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Steam turbine final assembly is a dynamic process, in which various interference events occur frequently. Currently, data transmission relies on oral presentation, while scheduling depends on the manual experience of managers. This mode has low information transmission efficiency and is difficult to timely respond to emergencies. Besides, it is difficult to consider various factors when manually adjusting the plan, which reduces assembly efficiency. The purpose of this paper is to propose a knowledge-based real-time scheduling system under cyber-physical system (CPS) environment which can improve the assembly efficiency of steam turbines.

First, an Internet of Things based CPS framework is proposed to achieve real-time monitoring of turbine assembly and improve the efficiency of information transmission. Second, a knowledge-based real-time scheduling system consisting of three modules is designed to replace manual experience for steam turbine assembly scheduling.

Experiments show that the scheduling results of the knowledge-based scheduling system outperform heuristic algorithms based on priority rules. Compared with manual scheduling, the delay time is reduced by 43.9%.

A knowledge-based real-time scheduling system under CPS environment is proposed to improve the assembly efficiency of steam turbines. This paper provides a reference paradigm for the application of the knowledge-based system and CPS in the assembly control of labor-intensive engineering-to-order products.

By leveraging various designs for assembly and designs for manufacturing methods, manufacturing industry can apply solid modeling, or 3D design, to increase profit margins and decrease the time to market of its product. Specific to torque converter development, an engineer can utilize a CAD package and gain all of the advantages of designing in 3D without the drawback of increased design time. In this paper we propose a behavioral modeling technique to capture design intent and utilize the intent maps for obtaining 3D solid models in a similar amount of time as on a 2D CAD system, but with the advantage of a life‐like final design. This results in fewer modifications and less inaccuracies associated with 2D design. A 3D model so generated also assists in drawing interpretation. In general, using the proposed techniques will streamline the torque converter design cycle and move readily towards desired assembly automation. Torque converter design for assembly is implemented as an illustrated example.

The assembly sequence in the product assembly process has effect on the final product quality. To solve the assembly sequence optimization problem, such as rotor blade assembly sequence optimization, this paper proposes a small world networks-based genetic algorithm (SWN_GA) to solve the assembly sequence optimization problem. The proposed approach SWN_GA consists of a combination between the standard Genetic Algorithm and the NW Small World Networks.

The selection operation and the crossover operation are improved in this paper. The selection operation remains the elite individuals that have greater fitness than average fitness and reselects the individuals that have smaller fitness than average fitness. The crossover operation combines the NW Small World Networks to select the crossover individuals and calculate the crossover probability.

In this paper, SWN_GA is used to optimize the assembly sequence of steam turbine rotor blades, and the SWN_GA was compared with standard GA and PSO algorithm in a simulation experiment. The simulation results show that SWN_GA cannot only find a better assembly sequence which have lower rotor imbalance, but also has a faster convergence rate.

Finally, an experiment about the assembly of a steam turbine rotor is conducted, and SWN_GA is applied to optimize the blades assembly sequence. The feasibility and effectiveness of SWN_GA are verified through the experimental result.

IT is nearly fifteen years since the introduction into civil operations of the Dart turboprop in the Vickers Viscount and the Ghost turbojet in the dc Havilland Comet. For many years it was thought that the turboprop would remain dominant in the short and medium haul classes, but the continued demand for higher cruising speeds and the passenger appeal of the jet have been largely responsible for the turboprop aircraft being superseded by the new generation of turbofan aircraft.

This paper presents a versatile and economical knowledge‐based assembly design of blade and shell assemblies by employing behavioral modeling concepts. Behavioral modeling is a new generation CAD concept aimed at achieving ultimately optimum results with the efforts made in the early stage of the product development cycle. As a result, the assembly process of any odd‐configured parts such as torque converter blades, can be accurately planned, and made adaptable to all potential in‐process alterations due to either changes of components design or that of the assembly kinematics. Optimum assembly design is achieved when the volumetric interference meets a desired value based on an expert's determination. Experimental verification of the proposed optimum assembly design conducted in Luk, Inc. with two different blades' assemblies demonstrates satisfactory results.

A Description of the Early Problems Encountered by Rolls‐Royce Ltd., which Led to the Appointment of a Specialist ‘Rotor Balance’ Engineer, and a Review of the Company's Current Balancing Techniques. THE advent of the gas turbine aero engine brought a state of passenger comfort, never before experienced, into the field of civil air transport; this was possible because the unbalanced forces due to reciprocating masses are entirely absent and the purely rotating masses of a turbine engine can, theoretically, be brought into perfect balance. The resulting smooth running engines produce lower levels of passenger fatigue due both to physical effects (i.e. a reduced feeling of ‘pins and needles’ in those parts of the anatomy touching the cabin floor or scat) and to aural effects (i.e. a lower noise level from engine buzz or cabin panels and fittings resonances).

NOW that the Air Ministry has released information on German power plants it is possible to give a detailed description and critical examination of the Jumo 004 jet engine. Most of the work of examination, including the repair and testing of an engine, was done some months preceding the final collapse of Germany. In this article it is hoped to supplement the information already given in the technical press.

This paper aims to provide a precision assembly method to improve the aircraft engine quality of initial unbalance with the purpose of founding the process for mass eccentricity propagation and demonstration of assembly process. The proposed method can be used for assembly guidance, tolerance allocation and so on, especially for the assembly with a large number of rotors and the assembly requirements of initial unbalance and coaxiality in high precision.

This paper proposes a constrained optimization-build method to minimize initial unbalance of aircraft engine assembly, which takes amount of unbalance and concentricity of each rotor into account. A constrained nonlinear programming model is extracted by choosing the initial unbalance as the objective function, and choosing the coaxiality and assembly orientations as the nonlinear constraints. The initial unbalance is reduced stage-by-stage by controlling the assembly angle of each rotor.

The validity and accuracy of the proposed method is verified by the multistage rotors assembly through experiments run with the measuring instruments. Compared with the direct-build method, the initial unbalance of final assembly using proposed method is reduced by 22.2% in four rotors assembly.

Different from the geometric eccentricity propagation control methods to reduce the initial unbalance indirectly, this paper establishes mass eccentric propagation model in multistage rotors assembly of aircraft engine for the first time. It provides a new idea to establish the relationship between the amount of unbalance of each rotor and the initial unbalance of multistage rotors.

This paper aims to provide an assembly method to improve cylindrical components assembly quality. The proposed method not only could be applied to tolerance allocation, but also could guide the assembly of cylindrical components.

The paper claims to provide a stack-build assembly method using a connective assembly model to take the location and orientation tolerances of a rotor stage into account. Through the separate analysis of the location and orientation tolerances propagation process in the assembly, the quality of the final assembly of the rotationally symmetric cylindrical components assembly could be improved by properly selecting component orientations to minimize the eccentric deviation in the assembly.

The effectiveness of the proposed stack-build assembly technique in improving the tolerance propagation in the assembly of cylindrical components was verified through experiments run with a measuring machine. A real aero-engine rotor was assembly using the proposed method; compared to the direct-build assembly technique, which had the component orientations without consideration, the stack-build assembly technique could be used to reduce the eccentric deviation in cylindrical components assembly by nearly 50 per cent.

Different with the old methods, the new method defined the tolerances in detail, such as perpendicularity and angle of the lowest point, and could guide the assembly by the features of surfaces on different components. Through measuring the special tolerances of surfaces on the components, the best assembly angle for each component could be obtained.