Thermomechanical analysis of the stretchable serpentine heaters considering finite deformation

Stretchable heater, as a newly developed heating device, can perfectly fit with undevelopable curved surfaces via mechanical deformation. Inspired by serpentine interconnects, we developed a new design of stretchable serpentine heater (SSH), where the serpentine heat source embedded into the softer and highly stretchable materials (such as Ecoflex and Silbione) provides an effective approach to achieving both high stretchability and thermal uniformity. It can provide uniform heating for objects with curvilinear contours, such as uniform thermal manikins, defogging curved windows and thermotherapy. However, under large mechanical deformation, the thermal field of SSH will drastically change on account of the morphology change of embedded serpentine heating wire. Therefore, the present study presents an accurate theoretical model to predict the thermomechanical behaviors of SSH considering finite deformation. After a validation via finite element analysis (FEA) and experiments to verify the present theory, the effects of geometric parameters of SSH on the mechanical and thermal behaviors are investigated to identify the most effective way to achieve both better stretchability and thermal uniformity in the process of stretching. This study can help guide the design and fabrication of SSH based on Ecoflex substrate to achieve the goal of uniform heating on complex curved surfaces in future applications.