Woven Hybrid Inserts for Lightweigt Affordable Aircraft Structures

The latest generation of three dimensionally reinforced carbon/epoxy composites have demonstrated the ability to carry significantly higher ultimate loads than conventional laminated composites in structural configurations such as T-sections. The failure modes of these composites are complex and not covered by the technology of laminated composites. Recent advancements on automated perform fabrication and molding concepts indicate that substantial cost savings can be applied. Techniweave, Inc (TI), as the prime contractor, and McDonnell Douglas Aerospace (MDA), as a subcontractor, propose to develop a method of test and evaluation to set appropriate allowable loads for composite joints that incorporate 3-dimensional fiber reinforcements. Testing will be done on composite samples made with TI's fiber insertion process. The samples will be tested for mechanical properties while using acoustic emissions to monitor the occurrence of the internal damage. Microscopic evaluation of the internal damage at varying loads plus fatigue testing at similar loads will also be performed.