Analysis Of Preload, Stress, Rellability Of Titanium Screw Joint Structure

Screw joint structure is n basic device mostly used in aerospacecrafts. The reliability of screw joint structure has a direct effect on the success flight of aerospacecrafts. Choosing the fitting fasteners and controling the preload is the key to ensure the reliability of screw joint structure. The shortcomings of the titanium screw joint fasteners is overcame, and the precision of the preload is improved, when we torque M0S2 lubricative titanium screw joint structures (MLTSJS) to control the preload. Therefore, the demands of lightweight, high-strength, high-reliability, electro-matching in the structures of aerospacecrafts are satisfied.In this dissertation, three aspects which are preload, stress, reliability of representative MLTSJS in aerospacecrafts are researched aiming at the relationship of torque and preload. The main works follow:1) Assuming the screw joint structures as the rigid body,we get the relation of torque and preload.2) Through the experiments of preload-torque, we obtain the curve of preload-torque of MLTSJS; Through the experiments of engineering application, we determine the MLTSJS installation match and requirements in aerospacecrafts; Through the vibration test, we examine the adaptability of the representative MLTSJS in the aerospacecrafts vibrational environment. Through the experiments of reliability, we affirm the reliability of representative MLTSJS in the aerospacecrafts. 3) By using the non-linear FEA contact analyses, we obtaine the preload and stress in the parts of the three typical screw joint structures, show the rationality of the approach which the preload is controled by torque, and verify whether the screw joint structures can satisfy the aerospacecraft launching requirements.4) According to the calculation of reliability, we get the reliability of the typical screw joint structures the preload.of which is controled by torque.We obtained the parameters and evidences which designers want. The results in the dissertation provide the reliable data and evidences to aerospace engineering, and are successfully used in the aerospacecraft design.