Advanced Materials Research Vols. 189-193

Abstract: W1002 excavator has been widely used in iron and steel corporations in northern China. As the main component of excavator, the dipper handle is the most important to design and manufacture. Because of the worse working conditions and large force, the dipper handle is still easily damaged and many fracture accidents have led to great economic losses of enterprises. The requirements of designing, if only based on the simple contracture strength calculations, are not enough. So it is necessary to study influence of the impact to service performance. In this paper the finite element method is used to analyze dipper handle and find out the weakness in the structure and factors impacting the service life of dipper handle. The improved dipper handle was used in the device and inspected by test instruments. The stresses are measured in same conditions in stall process and the results were also in consistence with the theoretical analysis. Improved model is fund out after using the 3D model to recalculate the stress. Since the improved dipper handle was used in practice to now, fracture accidents have not happened again.

Abstract: High speed machining (HSM) technology is used in a broad range of applications to machine ferrous metals and nonmetallic material. The electrical spindle is one of the major elements to keep the machine running at high productivity. In recently years, the requirement of rotational speed and rigidity of electrical spindle is getting higher and higher in order to satisfy the high speed processing. So a high speed grinding electrical spindle equipped with hot isostatic pressed silicon nitride (HIPSN) fully-ceramic ball bearings without inner rings and yttria partially stabilized tetragonal zirconia polycrystal (Y-TZP) ceramic spindle shaft is designed for higher speed and rigidity. Because the processing precision is relevant to the vibration of electrical spindle, it is necessary the vibration and noise of the ceramic electrical spindle is detected. This paper presents results of vibration and noise of the ceramic electrical spindle and analysis the reason of phenomenon. The analysis shows the vibration and noise of the ceramic electrical spindle is up to the standard.

Abstract: In order to save energy and material, and reduce productive costs, in accordance with the geometrical characteristics of rear axle housing of trucks, the redesign of integral product with new technology was completed, and then, two kinds of forming technology were developed. Afterwards, rear axle housing of light trucks was formed by adopting hydraulic bulging and neck-spinning, and the housing of heavy trucks by adopting hot mechanical expanding and hot neck-spinning with the tube. The research of this paper has practical value and results in great economic returns.

Abstract: In order to enhance the lubricating capacity of the magnetic lubrication on the surface of the porous material, a new magnetic lubricating field has been designed by simulating method based on the coupling relationship between the pores and micro-magnets structure. The results show that the output characteristics of magnetic fluids in the pores of the material play a significant role in the design, whereas the output characteristics depend on micro-magnets and the pores’ size such as length and diameter, for example, when the ratio of length/diameter of the pore is larger than 3.2 ,the output capacity of the magnetic fluids in the pores presents a stable value, but when the ratio is smaller than 3.2, the output capacity obviously decreases. It is also found when the distance among the pores changes from 5 mm to 8 mm, the output capacity also presents a stable value; however, the output capacity obviously decreases with the increased distance among the pores beyond 8 mm. Furthermore, the effect of the parameters of micro-magnets structure on the output capacity of magnetic fluids is also investigated in the paper. The research results are helpful to improve the lubricating properties of the magnetic fluids on the surface of the porous material.

Abstract: In order to study the low-temperature expansion process of NiTiNb shape memory alloy, this paper makes use of numerical simulation method to complete the simulations and analysis. The shape memory effect of NiTiNb alloy pipe joints under different expansion temperatures and expansion strains have been compared and evaluated. Through simulations of low-temperature expansion and elevated temperature shape recovery of NiTiNb alloy pipe joints, the relationships between elastic deformation, phase transformation deformation and recovery ratio under different expansion temperatures and expansion strains have been acquired. The results show that the highest expansion strain should below 11%, in consideration of recovery ratio and recovery temperature, the optimal expansion temperature range is -60~-50°C .

Abstract: 1MW variable speed constant frequency wind turbine tower of steel structure is analyzed by using the software ANSYS, the coupling between the wind and the tower is realized through the order coupling method. The maximum Von Mises stress and the deformation of the tower in the case of limit loads are obtained, and then these results are compared with that without wind load. Comparison result shows that the effect of wind load on the tower’s displacement along the wind speed is great, and the maximum Von Mises stress of the tower becomes larger after considering the influence of wind load, the increase extent is determined by wind load case.

Abstract: Based on the study on the characteristics of a limonite ore, research was made on single reverse flotation for Xinjiang limonite ore. The test results indicate that we can obtain an iron concentrate grading about 54.07％ at a recovery of 62.65％ from an iron ore assaying around 41.85％ iron，rather good metallurgical performances.

Abstract: The subject of this research mainly focuses on the gravel formation along the western foothill of Taiwan. Numerical simulations are performed using discrete element method (DEM) based the software Particle Flow Code (PFC). Physical properties and internal friction angle of gravels are obtained from the three dimensional modeling of in-situ direct shear tests. The numerical experiments using PFC2D are used to model single-vertical anchor installed at shallow depths. The numerical results indicate that the failure range for the tension-type anchor is smaller than the range for compression-type anchor at the same bonded length and friction angle. The pullout resistance for the compression anchor is also greater than the tension anchor. Similar results have been obtained from the field pullout tests. The transmission of forces along the anchor is significantly affected by way of particle permutation with the anchor. If bigger size particles are piled around the anchor, the transmission of forces along the anchor will be faster and the affecting range of particles is also larger.

Abstract: This study investigates the effect of air pressure on workpiece temperature in through tool minimum quantity lubrication (MQL) deep-hole drilling. Experiments on 200 mm deep holes drilled by a 10 mm carbide drill were conducted under regular (500 kPa) and high (1000 kPa) air pressure conditions. Torque data shows that the chip clogging problem occurring under regular air pressure can be solved by the high air pressure. An inverse heat transfer method is utilized to quantify the heat fluxes and calculate the temperature distribution during drilling based on embedded thermocouples along the depth. Results show that temperature around the hole increases rapidly when the chips start accumulating in the hole under regular air pressure and cause high heat flux on the drilled hole wall surface. The high pressure condition, prevents chip accumulation, thus reducing the total heat flux.

Abstract: This study developed new algorithms to simulate the grain pattern and orientation of radiata pine boards based on the geometrical and growth features of radiata pine trees. Scenario simulation is presented in the article. The established methodology offers insights for sawmills to establish feasible log breakdown strategies and maximize radiata pine timber value.