To evaluate system reliability of a composite structure consisting of more than two structural members, it is necessary to identify that the members are connected to each others in parallel or in serial. Especially for parallel composite system, it is also necessary to confirm that mechanical properties of materials for the members are brittle or ductile. For parallel system of brittle materials, if one part fails, that part cannot resist load anymore and the whole load transfers to the other part. However, for parallel system of perfectly plastic materials, if one part fails, that part can maintain the amount of its maximum load capacity and the remaining load transfers to the other part. In this study, a methodology to determine reliability index for composite structures consisting of quasi-brittle materials. By assuming quasi-brittle materials as brittle or perfectly plastic materials, the upper and lower bounds of the reliability index can be determined. The reliability index for parallel system of quasi-brittle materials is then determined by interpolating the upper and lower bounds indices using ductility number extracted from stress-strain curves of quasi-brittle materials.

ABSTRACT
 1. 서 론
 2. 연구방법
  2.1 신뢰성 지수
  2.2 시스템 신뢰성 해석
  2.3 연성도(준취성도)
 3. 결론
 References

• 김정중(경남대학교 토목공학과) | Kim Jung Joong