PSI - Issue 79

Manish Singh Rajput et al. / Procedia Structural Integrity 79 (2026) 26–33

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4. Results After performing a validation study of the presented thermo-mechanical PFM, it is implemented to investigate crack growth in a CFRC structure. In which three carbon fibers are reinforced into an alumina (Al 2 O 3 ) matrix, because the alumina matrix has good thermal stability and performs better under thermo-mechanical loading environment. Material properties are described in Table 2. The geometry and loading condition for the CFRC structure under thermo-mechanical loading environment are illustrated in Fig. 3(a). The Total number of elements is 80,000. The length scale parameter is 0.025 mm, and the constant displacement step value is 1×10 −5 mm. Table 2. Material properties of the CFRC structure [19-21] Property Material components Carbon fiber Alumina matrix Interface Elastic modulus (GPa) E xx = 12.9, E yy = 229, E zz = 12.9 E = 380 E = 380 Poisson’s ratio xy = 0.3, yz = 0.46, xz = 0.3 = 0.25 = 0.25 Shear modulus (GPa) G xy = 11.3, G yz = 4.45, G xz = 11.3 G = 152 G = 152 Density (kg m -3 ) = 1800 = 3965 = 3965 Specific heat (KJ kg -1 K -1 ) C p = 0.72 C p = 0.88 C p = 0.88 Thermal expansion coefficient (10 -6 K -1 ) xx  = - 0.5 , yy  = 15 β = 6.54 β = 6.54 Thermal conductivity (W K -1 m -1 ) k xx = 170, k yy = 12 k = 25 k = 25 Critical energy release rate (N/mm) c G = 0.0183 c G = 0.01 c G = 0.001 4.1 Effect of the thermo-mechanical environment The effect of different thermo-mechanical loading environments (heating, cooling or pure mechanical loading) is observed in this sub-section. The crack growth plots and corresponding temperature field plots under pure mechanical loading, thermo-mechanical heating, and cooling conditions are shown in Fig. 4 and Fig. 5, respectively. Various composite fracture phenomena, like interfacial debonding, matrix cracking, and fiber breakage, are observed in the obtained crack growth plots of the CFRC specimen under different thermo-mechanical loading environments. Additionally, it can be observed that crack propagation varies under different thermo-mechanical loading conditions, and the fracture response of the structure under truly mechanical loading differs from the thermo-mechanical heating and cooling conditions. From the load displacement response (refer to Fig. 6) of the CFRC structure under different thermo-mechanical loading conditions (Purely mechanical, thermo-mechanical heating, and cooling), it is found that the crack initiation occurs earlier in the case of thermo-mechanical cooling conditions because of the generation of tensile thermal strains.

Fig. 3. Geometry and loading condition of the CFRC structure subjected to (a) top edge thermal loading, (b) right edge thermal loading.