Papers by Author: Hong Feng Wang

Abstract: In this paper, the dynamometer for measuring the forces of the tool in FSW process was designed. The design principle of the dynamometer was adopted octagonal ring deformation to get the forces in FSW process. The design dynamometer was calibrated, the result showed the linearity and cross sensitivity of the dynamometer in allowed range, the worked reliable of the dynamometer was good. It can be used to measure the forces in FSW process.

Abstract: The impact experiment of the joining workpiece of the friction stir jointing for 7022 aluminum alloy was made by the impact load experiment machine. The objective was studying the effect of the different joining process parameters of the FSJ on impact toughness. The results showed the impact toughness of the joining region was lower than that of the base metal when the rotation speed of the tool was 300rpm and the feed speed was 30 and 50mm•min-1, the impact toughness of the joining region of the other joining process parameters was higher than that of the base metal. The impact toughness of the joining region was the best when the rotation speed of the tool was 400rpm and the feed speed was 100mm•min-1. It is higher than 22.3% of the base metal. The impact fracture of the joining region was mainly dimple; only fracture edge appeared a small amount of the quasi cleavage. The fracture presented good toughness.

Abstract: Analysis about the cause of the main failure and the forces of the main welding outer cylinder of the recent large aircraft landing gear were given. The impact load for main welding outer cylinder in the process of the taking off and landing was calculated of 580MPa. Finite element model of the main welding outer cylinder was then established and the influence of the impact loading to the main welding outer cylinder was analyzed. The results showed that crack was most likely take place on the top of the outer cylinder, and then on the two welds. The crack expanded in an S shape. This study could provide an important basis for the safety of the aircraft landing gear inspection and service life prediction.

Abstract: High-tech local war drives higher requirement of speed and accuracy performance of equipment logistics. In this paper, using LABVIEW as data acquisition platform and control program environment, an automatic control equipment logistics system is designed. This system integrates bar code technology and warehouse position system based on microprocessor STM32. Whole process monitoring and management can be realized by this system, which has a high significance of improving the military equipment configuration capabilities.

Abstract: Milling process of jointing blank of 7022 aluminum alloy was simulated by ANSYS. The results show that the maximum residual tensile stress and pressure stress are mainly concentrated in the jointing seam zone when the jointing blank is milled. The milling deformation of jointing blank is shown as “wave” shape. The milling deformation of key eye side is shown upwarp. The jointing initiating terminal is shown downward displacement. The maximum downward displacement is present to the middle of jointing seam central line. In additional, the milling deformation along sheet length direction is shown outward extension.

Abstract: The effects of discharge parameters on micro-surface topography in mirror-like surface electrical discharge machining (EDM) process were investigated, and the optimization scheme was obtained. The realization of the process parameters and their effects were analyzed by the Taguchi method. The surface roughness amd 2D micro-surface topography were measured. An L16 (44×23) Taguchi standard orthogonal array was chosen for the design of experiments. The level of importance of the parameters parameters on surface roughness was determined by using analysis of variance (ANOVA). The experimental results confirmed that peak current and open discharge voltage have more influence on the surface roughness on mirror-like surface EDMed workpiece in comparison with pulse duration and pulse off-time.

Abstract: The ideal of genetic algorithm was introduced in optimizing tap parameters for internal thread cold extrusion of high strength steel. The use of genetic algorithm was analyzed in the optimization design of the extrusion tap. Based on optimal result, the extrusion tap was machined to reduce the extrusion force effectively. It was completely feasible to using genetic algorithm to optimize tap parameters for internal thread cold extrusion of high strength steel. Results from this study provide important basis for practical application of internal thread cold extrusion of high strength steel.

Abstract: The heat source model and the heat input model were built by analyzing welding process. The rationalities of model were verified by finite element simulation. The method of prestressed welding was employed in order to reduce welding residual stress. The welding residual stress would be widely impacted by imposed prestress of 90% yield strength welding. At the same time the propagation of welding heat cracking in the heat-affected zone was properly controlled by prestressed welding.

Abstract: Shot peening is known to improve the fatigue performance of materials. The improvement in fatigue is that plastic deformation in the surface increases hardness, yield stress and microstrain of thinning Crystal block and dislocation density, and formed advantaged compress residual stress that are introduced into the near-surface of the components and which hinder crack initiation and growth. But over peening effect is produced when shot peening strengthening goes beyond a certain limit, which was adverse to improve surface quality. This paper adopted the optimization of the critical peening parameters to avoid appearing over peening effect. The experimental result showed that arc high value of optimal shot peening was 0.40mm.

Abstract: In order to provide effective guarantee for the prediction of residual stress and deformation after welding process of large-sized aluminum alloy structures, temperature field and thermal efficiency during double-sided multi-layer TIG welding of aluminum alloy was studied. By integratedly considering temperature-depended material properties, convection, radiation, filling rate of solders, et al, numerical analysis about the form of molten pool and temperature field was given. Element birth and death technique was taken during the simulation. Double-sided multi-layer TIG welding experiment was carried out and sample of cross section of weld seam after welding was prepared. By trying different thermal efficiency for calculation, simulation result consistent with experimental result was obtained finally, making the present thermal efficiency as the aim result for study. Confirmation was given by comparing temperature value from experiment with simulation one.