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THREE-DIMENSIONAL MODELING FOR THIN PLATE-LIKE STRUCTURES INCluDING SURFACE EFFECTS BY USING STATE SPACE METHOD

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Acta Mechanica Solida Sinica 2010年第3期23卷 260-270页

作者： Hongyu Sheng pin lu Institute of Civil Engineering Hefei University of Technology Hefei 230009 China Institute of Materials Research and Engineering A ^＊STAR (Agency for Science Technology and Research) 3 Research Link Singapore 117602

A three-dimensional （3-D） approach based on the state space method is proposed to study size-dependent mechanical properties of ultra-thin plate-like elastic structures considering surface effects. The structure is modeled as a laminate composed of a bulk bounded with upper and bottom surface layers, which are allowed to have different material properties from the bulk layer. State equations, including the surface properties of the structure, can be established on the basis of 3-D fundamental elasticity to analyze the size-dependent static characteristics of the thin plate-like structure. Compared with two-dimensional plate theories based size-dependent models for thin film structures in literature, the present 3-D approach is exact, which can provide benchmark results to assess the accuracy of 2-D plate theories and various numerical approaches. To show the feasibility of the proposed approach, a 3-D analytical solution for a simply supported plate-like thin structure including surface layers is derived. An algorithm is proposed for the calculation of the state equations obtained to ensure that the numerical results can reveal the surface effects clearly even for extremely thin surface layers. Numerical examples are carried out to exhibit the surface effects and some discussions are provided based on the results obtained.

关键词： micro-structures surface effects size-dependence state equation three-dimensional modeling

FURTHER STUDIES ON STROH-TYPE FORMALISMS FOR ANISOTROPIC PLATES WITH BENDING-EXTENSION COUPLING

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Acta Mechanica Solida Sinica 2007年第4期20卷 324-332页

作者： pin lu HaiBo Chen CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern Mechanics University of Science and Technology of China Hefei 230027 China Institute of High Performance Computing 1 SciencePark Road #01-01 The Capricorn Science Park II Singapore 117528

Stroh-type formalisms for anisotropic thin plates in literature axe reviewed and discussed, and two kinds of hybrid Stroh-type formalisms axe compared. It is seen that the two Stroh-type formalisms are essentially equivalent. With simple transfer relations, they can be expressed each other. In addition, with properly defined notation systems, the two Stroh-type formalisms can also be written in unified forms, which will be convenient in applications.

关键词： Stroh formalism anisotropic plate Stroh-type formalism composite laminates

Assessment of highway slope failure using neural networks

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第1期10卷 101-108页

作者： Tsung-lin LEE Hung-ming LIN Yuh-pin lu 1Department of Construction and Facility Management Department of Resource and Environment Leader University

An artificial intelligence technique of back-propagation neural networks is used to assess the slope ***-site slope failure data from the South Cross-Island Highway in southern Taiwan are used to test the performance of the neural network *** numerical results demonstrate the effectiveness of artificial neural networks in the evaluation of slope failure potential based on five major factors,such as the slope gradient angle,the slope height,the cumulative precipitation,daily rainfall and strength of materials.

关键词： Neural network Prediction Highway Slope failure

Modeling blue stragglers in young clusters

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Research in Astronomy and Astrophysics 2011年第11期11卷 1336-1350页

作者： pin lu Li-Cai Deng Xiao-Bin Zhang Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academyof Sciences Beijing 100012 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

A grid of binary evolution models are calculated for the study of a blue straggler （BS） population in intermediate age （log Age = 7.85 - 8.95） star clusters. The BS formation via mass transfer and merging is studied systematically using our models. Both Case A and B close binary evolutionary tracks are calculated for a large range of parameters. The results show that BSs formed via Case B are generally bluer and even more luminous than those produced by Case A. Furthermore, the larger range in orbital separations of Case B models provides a probability of producing more BSs than in Case A. Based on the grid of models, several Monte-Carlo simulations of BS populations in the clusters in the age range are carded out. The results show that BSs formed via different channels populate different areas in the color magnitude diagram （CMD）. The locations of BSs in CMD for a number of clusters are compared to our simulations as well. In order to investigate the influence of mass transfer efficiency in the models and simulations, a set of models is also calculated by implementing a constant mass transfer efficiency,β=0.5, during Roche lobe overflow （Case A binary evolution excluded）. The result shows BSs can be formed via mass transfer at any given age in both cases. However, the distributions of the BS populations on CMD are different.

