The high cutting temperature and poor thermal diffusion efficiency of nickel-based alloys during deep hole machining have become technical challenges in the hole machining field. In this paper, a finite element simulation model of Inconel-718 BTA ordinary drilling and vibration drilling processes was established by using Deform-3D finite element simulation software. The variations in the temperatures of the tool teeth and the workpiece at different positions of the nickel-based alloy under ordinary drilling and vibration drilling were investigated. Additionally, the wear pattern of each tool tooth under the two drilling methods was further analyzed by building an experimental platform for workpiece temperature detection, which reveals the wear and cooling mechanism of nickel-based alloy BTA deep hole drilling. The results show that the average temperatures of the external, intermediate, and central teeth were reduced by 18.1%, 21.1%, and 17.8%, respectively, during vibration drilling. In addition, the workpiece hole wall and hole bottom temperatures were reduced by 5.7% and 4.6%, respectively. To conclude, the experimental tests were consistent with the simulated temperature trends. BTA vibration drilling optimizes the heat exchange conditions between the cutter teeth and the workpiece during the drilling of nickel-based alloys, which effectively reduces the cutting temperature and, thus, improves the wear resistance of the cutter teeth.

The internal stress difference between soft-ductile aluminum alloy substrate and hard-brittle Ni–W alloy coating will cause stress concentration, thus leading to the problem of poor bonding force. Herein, this work prepared the Ni–W graded coating on aluminum alloy matrix by the pulse electrodeposition method in order to solve the mechanical mismatch problem between substrate and coatings. More importantly, a backward propagation (BP) neural network was applied to efficiently optimize the pulse electrodeposition process of Ni–W graded coating. The SEM, EDS, XRD, Vickers hardness tester and Weighing scales are used to analyze the micromorphology, chemical element, phase composition, and micro hardness as well as oxidation weight increase, respectively. The results show that the optimal process conditions with BP neural network are as follows: the bath temperature is 30 °C, current density is 15 mA/cm² and duty cycle is 0.3. The predicted value of the model agrees well with the experimental value curve, the relative error is minor. The maximum error is less than 3%, and the correlation coefficient is 0.9996. The Ni–W graded coating prepared by BP neural network shows good bonding with the substrate which has flat and smooth interface. The thickness of the coating is about 136 μm, which slows down the oxidation of the substrate and plays an effective role in protecting the substrate.

Interference fit is widely uesd in the high-speed coupling of micro gas turbine since it can transfer large torque, are easy to produce and offer significant cost advantages. In this paper, a interference fit model was developed to analyse the contection strength of coupling and shaft for micro gas turbine. Then using elastic theory, the radial stress, tangential stress and radial displacement of high-speed coupling are derived with taking account of contact pressure, angular velocity and the thickness of coupling. Finally taking a 100kW micro gas turbine as an example, the above solutions were calculated by using the numerical method and results show that the contact pressure, angular velocity and thickness of the coupling, should be considered for the design of the interference fit between the coupling and shaft in micro gas turbine. The direction of the radial stress of the coupling is determined by the value of the contact pressure. The tangential stresses of the coupling are identically greater than zero. The radial displacement of the coupling is a monotony decrease function of the radius and positively correlated with the contact pressure, angular velocity and thickness of the coupling.

Interference fit is widely uesd in micro gas turbine to transfer large torque and offer significant cost advantages. In this paper, a interference fit model was developed to research the contection characteristics of quill shaft for micro gas turbine. The radial stress, tangential stress, radial displacement and the Von Mises stress of the quill shaft are derived by using elastic theory to analyze the influence of the contact surface pressure and angular velocity on the strength of the quill shaft. Numerical calculated results show that The radial stress of the quill shaft is identically greater than zero and positively correlated with the contact press and angular velocity. The direction of the tangential stress of the quill shaft is determined by the value of the contact pressure. The radial displacement of the quill shaft is a monotony decrease function of the contact pressure and a monotony increase function of the angular velocity. Generally, the maximum stress of the quill shaft happens in the inner surface of the quill shaft regardless of the angular velocity.

Reliability evaluation is widely uesd in electrical system which determines operation stability and environment safety of ships and vessels since it can discover potential safety hazard scientifically and accurately. Analytic hierarchy process (AHP) is an effective and useful method for reliability evaluation and indicator system establishment due to its simplicity and convenience. In this paper, a hierarchical structure of indicator system for ship's electrical system is established based on AHP, and three judgement matrixes of the reliability, basic reliability and mission reliability are constructed. Then a calculation method of the maximum eigenvalue is introduced to solve the ranking weight vector of the three matrixes which can determine the weight of the indicator system for reliability evaluation of marine electrical system. Consistency index and its evaluation method are given for checking the judgement matrixes and conclusions. Finally taking a ship's electrical system as an example, the above solutions were calculated and results show that APH can grantee the validity and accuracy of the establishment and application of the key indicator system. lower hierarchies and indicators could be considered due to the growing demand of the mission and service of ship's electrical system.