FLEXURAL BEHAVIOR OF STAGED LAMINATES FOR COMPOSITE REPAIR

The flexural properties of staged composite materials are extremely important since many aerospace companies are investigating composite repair technologies. In general, the term staging involves two steps. First, the layup is debulked below the gelation temperature, releasing exothermic energy, allowing the laminate to be stored at room temperature. The final cure at the gelation temperature is then completed later. Testing was done to determine the flexural properties of specimens debulked at various times and temperatures. From the flexural load-displacement curve, various material properties can be derived. The data indicates that composites debulked for 30 minutes have high flexural strength and a higher modulus of elasticity than those debulked for 60 minutes. With an understanding of the flexural properties that result from various debulking times and temperatures, these variables can be designed to optimize these intermediate flexural properties. This allows for more control of the final material strength.