Correlation of Accelerated Tests with Human Body Measurements for Flexible Electronics in Wearable Applications

The increase in the use of flexible electronics in wearable applications has resulted in an increased focus on the study of movement characteristics of the human body and its impact on electronics under various day-to-day actions. The flexible electronics that are attached to the human body are tested for reliability under various conditions of human activity such as walking, jumping, squats, lunges, and bicep curls. The human body motion data during these different actions were measured using a set of ten Vicon cameras to measure the position, velocity, and accelerations of a standard full-body sensor location of a human body. The reliability model presented in this study uses the angle variations of each joint in the human body for all the five human activities listed above. Statistical analysis on the difference of each joint angle was tested with hypothesis testing strategies with different subjects and with various human body actions as well. Acceleration factor modeling on the reliability of the electronics was carried out using test data of flexible electronics subjected to bending, twisting, stretching, and folding experiments. These experiments are conducted on flexible electronic substrates until failure with in-situ resistance measurements to monitor the changes in the board during each of these experiments. The experimental measurements of the boards were combined with the human body motion data to model the acceleration factor for each of these tests.