PSI - Issue 13

M. Khodjet-kesba et al. / Procedia Structural Integrity 13 (2018) 181–186 KHODJET KESBA Mohamed/ Structural Integrity Procedia 00 (2018) 000–000

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0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 0,45 0,50 0,55 0,60 0,65 0,70 0,75 0,80 0,85 0,90 0,95 1,00  =40°  =0°  =15°  =30°  x(i) /  xo(i) (i=1,2,3) Crack density (1/mm) i=1:T=22°C i=2:T=60°C i=3:T=122°C

Fig.5. Hygrothermal effect on the Poisson’s ratio degradation due to transverse cracks in a [θ/90 3 ] s graphite/epoxy (T300/5208).

4. Conclusion The mechanical properties degradation was predicted using simple analytical models on the angle-ply [θm/90n]s laminate including the effect of transverse cracks and under different environmental conditions by the variation of temperature and transient moisture concentration distribution in absorption case. The results show good agreement between prediction models and experimental data. On the other hand, when the angle-ply laminate is subjected to hygrothermal conditions, the mechanical properties largely depend on the crack density, fibre orientation angle θ of the outer layers, matrix diffusivity and operational temperature. References Adda bedia, E.A., Bouazza, M., Tounsi, A., Benzair, A. and Maachou, M. 2008, Prediction of stiffness degradation in hygrothermal aged [θm/90n]s composite laminates with transverse cracking”, Journal of Materials processing, 199, 199-205. Benkhedda, A., Tounsi A. and Adda bedia, E.A. 2008, Effect of temperature and humidity on transient hygrothermal stress during moisture desorption in laminated composite plates, Composite Structure, 82, 629-635. Berthelot, JM., Leblonb, P., El mahi. and Le core, J.F. 1996, Transverse cracking of cross ply laminates: part Analysis, Composites, 27A, 989 1001. Hashin, Z., 1985. Analysis of cracked laminates: a variational approach. Mech. Mater. 4, 121–136. Joffe, R., Krasnikovs, A. and Varna, J. 2001, COD-based simulation of transverse cracking and stiffness reduction in [S/90n]s laminates, Compos. Sci. Technol, 61, 637–656. Katerelos, D.T.G., Krasnikovs, A. and Varna, J. (2015), Variational models for shear modulus of symmetric and balanced laminates with cracks in 90°-layer, International journal of solids and structures, 71, 169-179. Khodjet-kesba M, AddaBedia EA, Benkhedda A, Boukert B., 2015. Hygrothermal effect in [θm/90n]s cracked composite laminates-desorption case. Pro. Eng. 114. 110-117. Khodjet-kesba M, AddaBedia EA, Benkhedda A, Boukert B., 2016. Prediction of Poisson’s ratio degradation in hygrothermal aged and cracked [θm/90n]s composite laminates. Ste.& Comp. Struc. 21. 57-72. Khodjet-kesba M., AddaBedia E.A., Benkhedda A., Boukert B. and Rezoug, T., 2016. The influence of hygrothermal effects on the cross-ply composite laminate with transverse cracking in transient mode. Mech. And Indus. 18. 102-110 Shen, C.H. and Springer, G.S., 1981. Moisture absorption and desorption of composite materials, Environmental effects on composites materials, ed. G.S. Springer, Technomic Publishing Co., Lancaster, PA. Tsai, S. W. 1988, Composites Design, Think Composites, Dayton, Paris, Tokyo. Tounsi, A., Amara, K.H., Benzair, A. and Megueni, A. 2006, On the transverse cracking and stiffness degradation of aged angle-ply laminates, Materials Letter, 60, 2561-2564. Vingradov, V. and Hashin, Z. 2010, Variational analysis of cracked angle-ply laminates, Composite science and technology, 638-646.