P‐5.1: FPC Bending Simulation and Analysis for Wearable Products

In this paper, based on ANSYS Workbench the FPC physical model is established to analyze the bending stress and strain under reliability bending test condition. Before the improvement measures are applied, the stress is 760Mpa, larger than ultimate stress for both PI and copper film, with strain larger than 10 percent, so it is obvious that there is a risk of crack appearing on FPC. After changing the stack design of FPC, the stress and strain can reduce significantly, which are 550Mpa and 7 percent respectively. Considering the time consumption for three‐dimensional model calculation, a simplified model is introduced, which just focus on material properties and film stacking. The simulation result shows that the difference of calculation results between three‐dimensional model and simplified model is just less than 5 percent, which means the simplified model is verified to be reliable to analyze the bending stress and bending strain.