Fatigue life and performance evaluation of wearable flexible thermoelectric devices under thermomechanical loads

IF 5.7 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue Pub Date : 2025-02-08 DOI:10.1016/j.ijfatigue.2025.108861

Shifa Fan , Yuanwen Gao , Zhiqiang Li

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引用次数: 0

Abstract

Wearable flexible thermoelectric generators (WFTEGs) offer a promising solution for integrating power sources with electronics in wearable technologies. However, the longevity of these devices is compromised by fatigue propagation in brittle thermoelectric materials due to internal cracks. This study presents a three-dimensional (3D) numerical model of WFTEGs with through-thickness cracks, accounting for body heat and thermal contact resistance. The effects of flexible substrate thickness, heat sink convection coefficient, and bending radius on the output power density, conversion efficiency, and fatigue life of WFTEGs are comprehensively examined. The results reveal that although increased body heat enhances thermoelectric performance, it simultaneously reduces fatigue life. Removing the cold-end flexible substrate and utilizing an efficient heat sink can improve both thermoelectric performance and fatigue life. Interestingly, the fatigue life initially decreases but then increases as the bending radius decreases, which is attributed to the crack closure effect on fatigue crack propagation. To prevent accelerated fatigue and optimize device durability, environments with a bending radius of approximately 14.33 mm should be avoided. These findings provide valuable insights into the structural optimization of WFTEGs, ensuring their long-term reliability and safety.

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来源期刊

International Journal of Fatigue 工程技术-材料科学：综合

CiteScore

10.70

自引率

21.70%

发文量

619

审稿时长

58 days

期刊介绍： Typical subjects discussed in International Journal of Fatigue address: Novel fatigue testing and characterization methods (new kinds of fatigue tests, critical evaluation of existing methods, in situ measurement of fatigue degradation, non-contact field measurements) Multiaxial fatigue and complex loading effects of materials and structures, exploring state-of-the-art concepts in degradation under cyclic loading Fatigue in the very high cycle regime, including failure mode transitions from surface to subsurface, effects of surface treatment, processing, and loading conditions Modeling (including degradation processes and related driving forces, multiscale/multi-resolution methods, computational hierarchical and concurrent methods for coupled component and material responses, novel methods for notch root analysis, fracture mechanics, damage mechanics, crack growth kinetics, life prediction and durability, and prediction of stochastic fatigue behavior reflecting microstructure and service conditions) Models for early stages of fatigue crack formation and growth that explicitly consider microstructure and relevant materials science aspects Understanding the influence or manufacturing and processing route on fatigue degradation, and embedding this understanding in more predictive schemes for mitigation and design against fatigue Prognosis and damage state awareness (including sensors, monitoring, methodology, interactive control, accelerated methods, data interpretation) Applications of technologies associated with fatigue and their implications for structural integrity and reliability. This includes issues related to design, operation and maintenance, i.e., life cycle engineering Smart materials and structures that can sense and mitigate fatigue degradation Fatigue of devices and structures at small scales, including effects of process route and surfaces/interfaces.