Papers by Author: Tie Wang

Abstract: This paper makes study on the 42CrNiMo gear contact fatigue strength, applying the rapid measure method of the gear contact fatigue stress value with a few gear samples to get the estimated value of the gear fatigue limit value precisely and rapidly. And the gear fatigue life curve and fatigue damage accumulation curve are got by MATLAB simulation. Comparing with the traditional test method, this method can reduce the cost and save the time.

Abstract: Tooth contact analysis (TCA) is an effective tool for meshing analysis of the double circular arc profile spiral bevel gear (DCAPSBG), and it is the basis of loading tooth contact analysis and finite element analysis. The TCA application is developed by Visual Basic and MATLAB mixed programming method, this paper compared the results of the TCA application analysis with the results of contact area check experiment on one pair of gears with given parameters. The TCA application had been verified by real experiment, this provided an effective approach for the design of DCAPSBG.

Abstract: An experimental investigation was conducted on 4100 engine to study the influences of different percentages of methanol in DME/diesel blended fuel on combustion and emission performance. The result indicates that a certain amount of methanol in DME/diesel blended fuel can reduce production cost, improve the engine's power performance at the same time, but when the methanol percentage is increased (over 2%), the power performance will decrease. With the increase of methanol proportions, the maximum cylinder pressure is slightly increased, the peak of heat-release curves are declined and delayed, the cylinder temperature is decreased, the ignition timings are delayed and the combustion duration is shortened. In addition, NOx emissions were further reduced, but the HC emission, the CO emission and the soot emission has a little rise.

Abstract: A variable-grain strategy is proposed to solve the complicated problem of optimization design on high-speed transmission helical gears with multiple objectives and restrictions. Based on the theory of gear meshing noise and the superiority criteria, a multi-objective evaluation index system is brought forward which gives consideration to the increase of the contact ratio and the decrease of the noise generated by the slide ratio of the tooth flank meshing and the mutation of friction torque, and then the variable-grain multi-objective optimization models of high-speed helical gears are established. The coarse-grained model is utilized in the early design to efficiently determine the direction to the optimal solution. Then the grain is refined and the fine-grained model can be utilized to acquire the optimal result.

Abstract: In order to meet the need of identifying obstacles and navigating for the Coal Mine Detection Robot which is used to rescue life and detect environment from coal mine disaster, binocular stereo vision is researched and 3D model of objects around the robot is reconstructed by means of two cameras of visual system built in the robot. The two cameras are calibrated and two projection matrices of them are obtained. Then, two images of the same scene are obtained by the two cameras. The matching points of two-dimensional coordinate are got through Harris corner extraction and stereo matching. According to the principle of binocular vision, equations are obtained and solved by least square method, which can calculated the discrete points of 3D coordinate.

Abstract: For early failure problems, which are broken teeth of the first transmission driving gear in the test, this paper studies the problem in the failure mechanisms such as chemical composition analysis, fracture surface analysis as well as the metallographic structure morphology inspection analysis of failure gear. The results show that the main reasons causing abnormal fracture of the failure gear are the insufficient root shot peening strengthening, the small fillet of the spline groove and the inadequate rim thickness of the rim. This paper uses the finite element method to analyse the contact stress of failure gear and puts forward an improving design method.

Abstract: This paper introduces the installment method of experimental machine and gears, and the definition of stress levels, based on the contact fatigue experiment of 18Cr2Ni4WA carburizing and quenching gears, the few experimental points combination method was applied. The experimental points data was obtained by failure criteria. The S-N curve is fitted according to experiment data, and the experimental points data processing method is also explained in the paper.

Abstract: This paper put forward the rapid measure method of the gear contact fatigue stress value with a few gear samples, which can get the estimated value of the gear fatigue limit value precisely and rapidly. And the gear fatigue life curve and fatigue damage accumulation curve are simulated by MATLAB. Comparing with the traditional test method, this method can reduce the cost and save the time.

Abstract: In order to meet high-volume, low-cost reducer and ensuring quality in the production of reducer, a new design method is necessary. This paper applies the design method of ‘modular’ in high-volume reducer production, preferred numbers and mechanical optimization design thought, then based on access database and VB programming software research modular design process of the volume reducer. Higher degree basic modular parameters of volume reducer are obtained.

Abstract: Firstly the engine models with different types of crankshaft are built, and the load condition of the crankshaft is simulated .After comparing the simulation results, a conclusion is obtained that the model with beam crankshaft or flexible crankshaft corresponds with actual situation. Then the selection of the balance target is discussed .At last, using a certain 60°V8 engine as an example, two kinds of counterweight arrangement schemes are studied, and the simulation results shows that both schemes can achieve good balance effect.