Applied Mechanics and Materials Vols. 80-81

Abstract: In order to select the optimal location points for automated drilling and riveting process, an optimization method selecting the location points of Aircraft’s Wing Panel in Automatic Drilling and Riveting System is presented. This method includes three steps: 1) building the matching model based on the multiplicity; 2) presenting the matching method based on scatter search algorithm; 3) selecting the optimal location points according to the minimal deviation based on linear programming method. This method was applied in a panel to match the mathematical surface and the fitting one of this panel perfectly and select the optimal location points. The efficacy and quality during the process of drilling and riveting of this panel was improved greatly.

Abstract: Aero engine running is complex mechanical experiments. In the last two decades, many computer aided testing (CAT) systems were developed and employed in aero engine running. Traditionally, the main role of a CAT system is data acquisition, which developed with the client/server (C/S) architecture. Now, a CAT system plays more and more important roles in information management, such as measurement channels management, experiment design and management, data analysis and report management, and so on. Users may work on local place or on remote. So, it is not only a data acquisition system, but also an information system. In this paper, we introduce hybrid architecture of C/S and browser/server (B/S) to take advantages of both of them. For local users, clients are realized to provide local monitor and operation. For remote users, browsers provide not only real-time measurement data, but also querying and management of the history data. It demonstrates that the CAT system meets the requirement of aero engine running.

Abstract: The MBD technology use a integration model to express all of the product geometry information and process planning information, and make it becomes the only basis for the subsequent process design and tooling design. It will cause a revolution in the digital automobile manufacturing technology, and really open a 3D digitizing automobile manufacturing era. So it is important and nessary to research the MBD based application method in process of automotive manufacturing. In this paper, the MBD based application framework was put forward to realize full digital, no-drawing automotive manufacturing technology. It was constituted by MBD based digital product definition and coordinate system, process flow centered process data organization and management system, digital process field application system. At the same time, the key technology to realize the MBD based application framework was analyzed. The essence of MBD, master model based product data organization, data maturity based collaborative process control and configuration management was expounded in detail. In addition, the standardization system of MBD based manufacturing technology was described.

Abstract: Logix gear is a new gear based on new tooth profile theory. On the primary, the forming principle of the logix gear tooth profile is analysed. Then the tooth profile curve equations of logix gear are derived, and their center coordinate equations of base circle are given. According these equations, their curves are simulated using Matlab, which are corresponded to practical tests. The study lays a foundation of computer aided design of the logix gears. And the study can be used to perfect mathematical models and to optimize manufacturing methods.

Abstract: A PM-OLED driving circuit is presented. This scheme, aiming at PWM PM-OLED driving circuit, gives the corresponding row-column driving circuit, and uses a new switch network instead of traditional switch network, to make up for the latter some shortage.

Abstract: This paper designs an electronic control EGR system used in diesel engine and researches the influence of different EGR rate on engine economy and the emission characteristics of the 13- modes cycle. The results show that the specific fuel consumption of the test engine rises at different degrees after using electronically controlled EGR technology, especially in high load areas; NOx emissions have a more significant decline and particles increase to a certain extent; Overall, however, emissions of HC do not nearly change; CO emissions are closely related to EGR rate.

Abstract: The three-dimensional model of new rotor was imported into EDEM for dynamic simulation, the maximum speed and force were analysied in the EDEM,indicating that the material along the deterministic trajectory collide with the impact plate for second acceleration after the first acceleration in new rotor, the velocity after second acceleration was 2.3 times than the first acceleration.The impact force and angle did not substantial effect on the second acceleration by comprehensive comparing,the 69m/s speed and less impact force were generated in the new rotor with 2° impact plate installation angle.

Abstract: When the Micro Inertial Measurement Unit is been placed randomly in the case of stationary, the sum vectors that measured by the inertial devices configured orthogonally along three axis, are constant vectors. In view of the above objective facts, a field calibration method of micro inertial measurement unit was proposed. On the base of the establishment and optimization of calibration model, all parameters to be calibrated can be obtained through the least square by the ellipsoid fitting, with the result of high-precision field calibration for micro inertial measurement unit. Finally, a filed calibration program for micro inertial measurement unit is scheduled reasonably. The experiment results show that the method has such characteristics such as easily-operation, time-saving, higher calibration accuracy, and not depending on the baseline direction and datum offered by precision instruments. Especially, it fits for inertial measurement systems which work short time and ask for high accuracy. In addition, it can also significantly increase the measurement accuracy of micro inertial measurement system in practical application.

Abstract: To make design of rotation cup device more reasonable, the air-flow-field in rotation cup should be analyzed. Numerical simulation is conducted on 3D flow in rotation cup of rotor spinning with Fluent and the simulation results reveal the airflow characteristics as: the vortex is generated in rotation cup and the airflow speed decreases gradually on slip plane; the airflow in the type of V accumulation groove is more intensive and a little faster than that in the type of U accumulation groove in the same condition; there exist two strands of reverse direction airflow in accumulation groove; there exist two high pressure regions on slip plane and accumulation groove.

Abstract: The relations between stresses and leakage magnetic signal of concentration area of the airplane’s landing gear under varying load were studied. The finite element method was used to calculate the stress of axle under different conditions; An experiment was designed to simulate the stress status under the bending moment, the slight magnetic signals on specimen were measured, and the relation of the signals and stress was studied. The new testing method was explained with the theory of ferromagnetic and the significance of this technique for detecting defects of the airplane structural part was discussed. The safety of airplane’s main bearing parts plays an important role during its operation and it often comes to bad situation of fatigue damage for stress concentration [1, 2]. To prevent the breaking down of structural parts and get rid of big accidents, it becomes important and necessary to find out the early concentration and damage zone, and to make some certain examination of damage and stress status [3]. The method of magnetic memory testing would be effective for the confirming of stress concentration zone in the equipment or structural parts, and could lead the way ahead the matters of fatigue analysis, evaluation of equipment life and technological design. The method can detect the endurance failure of the airplane’s undercarriage shaft, which is composed of ferromagnetic materials, and that provides the experimental basis for the prevention of parts’ fatigue defects.