Key Engineering Materials Vol. 693

Abstract: As the premise, exploring aero-engine structure parts damage accurately can guarantee safety of the aero-engine structure parts, which are restricted by the working condition under the high temperature, high pressure and high speed. Analyzed the structure parts modal parameters by the modal theory, and researched the facts how to influence the modal parameters based on the different damage extent of the structure parts. Then construct the different damage extent structure models on the structure junctions with the finite element analysis method. At last, constructed and verified seven models with the example of aero-engine turbine structure damage in the constant temperature. The results were shown that the characteristic parameters with the inherent frequency and the inherent frequency deviation square can explore the structure damage accurately, but have no significant influence on the structural damages. So it will be important for us to ensure reliable operation and structure damage identification timely by the proposing the structure damage parameters.

Abstract: As an important measurement instruments of trade metering, gas flowmeter has been more and more widely used, and the quantity value transfer of the flow meter is becoming increasingly significant. In order to realize the accurate measurement, the method of the coaxial connection between gas flowmeter and critical flow Venturi nozzle gas flow standard device is studied in this paper, and the coaxial error between this gas flowmeter and standard device within ±1mm is achieved.

Abstract: In the wood engraving industry, the double swing motor spindle or the double rotation motor spindle is often used as the spindle of five-axis wood engraving machine to achieve three-dimensional sculpture. However, the rough and motor spindle may interfere with each other during machining. Hence, many small regions of rough cannot be machined. To solve this problem, an anthropomorphic double-swing-head mechanism is designed. Instead of motor spindle, the designed mechanism is used as spindle of five-axis wood engraving machine. The level of automation and machining scope of the machine are improved. The workload of subsequent artificial modification is reduced. Then, the machining efficiency and quality of wood products are enhanced, and their production costs are reduced.

Abstract: The impact caused by clutch engagement or disengagement leads to vehicle jerking problem. To solve the jerking vibration, the model of the power train and the process of the clutch engagement is built up, and the numerical relations between jerking vibration and key factors (such as the stiffness of clutch disc, the stiffness and damper of side shaft and flywheel) are established, the validity of the model is verified by comparing simulation results and results of measurement, finally the key factors influencing the vibration amplitude and frequency are identified by vehicle tests.

Abstract: According to the structure and production processing requirements of polyester filament winding head, a finite element dynamic model of the winding system in parameters time-varying was established. By using the method of numerical calculation, the dynamic characteristics of the winding head were analyzed in three processes: rapid starting-up in empty volume, winding filament process and stopping in full volume. By studying the influence of the three processing under large stiffness coupling and soft stiffness coupling in the winding head, the role of the coupling stiffness and spindle structure was revealed in different working process.

Abstract: According to the engineering application of vibration stress relief (VSR) based on lateral and torsional coupling, the controlled single-phase series motor is used to create alternating electromagnetic torque, which excites the torsional vibration of the shaft. After adding the expression of the electromagnetic torque to the multi-dof dynamic equation of the lateral and torsional coupling, the dynamic response of lateral and torsional coupling can be calculated. The result has value in the application of VSR based on lateral and torsional coupling.

Abstract: It has been easy to deformation for car doors which opened and closed parts of a vehicle to withstanding various loads. Not only affected the car's appearance and degree of opening, but also deformation increased when subjected to collision. Therefore, it is great significance to internal board dynamic design of the car safety through dynamic analysis of the key pieces of the door to access to inner door panel features. In the paper, the method based on the calculation mode is proposed to analyses the dynamic characteristic of the car doors. The modal analysis of the inner door panel is respectively the inner door panel and the circumference of the fixed constraint on the free-state. The modal parameters and the mode shapes are calculated through finite element analysis. According to these FEM calculating results, the low-order natural frequencies and modal vibration shapes of the inner door panel are computed and identified on the two states. On the basis of these modal parameters, the faults of the inner door panel are shown and its weak points of the design are illustrated. The reason for deformation is analyzed and relevant measures employed to reduce faults are proposed. These improvements can guarantee the normal work of the tool cutter.

Abstract: The antenna pattern far-field measuring site is important to measure antenna accurately, most of the measuring sites have some problems, which make some deviation comparing simulation results with the standard existence, and will block the design and development of antenna. Therefore, on the basis of the common antenna pattern measurement method, a set of antenna far-field test equipment with level acquisition has been designed, and based on that device some calibration and test methods of antenna pattern suitable for outdoor was proposed. According to this method, it is possible for the same test site to contrast and check the testing data, and the accuracy of the site can be verified and corrected by comparing the measured obtaining within a certain range of the standard level data.

Abstract: Press was an important kind of mechanical equipment manufacturing need, and it has been widely used in equipment manufacturing, but its security problem had not been solved. Accidents have caused wide attention. Through the analysis of press injury accident, this paper expounded the importance of press safety protection system. According to the study of existing press safety protection system analysis and the theory of knowledge, a specific design scheme was put forward.

Abstract: It is discovered that the vibration resistance of spindle systems needs to be improved based on the statics analysis, modal analysis and heating-force coupling analysis of spindle systems of CNC gantry machine tools. The design variables of optimization are set according to sensitivity analysis, multi-objective and dynamic optimization design is realized and its designing scheme is gained for spindle structure. The research results show that vibration resistance can be improved without change of the quality and static property of spindle systems of CNC gantry machine tools.