关键词： stars blue stragglers-stars binaries close

Comparative study on microstructure evolution and failure mechanisms of ordinary and refurbished EB-PVD TBC under cyclic oxidation

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Journal of Advanced Ceramics 2023年第9期12卷 1805-1820页

作者： Pan Li Xiaochao Jin pin lu Delin Liu Rende Mou Xueling Fan Xi’an Key Laboratory of Extreme Environmental Serviceability and Protection Technologies School of Aerospace EngineeringXi’an Jiaotong UniversityXi’an 710049China AECC Beijing Institute of Aeronautical Materials Beijing 100095China

Refurbishment of thermal barrier coating(TBC)has become a valuable technique to prolong the service life of high-temperature *** study investigates the effect of the refurbishment process(coating removal and recoating)on the microstructure evolution and physical properties of TBC,including oxidation characteristics,element diffusion behavior,and crack failure *** results showed that a certain amount of interdiffusion zone(IDZ)with Cr-rich would be retained in DD6 superalloy substrate after coating *** microstructure of the refurbished specimens showed equiaxedβ-NiAl phases,while the ordinary specimens have elongated grain shapes with a high aspect ***,mixed oxides in the refurbished TBC specimens were earlier observed during cyclic oxidation,with a greater thickness compared to ordinary TBC,due to the influence of BC layer phase *** growth mechanism of thermally grown oxide(TGO-Al_(2)O_(3)layer)in the refurbished TBC specimens was also different,resulting from the different mechanisms of mixed oxides ***,under cyclic oxidation with water quenching at 1100℃,the cracks in the refurbished specimen tend to occur in the mixed oxides layer,while the cracks in the ordinary specimen occur in the top coat(TC)layer,attributing to the earlier and thicker mixed oxides layer formed in refurbished specimens.

关键词： thermal barrier coating(TBC)systems coating removal refurbishment cyclic oxidation microstructure evolution failure mechanism

Optimization design and residual thermal stress analysis of PDC functionally graded materials

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第8期7卷 1318-1323页

作者： CAO pin-lu LIU Bao-chang YIN Kun ZHANG Zu-pei College of Constructzon Engineering Jilin University Changchun 130026 China Key Laboratory of Geo-exploration Instrumentation Ministry of Education Changchun 130026 China

The distribution of thermal stresses in functionally graded polycrystalline diamond compact (PDC) and in single coating of PDC are analyzed respectively by thermo-mechanical finite element analysis (FEA). It is shown that they each have a remarkable stress concentration at the edge of the interfaces. The diamond coatings usually suffer premature failure because of spallation, distortion or defects such as cracks near the interface due to these excessive residual stresses. Results showed that the axial tensile stress in FGM coating is reduced from 840 MPa to 229 MPa compared with single coating, and that the shear stress is reduced from 671 MPa to 471 MPa. Therefore, the single coating is more prone to spallation and cracking than the FGM coating. The effects of the volume compositional distribution factor (n) and the number of the graded layers (L) on the thermal stresses in FGM coating are also discussed respectively. Modelling results showed that the optimum value of the compositional distribution factor is 1.2, and that the best number of the graded layers is 6.

