Structural Flaw Detection in Composites

ACIT will design and demonstrate a remotely addressed crack/flaw detection system for composite materials. It will consist of a passive embedded sensor and a handheld portable detector, operating on the principle of the coupling of the LC tank circuit withthe behavior of a strain sensitive resistor. This system uses well known principles of an electronic circuit with carefully balanced forces of inductance and capacitance, applied in a novel manner to provide the following advantages: The passive embeddedsensor is affordable. The response of the embedded sensor is highly reproducible, based on the inherent properties of its fabrication process. The sensor can be tuned for excellent sensitivity in a variety of configurations and applications. The embeddingprocess does not impact the mechanical properties of the host. Used in composite applications, internal composite crack/flaw may be assessed remotely. The detector will exploit the properties of the gate dip meter and its ability to detect resonance inthe RCL circuit and the sharpness of that resonance, Q. The detector will be designed for ease of operation. Its operation is remote, non-destructive, and allows simple data interpretation. This crack/flaw detection system offers military andcommercial contractors an essential new tool to portably monitor and periodically measure small cracks and flaws in advanced composites much the way they now keep track of cracks in aluminum airframes and structures. This is all done on a non-intrusivebasis without the need for disassembly. One example is the composite inspection needed at a deployed logistics support center for composites in the THAAD program.