Advanced Materials Research Vols. 912-914

Abstract: After studying the influencing factors and interaction rules of the damage for reinforced carbon fiber in different jet medium on the basis of analyzing carbon fiber damage for traditional acupuncture process, a lower damage process scheme of preform based on jet for layered carbon fiber composite is proposed in this paper. Firstly, the carbon fiber puncture damage is clustered and formal described by using graph theory, which the analytical method for a complex combination of puncture damage is obtained successfully. Then the stress and strain distribution of carbon fiber puncture damage is analyzed through simulation. So this paper has proposed a new technical approach for improving the quality of the needle perform.

Abstract: The desired compression-shear loading were applied by the beveled ends with different angles, and this new technique based on split Hopkinson pressure bar can be used to investigate the dynamic response of materials. A series of experiments of NiTi shape memory alloy were performed at different impact velocities and different loading angles, and the dynamic equivalent pressure curves were given. The initial phase transition points under different impact velocities were plotted on σ-τ stresss space, and the phase transition surfaces predicted by a dynamic phase transition criterion were given.

Abstract: This article firstly introduces the ultrasonic TOFD (Time-of-flight - Diffraction) detection technology of detection principle, advantages and disadvantages, and then summarizes the ultrasonic TOFD technique related testing standard, finally combining the reality of tube mill, analyses the pipe material testing near the surface of the blind area and radian impact problems, discusses the ultrasonic TOFD in application prospect in the field of thick wall tube welding seam detection.

Abstract: LiNi_0.4Co_0.2Mn_0.4O₂, as the cathode materials for lithium ion battery, were prepared from the precursors, Ni_0.4Co_0.2Mn_0.4 (OH)₂ which were synthesized by chemical co-precipitation method. The crystal structure and morphology of the prepared powders have been characterized by X-ray diffraction and SEM, respectively. The results show that Li⁺/Ni²⁺ cation mixing decreases with increase of calcination temperature in the range of 700-900°C.The lower degree of cation mixing can improve the transfer of Li ions and lead to layered structure more stable. The discharge capacity and the capacity retention rate of the material is strongly impacted by the reaction temperature.The powders sintered at 900°C show the best electrochemical performance and the initial discharge capacity is 148.3mA·h/g, after 40 cycles, the capacity retention rate is 93.9%.

Abstract: The influence of high temperature stays process on the directly cooling experimental ULCB steel had been investigated. We found that the process of high temperature stays had effect on the ULCB steels phase transformation point, and made the CCT curve move to top left. When the cooling rate increased, the formation and growth of granular bainite would be inhibited, but the formation and growth of bunchy bainite would be promoted. And the high temperature stays process had a weaker effect on the specimens structure when specimens were cooled slowly. Key Words: high temperature stays; cooling rate; bunchy bainite; granular bainite

Abstract: The low-energy impact experimental research and monitoring the response of composites structure at different impact positions was conducted by embedding fiber bragg grating strain sensor into composite laminates. Simulation work on the experimental models was conducted and compared to the results of the experiment. According to the Hashin failure criteria, a suitable calculation model was established to investigate the action of the laminates under high energy impact load. The spreading of the fiber damage areas could be observed in the structure until the macroscopic cracks appear. It was indicated that a proper model can be used to simulate the damage evolution and failure behavior of composites structure under the impact load.

Abstract: nanozerovalent iron particles coated with biopolymer nanoskin were prepared by liquid phase method. For a period of time, the remaining xanthan layer can prevent oxidation of nanoiron in air. The goal of this study is to demonstrate that magnetic properties of magnetic fluid which suspend nanoiron particles coated with xanthan in xanthan/guar fluid. Magnetic hysteresis loops were measured at room temperatures and field-cooled / zero-field-cooled magnetization curves were obtained at low temperature by a vibrating sample magnetometer. The results interpret that biopolymer nanoskin did not strongly weaken the magnetic interaction between nanoiron particles.

Abstract: In recent years, acoustic emission (AE) testing technology is the one of the most important non-destructive testing (NDT) methods. The characteristics can be described by AE signals, including the location, nature and severity. In order to obtain the basic data for monitoring the wind turbine blade composite structure, the experiment adopted Φ0.5 mm lead pencil as artificial acoustic emission source and measured AE parameters, attenuation and source location of resin matrix for wind turbine blade. This paper introduced linear location and two-dimensional positioning technology of time arrival location method about the burst AE signal. The result shows that the location of AE source basically reflects the location of stimulation AE source, the location of AE source for resin matrix can agree well with the simulated location of AE source, the more close to the middle area, the more accurate location.

Abstract: Potassium zinc hexacyanoferrate (KZnFc) was synthesized, and the adsorption amount at equilibrium and adsorption rate of uptake of cesium (I) on KZnFc from several aqueous solutions was investigated comprehensively by varying the initial cesium concentration and temperature. The rate of uptake of cesium was analyzed using pseudo-first-order and pseudo-second-order kinetic models. This study will be helpful for understanding the adsorption mechanisms of cesium ion, and KZnFc could be used as potential adsorbent for adsorbing Cs (I) from oil field water of Nanyishan.