Evolution of Permanent Composite Repair Designs

The composite community has given a great deal of emphasis to the design, materials selection, analy­sis, and manufacture of composite structures, but has paid limited attention to the repair of those structures. This may be due to a lack of appreciation of the difficulties associated with the repair of com­posite structures. This paper emphasizes the chal­lenges in composite repair by presenting two repair concepts developed under the V-22 Composite Re­pair Development (VCRD) program. These two con­cepts represent repair designs of high-strain struc­ture and of stability-critical structure. A general description of the repair design process, the design drivers, and repair issues associated with each de­sign concept is provided. The paper highlights the different philosophy between repairs of high-strain structure and stability-critical structure. The re­sults of finite-element analysis and design support tests are presented for each type of repair. The im­portance of concurrent engineering (consisting of de­sign engineering specialists, logistics engineers, and Government repair specialists) on the final repair design is also discussed. Lessons learned and specif­ic problem areas associated with each concept are emphasized.