Patent ID: 7141990

Claim:
An assembly comprising: a ceramic heat shield deemed acceptable only in the absence of any crack propagating from an edge of the heat shield toward a center of the heat shield to a critical location of the heat shield, the heat shield deemed acceptable with cracks not extending to the critical location, a length of a crack extending from the edge to the crucial location defining critical length; a monitoring structure applied to the heat shield and comprising a radiofrequency resonant circuit, the radiofrequency resonant circuit further comprising an electrical conductor attached to the heat shield at a distance equal to the critical length from the edge of the heat shield; and a monitoring device comprising an antenna adapted for remote wireless interrogation of the monitoring structure via radiofrequency excitation of the radiofrequency resonant circuit; wherein a crack propagating from the edge of the heat shield toward the center of the heat shield exceeding the critical length will cause a crack in the electrical conductor, thereby changing a radiofrequency resonance of the radiofrequency resonant circuit that is remotely detectable by the monitoring device for identifying the heat shield as defective.