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In silico optimization of actuation performance in dielectric elastomercomposites via integrated finite element modeling and deep learning

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Theoretical & Applied Mechanics Letters 2024年第1期14卷 48-56页

作者： Jiaxuan Ma sheng sun Materials Genome Institute Shanghai UniversityShanghai 200444China Zhejiang Laboratory Hangzhou 311100China Shanghai Frontier Science Center of Mechanoinformatics Shanghai UniversityShanghai 200444China

Dielectric elastomers(DEs)require balanced electric actuation performance and mechanical integrity under applied *** high dielectric particles as fillers provides extensive design space to optimize concentration,morphology,and distribution for improved actuation performance and material *** study presents an integrated framework combining finite element modeling(FEM)and deep learning to optimize the microstructure of DE *** first calculates actuation performance and the effective modulus across varied filler combinations,with these data used to train a convolutional neural network(CNN).Integrating the CNN into a multi-objective genetic algorithm generates designs with enhanced actuation performance and material modulus compared to the conventional optimization approach based on FEM approach within the same *** framework harnesses artificial intelligence to navigate vast design possibilities,enabling optimized microstructures for high-performance DE composites.

关键词： Dielectric elastomer composites Multi-objective optimization Finite element modeling Convolutional neural network

Theoretical Study on the Reaction Mechanism of F_2+2HBr = 2HF+Br_2

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Chinese Journal of Structural Chemistry 2005年第11期24卷 1328-1333页

作者： sun De-sheng WANG Zun-Yao YANG Chun-sheng School of Chemistry and Chemical Engineering Nanjing University of Technology Jiangsu Nanjing 210009 China Department of Chemical Engineering Yancheng Institute of Technology Jiangsu Yancheng 224003 China

The gas phase reaction mechanism of F2 ＋ 2HBr = 2HF ＋ Br2 has been investigated by （U）MP2 at 6-311G＊＊ level, and a series of four-center and three-center transition states have been obtained. The reaction mechanism was achieved by comparing the activation energy of seven reaction paths, i.e. the dissociation energy of F2 is less than the activation energy of the bimolecular elementary reaction F2 ＋ HBr → HF ＋ BrF. Thus it is theoretically proved that the title reaction occurs more easily in the free radical reaction with three medium steps.

关键词： (U)MP2,transition state reaction mechanism free radical reaction.

Size-and temperature-dependent Young's modulus and size-dependent thermal expansion coefficient of nanowires

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Science China(Technological Sciences) 2018年第5期61卷 687-698页

作者： sun HongLiang CHEN LiuYan sun sheng ZHANG Tong-Yi Materials Genome Institute Shanghai University and Shanghai Materials Genome Institute

Nanowires(NWs) exhibit size-dependent mechanical properties due to the high surface/volume ratio, in which temperature also plays an important role. The surface eigenstress model is further developed here to quantitatively predict the size-dependent mechanical properties of NWs and results in analytic formulas. Molecular dynamics(MD) simulations are conducted to study the size-dependent mechanical of [100], [110] and [111] Ni and Si nanowires within the temperature range of 100–400 K and the MD results verify perfectly the newly developed surface eigenstress model.

关键词： surface eigenstress model size-and temperature-dependent Young's modulus size-dependent thermal expansion coefficient nanowires molecular dynamics simulations

Grain boundary segregation and relaxation in nano-grained polycrystalline alloys

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Science China(Physics,Mechanics & Astronomy) 2021年第2期64卷 72-90页

作者： Tong-Yi Zhang Ying-Xin Gao sheng sun Materials Genome Institute Shanghai UniversityShanghai200444China

The present study carries out systematic thermodynamics analysis of Grain Boundary(GB)segregation and relaxation in NanoGrained(NG)polycrystalline *** segregation and relaxation is an internal process towards thermodynamic equilibrium,which occurs naturally in NG alloys without any applied loads,causes deformation and generates internal *** analysis comprehensively investigates the multiple coupling effects among chemical concentrations and mechanical stresses in GBs and grains.A hybrid approach of eigenstress and eigenstrain is developed herein to solve the multiple coupling *** analysis results indicate that the GB stress and grain stress induced by GB segregation and relaxation can be extremely high in NG alloys,reaching the GPa level,which play an important role in the thermal stability of NG alloys,especially via the coupling terms between stress and *** present theoretic analysis proposes a novel criterion of thermal stability for NG alloys,which is determined by the difference in molar free energy between a NG alloy and its reference single crystal with the same nominal chemical *** the difference at a temperature is negative or zero,the NG alloy is thermal stable at that temperature,otherwise unstable.

