Theoretical and experimental investigations of transient thermo-mechanical analysis on flexible electronic devices

Flexible electronic devices (FEDs), especially in the applications of diagnosis, clinical monitoring and treatments, have attracted much attention due to their special mechanical properties. And on account of their special materials, transient thermo-mechanical analysis becomes very critical for FEDs since the overheating and excessive thermal strain from the short circuit or unexpected high current of the devices may cause damage to the devices or danger to the human. In this paper, a three-dimensional transient analytical thermo-mechanical model for a typical FED is developed to investigate the thermo-mechanical behaviors of the FED based on the transfer matrix method by accounting for the Fourier integral transform in space and the Laplace integral transform in time. In order to confirm the analytical model, IR camera and digital image correlation (DIC) are adopted to measure temperature increase distributions and thermal strain distributions for the typical FED, which can further validate these distributions obtained by finite element analysis (FEA). Geometric parameter studies are systematically carried out to guide the design and fabrication of the FEDs considering the transient thermo-mechanical behaviors.