hello every one.
i performing delamination buckling on composite shell with cutouts...the result show that the buckling load for Filleted square cutout is less than that of the square shape cutout placed at the same depth position ,,my question is what is the possible explanation for this result..kindly let me know
thank u in advance
Hallo Mr. Khan,
this investigation was conducted in my Master Thesis, answere to your question is as following:
idealizations of delamination shape (realistic to elliptical then Circular ending with recatangular) lead to a residual strength (i.e. peak load) underestimation for the delaminated structure. However, that difference is fairly low. Residual strength for the original realistic shape (D-Scan) is predicted to be only 8% less than the failure load of an undamaged structure (Healthy one), whereas all idealizations are predicted to fail at a load of 12% in my study. which is in disagreement with what Mr. Obdržálek and Vbrka wrote in his Paper.
Though, this behavior can be explained by examining the sequence of phenomena leading to sudden load drop, which is very similar for all models. The first phenomenon occurring is global buckling, meaning that both sublaminates experience identical deformations. This occurs at significantly lower shortening than in the undamaged model, which is attributed to the lower bending stiffness in the delamination region which intreduces instability. Then, fiber compressive, matrix compressive and tensile failure, predicted according to the Hashin criterion, occur almost simultaneously with sublaminate buckling. These failure modes establish in the center region where tensile and compressive strains are highest due to global buckling deformation. Strains become even larger as sublaminate buckling develops, causing the aforementioned damage modes to spread throughout the structure, thus degrading fiber and matrix stiffness. As shortening is carried forward and degradation increases, the specimen’s stiffness decreases gradually, until the peak load is reached. Fiber tensile failure establishes just prior to sudden load drop which is characterized by high stiffness degradation in longitudinal and transverse directions having spread throughout the specimen’s width and most of the layers.
you can read my paper. I belive this will be very intresteing for you!.
Regards,
Tamer
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