Authors: You Feng Zhang, Qing Chang Meng, De Chang Jia, Yu Zhou
Abstract: The Al2O3/LiTaO3 (ALT) composite ceramics were fabricated by hot pressing method
and polarization treated at different temperatures along height and width directions. Effects of
polarization treatment on mechanical properties of the ALT composite ceramic were investigated.
Flexural strength decreased with the increase of polarization temperature. Meanwhile, the flexural
strength of samples polarized in height direction is higher than that polarized in width direction. The
composite ceramic fractures intragranularly, and many rupture steps in polarization direction were
observed on fractographs of the composite ceramics. Domain switching in LiTaO3 particles
increased the resistance of crack propagation and improved the mechanical properties of the
polarized ALT composite ceramics.
1314
Authors: Xiao Wei Liu, Rong Yan Chuai, You Feng Zhang, Q.F. Tao
Abstract: The paper presents a micro-fluidics cooling system which is designed on a silicon substrate
including a micro-pump, two temperature sensors, a flow sensor and some microchannels. To design
the cooling system optimally, a finite element model is built. The temperature distribution on the
silicon substrate is analyzed using the model. Moreover, the quantitative relation is given of the
temperature distribution, flow velocity and driving capability of the micro pump. Consequently, the
structure parameters and design requirements of the cooling system are obtained.
490
Authors: You Feng Zhang, Yu Zhou, De Chang Jia, Qing Chang Meng
Abstract: Effects of different sintering methods such as pressureless sintering and hot press sintering on
relative density and microstructure of the Al2O3p/LiTaO3 (ALT) composite ceramics were investigated to
obtain a preferable sintering process. Relative densities of all ALT composites are below 90% when
sintered with the cold isostatical pressing followed by pressureless sintering at temperatures of 1250 to
1350°C. The relative densities and microstructure of ALT composite ceramics with the hot press sintering
process in a N2 atmosphere at 1150 and 1300°C were investigated. The relative density of ALT composite
hot pressed at 1150°C is only 77%, and almost theoretical density at 1300°C. This indicates that sintering
pressure plays an important role in the densification of ALT composite ceramics in temperature range of
1150 to 1350°C. Investigation on morphologies of the composites shows that the Al2O3 particles
distributed along grain boundaries of LiTaO3, which leads to a fine-grained microstructure in the ALT
composite ceramics
2363
Authors: Li Xing Huo, Min Liu, You Feng Zhang, Fang Juan Qi
Abstract: To increase the accuracy of R-F method, it is necessary to solve the problems of the linear expansion of failure function and non-normal variables. In this paper, the improved FOSM method was applied to calculate the failure probability of welded pipes with cracks. The examples show that this method is simple, efficient and accurate for reliability safety assessment of welded pipes with cracks. It can save more time than the Monte Carlo method does, so that the improved FOSM method is recommended for general engineering reliability safety assessment of welded pipes with cracks.
561
Authors: Fang Juan Qi, Li Xing Huo, You Feng Zhang, Hong Yang Jing
Abstract: Butt-fusion welding is the main technology to join high-density polyethylene (HDPE) plastic pipes, which are widely used in transport the water, gas and corrosive liquid. Investigation shows that one of the failure modes of HDPE pipe is the crack slowly grows across the thick direction and leads to failure at last, so that it is very important to study the resistance to crack initiation of HDPE pipe and its butt-fusion welded joint. In this study, the elastic-plastic fracture mechanics parameter, crack opening displacement (COD) is used to describe the fracture initiation behaviors for the HDPE materials and its butt-fusion welded joints. The resistance to initiation fracture of HDPE pipe materials and butt-fusion welded joints were investigated at different temperature by using multiple specimen resistance curve method and silicon-rubber replica method. The results show that saturation initial crack COD- δis of HDPE pipe materials and butt-fusion welded joints decreases with the decreasing temperature. The δis of butt-fusion welded joints is lower than that of HDPE pipe materials. Investigation also proved that the silicon-rubber replica method is more suitable for HDPE engineering material than the multiple specimen method. At the same time the statistic distribution of the δis of HDPE butt-fusion welded joint was conducted. The results show that the value of the δis has the statistic variance inherently. The optimum fitting distribution of COD is Weibull distribution with three parameters.
153
Authors: Yu Long Zhang, Xue Jun Jin, T.Y. Hsu, You Feng Zhang, Jian Lin Shi
573
Authors: Li Xing Huo, Buolin He, You Feng Zhang
613
Authors: Li Xing Huo, Y.I. Liu, You Feng Zhang, Hong Yang Jing
1327
Authors: Li Xing Huo, Dongpo Wang, You Feng Zhang, Jun Mei Chen
1315
Authors: Jing Kun Guo, Jian Lin Shi, You Feng Zhang, Ying Shi, Zhen-Yan Deng
559