Applied Mechanics and Materials Vols. 229-231

Abstract: A new modified model based on the non-parallel primary shear zone is presented in this paper. Experiments showed that the primary shear zone in cutting process wasn’t an absolutely parallel-sided zone. In fact, there are small inclined angles in the primary shear zone. Therefore, in this paper, a correction coefficient is proposed to predict cutting forces exactly. The coordinate mapping approach is adopted to obtain the correction coefficient and the software MATLAB is utilized to predict cutting forces. The material of stainless steel 316L is used to validate the modified model. By comparison between predicted analysis and experimental results, the proposed model shows good agreements with experiments.

Abstract: The powertrain of vehicle is actually a multi-freedom torsional vibration system, its torsional vibration directly affect the vehicle’ ride comfort and safety. In this paper, the effects of elastic couplings on the newly built torsional vibration test-bed were researched. Firstly, using the basic principle of equivalent conversion, established the torsional vibration equivalent model. Secondly, analyzed the free torsional vibration of the powertrain by the dynamics analysis software-ADAMS and obtained the torsional vibration characteristic of the powertrain with different elastic couplings. Finally，fitted out the curve of stiffness and natural frequency by the least squares method.

Abstract: This paper works on the dynamic characteristics of implement mechanism of mining excavator. The dynamic model of the working implement is established based on the application of Lagrange's equation. Digging resistant force, crowd force and ore gravity were discussed in detail. A full working cycle is simulated by using Matlab/Simulink. The results show the validity of the established dynamic model and the importance of the dynamic analysis for the mining excavator.

Abstract: Titanium alloys, as difficult-to-cut materials, have poor machinability due to their superior mechanical properties, heat resistance and corrosion resistance. High cutting temperature and great cutting force that will greatly accelerate tool wear often occurs in titanium alloys cutting process. In this paper, an ultrasonic vibration turning method was used to lower diamond tool wear during TC4 titanium alloy turning process. Ultrasonic vibration turning tests were carried out with various cutting parameters. Experimental results indicated that there’s a significant reduction of the wear rate of diamond tools by means of ultrasonic vibration in TC4 turning process. For ultrasonic vibration turning, spindle speed, the amplitude and frequency of vibration of the tool are the greatest impact of tool wear, followed by feed rate, then the cutting depth.

Abstract: When the crane jib is in the maximum elevation angle，luffing jib tower cranes can happen to produce accidents of crane jib backward- tipping. The anti-backward-tipping device is the necessary safety device luffing jib tower crane. Based on the study of several anti-backward-tipping devices, this paper analyzes the causes and forced state of crane jib backward- tipping and proposes several factors to be put into consideration in designing anti-backward-tipping device. It proposes a design method and calculation method of dual-spring anti-backward-tipping device, which has been applied and verified in product design.

Abstract: To increase the lower order natural frequency of MM7140 grinder’s support parts is an effective measure to improve structural rigidity, avoid resonance and reduce amplitude. The finite element models of MM7140's lathe bed and column, were established by 3-D software UG, and led into ANSYS for modal analysis. Then, found the column was the weak link based on the modal analysis results, and brought out the more effective improvement program. This paper offers a reliable basis for the design and renovation of MM7140 grinder.

Abstract: This paper analyzes the basic combustion characteristics of dual-fuel engine with diesel-natural gas, including the engine’s running characteristics, the external characteristics and the low-load performance. Taking the development and application of natural gas for consideration, this paper also makes studies on how to improve the dynamic performance of the dual-fuel engine CA6110ZLA5N2.

Abstract: The car engine failures in the course of time and place have many possibilities. The engine fault diagnosis system developed in .NET platform. The core of the system make use of noise wavelet energy features and non-linear support vector machine classification. After the experiment, the system has fairly good results.

Abstract: Based on analyzing the contact condition of the cutter and the work piece in orthogonal turn-milling machining, orthogonal cutting experiments were implemented with several machining parameters, and finally obtained conclusions about cutter wear and work piece roughness influenced by 3 factors. The biggest effect factor which affects the cutter wear is the cutter offset, the number of cutter teeth takes the second place, and the axial feed rate affects the least to cutter wear. This conclusion can be used to choose fit machining parameters in turn-milling machining.

Abstract: In this document, the electrolytic in-process dressing ( ELID ) grinding technique is used for ultra-precision processing experimental research on the carbonized cold-rolled steel (HRC60～80).A surface roughness of Ra6～8nm was obtained after ELID precision grinding. The results proved that adopting micro grain size (W1.5～W36) and high hardness cast iron based diamond grinding wheel, increasing the wheel peripheral velocity (18～20m/s) and reducing grinding depth can effectively improve surface quality and bring the surface roughness down. The wheel peripheral velocity, grinding depth as well as grinding fluid are the main factors during ultra-precision grinding.