关键词： Functionally graded materials (FGM) Optimum design Polycrystalline diamond compact (PDC) Residual thermal stress Finite element method (FEM)

Thermal Analysis of Turbine Blades with Thermal Barrier Coatings Using Virtual Wall Thickness Method

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Computer Modeling in Engineering & Sciences 2023年第2期134卷 1219-1236页

作者： Linchuan Liu Jian Wu Zhongwei Hu Xiaochao Jin pin lu Tao Zhang Xueling Fan Joint Research Center for Extreme Environment and Protection Technology School ofAerospace EngineeringXi’an Jiaotong UniversityXi’an710049China AEEC Sichuan Gas Turbine Establishment Chengdu610500China

Avirtual wall thicknessmethod is developed to simulate the temperature field of turbine bladeswith thermal barrier coatings(TBCs),to simplify the modeling process and improve the calculation *** results show that the virtualwall thickness method can improve themesh quality by 20%,reduce the number ofmeshes by 76.7%and save the calculation time by 35.5%,compared with the traditional real wall thickness *** average calculation error of the two methods is between 0.21%and 0.93%.Furthermore,the temperature at the blade leading edge is the highest and the average temperature of the blade pressure surface is higher than that of the suction surface under a certain service *** blade surface temperature presents a high temperature at both ends and a low temperature in themiddle height when the temperature of incoming gas is uniformand *** thermal insulation effect of TBCs is the worst near the air film hole,and the best at the blade leading *** to the calculated temperature field of the substrate-coating system,the highest thermal insulation temperature of the TC layer is 172.01 K,and the thermal insulation proportions of TC,TGO and BC are 93.55%,1.54%and 4.91%,respectively.

关键词： Turbine blade thermal analysis thermal barrier coatings finite element method virtual wall thickness

Optimization Design and Finite Element Analysis of Core Cutter

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Journal of China University of Mining and Technology 2007年第3期17卷 399-402页

作者： CAO pin-lu YIN Kun PENG Jian-ming LIU Jian-lin College of Construction Engineering Jilin University Changchun Jilin 130026 China Key Laboratory of Geo-exploration Instrumentation Ministry of Eduction Changchun Jilin 130026 China

The hydro-hammer sampler is a new type of sampler compared with traditional ones. An important part of this new offshore sampler is that the structure of the core cutter has a significant effect on penetration and core recovery. In our experiments, a commercial finite element code with a capability of simulating large-strain frictional contact between two or more solid bodies is used to simulate the core cutter-soil interaction. The effects of the cutting edge shape, the diameter and the edge angle on penetration are analyzed by non-liner transient dynamic analysis using a finite element method （FEM）. Simulation results show that the cutter shape clearly has an effect on the penetration and core recovery. In addition, the penetration of the sampler increases with an increase in the inside diameter of the cutter, but decreases with an increase in the cutting angle. Based on these analyses, an optimum structure of the core cutter is designed and tested in the north margin of the Dalian gulf. Experiment results show that the penetration rate is about 16.5 m/h in silty clay and 15.4 m/h in cohesive clay, while the recovery is 68% and 83.3% resoectively.

关键词： hydro-hammer sampler finite element analysis core cutter-soil interaction optimum design

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古玻璃风化表面预测内部化学成分方法研究

黑龙江科学 2024年第16期15卷 58-62页

作者：肖叙昕张佳怡谢欣欣鲁萍西安建筑科技大学理学院西安710399

古代玻璃在埋藏过程中的风化会导致其化学成分比例发生变化。针对古玻璃风化表面化学成分还原为内部化学成分数据方法进行研究,构建基于统计学和机器学习方法相结合的风化数据还原模型,依据表面化学成分对样本进行风化程度定义,设计无... 详细信息

古代玻璃在埋藏过程中的风化会导致其化学成分比例发生变化。针对古玻璃风化表面化学成分还原为内部化学成分数据方法进行研究,构建基于统计学和机器学习方法相结合的风化数据还原模型,依据表面化学成分对样本进行风化程度定义,设计无监督特征选择集成决策方法进行重要特征选取,对重要特征使用K-means模型划分风化程度类别,针对风化程度类别的统计特征及成分相关性特点建立回归、映射等风化还原模型,使用该模型还原的内部化学成分满足有效性要求,结果合理性检验使用预测误差和类别还原准确率两个指标,化学成分预测平均准确率约为67.3%,类别还原准确率约为90%。

关键词：无监督学习特征选择机器学习 K-means模型科技考古风化还原