Applied Mechanics and Materials Vols. 268-270

Abstract: Put forward a new method of spatial linkage analysis and synthesis of the vector fitting. The core idea is: all components available in mechanisms can be represent by one or one group of vectors, all vectors are transformed from unit vector, and the mechanism is a assemblage of those vectors. Because of kinematic variables (position, direction, changing when moving ) and design variables (shape, size, unchanging when moving ) is been properly separated which can improve the efficiency of analysis and calculation. The example shows that the method is efficient, and can be used both in the analysis and design of the mechanism.

Abstract: In order to realize the buckling strength design for the opening door of the large-scale horizontal axis wind turbine tower, the method combined with the engineering method and the FEM was presented. The FE model of the door was established. The first-order buckling eigenvalues and buckling modes for three different structures were calculated and analyzed. Based on engineering method, the stress and buckling strength for the sections of tubular tower were obtained. Corrected by FEM results, the tower door with opening buckling strength were checked by engineering method. The results were compared with those by FEM. The safe design structure anti-buckling were presented. The method presented in this paper is feasible and effective for the opening door design in large-scale horizontal axis wind turbine tower.

Abstract: With the growth of the natural gas market, the long distance natural gas pipeline system is getting more and more important in nowadays. As a united and enclosed hydraulic system, the operation conditions of the whole line will be changed by the influence of the condition change in one station. On the one hand, the condition change made people analyze operation scheme more difficult, on the other hand, pipeline system operating conditions directly affect the relationship between the production and the sales of natural gas. Therefore, the operation of the gas pipeline must be optimized, which brings huge economic and social benefits. This paper constructed a simulation model of a long distance natural gas pipeline by TG.net, and then analyzed the change of the operating condition of the pipeline after a compressor station shut down, found out the regularity.

Abstract: Aiming at spring in pre-positioned fixture of shaft pressing and assembling machine subjected to alternating load and impact load, high working frequency and easy to fatigue failure, to guarantee spring service life and make the fixture more application scope, a multi-objective optimal math model had been established in this paper. In the model, spring’s basic structural parameters are used as design variables; strength, stiffness, and spring index and so on are used as constraint conditions; spring fatigue strength safety factor and volume are used as objective functions. And the model had been solved by using the unified objective function method and LINGO software. The example operation result shows that optimal spring volume is smaller than one of traditional design. And design purpose has been realized.

Abstract: This paper describes 4UMS-2700 cassava harvester’s overall structure and working principle, introduces its structural designs and main technical parameters, and explains the methods and basis to design its main working parts’ structures. Field experiments on its prototype was conducted and the experimental results show that the unit was reasonably designed with high productivity, low fuel consumption, and high operating reliability and can meet the agronomic requirements to harvest cassava.

Abstract: Through the thorough research on the related knowledge of the shearer running reliability, found performance quality of shearer walking mechanism directly affect the production efficiency and reliability of whole shearer, so the research puts forward based on the dynamic characteristics.For preliminary study on vibration condition of shearer walking unit during movement, establish shearer walking test-bed, and walking unit is tested by using three measuring points. Vibration law and affecting factors of walking unit was draw. Provide a theoretical basis for design study of walking unit.

Abstract: Hybrid excavator shafting finite element analysis model was established. Modal calculation results show that compared with traditional excavator, hybrid excavator shafting first modal frequency is decreased significantly. First modal shape and second modal shape are torsional vibration. Hybrid excavator shafting torsional vibration dynamic analysis model was established, dynamic calculation results show that cylinder pressure change is main reason of shafting torsional vibration. Maximum torsional angle is occurred at 2f₀. Hybrid excavator shafting torsional vibration experimental table was established and maximum torsional angel experiments under different throttle angle were carried out. Experimental results show that maximum torsional angle is occurred at 2f₀ under different rotate speed. Incentive frequency of shafting torsional vibration under different rotate speed is mainly concentrated in 0.5f₀~2f₀. Main drive source of hybrid power system shafting torsional vibration is diesel engine, not motor.

Abstract: Seed-filling device of plot seeder is the research object. Influences of the four test factors (motion velocity (v), rotation speed of filling device (ω), generatrix length of seed-filling device (l), base angle of seed-filling device (α)) on the uniformity in seeding-filling process for wheat seed are analyzed by DPS7.05. The effect order of four test factors on wheat seed is obtained. Optimum parameters for wheat seed established are as follows: motion velocity of plot seeder 0.4m/s, rotation speed of seed-filling device 0.25rad/s, generatrix length of seed-filling device 0.1m, base angle of seed-filling device 50º. The best plot length for the seed-filling device is 10m and the best CV in seed-filling process for wheat seed is 7.85% when seeding rate for wheat seed are 180g per plot.

Abstract: The extreme position angle θ 90 ° rocker in any position of the graphic features, crank angle between extreme positions rocker swing angle ψ and θ.

Abstract: Installation of inter-phase spacer can effectively protects against line fault caused by conductor galloping, non-synchronous swing and sleet jump etc large amplitude vibration, but sag of the conductor is changed if inter-phase spacer is installed. And installation of initial inter-phase spacer will cause change of inter-phase distance, which cause difficulty of successive installation. The empirical equation can’t accurately analyze change of the inter-phase distance caused during installation of the inter-phase spacer. In this paper, accurate conductor installation inter-phase spacer analysis model is established with non-linear finite element method. Change of the conductor sag after installation of the inter-phase spacer is calculated, and influence on inter-phase distance caused by different installation sequence is analyzed. The research result provides effective analysis method for length control of actual line installed inter-phase spacers, and ensures manufacturing and successful installation of the inter-phase spacer.