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Design and Researches on a Special Drillbit of Drilling Carbon Fiber Reinforced Plastics Bijin Wu 1, a, Guohong Yan 2, b, Yousheng Li 2, c, Zongming Huang2, d, Xiaofan Yang1, e 1College of Mechanical and Energy Engineering, Jimei university.
Many studies show that the drilling thrust force is the main cause of drilling defect, and the cutting parameters and the materials and shapes of drillbit are the main factors affecting on the thrust force [5, 6, and 7].
However, the chisel edge effect on the thrust force will be affected by the rotational speed of the spindle.
These properties will not only extend the cutting life but also improve the drilling quality.
Third, the diamond coating materials can still normal cutting at high temperature because its high hardness, wear resistance, stable chemical properties and low coefficient of friction, so the cutting edge is durable.

The mass production and usage of the Mg alloys, however, are still very limited because of its principle property; lack of ductility.
During thermomechanical processing, control of microstructure evolved by dynamic recrytsllization (DRX) is one of the most important factors to improve the ductility of Mg alloys.
The occurrence of DRX affects much on the uniform deformability of metallic materials.
After mechanical and electrolytic polishing, they were tensile tested at temperatures between 373 K and 673 K at an initial strain rate of 4.2 x 10 -4 s -1 with an Instron-type mechanical testing machine.
For a crystallographic analysis of crystal rotation and the DRX behavior of the deformed samples, orientation-imaging microscopy (OIM (Hitachi S-3500/TexSEM Inc.)) was employed after mechanical and electrolytic polishing.

Generally, the desired service life of many aircraft structures beyond twenty years, for these applications, residual stress relaxation in room temperature become a significant factor in limiting the beneficial effects of cold expansion.
Material properties Specimens were made from aluminium alloy 7050-T7451.
Fig.13 Tangential creep strain at hole edge Fig.14 Residual circumferential stress at hole edge relaxation for 20 years According to the results presented in Fig.11~14, it can be indicate that the initial value of residual stress has affected the creep rate predominantly, on the other hand, the residual stress relaxation was primarily due to creep.
References [1] SUN Xuan, WANG Min, XU HongChang: Mechanical Manufacture.
(In Chinese) [2] YANG HongYuan, LIU WenTing: Journal of Mechanical Strength.

Fabrication of Ultrasound-Gravity field flow fractionation devices using engraving machine and reliable sealing method Hai-yan Yin 1,2,a, Chun-cheng Zuo 1,b, Hong-yan Shi1,c 1.College of Mechanical Science and Engineering, Jilin University, Changchun 130025, China 2.
Among them, PMMA is the one of the most applications because of its low cost, stable mechanical properties, good optical transparency, easy fabrication and non-toxic characteristics.
Compared to the conventional bonding methods, this method can increase the effective bonding area, reduce channel deformation. 2 The principle of separation of the particles in the Ultrasound - gravitational field In the ultrasonic standing wave field, the micro nano-particles are mainly affected by two forces in the vertical direction of flow of the carrier medium, the acoustic field radiation force Fac and settlement force Fsed, compared with these two forces, other forces can be negligible.
First of all, set pressure at 1.5MPa and time at 15min, selected temperature at 70, 80, 90, 100, 110 ° C for single-factor experiments.
In order to ensure the structural integrity of the polymer substrate, we proposed a low-pressure sealing technology and selected pressure at 0.8, 1.0, 1.5, 2.0, 2.5 Mpa separately to conduct a single factor experiment.

Diamond is considered a very attractive material for thermal spreading because it exhibits the highest thermal conductivity (20W/cmK), tolerance of high temperatures, chemical and mechanical stability [2].
The highly rough surface of the MCD films is the main limiting factor in the use of diamond films on most electronic, optical and especially thermal applications.
However, because of extreme hardness of diamond the mechanical polishing is a difficult and time-consuming procedure [3-4].
However, the grain sizes of the order of nanons which leads to high density of grain boundary greatly affect the thermal efficiency of NCD films [6-7].
Effect of activated hydrogen etching on surface roughness and optical properties of diamond films [J].

