G E. Youngblood et al. /Composites Science and Technology 62(2002)1127-1139 vf=0.4 口 Kf/Km= 100 o KI/Km=1 1000 Biot number b) 山 O Ki/Km= 0.001 10 1000 Biot number Fig 4. Nondimensional plot of the error between the finite element results and Eq (1)for Kd Km=1, 10 or 100 and (a)Vr=0. 4 and (b)vr=0.5 decoupled fibers. As expected, the differences for the Based on values reported in the literature, h-values Ve=0.5 case are somewhat larger than for the Vf=0.4 between 0. 1 and 105 W/(cm2K)are possible [12, 24, 25 case. However, for r< 10 the differences are less than The H-J model should satisfactorily describe Keff of 5%. Thus, for composite systems with V<0.5 and many ceramic matrix composites, including SiC/SiC r-values between I and 10, the H-J model is applicable with simple unidirectional or cross-ply laminate fiber over a wide range of h-values. This criterion is often met architectures. More complicated theories that take into by typical commercial ceramic matrix composites. account fiber interaction may only be necessary whendecoupled fibers. As expected,the differences for the Vf=0.5 case are somewhat larger than for the Vf=0.4 case. However,for r410 the differences are less than 5%. Thus,for composite systems with Vf40.5 and r-values between 1 and 10,the H–J model is applicable over a wide range of h-values. This criterion is often met by typical commercial ceramic matrix composites. Based on values reported in the literature, h-values between 0.1 and 105 W/(cm2 K) are possible [12,24,25]. The H–J model should satisfactorily describe Keff of many ceramic matrix composites,including SiCf/SiC with simple unidirectional or cross-ply laminate fiber architectures. More complicated theories that take into account fiber interaction may only be necessary when Fig. 4. Nondimensional plot of the error between the finite element results and Eq. (1) for Kf/Km=1,10 or 100 and (a) Vf=0.4 and (b) Vf=0.5. G.E. Youngbloodet al. / Composites Science andTechnology 62 (2002) 1127–1139 1131