Design and analysis of composite hydraulic cylinders developed for aerospace applications

Nowadays, aviation and space applications are technologies that are becoming increasingly important. It is essential that these technologies are highly energy efficient and can be applied effectively. The central systems of an aircraft can be listed as navigation and communication, power control systems, flight control systems, and collision avoidance systems. Hydraulic energy is required for the flight control systems, one of the central systems of the aircraft. In an aircraft, hydraulic systems can generally be used in flight control (such as ailerons, horizontal elevators, high-lift gear), landing gear (such as brakes, steering, and landing gear bending), door and stair systems (such as cabin and cargo doors, ramps), and main power (such as propeller brakes, reverse engine operation). Cylinders (actuators), the final element of power transmission in hydraulic systems, are among the most important movement elements. Hydraulic cylinders are elements that convert hydraulic energy into mechanical energy linearly. Hydraulic cylinders are usually made of steel, aluminum alloy, or titanium alloys in aviation. Hydraulic cylinders are heavy due to the high working pressure conditions they provide. This makes it challenging to use in aircraft. A heavy cylinder can also limit the desired mobility in the system to be limited, causing excessive fuel consumption, shortening the aircraft's mission time, and reducing the range. For these reasons, it has been observed that there is a tendency towards composite materials in aviation and space applications. This study evaluates that a hydraulic cylinder is optimized with appropriate calculations and design and made of composite material and titanium alloy. The strength values of the cylinder formed with carbon fiber wrapped on the titanium alloy cylinder tube at two different angles were compared with the finite element method. Two different windings were made with angles of 75/90/-75/90 and 45/90/-45/90 using the finite element method. As a result of the comparison, it was determined that the 75/90/-75/90 winding had approximately 25% higher strength value than the 45/90/-45/90 winding.