SUMMARY

Wearable electronics undergo stretching, flexing, bending, and twisting during the process of being put on and while being worn. In addition, wearable textile electronics also need to survive under repeated washing cycles as well as extended creep deformation while being worn. Thus, it is necessary to ensure that the wearable electronic components remain reliable under use conditions. The first objective of this work is to examine the strain distribution in the electronics, conductors and other supporting materials when a typical wearable smart garment is being put on. The strain distribution under monotonic stretching as well as combined stretching and bending conditions will be evaluated. A commercially available wearable garment will be used to validate the effectiveness of the proposed mechanical strain characterization procedure. The second objective is to study and understand the role of serpentine geometry on strain relief and to evaluate the effectiveness of the serpentine design with respect to the substrate stiffness when the serpentine structure is supported by a polymer substrate. Other innovative strain-relief configurations will also be evaluated. A machine learning model will be developed to optimize design for strain relief. The third objective of this work is to assess the reliability of wearable electronics under end-use conditions. The end-use cases include conductors undergoing creep deformation while the smart garment is being worn and the wearable system being incrementally damaged through washing cycles.