Principles of Composite Material Mechanics  PROBLEM 4

Principles of Composite Material Mechanics 
PROBLEM 4.20 For a unidirectional IM-9/8551-7 carbon/epoxy composite under tensile loading, what is the critical fiber volume fraction, 'okra, when the mode of failure is fiber failure as described in Figure 4.14a? How does this value of Ufa* compare with the typical fiber volume fraction, vf, for IM-9/8551-7 as described in Table 4.1, and what is the physical meaning of this observation? 
References 
I. Chamis, C. C. 1987. Simplified composite micromechanics thermal and mois-ture-related properties. In Weeton, J. W., Peters, D. M., and Thomas eds., Engineers Guide to Composite Materials, pp. 3-8-3-24. ASM Inter Materials Park, OH. 2. Daniel, I. M. and Ishai, 0. 1994. Engineerine' *-s of CornpoF Oxford University Press, New York, NY. 3. Hashin, Z. 1983. Analysis of composite Mechanics, 50, 481-505. 4. Hashin, Z. 1980. Failure criteria for Applied Mechanics, 47, 329-334. 5. Wu, E. M. 1974. Phenomenologir G. P. ed., Composite Materials, Me Academic Press, New York, N 6, Sendeckyj, G. P.1972, A brief 
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