Advanced Materials Research Vol. 1089

Abstract:

After surrounding rock is disturbed by some damage form a loosen circle in surrounding rocks of a roadway, in order to solving the range of loosen circle, mechanical mechanism of loosen circle was discussed on the basis of damage mechanics and loosen circle radius calculation formula proposed. This work has some certain reference for roadway support design.

Abstract: For the aspheric processing is complex , time consuming and difficult to guarantte the eccentricity ,this paper introduce a new method of aspheric processing --repairing and polishing methed and describe the principle . Best fit radius, removal function were computed by mathematical model method and the respective performance curves were given by simulation. This methed has the particular advantage of shortening the working time ,reducing the eccentric amount of the element and improving the processing efficiency. Through this processing method, do a series of processing experiments on the smaller aspheric tolerance single crystal silicon aspheric.As the result indicated , plane surface shape error PV 0.52 μm,surface roughness RMS value of single-crystal silicon 0.09 μm ,the center deviation was less than1μm and the surface smoothness meet the standard above the grade Π.

Abstract: According to ULCS production practice in domestic steel,in combination with laboratorial data, this paper analyzes the influence factors of ULCS carbonization. The statistical results shows that carburization of ultra-low carbon steel is affected by mold flux、continuous casting process and refractory,and some corresponding control measures are put forward.

Abstract: Three-dimensional printing technology based on deterministic electrochemical deposition method has been developed, which is generated from the electroplating. The traditional electroplating system has been improved to ensure the printing process controllable. Through accurate control of the deposition region, deposition rate, and the dwelling time in the printing process, a three-dimensional object of almost any shape can be obtained by deterministic manufacturing process. Through addition of alcohol to the electrolyte, Marangoni effect is generated, which will improve the property of the deposited layer. The deterministic electrochemical deposition not only can decrease the cost of the printing process, but also will promote the application of the 3D printing technique in many fields.

Abstract: Manufacture of micro holes in difficult-to-machine material is very difficult, electro-chemical machining (ECM) is one of the more appropriate approach. However, micro holes fabricated using ECM can have different diameters at the entrances and exits and such tapering effect is not localized. In this work, a new ECM method named electro-chemical micro drilling (ECMD) for machining high quality straight micro holes in difficult-to-machine material was introduced, and the micro-spherical electrode fabricated by a hybrid technique combining micro-ECM with one pulse electro discharge (OPED) was used in ECMD process. Micro-spherical electrode and ultra short pulses (tens of nanosecond scale) were used to locally dissolve the area with the effect of voltage, pulse width and pulse frequency on the localization distance being studied. High quality micro holes with a diameter of 42 µm in a 70 µm thick nickel foil were drilled using micro-spherical electrode with a sphere diameter of 30 µm.

Abstract: Carbon fiber reinforced plastics (CFRP) laminates with different top/bottom fiber direction angle (stacking sequences of each ply) are trimmed at various workpiece inclined angles. Four types of delamination are studied and discussed. The results indicate that fiber direction has great influence on the type of delamination and the workpiece inclined angle determines the proportion of each type of delamination expect a special cast that the delamination form turns into type I/II when the workpiece inclined angle is 58.6o. Stacking sequences of each ply have great influence on the numbers of damaged plies and the 0o fiber direction ply has the ability to prevent the development of damaged ply.

Abstract: The true stress-strain curves of 2198-T3 aluminum-lithium alloy in three different orientations (0°,45° and 90°) were measured by uniaxial tensile test. Finite element analysis technique was used to simulate the forming process of irregular cup, and the hydro forming experiments were conducted with YB32-100t press machine. The results showed that the key forming parameter-n values were similar in three orientations. Simulation results illustrated that the thickness of the blank reached the lowest value at the round corner. Experimental results verified friction was a significant factor to manufacture a qualified competent. Meanwhile, the experimental results agreed well with the simulation ones. The practical thickness distribution of 2198-T3 irregular cup along the section line was coincided with simulation.

Abstract: Composite panels with “I”-shape stiffeners are widely used, but cobonding process induces large warpage deformation after demoulding. Finite element simulation was used in this paper to analyze the effects of some representative processing parameters on the process-induced deformation. The results show that the deformation increases with the consolidation pressure, the CTE of mould and the friction coefficient. The deformation is more sensitive to the consolidation pressure and the friction coefficient for a shorter part, while it is more sensitive to the CTE of mould for a longer part.

Abstract: Fundamental theory of functions of basic tundish coving flux is analyzed at the first step. Several types of the flux used in deferent steel grade include ultra-low carbon steel, low carbon steel and micro-alloyed steel are involved . The result shows that the basic flux with CaO/SiO₂ to be 3~5 can help to control the SiO₂ be reduced by Al in steel within ±2%, and whole cleaness keeps stable with suitable component and proper process condition, marked with the T[O] content change ranged within 3ppm. But the basicity should be variable considering the productivity for different steel grade.

Abstract: Cutting temperature is a key factor in impacting the solid carbide end mill’s life, the rule of solid carbide end mill temperature field is the research focus. In this paper, the solid carbide end mill helical side edge is regarded as a helical coil heat source, the tool chip friction surface is considered as a surface heat source which consists of countless helical coil heat source. Based on heat source method, the model of continuous dynamic temperature field simulation of a solid carbide end mills cutting process is established.