Lugui CHEN
,
Yong LING
,
Xiuhong KANG
,
Lijun XIA
,
Dianzhong LI
材料科学技术（英）
A large-scale, thin wall duplex stainless steel impeller with complex geometry was deformed severely and unpredictably during casting and heat treatment processes resulted in dimensional failure for the final part. In this paper, the distortion of the impeller during casting and heat treatment was calculated. A commercial software, Experto-ViewCast, was used to simulate the transient heat transfer, solidification and mechanical behaviors during the casting and the heat treatment process. The coupled set of governing differential equations for mass, energy and mechanical balance were solved by finite control volume and finite element method. A thermoelastic-visco-plastic rheological model was used to compute the constrained shrinkage of the casting. At each time increment, a coupling of the heat transfer and mechanics was performed. Comparison of the experimental measurements with the model predictions showed good agreement. From the calculated displacements of key points of the blade, the proper inverse displacements were determined to provide an optimum casting pattern and to achieve a uniform and reasonable machining allowance for both faces of the blade.
关键词:
Numerical simulation
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null
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null
,
null
,
null
Kaifeng ZHANG
,
Wenbo HAN
,
Wei WU
,
Guofeng WANG
,
Dezhong WU
材料科学技术（英）
The research on numerical simulation for combinative process of SPF/DB is carried out in this paper. The contacting problem of sheets is analyzed by using the penalty method. In order to solve the contact problem of different parts of the sheet, a new algorithm for contacting judgment is proposed. According to the relation of the distance vector and the vector of contacting element area, and the condition of contact, it can be judged whether or not a node on the slave surface and the corresponding master surface are in the state of SPF/DB. The Mindlin shell element is employed to simulate SPF/DB process of an asymmetry double-cell cup of Ti-6Al-4V to examine the efficiency of the new algorithm using ARVIP-3D. The results of the numerical simulation are in good agreement with experimental results.
关键词:
Numerical simulation
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null
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null
,
null
Zhoushun ZHENG
,
Xuanhui QU
,
Yunping LI
,
Jianfeng GUO
材料科学技术（英）
A mathematical model of two-dimensional flows of PIM derived from the momentum, continuity equations and the heat transfer equation is obtained. The formula of calculating the flow conductance and the pressure equation are deduced when the no slip boundary condition is employed at the wall, and the pressure equation is a non-linear elliptic partial differential equation. The flow front locations, distribution of velocities, temperature and pressure are simulated by the finite element analysis software ANSYS. Simulation results indicate that it is in the final filled part that defects appear easily. The region in which the defects may occur during the PIM process can be predicted.
关键词:
Numerical simulation
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null
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null
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null
Lixia ZHANG
,
Jicai FENG
材料科学技术（英）
The maximum thermal stress and stress concentration zones of iron/TiC cermet joint during cooling were studied in this paper. The results showed that the shear stress on iron/TiC cermet joint concentrates on the interface tip and the maximum shear stress appears on the left tip of iron/TiZrNiCu interface. Positive tensile stress on TiC cermet undersurface concentrates on both sides of TiC cermet and its value decreases during cooling. Negative tensile stress on TiC cermet undersurface concentrates on the center of TiC cermet and its value increases during cooling. Brazing temperature has little effect on the development and maximum thermal stress.
关键词:
Numerical simulation
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null
,
null
,
null
S.H. Song Y.S. Byun T.W. Ku W.J. Song J. Kim B.S. Kang
材料科学技术（英）
It is known that fiber metal laminates (FML) as one of hybrid materials with thin metal sheets and fiber/epoxy layers have the characteristics of the excellent damage tolerance, fatigue and impact properties with a relatively low density. Therefore, the mechanical components using FML can contribute the enhanced safety level of the sound construction toward the whole body. In this study, the impact performance of carbon reinforced aluminum laminates (CARAL) is investigated by experiments and numerical simulations. Drop weight tests are carried out with the weight of 4.7 kg at the speed of 1 and 2 m/s, respectively. Dynamic non-linear transient analyses are also accomplished using a finite element analysis software, ABAQUS. The experiment results and numerical results are compared with impact load-time histories. Also, energy-time histories are applied to investigate the impact performance of CARAL.
关键词:
Fiber metal laminates (FML)
,
Carbon reinforced aluminum laminates (CARAL)
,
Numerical simulation
,
Impact performance
Ziliang LI
,
Junruo CHEN
,
Miao ZHANG
,
Yihong GUAN
材料科学技术（英）
Based on a transient temperature distribution of a 45 steel cylinder workpiece during magnetic quenching, which was obtained by solving the governing equations with nonlinear boundary on the condition of coupling effects of heat-magnetism. According to the theory of thermal non-elasticity, computational mechanics, ferromagnetism and phase transformation, a new constitutive equation considering effects of phase transformation is proposed and solved by means of finite element method. The transient thermal stress and residual stress are obtained and the influencing factors on the thermal stress of magnetic field are analyzed and discussed.
关键词:
Numerical simulation
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null
,
null
,
null
Nannan Song
材料科学技术（英）
A program on the solidification process of horizontal centrifugal casting coupled with eutectic carbides segregation has been developed in this paper. Due to the geometrical features of work roll, a cylindrical coordinate system was used. The temperature field of the outer layer at the end of filling process was imported as the initial temperature condition for the solidification process. The model of eutectic carbides segregation caused by different densities between eutectic MC and the molten steel was coupled in the program. The temperature field of the outer layer of work roll during horizontal centrifugal casting process was investigated. Results show that the outer layer has a "sandwich shape" solid fraction manner. Results also indicate that the segregation of eutectic MC is quite severe during centrifugal casting process. It forms four zones of different content of carbides in radial direction. The simulated results of MC carbides segregation phenomenon agree with the experimental observations.
关键词:
Numerical simulation
Shuyong DONG
,
Shoumei XIONG
,
Baicheng LIU
材料科学技术（英）
A mathematical model to calculate the size and distribution of microporosities was studied and coupled with a stochastic microstructure evolution model. The model incorporates various solidification phenomena such as grain structure evolution, solidification shrinkage, interdendritic fluid flow and formation and growth of pores during solidification processes. The nucleation and growth of grains were modeled with a cellular automaton method that utilizes the results from a macro scale modeling of the solidification process. Experiments were made to validate the proposed models. The calculated results of aluminum alloy castings agreed with the experimental measurements.
关键词:
Numerical simulation
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null
,
null
Hongyuan FANG
,
Chenglei FAN
,
Jianguo YANG
,
Ming LI
,
Zhen LUO
,
Xianzhong HOU
材料科学技术（英）
A new type of compound conduit is designed and the finite element method (FEM) is applied to analyze the mechanical performance of a typical compound conduit. The results of the numerical simulation confirm that the distributions of the strain, stress and the flexure distortion of the conduit are reasonable under the working conditions, and the stress and strain are continuous at the interface of the crust and the pipe liner. The conduit can endure 7.4 times of the working load before break, which fits well with that of the experiment and means that the conduit has good ability to bear overload. The peak value of the flexure distortion of the conduit (6 m) is about 3 mm in the middle bottom of the pipeline, which also accords well with that of the experiment.
关键词:
Compound conduit
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null
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null
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null
