype and process measurement data of shape memory actuators for reliability and risk prognosis

The Development and Verification of a Simulation Model of Shape-Memory Alloy Wires for Strain Prediction

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