关键词： nano-grained alloys thermal stability grain boundary segregation eigenstress eigenstrain

Boundary Dilatation and Degenerating Hamilton Sequences

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Acta Mathematica Sinica,English Series 2006年第1期22卷 139-142页

作者： Na sun sheng Jian WU LMAM and School of Mathematical Sciences Peking University Beijing 100871 P. R. China

In this paper, we study the boundary dilatation of quasiconformal mappings in the unit disc. By using Strebel mapping by heights theory we show that a degenerating Hamilton sequence is determined by a quasisymmetric f... 详细信息

关键词： Quasiconformal mapping Boundary dilatation Degenerating Hamilton sequence

Relationship between chloride diffusivity and pore structure of hardened cement paste

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第5期12卷 360-367页

作者： Guo-wen sun Wei sun Yun-sheng ZHANG Zhi-yong LIU Jiangsu Key Laboratory of Construction Materials.Southeast University Nanjing 211189china

Based on effective media theory, a predictive model, relating chloride diffusivity to the capillary pores, gel pores, tortuosity factor, and pore size distribution of hardened cement, is proposed. To verify the proposed model, the diffusion coefficient of chloride ions, the degree of hydration, and peak radius of capillary pores of cement paste specimens were measured. The predicted results for chloride diffusivity were compared with published data. The results showed that the predicted chloride diffusivity of hardened cement paste was in good agreement with the experimental results. The effect of the evolution of pore structures in cement paste on chloride diffusivity could be deduced simultaneously using the proposed model.

关键词： Hardened cement paste Chloride diffusivity Porosity Tortuosity factor Constrictivity Key words: Hardened cement paste, Chloride diffusivity, Porosity, Tortuosity factor, Conslrictivity

Temperature dependent Grüneisen parameter

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Science China(Technological Sciences) 2019年第9期62卷 1565-1576页

作者： ZHANG Xun sun sheng XU Tao ZHANG TongYi Materials Genome Institute Shanghai University

Grüneisen parameter is one of the most valuable quantities in thermodynamics, which links the material properties of bulk modulus, heat capacity at constant volume, thermal expansion coefficient, and volume together. A new thermodynamic model of temperature-dependent potential energy is proposed here to investigate the temperature dependent Grüneisen parameter of bulk material. The newly developed thermodynamic model leads to temperature dependent analytical solutions of Grüneisen parameter and other thermo-mechanical properties including the Grüneisen equation of state. Molecular dynamics simulations are conducted on single crystalline Ni, Cu, and Au bulk crystals and the simulation results verify the newly developed thermodynamic model and quantitively evaluate the theoretically derived physical quantities. In addition, the Debye model is also employed in the study of temperature dependent Grüneisen parameter and the results also verify the theoretical approach.

关键词： thermo-mechanical properties Grüneisen parameter thermodynamic model temperature-dependent potential energy molecular dynamics simulations

The New Fault Tolerant Onboard Computer for Microsatellite Missions

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The Journal of China Universities of Posts and Telecommunications 2006年第1期13卷 6-9页

作者： WANG Xin-sheng sun Han-xu Automation School Beijing University of Posts and Telecommunications Beijing 100876 P.R. China

This paper describes an onboard computer with dual processing modules. Each processing module is composed of 32 bit ARM reduced instruction set computer processor and other commercial-off-the-shelf devices. A set of fault handling mechanisms is implemented in the computer system, which enables the system to tolerate a single fault. The onboard software is organized around a set of processes that communicate among each other through a routing process. Meeting an extremely tight set of constraints that include mass, volume, power consumption and space environmental conditions, the fault-tolerant onboard computer has excellent data processing capability that can meet the erquirements of micro-satellite missions.

关键词： onboard computer fault tolerance commerciat-off-the-shelt

A Microstrip Leaky-Wave Antenna with Scanning Beams Horizontal to the Antenna Plane

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Chinese Journal of Electronics 2024年第5期33卷 1218-1223页

作者： Henghui WANG Peiyao CHEN sheng sun School of Electronic Science and Engineering University of Electronic Science and Technology of China

A leaky-wave antenna with horizontal scanning beams and broadside radiation is presented on the periodically modulated microstrip. The horizontal radiation is realized by periodically etching a set of resonant open-ended slots on the ground plane. Dispersion diagrams and Bloch impedance are first analyzed to investigate the propagation and radiation characteristics of the periodic structure. Subsequently, shunt matching stubs are installed aiming to obtain seamless beam scanning property through the broadside. Finally, a prototype is implemented as verification of the presented antenna. Results of the simulations and measurements agree well with each other, indicating the elimination of the open-stop band effect and the horizontal radiation beams. The fabricated antenna exhibits a beam range from -62° to +34°, and provides a maximum measured gain about 14.6 dBi at 10 GHz.

关键词： Antenna measurements Wireless communication Prototypes Microstrip antennas Gain measurement Leaky wave antennas Reflection coefficient