In this study, the behaviour of aluminium honeycomb structures under low-speed impact has been investigated by experimental and finite element analysis method. The production of aluminium honeycomb composite structures was carried out using different adhesives of different widths and heights. The low-velocity impact experiments of the honeycomb structures produced were performed according to ASTM D7766 standard. As a result of the experiment, the force values which caused damage to the structure were measured according to the time, and the maximum force values were taken. Findings have shown that the decrease in cell width, the increase in cell height, and depletion of multiwall carbon nanotubes increase the maximum impact force values in honeycomb composite structures. It is seen that the results obtained by the finite element method and the experimental results are approximately 85% in agreement. There was no statistically significant difference between the results as a result of conducted t-test.

In this study, we aimed to optimize the cutting parameters that affect the minimum temperature and power consumption in the turning of AISI 52100 bearing steel. For this, the Box-Behnken experimental design method, which was used for the lowest number of experiments in the experimental systems created using the response surface method (RSM), was used. The cutting parameters affecting the turning of the AISI 52100 bearing steel were determined as the cutting speed, depth of cut, and feed rate based on a literature research. The temperature and power consumption values were obtained via analyses according to the experimental design method determined by the finite element analysis (FEM) method. The results obtained were analyzed in Design Expert 13 software. According to the analysis results, the parameter values were determined for the minimum temperature and power consumption. The temperature and power consumption variables were affected by all three parameters, namely the cutting speed, depth of cut, and feed rate. For the minimum temperature and power consumption, a cutting speed of 162.427 m/min, depth of cut of 1.395 mm, and feed rate of 0.247 mm/rev, as well as the feed rate parameters, affected both the temperature and power consumption the most. In addition, it was determined that the cutting speed parameter had the least effect on both the temperature and power consumption variables. In addition, validation experiments were carried out in a real experimental environment with optimum values for the cutting parameters. The results showed that the output values obtained within the limits of the study with the obtained equation were quite close (3.3% error for temperature, 6.6% error for power consumption) to the real experimental outputs.

Objectives: Calcaneal fractures are the most common tarsal fractures following a foot-ankle trauma. The Böhler’s angle is an important measurable angle before, during, and after surgery. In this study, we aimed to investigate correlation between Böhler’s angle, calcaneal strength, and subtalar joint stress using a finite element analysis (FEA). Patients and methods: Between January 2016 and December 2016, computed tomography (CT) scans were used with MIMICS® software for FEA. The ankle and foot of a 23-year-old male person with a height of 180 cm and weighing 80 kg was modeled as reference. Raw coronal CT images were obtained in Digital Imaging and Communications in Medicine format with the resolution of 512X512 pixels and 0.3-mm slice intervals in 135 kV. The structures including tibia, fibula and 26 other bones (talus, calcaneus, cuboid, navicular, three cuneiforms, five metatarsals, and 14 components of phalanges), cartilage and ligamentous tissues were modeled to form ankle joint. After determining Böhler’s angle as 35 degrees for the reference model, a fracture line was created on calcaneus. Calcaneus was remodeled with the Böhler’s angle of 45, 40, 30, 25, 20, 10, and 0 degrees respectively. All models were transferred to ANSYS software for FEA and the loads on the lower extremities with normal posture were applied on models. Results: Analysis of all models based in the reference model revealed that maximum tension values on calcaneus increased, while the Böhler’s angle decreased, indicating a statistically significant difference. The decreased Böhler’s angle indicated statistically significantly higher maximum tension values (p=0.04). Action force in subtalar joint was evaluated by comparing with the forces in reference model. The increased Böhler’s angle was found to be associated with statistically significantly decreased amount of load on subtalar joint. The decreased Böhler’s angle was related to the statistically significantly increased amount of load on subtalar joint. Conclusion: Our study results suggest that decreased Böhler’s angle increases the possibility of subtalar arthrosis, although overcorrection of the Böhler’s angle seems not to increase the risk of subtalar arthrosis.