PSI - Issue 13

Emre Özaslan et al. / Procedia Structural Integrity 13 (2018) 535–541 M.A. Güler et al./ Structural Integrity Procedia 00 (2018) 000 – 000

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High accuracy of PSC predictions were also obtained for specimens that had the same W/D ratio but different sizes in terms of hole diameter and specimen width. For these specimens, as the specimen width and hole diameter doubled, the specimen failure strength reduces %13.2 because of the size effect. The PSC predictions and test results are compared in Fig. 9.

Fig. 9. PSC predictions with test results for size effect specimens

6. Conclusion

Investigation of W/D ratio and size effect on the stress concentration and strength was performed for carbon/epoxy composite plates. It is concluded that the stress concentration factor could be increased approximately %15 by decreasing W/D ratio from 6 to 3. The success of PSC method for prediction of the open hole specimen strength was observed. It is shown that the specimen strength can be increased up to %62 by quadrupling the W/D ratio with constant specimen width. In addition, doubling the specimen width and hole diameter, reduces failure strength by %13.2. Acknowledgements This study is funded by Defense Industry Undersecretariat (SSM) under Researcher Training Program for Defense Industry (SAYP) Toubal, L., Karama, M., Lorrain, B., 2005. Stress Concentration in a Circular Hole in Composite Plate. Composites Structures 68, 31-36 Kumar, A., Agrawal, A., Ghadai, R., Kalita, K., 2016. Analysis of Stress Concentration in Orthotropic Laminates, 3rd International Conference on Innovations in Automation and Mechatronics Engineering. Wu, H.C., Mu, B., 2003. On Stress Concentrations for Isotropic/Orthotropic Plates and Cylinders with a Circular Hole. Composites: Part B 34, 127-134 Bakhshandeh, K., Rajabi, I., Rahimi, F., 2008. Investigation of Stress Concentration Factor for Finite-Width Orthotropic Rectangular Plates with a Circular Opening Using Three-Dimensional Finite Element Model. Journal of Mechanical Engineering 54 2, 140-147 Hallett, S.R., Jiang, W.G., Wisnom, W.R., 2009. Effect of Stacking Sequence on Open-Hole Tensile Strength of Composite Laminates. AIAA Journal Vol.47, No.7 Wisnom, M.R., Khan, B., Hallett, S.R., 2008. Size effects in unnotched tensile strength of unidirectional and quasi-isotropic carbon/epoxy composites. Composite Structures 84, 21-28 Standard test method for tensile properties of polymer matrix composite materials, ASTM D 3039/D 3039M-00. American Society for Testing and Materials (ASTM). West Conshohocken, PA, USA. Standard test method for in-plane shear response of polymer matrix composite materials by test of a ±45 laminate, ASTM D 3518/3518M-94. American Society for Testing and Materials (ASTM). West Conshohocken, PA, USA. Whitney, J.M., Nuismer, R.J., 1974. Stress Fracture Criteria for Laminated Composites Containing Stress Concentrations. Journal of Composite Materials 8, 253 References