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Adaptive finite element-element-free Galerkin coupling method for bulk metal forming processes

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第3期10卷 353-360页

作者： lei-chao LIU Xiang-huai DONG Cong-xin LI National Die and Mould CAD Engineering Research Center Shanghai Jiao Tong University Shanghai 200030 China

An adaptive finite element-element-free Galerkin (FE-EFG) coupling method is proposed and developed for the numerical simulation of bulk metal forming processes. This approach is able to adaptively convert distorted FE elements to EFG domain in analysis. A new scheme to implement adaptive conversion and coupling is presented. The coupling method takes both advantages of finite element method (FEM) and meshless methods. It is capable of handling large deformations with no need of remeshing procedures, while it is computationally more efficient than those full meshless methods. The effectiveness of the proposed method is demonstrated with the numerical simulations of the bulk metal forming processes including forging and extrusion.

关键词： Meshless method Adaptive coupling method Bulk metal forming Numerical simulation

Non-isothermal creep age forming of Al-Cu-Li alloy:Experiment and modelling

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Chinese Journal of Aeronautics 2023年第5期36卷 566-581页

作者： Changhui WU Heng LI Tianjun BIAN chao lei Liwen ZHANG State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of High-Performance Precision Forming Technology and Equipment Northwestern Polytechnical UniversityXi’an 710072China School of Materials Science and Engineering Xi’an University of TechnologyXi’an 710048China

Non-isothermal Creep Age Forming(CAF),including loading,heating,holding,cooling and springback stages,is an advanced forming technique for manufacturing high performance large integral panels at short production period and low ***,the creep deformation and aging precipitation during heating stage is often neglected in experiments and modeling,leading to low forming *** achieve shape forming and property tailoring simultaneously,a deep understanding of the non-isothermal creep aging behavior and the establishment of predictive models are urgently required.A new five-stage creep feature of Al-Cu-Li alloy during the non-isothermal creep aging is *** microstructural interactions between the dislocations,solute atoms,Guinier Preston zones(GP zones)and T1 precipitates are found to dominate the five-stage creep aging *** physical-based model considering temperature evolution history is established to describe the five-stage creep *** springback and yield strength of non-isothermal creep age formed plates with different thicknesses are predicted and compared by non-isothermal CAF experiments and corresponding *** CAF experiments show that the springback and yield strength of the non-isothermal creep age formed plate are 62.1%and 506 MPa,*** results are in good agreement with experimental *** proposed model broadens the application of traditional CAF models that mainly focus on isothermal conditions.

关键词： Al-Cu-Li alloy Creep aging forming Microstructures Springback Mechanical properties Thickness

Forming condition and control strategy of ferrite decarburization in 60Si2MnA spring steel wires for automotive suspensions

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International Journal of Minerals,Metallurgy and Materials 2012年第2期19卷 116-121页

作者： chao-lei Zhang Ya-zheng Liu Le-yu Zhou chao Jiang Jin-fu Xiao School of Materials Science and Engineering University of Science and Technology BeijingBeijing 10083China

The ferrite decarburization behavior of 60Si2MnA spring steel wires for automotive suspensions, including the forming condition and the influence of heating time and cooling rate after hot rolling, was investigated comprehensively. Also, a control strategy during the reheating process and cooling process after rolling was put forward to protect against ferrite decarburization. The results show that ferrite decarburization, which has the strong temperature dependence due to phase transformation, is produced between 675 and 875°C. The maximum depth is found at 750°C. Heating time and cooling rate after rolling have an important influence on decarburization. Reasonable preheating temperature in the billet reheating process and austenitizing temperature in the heat-treatment process are suggested to protect against ferrite decarburization.

关键词： spring steel decarburization phase transformations controlled cooling

Insecticidal activities of garlic substances against adults of grain moth, Sitotroga cerealella （Lepidoptera： Gelechiidae）

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Insect Science 2012年第2期19卷 205-212页

作者： Feng-Lian Yang Fen Zhu chao-Liang lei Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory Huazhong Agricultural UniversityWuhanChina

The angoumois grain moth, Sitotroga cerealella （Olivier）, is one of the most serious stored grain pests around the world. In attempts to reduce the losses caused by the moth and to suppress its populations, the fumigant activities, behavioral influence and ovipositional inhibition of garlic （Allium sativum） essential oil and its two major components, diallyl disulfide and diallyl trisulfide, were investigated against the adult grain moth. Their effects on reduction in survival of first instar larvae to adult emergence were also evaluated. Results showed that these three materials （garlic essential oil, diallyl disulfide and diallyl trisulfide） had significant fumigant activity with 50% lethal concentration values at 1.33, 0.99, and 1.02/zL/L air space, respectively; meanwhile, the three materials possessed high behavioral deterrent activities against adults in the Y-tube olfactometer. When applied to rice grains, these materials reduced adult longevity and inhibited oviposition, with ovipositional inhibition above 70% at a concentration of 1.5uL/25 g in either no-choice or two-choice tests. In short, the study showed that both diallyl disulfide and diallyl trisulfide, like garlic essential oil, acted as fitrnigants, produced behavioral deter- rence and inhibited oviposition against angoumois grain moth. Our work here indicates that diallyl disulfide and diallyl trisulfide may serve as potential alternatives for grain protectants since both of them can be prepared easily from readily available chemicals.

