Applied Mechanics and Materials Vols. 152-154

Abstract: This paper considers two stage hybrid flow shop with identical parallel machine and evaluate performance of common dispatching rules; shortage processing time (SPT) longest processing time (LPT) earliness due date (EDD) and first in first out (FIFO). The objectives are to determine makespan and total tardiness have been minimized. To evaluated performance of dispatching rules, the results have been compared on each criterion. The experimental results show that SPT outperform than other rules with minimizes makespan as an objective function for all problems. On the other hand, for minimize total tardiness as an objective. The EDD rule outperform than other rules.

Abstract: The paper established the whole system for stress monitoring and safety assessment of metal structure aimed at kinds of cranes, based on LabVIEW software platform. Introduced function and composition of each subsystem in detail. The system consists of data acquisition, signal analysis and processing, data storage, historical data inquiry, safety assessment, critical security warning and estimation of fatigue life. The system adopted the wireless transmission method at the same time. As a result, feasibility of the system was proved by the case applied and it offered a convenient method for monitoring. The successful application of stress monitoring and safety assessment in the metal construction of large crane equipment makes foundation for its application in projects, which has great practical value.

Abstract: The nuclear power turbo-generator with large capacity is a basic unit of nuclear power plant, while the cooling technology becomes one of the key issues which affect its design and operation deeply. Axial-radial ventilation structure for rotor is commonly used in large nuclear power generator. In this article, according to the basic principles of computational fluid dynamics (CFD), ventilation’s structure and performance is analyzed, 3D flow model is also established. After the boundary conditions are determined, the numerical calculation and analysis is finished. And then, the rules of flow distribution is obtained, the flow field and the static pressure character of the gap is also computed, which could be very important to the ventilation system of the whole generator.

Abstract: In recent years, the Computer Aided Design (CAD) technology is being utilized in the textile and clothing industry, thus simplifying the overall process and shortening the cycle from design to manufacturing. This greatly improves the manufacturing efficiency and also the garment quality. This paper presents the trend of 3D Garment CAD technology, analyzes the intelligent apparel CAD systems, including parametric design, Combination of artificial intelligence and CAD and the closely relationship between CAD and the Internet.

Abstract: Based on RANS method, this paper studied leading-edge tubercle three-dimensional airfoil, which had effect on hydrodynamic performance of three-dimensional airfoil. Both section configurations of the two three-dimensional airfoil models were NACA0020 airfoil. The research method was numerical simulation. First, the leading-edge profile of the first airfoil model was normal. To get stalling angle of the first model, it analyzed hydrodynamic performance of the first model under different angle of attacks at Re=1.35*10⁵. Then, the second model had a sinusoidal leading-edge profile. The second model chose the same Reynolds number. By comparison the numerical calculation results between the first and the second model, the stalling angle of second model delays 3°than the normal airfoil, and the lift coefficient of the second model increases 11.92% than the normal model. The results have laid the foundation for optimization design of leading-edge tubercle three-dimensional airfoil.

Abstract: To show the influence of the synthetic jet on the wake of a cylinder and the aerodynamics performances, a piston-rod-crank actuator was designed to provide a synthetic jet with amplitude up to 20% of the free-stream velocity from the wind tunnel. The rod is driven in rotation by an electrical motor with variable frequency and maximum speed of 2800 rev/min corresponding to a frequency of 47 Hz.

Abstract: Active control of flow over a cylinder at Re=1800, based on the free-stream velocity U∞=0.67m/s, and cylinder diameter d=40mm, is carried out using a synthetic jet. The slot injectors are positioned at θinj = ± 70°. An actuator was used to produce a synthetic jet by exciting a cavity with an alternative piston system. The results show that for the frequency of control located around the natural frequency of the vortex emission a phenomenon of lock-in appear.

Abstract: In this paper, we intend to design a force-feedback device that meets the requirements in workspace. First, based on the modified Delta mechanism, we introduced a chain offset angle that is defined as alpha. We established the positive and inverse kinematics model by the vector method. According to the inverse kinematics formula, envelope body equation of single-open-chain subspace was deduced. We drew the geometric shape of the subspace under three situations while L1 was more than or equal to or less than L2. Then the influence of alpha on the whole workspace and mechanism size is deeply discussed. The cross section view of the space was also plotted by MATLAB. Finally, we gave an example using the Jacobin matrix condition number as the mechanism performance index for dimensional synthesis. The results show that the workspace meets the requirements well.

Abstract: An Unmanned Aerial Vehicle (UAV) is referred to as a remotely piloted aircraft or an unmanned aircraft which can be navigated with human operator in the loop. This paper discusses the design of a UAV with Vertical Take-Off and Landing (VTOL) capability for Maritime applications. The design provides a means for surveillance and communication in Maritime applications. The VTOL-UAV utilises a five-rotor propulsion system that can be launched from confined platforms such as ship-decks. The intended applications of this M-UAV drove the development of an innovative landing system which in the case of emergencies can allow the M-UAV’s soft and potential landing on the water surface. The other functionalities of this UAV are its capabilities to deploy communication Micro-sonobuoys which allows for communication with underwater Robot(s) via Operator in the loop. In this paper we also discuss the process of structural design modelling and evaluation of the development of the Maritime Unmanned Air Vehicle.

Abstract: A new morphology analysis method had been proposed to effectively extract the impulse components in the vibration signals of defective rolling element bearings. In the method, the morphology operator had been constructed by average of the closing and opening operator. For the construction of structure element (SE), the flat and zero was adopted as the shape and the height of SE, respectively, and the element numbers of the SE was optimized by a new proposed criterion (called SNR criterion). Vibration signals of two defective rolling bearings with an outer and an inner fault respectively are employed to validate the proposed method and the results are compared with ones calculated by envelopment analysis method. It shows that the proposed method is effective and robust to extract morphological features, and can be used to the on-line diagnostics of rolling element bearings in rotating machines conveniently.