Textile preforms for ceramic composites conclusions: (1) Although the fiber. the matrix and the infiltration conditions are identical for these composites their residual pore morphology and mechanical behavior are significantly different due to their distinct fiber architectures. (2)The morphological study identifies both intrayarn pores and interyarn pores in the 2-step and 4-step braided composites. (3)Both types of composites exhibit non-linear behavior under tensile loading. The damage development can be described through the stages as shown in Fig. 5. The damage is first matrix dominated. Then, the damage becomes fiber dominated and it differs significantly between the two types of composites I5I 7. CONCLUDING REMARKS The knowledge base for the design of textile preforms for thermo-elastic and damage resistant properties of CMCs under various simple loading conditions has been reasonably well developed. Future research should address the needs in designing of preforms for combined loading as well as the development of strengt criteria for textile structural composites under multi-axial loading REFERENCES 1. T. W. Chou. Microstructural Design of Fiber Composites. Cambridge University Press(1992) 2. T. W. Chou, Designing of textile preforms for ceramic matrix composites, in: Proc. HTCMC-3 Osaka Japan(1998) 3. T. D. Kostar. Analysis fabrication, and performance of three-dimensional braided composites, PhD Disserta niversity of Delaware, Newark, Delaware (1998) 4. J.H. Byun and T. w Chor Sci.Tech.56.235(1996) 5. P. Pluvinage, A. P. Majidi and T. W. Chou, J. Mater: Sci. 30. 232(1995)