Rastgele uyarıma maruz braket tipi bileşenlerin yapısal analizi ve yorulma ömürlerinin değerlendirilmesi

Fatigue is a significant issue when structures are subjected to dynamic and fluctuating loads, as encountered in commercial applications like automotive, military vehicles, defense, and aircraft. When the form of the loading is dynamic, the structure's dynamics will have an influence on fatigue. Furthermore, if the frequency spectrum of the loading is wide band, the potential for driving the structure's resonant frequencies becomes considerable. The assessment of fatigue damage in aeronautical structures, those exposed to unpredictable and random loading, is of major interest, and designs are improved according to those calculations. This thesis aims to demonstrate a methodology and improvement study that includes the fatigue life estimation of hydraulic reservoir tank system components with a modal stress approach and the natural vibration modes of the system. First, modal stress analysis of the hydraulic reservoir tank system is conducted to figure out the system behavior in a dynamic structure and to obtain fatigue hotspots. The time signal is represented by its power spectral density (PSD) in the frequency domain, and fatigue analyses are realized at these hotspots to shorten the total analysis time. The Dirlik method was chosen to compute the fatigue life directly from the PSD of stress. In this thesis, structural random-vibration fatigue evaluation of hydraulic reservoir tank system components with a modal stress approach is performed in the frequency domain by using Altair HyperWorks software with the OptiStruct solver. By performing optimization analyses for the system components, an optimized design that meets the system targets is obtained. Keywords: Dirlik method, modal stress approach, power spectral density (PSD), random-vibration fatigue, size/parameter optimization, topology optimization