Çam, Salim; Karslı, Nurver; Ghahramanzadeh Asl, Hojjat

A unilateral or bilateral posterior crossbite is a common and severe malocclusion characterized by maxillary transversal deficiency. Various expansion appliances are employed to correct this condition. The objective of this study was to evaluate the forces transmitted to the teeth and the deformation of the expander appliance resulting from modifications to the screw arms of a slow maxillary expander with different angles, using finite element analysis. All models were created in SolidWorks and analyzed using ANSYS Workbench. The analysis revealed that the models with different angular configurations of the expander screw arms (0°, 15°, and 30°) exhibited very similar reaction forces on the teeth. However, significant differences in deformation values were observed among the models. The most effective parameter is the force applied to the expander with a rate of 46%, followed by the arm angle with a rate of 44%, while the effect of material type is 10%. The most significant conclusion that can be drawn from these findings is that the arm angle is as important as the force applied to the expander. In situations where the force that can be applied is limited by various factors, it can be demonstrated that altering the arm angle can lead to the achievement of the desired outcome.

Baş, Fatih İrfan

Flexible pavements are considered more sustainable than concrete pavements primarily due to the higher long-term maintenance and rehabilitation costs associated with concrete pavements. Concrete pavements possess a higher modulus of elasticity, which allows them to distribute vehicle loads over a larger area, thereby enhancing the strength of the pavement. However, despite this advantage, their flexural strength is relatively low. As a result, there has been a growing focus on research to improve the flexural strength of concrete pavements to increase their overall performance and sustainability. This study aimed to reveal the effects of enhanced mechanical properties of concrete reinforced with glass fiber on concrete pavements, specifically under heavy vehicle loading as in real-world conditions. The impact of glass fiber on the thickness of both the concrete and base layers, as well as the quality of the base layer material and transverse joint spacing, was assessed. For this purpose, 3D finite element models were developed using ANSYS software, considering concrete thicknesses of 100, 150, and 200 mm, glass fiber ratios of 0%, 0.5%, and 1%, base layer elastic moduli of 100, 200, and 300 MPa, and transverse joint spacings of 300, 450, and 600 mm. It was determined that the concrete thickness and the base layer modulus of elasticity were the most influential factors in minimizing flexural stress, total deformation, and equivalent total strain. The glass fiber addition had a more notable impact on maximum principal stress, especially at the 1% ratio, but had a minimal effect on total deformation and strain. Transverse joint spacing had the least effect, although shorter spacings are still recommended to reduce the risk of transverse cracking in stiffer base layers.