Applied Mechanics and Materials Vols. 365-366

Abstract: The existence of the electromagnetic radiation may lead to diseases, which also includes cancer and cause the repellence of electrical compatibility. The textiles which have electromagnetic shielding effectiveness become more important in modern life. In the research, the PET/ Ni-coated Copper composite yarn were made by the wrapping machine, which the core yarn is Ni-coated Copper wire and the wrapped yarn is PET filament. After that, the composite yarn is fabricated by the automatic sampling loom into woven fabrics and had the tests of mechanical properties and electromagnetic shielding effectiveness. The test results revealed that the EMSE of the PET/Ni-Cu complex woven fabrics is 32.28dB, which the test frequency is 900 MHz, laminated layer number is 3 and the laminated angles are 0°/45°/90°, respectively.

Abstract: Hemostasis is the critical steps for trauma and emergency. When injured person is under circumstance of hemorrhage, the important step is immediate hemostasis because mild hemorrhage makes patient feeling pain and dizziness while abundant hemorrhage would lead to coma, shock even death. Therefore, hemostasis becomes an important rescue issue to bleeding patient. This study uses Polylactic acid (PLA) and Polyacrylate (HPA) to prepare PLA/HPA nonwoven fabric with different weight ratios of 100/0,95/5,90/10, 85/15, 80/20 wt%/wt%, following with discussions of tensile strength, tearing strength, softness, air permeability, water vapor transmittance, water absorption, water retention. The results show that, 80 wt%/20 wt% of PLA fiber and HPA fiber was the optimal blending ratio, and its water absorption, water retention and softness were respectively improved by 323 %, 245 % and 22.3 % by contrast with 100 wt%/0 wt% of PLA and HPA; but its tensile strength was decreased by 63 % even that still reaches the strength of absorbent cotton.

Abstract: This paper presents an analytical approach to predict the machining force, temperature and residual stress under minimum quantity lubrication (MQL) condition. Both the lubrication and cooling effects are considered to change the tribological and thermal properties in the modified Oxleys model, which is capable to predict the cutting force and temperature in MQL machining directly from cutting conditions. The machining-induced residual stress is predicted by modified McDowell hybrid algorithm. The predicted cutting forces and residual stresses are verified by orthogonal cutting tests for C45 steel and TC4 alloy steel.

Abstract: Depending on the experimental data of Water-based lubricant viscosity-temperature relationship, this paper adopts Fluent software to analyze how lubricant viscosity-temperature relationship affects load-carrying properties of hybrid sliding bearings. The results show that lubricants will rise obviously when hybrid sliding bearings are in high speed, which will greatly affect bearing capacity and stiffness of bearings. The maximum stiffness of hybrid sliding bearings appears when the eccentricity is from 0.4 to 0.5. This conclusion is dramatically different from bearing capacity number ignored lubricant viscosity-temperature relationship.

Abstract: In this study, the Erichsen test is used to identify the friction coefficient of the Coulomb friction model coupling experimental tests results with numerical ones. The evaluation of the Coulomb friction coefficient is based on the distance measured between the thinnest area of the specimen and the lateral surface of the blankholder. Two types of aluminium alloys, AA 2017 Al-Cu alloy and AA 5083 Al-Mg alloy, with thickness of 1.0 mm are selected as the experimental materials for Erichsen test. Specimens are tested in unlubricated condition as well as using two different lubricants, namely Grease LB4 and Mexmoly.

Abstract: According to the working condition of the finger seal, a geometric model applied to optimization of finger seal with arc curve (arc finger seal) is established based on mathematical relationship analysis of the finger seal structural parameters. Two performances, the hysteresis and contact pressure between finger pad and rotors surface, are put forward as the objectives for the structure optimization of the finger seal. The optimization model of C/C composites arc finger seal is presented and the multi-objective optimization process is carried out based on ANSYS software. An optimization design example is given which shows that comprehensive performance of finger seal can be obviously improved through the structure optimization. The performance comparison between a C/C composites and a metal material arc finger seal with the same structural and working conditions proves that the choice of C/C composites as the finger seal material, to a certain extent, may improve the sealing performance effectively. It provides a new choice for the design of the finger seal.

Abstract: La_0.7Mg_0.3(Ni_1-xCo_x)_3.5 (x=0.0-0.2) type hydrogen storage alloy was prepared. In order to optimizing the content of Co it was studied effects that Co replaced Ni on the structure and electrochemical properties of La_0.7Mg_0.3(Ni_1-xCo_x)_3.5(x=0.0-0.2) type hydrogen storage alloy X-ray diffraction (XRD) analyses showed that the alloys were composed of the LaNi5 phase with the CaCu5-type structure and the (La,Mg)₂Ni₇ phase with the Ce₂Ni₇-type structure. The maximum electrochemical discharge capacity increases with the increase of Co content. Moreover, the cycle stabilities of La_0.7Mg_0.3(Ni_1-xCo_x)_3.5 was improved remarkably by small quantity replacement Ni by Co, after 250 times, the discharge capacity was increased from 30% (x=0.0) to 65% (x=0.20).

Abstract: In order to reduce the effect of springback on the performance of stamping welded hydrodynamic torque converter in the blade manufacturing process, we carried on the numerical computation of stamping forming and springback on the pump blade of torque converter , which is based on the sheet metal forming finite element theory. Analysis of the influence factors on springback for the pump blade of torque converter includes the different die speed, die clearance, friction coefficient and sheet thickness, by which we obtained main rule effect springback of torque converter blades. This work provides an reliable basis for blades springback compensation design which can improve the forming accuracy of torque converter blades.

Abstract: Timoshenko beam model and the meshless method based on thin-plate spline radial basis function are used to analyze the free vibration of carbon nanotubes. The natural frequencies of the carbon nanotubes with different length-to-diameter ratios and boudary conditions are compared with the results of published literatures which demonstrate the high accuracy of present method.

Abstract: The cross-section area of straight fin is often considered to be equal in the thermal analyses of straight fin, but sometimes it is unequalin actual situation. Taking a straight fin with two unequal cross-sectional areas as an example,an analytical method of heat conduction for unequal section straight fin is presented. The analytical expressions of temperature field and heat dissipating capacity about the fin,which has a smaller cross-section area near the fin base and a larger one, is obtained respectively. The calculation results of the unequal cross-section are fully consistent with the equal area one, so the method is proved right. The results show that the larger the cross section areanear the base,the better is the heat transfer, and the temperature at the base with larger cross-section area is lower than that with smaller cross-section area when the amount of heat is fixed.