负Poisson比热电器件的热-电-力耦合弯曲特征及强度分析

The rapid development of smart wearable devices makes a higher requirement for the power supply components, including endurance, convenience and lightweight and so on. The thermoelectric devices can directly convert the thermal energy released by human metabolism into electricity, which can be further used to continuously power the wearable devices. With the global-local and micro-macro combined analysis method, the thermo-electro-mechanical coupling bending behavior and strength failure of a negative Poisson’s ratio thermoelectric device (NPR-TEG) were analyzed. Firstly, the macroscopic bending characteristics and the section with the largest stress were given through the establishment a homogeneous analysis model for the NPR-TEG. Then, the force analysis model for the thermoelectric honeycomb was built. The critical load for the strength failure of a mesoscopic cell wall was also derived with the thermodynamic strength theory. The results show that, the stress level of the thermoelectric honeycomb decreases first and then increases with the re-entrant angle. For the NPR-TEG, the strength failure occurred first in the middle part of the device. For the thermoelectric device with the traditional hexagonal honeycomb, the strength failure occurs at the end of the device rather than the middle part. With the fracture failure occurring in the thermoelectric device, the critical crack length of the middle fracture approximately equals that of the end fracture. The critical crack length could be fitted as an exponential function of the re-entrant angle.