Abstract: An electronics system may include a substrate, an electronic device bonded to the substrate, a plurality of photoluminescent particles disposed on the electronic device, an illuminator, a sensor, and a control module. The illuminator can illuminate the electronic device. The sensor can capture a first set of positions of the photoluminescent particles on the electronic device when the electronic device is not operating under a load and a second set of positions of the photoluminescent particles when the electronic device is operating under a load. The control module can determine thermomechanical stress on the electronic device based at least in part on a difference between the first set of positions and the second set of positions.