Chen D.,Shanghai JiaoTong University |
Chu X.,Shanghai JiaoTong University |
Sun X.,Shanghai Aerospace Equipments Manufacturer |
Li Y.,China University of Mining and Technology |
Su Y.,Shanghai JiaoTong University
Information Sciences | Year: 2015
This paper aims to develop a decision making approach based on the Information Axiom under hybrid uncertain environments. In these environments fuzziness and randomness co-exist. To model the hybrid uncertainties, the design range and system range of an evaluation criterion are expressed as a fuzzy variable and a random variable respectively. Calculating the Information Contents for these criteria would involve integrals whose bounds are fuzzy variables. To calculate these integrals, an expected Information Content Model (eICM) is proposed based upon the credibility theory. To reflect the designer's risk appetite accurately, the confidence levels are introduced and a credibility Information Content Model (cICM) based on the chance constrains programming model is constructed. Two algorithms based on fuzzy simulation methods and Genetic Algorithm are developed for these two models. Finally, a case study is illustrated to highlight the effectiveness and accuracy of the proposed approach. © 2015 Elsevier Inc. All rights reserved.
Mai C.,Harbin Institute of Technology |
Li M.,Harbin Institute of Technology |
Yang S.,Shanghai Aerospace Equipments Manufacturer
RSC Advances | Year: 2015
Silica glass pairs were directly bonded by wet chemical surface activation at a low temperature. A smooth joint interface with no voids and micro cracks was obtained with the assistance of a 250 °C heat treatment and a pressure of ∼30 MPa, and the excellent transmittance of the bonded pair was demonstrated by UV-Vis absorptions. This new method can tolerate a silica glass surface roughness as high as 6 nm. A demo chip with a microfluidic channel was also prepared by this method. A modified model for the glass-to-glass bonding mechanism is proposed based on the surface and interface characterization. Raman scattering analysis showed that Si-O-Si linkages at the silica glass surface were broken, and colloid-like hydrolyzed layers formed on the glass surface after the activation treatment. TEM and EELS results revealed that the 3D glass structure of the Si-O-Si linkages formed again at the interface of the directly bonded silica glass pairs after lowerature annealing. © The Royal Society of Chemistry 2015.
Liu C.,Jiangsu University of Science and Technology |
Yi X.,Shanghai Aerospace Equipments Manufacturer
Materials and Design | Year: 2013
Residual stress is a crucial factor when assessing the integrity of engineering components and welded assemblies. The internal longitudinal stresses in 4. mm and 8. mm thick AA6061-T6 aluminum alloy friction stir welding (FSW) specimens are measured with contour method. The measuring procedure of the contour method including specimen cutting under clamps with a wire electric discharge machine, precise contour measurement with a coordinate measuring machine, careful data processing and elastic finite element analysis are introduced in detail. Finally, the longitudinal residual stresses throughout the cut plane for the two joints are mapped, and the through-thickness longitudinal stresses of the two FSW joints are also analyzed. Investigated results show that the contour method can be applied to measure the internal residual stress in thin plates with a thickness of 4. mm; the longitudinal stress distribution in the present study is not an apparent M-shaped distribution in the transverse direction; within the weld region, the tensile longitudinal stress in the advancing side is larger than that in the retreating side; the longitudinal stresses are not uniform across the thickness of specimens; the peak tensile longitudinal stresses for both joints reach 168. MPa (amount to 61% of the yield strength of AA6061-T6 alloy at room temperature), and appear at a depth of 62.5% thickness at the edge of the tool shoulder in the advancing side of the weld. © 2012 Elsevier Ltd.
Xu W.F.,Northwestern Polytechnical University |
Liu J.H.,Northwestern Polytechnical University |
Chen D.L.,Ryerson University |
Luan G.H.,China Center Beijing Technology Co. |
Yao J.S.,Shanghai Aerospace Equipments Manufacturer
Scripta Materialia | Year: 2012
The microstructure and cyclic deformation behavior of three slices of a thick plate of friction-stir-welded Al-Cu alloy were investigated. Friction stir welding resulted in a composite-like nugget zone consisting of fine particles uniformly dispersed in the recrystallized fine-grained matrix. The top slice had larger grains, smaller particles, higher hardness, stronger cyclic hardening, higher hysteresis energy and lower fatigue life than the bottom slice. Fatigue cracks initiated from near-surface particles in the low-hardness zone, and propagated via striation formation mechanisms along with particle cracking. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Li S.,Beijing University of Chemical Technology |
Zuo Y.,Beijing University of Chemical Technology |
Ju P.,Shanghai Aerospace Equipments Manufacturer
Applied Surface Science | Year: 2015
Abstract A Co-Pd film was deposited on 316L stainless steel by electroplating. The erosion-corrosion behavior of the Co-Pd plated samples in hot sulfuric acid solution with SiO2 particles was investigated. The results showed that there was a significant synergistic effect between erosion and corrosion. At higher stirring speed, even in such strong corrosive environment the erosion-corrosion rate of Co-Pd plated samples was controlled mainly by the erosion resistance. The erosion-corrosion resistance of pure Pd plated sample decreased rapidly with increasing stirring speed, whereas that of Co-Pd plated sample kept almost stable under the tested conditions due to the high micro-hardness and good corrosion resistance of the film. © 2015 Elsevier B.V. All rights reserved.