| abstract |
A method of determining stress within a composite structure is provided which includes coupling a sensor to a composite structure under load having embedded therein a plurality of particles, wherein the particles at room temperature are paraelectric or ferroelectric, transmitting an electromagnetic radiation to the sensor, thereby generating an electromagnetic field into the composite structure, sweeping frequency from a first frequency to a second frequency in a pulsed manner, receiving reflected power from the composite structure, determining the resonance frequency of the sensor, and translating the resonance frequency of the sensor to stress within the composite structure. |