Applied Mechanics and Materials Vol. 415

Abstract: The processing of worm gear components is quite simple, and manufacturing method is relatively complete, theres no need to make special equipment. But to new energy equipment, research new-type of manufacturing technology is required. On the basis of meshing theory and drawing on manufacture of the planar enveloping as well as the tapper enveloping hourglass worm, a research of manufacture technique about the non-backlash double-roller enveloping hourglass worm drive has conducted on the Y3180E gear-hobbing machines and four-axis four-linkage NC machines. The key pieces have been processed out, and a calibration has been conducted on the single-head worm. All of these work will provid a theoretical foundation and practical experience for the actual manufacture.

Abstract: A transmission experiment platform was built to make an explicit test plan for the non-backlash double-roller enveloping hourglass worm drive reducing device, according to the type test and performance analysis, the noise, temperature, and efficiency of the new worm was obtained under different load and rotational speed. The results show that the non-backlash double-roller enveloping hourglass worm gearing possesses a excellent meshing performance as expected, which can eliminate the backlash, and it indicates that the new drive has achieved the anticipated project objective, eliminated the hysterisis error in transmission, and has the advantages of low noise, high transmission efficiency.

Abstract: In our country oil field workover wellhead operation process, constructors need to manipulate the tubing elevator, but sometimes they forget to bolt or too late to do it, this will produce safe hidden trouble, to this end, this paper puts forward some ideas of semi-automatic tubing elevator. Semi-automatic tubing elevator can realize automatic bolt and semi-automatic lifting pin, it not only can reduce safety hidden trouble, also can reduce the work of the bolt and lifting pin, further reduce the chance of fatigue. In this paper, the semi automatic tubing elevator is described, using Pro/E to model, and using ANSYS to carry out strength check, verifying the rationality of its structure.

Abstract: Laser Doppler Vibrometry (LDV) is a well established technique able to accurately measure vibration velocity of any kind of structure in remote, i.e. non-intrusive way, this allowing to overcome the problem of mass loading, typical of contact sensors as accelerometers and strain-gauges, which has strong influence in case of lightweight structures. Moreover, the possibility of driving automatically the laser beam, by means of moving mirrors controlled with galvanometer servo-actuators, permits to perform scanning measurements at different locations with high spatial resolution and reduced testing time and easily measure the operational deflection shapes (ODS) of the scanned surface. The exploitation of the moving mirrors has allowed to drive the laser beam in a continuous way making it to scan continuously over the structure surface and cover it completely. This way of operation, named Continuous Scanning LDV, permits to perform full-field measurements, the LDV output carrying simultaneously the time-and spatial-dependent information related to the structural vibration. A complementary strategy making use of the LDV coupled with moving mirrors is the so called Tracking LDV, where the laser beam is driven to follow a moving object whose trajectory must be known a priori or measured during operation (e.g. via an encoder in the case of rotating structures). In this paper some applications of the Tracking Laser Doppler Vibrometry (TLDV) and Continuous Scanning Laser Doppler Vibrometry (CSLDV) will be described they concerning, specifically modal and vibrational analysis of rotating structures.

Abstract: Combined with low-speed wind tunnel experiments, this study adopted computational fluid dynamics (CFD) and the MATLAB/Simulink control software to analyze the aerodynamic attributes of a tail fin-stabilized projectile and subsequently simulate its flight trajectory with four degrees of freedom under a flight condition (M) of 0.6 and an angle of attack (α) between-60° and 60°. Comparing the CFD calculation results with the revised experiment data using the Karman-Tsien Rule showed that the aerodynamic coefficients C_D, C_L, and C_M were similar within an angle of attack between-30° and 30°. The projectile further demonstrated excellent aerodynamic attributes within an angle of attack between-60° and 60°, maintaining stable flight. Furthermore, comparing the four-degrees-of-freedom simulation results with data from the firing table showed that the maximum height difference of trajectories at varying angles of elevation (mil) ranged from 3.07% to 4.68%, and the difference in the firing range distance ranged from 0.15% to 5.72%. To reduce the costs of field testing, this study establishes a method to design aerodynamic systems, analyze and compare flow fields, and simulate flight trajectories.

Abstract: For differences of time-domain energy distribution of different gear fault vibration signal, an analytical method based on local mean decomposition (LMD) and least squares support vector machine (LS-SVM) is proposed to apply to gear fault diagnosis. First vibrational signal of gear is decomposed into a series of product functions (PF) by LMD method. Then extracting energy characteristic parameters of PF components which contain main fault information to constitute a fault feature vectors, which is considered as input sample of well-trained LS-SVM, and then identifying working state and fault type of different gear can be identified accurately and effectively by diagnostic method based on LMD and LS-SVM.

Abstract: Symmetrical floating plate of the high pressure and large displacement gear pump in rated conditions is inability to achieve the floating moment balance. To solve this problem, a new balancing mechanism is presented in this paper, which is asymmetric with a V-shaped groove structure on its driven side, called asymmetric balancing mechanism. Compared with traditional symmetric balancing mechanism, the floating plate with asymmetric balancing mechanism the can the coupling problem between the gear shaft and gear inner flow field through its own asymmetrical structure, so that the gear pumps internal flow field was the symmetrical distribution. According to the structural characteristics of the floating plates, Parameterized moment model based on discrete feature points was established. Theoretical analysis and experimental tests show the result , when suffered floating moment as evaluation criteria, in rated conditions, compared with the traditional symmetrical balancing mechanism one, that the balance performance of the floating plate with V-shaped groove asymmetric balancing mechanism improve by 41.42%.

Abstract: In order to overcome the shortcoming as the model is too simple to reflect the whole vehicles mechanical characteristics in traditional simulation for electric drive vehicle, the method of mechanical-electrical co-simulation is put forward. The virtual model of 8×8 wheeled vehicle is constructed by ADAMS, and then the co-simulation model is built. The co-simulation experiment is taken under the working condition of accelerating on low adhesive road,the accurate of the control model is validated according to the result, which will contribute to the research on driving antiskid control for in-wheel motor drive vehicle.

Abstract: On the basis of traditional static finite element simulation, the paper adopts time spectral element method with higher accurate of interpolation precision to disperse the alternating mechanical load, meanwhile, applies the load results to its piston dynamic analysis to get the time history curve of piston stress and distortion. What we get from the experiment provides theoretical foundation for further study of piston fatigue analysis and life prediction.

Abstract: According to the complexity and non-linear characteristics of car interior sound quality evaluation, the technology of BP neural network is used in sound quality evaluation. The interior noise samples from actual cars were obtained by road experiment. The subjective evaluation test of sound quality annoyance was carried out. Meanwhile, several objective psycho-acoustical parameters of these samples were calculated. The sound quality prediction model of vehicle interior noise was established based on BP neural network. Annoyance of samples was obtained by means of the prediction model and the results were compared with that obtained by multiple liner regression prediction model. The results indicate that the prediction results from BP neural network model were close to the measured values. The BP neural network model was more effective than multiple liner regression model, and it can be used effectively to the evaluation of modern car noise.