关键词： behavioral deterrence essential oil fumigant garlic oviposition inhibition,Sitotroga cerealella

Effects of Niobium and Vanadium on Hydrogen-Induced Delayed Fracture in High Strength Spring Steel

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Journal of Iron and Steel Research International 2011年第6期18卷 49-53页

作者： ZHANG chao-lei LIU Ya-zheng JIANG chao XIAO Jin fu School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

Influence of vanadium and/or niobium additions on delayed fracture behavior in high strength spring steel was studied by hydrogen permeation method and slow strain rate technique （8SRT）, and its mechanism was analyzed. The results show that apparent diffusion coefficient of hydrogen in microalloyed spring steels Nb-V-steel and Nb-steel is lower than that in non-microalloyed steel 60Si2MnA. Percentage of strength reduction in SSRT in air after precharged hydrogen of the microalloyed steels is smaller than that of 60Si2MnA. Addition of the microalloys changes the fracture characteristics. Thence, vanadium and/or niobium additions are a very effective and economy means to improve the hydrogen-induced delayed fracture resistance of high strength spring steel.

关键词： spring steel microalloy hydrogen-induced delayed fracture slow strain rate technique hydrogen permeation

Surface decarburization characteristics and relation between decarburized types and heating temperature of spring steel 60Si2MnA

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International Journal of Minerals,Metallurgy and Materials 2013年第8期20卷 720-724页

作者： chao-lei Zhang Le-yu Zhou Ya-zheng Liu School of Materials Science and Engineering University of Science and Technology Beijing

The characteristics of complete and partial decarburizations in spring steel 60Si2MnA were systematically investigated, including the microstructure, the hardness gradient, and the formation mechanism. The relation between decarburized types and heating temperature of the steel was comprehensively discussed. It is found that heating temper- ature has an important influence on the decarburized types. With the rise of heating temperature, the decarburized types change from no decarburization to complete decarburization, complete and partial decarburizations, partial decarburiza- tion, and no decarburization.

关键词： spring steel decarburization temperature microstructure hardness

Enhancing force sensing in a squeezed optomechanical system with quantum nondemolition measurement

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Communications in Theoretical Physics 2024年第1期76卷 49-60页

作者： Shi-lei chao Zi-Hao Li Xin-You Lü School of Physics Huazhong University of Science and Technology430074 WuhanChina

A theoretical scheme is proposed to enhance the sensitivity of force sensors with quantum nondemolition measurement(QND)in an optomechanical setup assisted by four-tone optical driving and an optical parametric amplifier(OPA).With the help of special drive,the system can be simplified as the typical type of QND for force sensing,so that the backaction noise can be evaded to surpass the standard quantum ***,the added noise can be suppressed owing to the modified optical susceptibility resulting from the *** introducing two oscillators coupling with two charged bodies respectively,the signal can be enhanced with the nonlinearity caused by Coulomb interaction,while the noise presents an exponential ***,considering the homodyne detection effect,the range of system parameters and frequency bands will be *** present investigation may provide a route toward simultaneously evading backaction noise,reducing the mechanical thermal noise,and enhancing the external signal,which can be an alternative design for sensitive devices.

关键词： force sensing optical parametric amplifier quantum non-demolition measurement optomechanical system

Microstructure and Optical Properties of Ti_(54.5)Ni_(45.5) Nanocrystalline Thin Film

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Acta Metallurgica Sinica(English Letters) 2017年第12期30卷 1231-1235页

作者： Xin Zhang Jie-He Sui Yong-chao lei Wei Cai School of Materials Science and Engineering Tianjin University of Technology National Key Laboratory Precision Hot Processing of Metals Harbin Institute of Technology

Nanocrystalline Ti54.5Ni45.5 thin film was prepared by magnetron sputtering followed by rapid thermal annealing. The film displayed martensite structure and （001） compound twin substructure, and the transformation temperatures Ms and As are 313 and 365 K, respectively. The reflectivity for the wavelength from 200 to 800 nm at 298 and 393 K was investigated, and the results showed that the optical reflectivity contrast between martensite and austensite at 780, 650, 514 and 405 nm was 105.64, 170.83, 112.22 and 149.92%, respectively, which were larger than those of other reported optical recording materials.

关键词： Ti–Ni thin films Sputtering Shape memory alloys Optical properties Microstructure

En Echelon Faults and Basin Structure in Huizhou Sag, South China Sea: Implications for the Tectonics of the SE Asia

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Journal of Earth Science 2015年第5期26卷 690-699页

作者： Boubacar Hamidou Leyla Jianye Ren Jing Zhang chao lei Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education China University of Geosciences Faculty of Earth Resources China University of Geosciences

The Huizhou sag is situated on the continental shelf of the northern continental margin of the South China Sea. In this paper we present a grid of reflection seismic and well data to characterize the basin structure and prominent unconformities. We employ EBM and 2DMOVE softwares to explore the subsidence history and stratigraphic development history of the basin. We found a rapid subsidence period since 15.5 Ma. Moreover, we calculated the stretching factors of the upper crust and the whole crust in the Huizhou sag. The results show the values are 1.10–1.13 and 1.08–1.31, respectively, indicating faulting in Huizhou sag is relatively small. It is noteworthy that the faults map reveals en echelon distribution at the north and south margins of the basin. We suggest en echelon faults here are caused by the subduction of Proto-South China Sea toward NW Borneo block and cease of the South China Sea. Considering the pronounced unconformities, subsidence rates, fault activities and sediment thickness, the Cenozoic tectonic evolution of the basin can be divided into rifting（49–32 Ma）, post-rifted（32–15.5 Ma） and rapid subsidence（15.5–0 Ma） stages. Our study will shed new light on the tectonics of SE Asia and petroleum exploration in the South China Sea.

关键词： South China Sea Pearl River Mouth Basin basement subsidence en echelon faults