Lim 2,c,* 1 Institute of Industrial Science, The University of Tokyo, Komaba, Meguro, Tokyo, 153-8505, Japan 2 School of Mechanical Engineering Sungkyunkwan University, 300, Chonchon-dong, Jangan-gu, Suwon, Kyonggi-do, 440-746, Korea a agassi12@hotmail.com, bkultra@skku.edu, cbslim@skku.edu *Corresponding author.
properties of a structure according to the different loading type and presence of a crack.
Also, the heat affected zone(HAZ) of P92 weldment and base metal were used for creep-fatigue tests.
Fig.2 shows creep crack length vs. time according to temperature change at the initial stress intensity factor of 25.5MPa√m.
The crack growth and void characteristics were measured according to the change of temperature and the initial stress intensity factor.

Gao Department of Mechanical Engineering, Zhejiang University of Technology Hangzhou, 310014, China Keywords: Photosensitive resin, SiO2 particles, Fractal distribution, Dicing blade Abstract.
Researchers have the common idea, on high molecular polymer material, that adding rigid inorganic particles can improve mechanical properties of polymer material [5-6].
Furthermore, the tensile strength of thin dicing blades is significantly affected by two factors, i.e. the quantity of SiO2 particles and their spatial distribution in the photosensitive resin.

Gearbox installation at altitude, within the narrow space top gear under the heavy load between super-normal speed, once appear fault, its maintenance and maintenance costs also is very difficult, so its demand of high reliability and service life is higher than general mechanical equipment requirements[2].
Gearbox Heat Analysis Fan impeller turns will pass kinetic energy through motor spindle to the gearbox, gear box gears, axis and bearing and produce driving friction heat, the faster the place generation more heat, so the quantity of heat of the gearbox temperature is imbalance, its steady heat transfer, the process has many factors.
Gear modelling accuracy will directly affect the accuracy of the finite element analysis results.
Definition gear surface for the load area, and the load type is Distribute Flux, value for heart for every square metre 2500 tile, convection and radiation environment temperature setting for 20 degrees Celsius, the definition chhilun material properties including convection and radiation characteristics, define the higher quality of the wide grid, get more accurate results of calculation, but also will greatly increase calculation time, so when the grid in points through the number of the control unit to obtain appropriate grid quality.
Gear box gears, bearings friction heat cause gear and bearing temperature trends, increased temperature cause thermal stress concentration, mechanical parts in heavy load, so the performance degradation under deformation will happen, even parts failure.

Introduction High-power marine gearbox is one of the important equipments for marine engine systems, its load condition is also relatively complex and often subject to large torques, bending moments, and even accompanied by the effect of the impact forces, there may result in certain aspects of the system to malfunction or damage, and even affects the whole transmission system running [1,2].
Table 1 The material properties of the circular saw Name Density(ρ/Kg·m-3) Poisson ratio(µ) Elastic modulus(E/*105Mpa) HT250 7150 0.26 1.40 Fig. 3 The radial force distribution Fig. 4 FEM modal for the gearbox case Results of the modal calculation.
The topology optimization is a structural design method through the finite element analysis and optimization method solves constraints within a given region of the design space[5,6].The SIMP method introduces a hypothetical relative density variable between 0 and 1, and assuming the macroscopic elastic constants of the material and its density is non-linear relations, using penalty factor constraint inhibition ranged between 0 and 1 units.
Tan: Manual of Mechanical Vibration, China Machine Press, China, (2000)
Chen: China Mechanical Engineering, 2004, 15(21): 1886~1890.

Introduction Owing to its excellent mechanical properties, FRP has been widely used in such fields as aviation, aerospace and automobile.
Its static strength accords with the Rayleigh distribution[6] (Figure 3), and the probability density function and the distribution function are respectively: ; (7) Fig.2 The growth of fiber breakage rate Fig.3 The distribution function of fiber static strength For the actual single ply, because of such influencing factors as the uneven laid fibers and remaining thermal stress, the fiber strength is far from the ideal condition shown in Figure 3(a).
Fiber Breakage in the Laminate Since the elasticity modulus of the fiber is far larger than that of the matrix under the tensile load of the single ply, it can be assumed that the matrix crack doesn’t affect the longitudinal stiffness of the single ply, but for the laminate with off-axis layers, the matrix crack produced by the off-axis layers will result in obvious drop in the stiffness of the laminate.
Meso-Mechanical Ana lys is of Stif fness Reduction of FRP Laminates by F ibre Breaking.