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A TWO-LEVEL GENETIC ALGORITHM FOR SCHEdULING IN ASSEMBLY ISLANdS WITH FIXEd-POSITION LAYOUTS

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Journal of Systems Science and Systems Engineering 2010年第2期19卷 150-161页

作者： George q.huang department of Industrial and Manufacturing Systems Engineering The University of Hong Kong

This paper focuses on the scheduling problem in assembly islands environment with fixed-position layouts. In such configuration, the product normally remains in one location for its entire manufacturing period while machines, materials and workers are moved to an assembly site called an assembly island. This production layout has some unique features such as moving assembly workers, tools and materials; limited space at assembly site; considerable distance between islands. The authors first give the definition and mathematical model for the scheduling problem and then propose a two-level genetic algorithm to obtain a near optimal solution to minimize the makespan. Experimental results show that this algorithm is effective. The performance analysis of the proposed algorithm indicates that it is more efficient in the airline or shipbuilding industry than in the machine or tool final assembly companies.

关键词： Assembly islands scheduling genetic algorithm

THE FULLY PLASTIC J-INTEGRAL OF CORNER CRACKS AT A HOLE IN A PLATE

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Acta Mechanica Solida Sinica 1997年第2期10卷 131-137页

作者： Gao, q huang, ZZ SW JIATONG UNIV INST APPL MECHCHENGDU 610031PEOPLES R CHINA

The line-spring model of surface cracks is applied to the fully plastic analysis of corner cracks at a hole in a plate. The generalized fully plastic constitutive relations and the fully plastic J-integral, as well as its coefficients in polynomial expressions are given. The model obtained is incorporated into a finite element program. The corner cracks at a hole in a plate subjected pure tensions are calculated by the present model. The fully plastic J-integral is then estimated. The results obtained show that the line-spring model is effective for the analysis of corner cracks. The influence of the crack depth and the hardening exponent on the fully plastic J-integral is also discussed.

关键词： corner crack line-spring model fully plastic J-integral

dynamic Analysis and Numerical Simulation of a Kind of Arrestor Arresting Buckle Propagation by FEM

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China Ocean Engineering 1998年第3期13卷 323-332页

作者： huang, YY qian, q Jin, T Huazhong Univ Sci & Technol Dept Mech Wuhan 430074 Peoples R China

For exact estimation of efficiency of a buckle arrestor, it is necessary to take the effect of structural inertia into account in the analysis of buckle propagation on elastic structures after meeting arrestors. Under this consideration, this paper deals with the dynamics of buckle arrest and its numerical simulation on the basis of the beam system model used by Chater and Hutchinson (1983). The FEM combined with an improving are-length control method is adopted to solve the dynamic equations describing the arresting of buckle propagation. A new group of parameters for arrestor design which differs greatly from that by the quasi-static analysis is obtained. The present results support the conclusion that the inertia of the beam cannot be neglected in such analysis.

关键词： buckle propagation arrestor beam nonlinear foundation finite element method

SCALING PROPERTIES OF INTERFACES IN CRYSTALS UNdER NONEqUILIBRIUM CONdITIONS

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Acta Metallurgica Sinica(English Letters) 1997年第5期10卷 415-418页

作者： Shi, d.W. huang, J.Y. Long, q.W. Inst of Metal Research Chinese Acad of Sciences Shenyang China

An equation of Langevin type was proposed to describe the interface evolution in crystals under nonequilibrium conditions (such as in Cu-Fe or Cu-Co system upon ball milling). The scaling properties (H) of this equation is in good agreement with the Monte Carlo simulations described by Bellon and Averback. In this equation the volume diffusion and interface diffusion are all important and this is consistent with some experimental results.

关键词： Ball milling Binary alloys Crystals Mathematical models Nanostructured materials Surface roughness

On the texture evolution of Mg-Zn-Ca alloy with different hot rolling paths

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Journal of Magnesium and Alloys 2017年第2期5卷 166-172页

作者： q.Li G.J.huang X.d.huang S.W.Pan C.L.Tan q.Liu College of Materials Science and Engineering Chongqing UniversityChongqing 400044China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China

In the present study,the texture evolution and mechanical anisotropy in a typical Mg–Zn–Ca alloy through hot cross rolling(CR)and unidirectional rolling(UR)were systematically *** results show that the rolling path greatly affects the annealed *** UR develops a texture with basal poles mainly distributing along the transverse direction(Td).By contrast,an ellipse-like(0002)texture with basal pole inclining largely away from the normal direction(Nd)is developed after hot cross rolling and ***,the CR is an effective method to tailor the texture of the experimental ***,this ellipse-like texture could not reserve during the subsequent unidirectional hot rolling and *** UR and CR plates exhibit a strong planar mechanical anisotropy compared with the traditional unidirectional rolled plate.

