Abstract: In the design of afflux device for the air dryer safety valve, a rational structure can improve the gas flow condition and suppress the pulsation noise as well. This paper designed an afflux device required little installation space, its physical and mathematical model were built up then. The simulation of the internal flow field is processed with the CFD (Computational Fluid Dynamics) software Fluent, which interprets the device inner structure’s impact on the flow field characteristics and silencing performance. The numerical simulation provides the designers with a reliable approach for the design of the afflux device.
Abstract: The modal analysis was carried out to investigate the proposed improved curvature based finite element method (ICFE) for parallel manipulator with flexible links. The flexible link was discretizatied with ICFE first, and with the proposed rigid-flexible coupling technique, the flexible displacement of the moving platform and passive links was obtained, then through Lagrange equation, the structural model was derived. At last, to investigate the accuracy and efficiency of the ICFE and rigid-flexible coupling technique, modal analysis of ICFE model with different nodes and comparison studies with CFE and the ABAQUS model was carried out.
Abstract: Nowadays the world of manufacturing and production has been encountered with a constantly changing behavior’s of customers. Moreover in the global market, a company can survive if it has the efficient capabilities for rapid product development.These capabilities are known to be important and they mainly affect on the market penetration and cost reduction. One way to enhance such capabilities is to integrate the essential activities of a manufacturing with the help of information technology. In recent years, the researchers have proposed integration of the computer-aided design (CAD), computer-aided manufacture (CAM) and computer-aided process planning (CAPP) as the main phases of product development lifecycle. These phases play an important role in the manufacturing environment and their integration will result in high-class production with minimum lead time. This paper focuses on the die design and process planning activities to produce the molds seamlessly . It studies the recent works on integration solutions and proposes an integration framework for glass bottle manufacturing companies.The paper considers the integration of the part design, macro process planning and the mold design activities. Moreover, the solution has used the ISO 10303 (STEP standard-International Standard for the Exchange of Product data). The novel aspects of the framework have been discussed through a case study. The case study highlights the integration of glass bottle design, process planning and bottle mold design to show the capabilities of the proposed framework.
Abstract: The precise model and the analysis of nonlinear response are important for the landing gear research. In this paper, the FEM model of landing gear was established. The shock absorber is modeled with the nonlinear spring and damper. Random displacements were applied for simulating runway unevenness at aircraft taxiing. Through the simulation, the nonlinear FEM dynamic response of landing gear was acquired. The results show that: the stress of landing gear is large in the landing progress, especially for the random displacements; the weakness of landing gear is the axle sleeve. So the material and technology of the axle sleeve are important in the design of landing gear.
Abstract: The magneto-rheological(MR) suspension system has been established, by employing the modified Bouc-wen force-velocity (F-v) model of magneto-rheological damper(MRD). The possibility of chaotic motions in MR suspension is discovered by employing nonlinear systems stability theory. With the bifurcation diagram and corresponding Lyapunov exponent spectrum diagrams detected through numerical calculation, we can observe the complex dynamical behaviors and oscillating mechanism of alternating periodic oscillations, quasi-periodic oscillations and chaotic oscillations with different profiles of road excitation, as well as the dynamical evolution to chaos by period-doubling bifurcations, saddle-node bifurcations and reverse period-doubling bifurcations.
Abstract: In order to meet the requirements of the bionic flying, traditional Half-Rotating Mechanism (HRM) should be simplified because its structure was too complex and heavy. The design idea of simplified HRM was firstly introduced in this paper. Simplified HRM could be achieved by adding a local constraint made of positioning slider and shaft with groove in the slider-crank mechanism. To make sure the movement of simplified HRM was smooth and reliable, relative motion characteristics of positioning slider in groove of shaft had been analyzed and the curve of shaft with groove had been designed. The key parameters, such as radius and center position of inner and outer arc, had been calculated. A case study based on Unigraphics software was finally given and different states of positioning slider in one running cycle had been shown. The study results indicated that the method of simplifying HRM was effective and design of local constraint was accurate. The above research would provide some helpful advices for HRM application.
Abstract: The purpose of this paper is to study the conceptual design and optimization of a compound coaxial helicopter. At the conceptual design phase, the compound coaxial helicopter design work was based on the conventional helicopter and fix-wing aircraft design method. The intersection of these aspects makes the design work more complex, thus, a program for the sizing and performance optimization was developed for the aircraft. The program included the total weight design, aerodynamic analysis, flight dynamics analysis, performance calculation and particle swarm optimization analysis. Under the restricted condition of the flight performance requirements, optimize the design parameters which make the weight efficiency factor decrease. Therefore, the study of optimum design process was warranted.
Abstract: During the oil drilling process, the eccentric rotation of rotating devices such as rotary table may excite abnormal vibration of the drilling rig which will worsen the working condition of the rig and cause structure failure. In this paper, a ZJ70 drilling rig is taken as the study object, the harmonic response analysis of which is conducted by using FEM software and the frequency response characteristic of the substructure is obtained. Result shows the stiffness of rear substructure is insufficient. On the basis of harmonic response analysis, the modification of the substructure is carried out through enlarging the rear connection frame. Further calculation shows the first 3 order natural frequencies of the substructure are increased, thus the abnormal vibration of the substructure caused by the rotary table with certain rotation speed can be effectively reduced. In addition, the displacement response of both first two orders are greatly decreased with that of central and rear positions are respectively decreased by 17.5% and 42.1%, which demonstrates the dynamic characteristic of the substructure is significantly improved.
Abstract: In this paper it is aimed to present the detailed design procedure of the first solar power system in Jeddah. A prototype of solar power tower system was built at King Abdulaziz University in Jeddah, Saudi Arabia where direct irradiation is very high. Heliostats were used to track the incident sun rays and focus the energy flow towards a solar receiver. The system consists of 10 heliostats directing incident solar rays to a tower of height about 7 meters. Two motors were used to control the heliostat rotational and elevation movements. A solar receiver made of alloy steel is installed at the top of the tower to collect solar energy reflected from the heliostats. A molten salt fluid consists of sodium and potassium nitrates (60/40) re-circulated in the receiver transfers the collected heat in the receiver to a storage tank. A cylindrical vessel with height of 1 m and diameter of 1.5 m was adopted for each of the cold and hot tanks. The design thermal power was 13 kW. The percentage error in the thermal power obtained is about 5.3%.