PSI - Issue 60

Amardeepa KCS et al. / Procedia Structural Integrity 60 (2024) 60–74 Amardeepa KCS/ Structural Integrity Procedia 00 (2023) 000–000

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domain using Excel spreadsheets, and computed the maximum values of shear and normal stress values are compared with their respective allowable strength properties. The study shows that the L angle fails in shear between composite layers (1-2) at the internal fuel pressure of 26.78 PSI if applied, which is more than the design fuel pressure of 12.5 PSI. Therefore, the L angle at the stringer cut-out region is safe to carry the designed internal fuel pressure of 12.5 PSI. Therefore, L angle has a margin of safety value of 1.14 against internal fuel pressure. Similar studies can be carried out for different thicknesses and radius if any change occurs. Therefore, the composite parts are safe from the strength and stability point of view for the critically designed internal fuel pressure load cases. The novelty of the FE modelling approach adopted in this study is that it precisely estimates the third directional /out-of-plane stress values through two-dimensional finite element analysis. It also precisely captures the location of peak stress and estimates its values. The failure criterion also helped estimate the ultimate failure load regarding design values. ACKNOWLEDGEMENTS The authors carried out this study to meet the design requirements of internal aerospace programs of national importance undertaken at CSIR-National Aerospace Laboratories Bangalore, an autonomous research organization funded by the Government of India. The available infrastructures of the organization are used to a greater extent for completing the studies without financial and technical support from any other institute or organizations. The authors thank the Director of CSIR-National Aerospace Laboratories Bangalore for the administrative and financial support. References 1. S. G. Lekhnitskii, Anisotropic plates, Gordon and Breach Science Publishers ,1968 2. Baba, M.N., 2019, October. Delamination assessment of composite curved angles using simplified FEA model's build up by 2-D layered shell elements. In IOP Conference Series: Materials Science and Engineering (Vol. 659, No. 1, p. 012011). IOP Publishing. 3. Thurnherr, C., Groh, R.M., Ermanni, P. and Weaver, P.M., 2017. Investigation of failure initiation in curved composite laminates using a higher-order beam model. Composite Structures , 168, pp.143-152. 4. J. S. Charrier, F. Laurin, N. Carrere, S. Mahdi, Determination of the out-of-plane tensile strength using four-point bending tests on laminated L angle specimens with different stacking sequences and total thicknesses, Composites Part A: Applied Science and Manufacturing 81 (2016) 243– 253. 5. W. Hao, D. Ge, Y. Ma, X. Yao, Y. Shi, Experimental investigation on deformation and strength of carbon/epoxy laminated curved beams, Polymer Testing 31 (4) (2012) 520–526. 6. Polagangu, James., and Byji, Varughes., Analytical Qualification of Composite Co-Cured T-Joint for The Internal Fuel Pressure Requirement Using a Novel FE Analytical Approach: Bubbles in Bermuda Triangle. ISAMPE-National Conference on Composites. INCCOM-16, CPID-8, SL. No 19, (2019). 7. Polagangu, J., Mahesh, K. and Byji, V., 2019. Estimation of failure load of composite bonded joints using 1D and 2D FE analysis and the mathematical equation of strain and bond energy in the adhesive layer. Mechanics of Advanced Materials and Structures , 26(1), pp.20-28. 8. Martin, R.H., 1992. Delamination failure in a unidirectional curved composite laminate. Composite materials : Testing and design., 10, pp.365-383. Polagangu James, Vijayalaxmi. B, Byji Varughese, "SAGAR PLot: A Study Carried out on Composite Co-Cured Wingbox to Reduce Peel Load due to Internal Fuel Pressure," MST-028, NCSCSTASE -2018, CSIR-National Aerospace Laboratories, Bangalore. Karnataka. India, 2018. 9. Polagangu James, Vijayalaxmi. B, Byji Varughese, "SAGAR PLot: A Study Carried out on Composite Co-Cured Wingbox to Reduce Peel Load due to Internal Fuel Pressure," MST-028, NCSCSTASE -2018, CSIR-National Aerospace Laboratories, Bangalore. Karnataka. India, 2018. 10. Polagangu James, S. Suresh, Manisha M Banker, Byji Varughese, Ramesh Sundaram, SAGAR PLot: Imitating River Meandering to Identify the Stringer Cutout Shape for Reduced Peel Load in Composite Co-cured Joint, Volume 4, Issue 8, 2017, Pages 8486-8497, Materialstoday Proceedings.