关键词： Mg alloys Hot cross rolling Texture Mechanical anisotropy

Microstructure evolution and mechanical properties at high temperature of selective laser melted AlSi10Mg

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Journal of Materials Science & Technology 2021年第3期62卷 162-172页

作者： Y.Cao X.Lin q.Z.Wang S.q.Shi L.Ma N.Kang W.d.huang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Key Laboratory of Metal High Performance Additive Manufacturing and Innovative design MIIT ChinaNorthwestern Polytechnical UniversityXi’an 710072China

In this study,the microstructure and tensile properties of selective laser melted AlSilOMg at elevated temperature were investigated with focus on the interfacial ***-situ SEM and in-situ EBSd analysis were proposed to characterize the microstructural evolution with *** as-fabricated AlSilOMg sample presents high tensile strength with the ultimate tensile strength(UTS)of~450 MPa and yield strength(YS)of~300 MPa,which results from the mixed strengthening mechanism among grain boundary,solid solution,dislocation and Orowan looping *** holding at the temperature below 200℃for 30 min,the micro structure presents little change,and only a slight decrement of yield strength appears due to the relief of the residual ***,when the holding temperature further increases to 300℃and 400℃,the coarsening and precipitation of Si particles inα-Al matrix occur obviously,which leads to an obvious decrease of solid solution *** the same time,matrix softening and the weakness of dislocation strengthening also play important *** the holding temperature reaches to 400℃,the yield strength decreases significantly to about 25 MPa which is very similar to the as-cast Al *** might be concluded that the YS is dominated by the matrix *** the softening mechanism counteracts work hardening,the extremely high elongation occurs.

关键词： Selective laser melting AlSi10Mg Microstructure In-situ EBSd High temperature tensile property

A TIME dOMAIN BOUNdARY ELEMENT METHOd FOR WATER-SOLId IMPACT ANALYSIS

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Acta Mechanica Solida Sinica 1995年第4期8卷 337-348页

作者： huang, YY Yue, dY qian, q HUAZHONG UNIV SCI & TECHNOL DEPT MECHWUHAN 430074PEOPLES R CHINA

A reciprocal theorem of dynamics for potential flow problems is first derived by means of the Laplace transform in which the compressibility of water is taken into account. Based on this theorem, the corresponding time-space boundary integral equation: is obtained. Then, a set of time domain boundary element equations with recurrence form is immediately formulated through discretization in both time and boundary. After having carried out the numerical calculation two solutions are found in which a rigid semicircular cylinder and a rigid wedge with infinite length suffer normal impact on the surface of a half-space fluid. The results show that the present method is more efficient than the previous ones.

关键词： fluid-structure impact potential flow problem time domain boundary element method interaction between fluid and structure

High strength Al-Cu-Mg based alloy with synchronous improved tensile properties and hot-cracking resistance suitable for laser powder b e d fusion

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Journal of Materials Science & Technology 2023年第10期141卷 155-170页

作者： q.Z.Wang N.Kang X.Lin M.EL Mansori W.d.huang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Arts et Metiers Institute of Technology MSMPHESAM UniversitéChâlons-en-Champagne F-51006France Key Laboratory of Metal High Performance Additive Manufacturing and Innovative design MIIT ChinaNorthwestern Polytechnical UniversityXi’an 710072China Texas A&M Engineering Experiment Station Institute for Manufacturing SystemsCollege StationTX 77843USA

In present work,a novel crack-free Al-Cu-Mg-Si-Ti alloy with synchronous improved tensile properties and hot-cracking resistance was proposed and successfully manufactured by laser powder bed fusion(LPBF).The microstructure evolution behaviors and the corresponding strengthening mechanisms were investigated in *** LPBF-processed Al-Cu-Mg-Si-Ti alloy presents a heterogeneous microstructure consisting of ultrafine equiaxed grains(UFGs)at the boundary and coarse columnar grains(CGs)at the center of the single molten ***-precipitated d022-Al 3 Ti particles were found to act as the nuclei to refine the grains at the boundary of the molten pool during solidification process,which is attributed to the low cooling rate providing the sufficient incubation time for the precipitation of d022-Al 3 *** are two orientation relationships(ORs)betweenα-Al and d022-Al 3 Ti,i.e.[001]α-Al//[001]d022-Al3Ti,(200)α-Al//(200)d022-Al3Ti and[1¯1¯2]α-Al//[¯111]d022-Al3Ti,(1¯11)α-Al//(¯11¯2)d022-Al3Ti,which are two of the eight ORs predicted with the E2EM *** grains in present alloy,no matter for UFGs or CG,exhibited high critical hot-cracking stress,which means a strong hot-cracking ***-nanoprecipitation of Cu-,Mg-,and Si-rich q’and S’phases was introduced to enhance the mechanical performance ofα-Al *** as-built sample exhibits superior tensile properties,with the yield strength(YS)of 473±8 MPa,ultimate tensile strength(UTS)of 541±2 MPa and elongation(EI)of 10.9%±1.2%.

关键词： Laser powder bed fusion High strength Al-Cu-Mg alloys duplex microstructure Precipitation Tensile properties

A STUdY ON AGING TREATMENTS FOR ALLOY 2195

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Acta Metallurgica Sinica(English Letters) 1998年第1期11卷 45-50页

作者： B.P.huang Z.q.Zheng Central South Univ of Technology Changsha China

Effects of various aging treatments on mechanical properties and microstructure of alloy 2195 have been investigated. The experimental results showed that a promising combination of strength and ductility was achievable under T8 temper. The lower aging temperature reduced subgrain-or grain-boundary T1 precipitation and favored uniform dispersion of T1 phases, resulting in better strength and ductility. Prior deformation improved aging strength with promising ductility. Pre-aging after prior deformation had little effect on the age-hardening behavior of alloy 2195.

关键词： Al alloy 2195,aging mechanical property microstructure