Deveci, H. Arda; Artem, H. Seçil

In this study, a fatigue life prediction model termed as Failure Tensor Polynomial in Fatigue (FTPF) is applied to the optimum stacking sequence design of laminated composites under various in-plane cyclic loadings to obtain maximum fatigue life. The validity of the model is investigated with an experimental correlation using the data available in the literature. The correlation study indicates the reliability of FTPF, and its applicability to different composite materials and multidirectional laminates. In the optimization, a hybrid algorithm combining genetic algorithm and generalized pattern search algorithm is used. It is found by test problems that the hybrid algorithm shows superior performance in finding global optima compared to the so far best results in the literature. After the verifications, a number of problems including different design cases are solved, and the optimum designs constituted of discrete fiber angles which give the maximum possible fatigue lives are proposed to discuss. A comparison study is also performed with selected design cases to demonstrate potential advantages of using non-conventional fiber angles in design.

Bulut, H. Alperen; Şahin, Remzi

It is aimed to research the effects of electronic plastic waste (e-plastic) on the mechanical properties of polymer concrete. E-plastic was used as a part of the filling materials (quartz sand and gravel) to obtain polymer concrete in this study. Unsaturated polyester resin material has been chosen as the polymer material and used as binder in polymer concrete production. Resin/filling material ratio has been determined as 10–90%, 15–85% and 20–80%, e-plastic/filling material ratio has been decided to be 0%, 5%, 15% and 25%. 28-Day of axial compressive, flexural and splitting tensile strength values of the test samples were evaluated. The increase in the ratio of resin, increases the compressive strength while it does not cause a dramatic increase or decrease in the flexural and splitting tensile strength. Compressive, flexural and splitting tensile strength values decrease as the ratio of e-plastic increases. On the other hand, electronic plastic waste increases the polymer concrete's ductility. Experimental study shows that ideal resin ratio and ideal e-plastic ratio values are 15% and 5%, respectively.