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Path-Dependent Progressive Failure Analysis for 3D-Printed Continuous Carbon Fibre Reinforced Composites

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Chinese Journal of Mechanical Engineering 2024年第4期37卷 84-93页

作者： Yuan Chen Lin ye School of System Design and Intelligent Manufacturing(SDIM) Southern University of Science and TechnologyShenzhen 518055China Shenzhen Key Laboratory of Intelligent Manufacturing for Continuous Carbon Fibre Reinforced Composites Southern University of Science and TechnologyShenzhen 518055China

In order to predict the damage behaviours of 3D-printed continuous carbon fibre(CCF)reinforced composites,when additional short carbon fibre(SCF)composite components are employed for continuous printing or special functionality,a novel path-dependent progressive failure(PDPF)numerical approach is ***,a progressive failure model using Hashin failure criteria with continuum damage mechanics to account for the damage initiation and evaluation of 3D-printed CCF reinforced polyamide(PA)composites is developed,based on actual fibre placement trajectories with physical measurements of 3D-printed CCF/PA ***,an elastic-plastic model is employed to predict the plastic damage behaviours of SCF/PA ***,the accuracy of the PDPF model was validated so as to study 3D-printed CCF/PA composites with either negative Poisson's ratio or high *** results demonstrate that the proposed PDPF model can achieve higher prediction accuracies in mechanical properties of these 3D-printed CCF/PA *** analyses show that the stress distribution is generally aggregated in the CCF areas along the fibre placement paths,and the shear damage and matrix tensile/compressive damage are the key damage *** study provides a new approach with valuable information for characterising complex 3D-printed continuous fibre-matrix composites with variable mechanical properties and multiple constituents.

关键词： 3D printing Continuous carbon fibre Modelling Energy absorption Negative Poisson's ratio

Performance Prediction for Performance-Sensitive Queries Based on Algorithmic Complexity

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Tsinghua Science and Technology 2013年第6期18卷 618-628页

作者： Chihung Chi ye Zhou Xiaojun ye School of Software Tsinghua University Department of Computer Science and Technology Tsinghua University

Performance predictions for database queries allow service providers to determine what resources are needed to ensure their performance. Cost-based or rule-based approaches have been proposed to optimize database query execution plans. However, Virtual Machine （VM）-based database services have little or no sharing of resources or interactions between applications hosted on shared infrastructures. Neither providers nor users have the right combination of visibility/access/expertise to perform proper tuning and provisioning. This paper presents a performance prediction model for query execution time estimates based on the query complexity for various data sizes. The user query execution time is a combination of five basic operator complexities： O（1）, O（log（n））, O（n）, O（nlog（n））, and O（n2）. Moreover, tests indicate that not all queries are equally important for performance prediction. As such, this paper illustrates a performance-sensitive query locating process on three benchmarks： RUBiS, RUBBoS, and TPC-W. A key observation is that performance-sensitive queries are only a small proportion （20%） of the application query set. Evaluation of the performance model on the TPC-W benchmark shows that the query complexity in a real life scenario has an average prediction error rate of less than 10% which demonstrates the effectiveness of this predictive model.

关键词： query performance data size query complexity performance-sensitive query

Real-time recognition of human lower-limb locomotion based on exponential coordinates of relative rotations

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Science China(Technological Sciences) 2021年第7期64卷 1423-1435页

作者： XU Sen DING ye State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai200240China

This paper proposes a data-driven method using a parametric representation of relative rotations to classify human lower-limb locomotion, which is designed for wearable robots. Three Inertial measurement units(IMUs) are mounted on the subject's waist,left knee, and right knee, respectively. Features for classification comprise relative rotations, angular velocities, and waist acceleration. Those relative rotations are represented by the exponential coordinates. The rotation matrices are normalized by Karcher mean and then the Support Vector Machine(SVM) method is used to train the data. Experiments are conducted with a time-window size of less than 40 ms. Three SVM classifiers telling 3, 5 and 6 rough lower-limb locomotion types respectively are trained, and the average accuracies are all over 98%. With the combination of those rough SVM classifiers, an easy SVMbased ensembled-system is proposed to classify 16 fine locomotion types, achieving the average accuracy of 98.22%, and its latency is 18 ms when deployed to an onboard computer.

关键词： locomotion recognition exponential coordinate relative rotation support vector machine

A review of flotation and selective separation of pyrrhotite:A perspective from crystal structures

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International Journal of Mining Science and Technology 2022年第4期32卷 847-863页

作者： Xiaoqin Tang ye Chen School of Chemistry&Chemical Engineering Guangxi UniversityNanning 530004China School of Resources Environment and MaterialsGuangxi UniversityNanning 530004China Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured Materials Guangxi UniversityNanning 530004China

Pyrrhotite is an associated mineral that exists widely in sulfide ore. The presence of pyrrhotite will affect the recovery of platinum group minerals. Therefore, researchers have paid increasing attention to the flotation separation of pyrrhotite. Pyrrhotite superstructures owning different Fe/S ratios results in various crystal structures, corresponding to different physical, chemical and electronic properties, and consequently different flotation behavior. In the present paper, a comprehensive review is conducted to discuss the influence of crystal structures on the natural floatability, mineral-reagent interaction, surface oxidation and flotation electrochemistry of pyrrhotite. The selective flotation process of pyrrhotite from its associated minerals is also reviewed in this paper. It is hoped that this review can summarize the newly published research results combined with some representative results from the past, to provide a theoretical basis for the study of the flotation mechanism of pyrrhotite and provide a new direction for future research on pyrrhotite.

关键词： Pyrrhotite Flotation Crystal structures Surface properties

High-temperature electrocatalysis and key materials in solid oxide electrolysis cells

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Journal of Energy Chemistry 2021年第3期30卷 736-745页

作者： Lingting ye Kui Xie Key Laboratory of Optoelectronic Materials Chemistry and Physics Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002FujianChina Key Laboratory of Design&Assembly of Functional Nanostructures Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002FujianChina

Solid oxide electrolysis cells(SOECs)can convert electricity to chemicals with high efficiency at ~600-900℃,and have attracted widespread attention in renewable energy conversion and *** operate in the inverse mode of solid oxide fuel cells(SOFCs)and therefore inherit most of the advantages of SOFC materials and energy conversion ***,the external bias that drives the electrochemical process will strongly change the chemical environments in both in the cathode and anode,therefore necessitating careful reconsideration of key materials and electrocatalysis *** importantly,SOECs provide a unique advantage of electrothermal catalysis,especially in converting stable low-carbon alkanes such as methane to ethylene with high ***,we review the state-of-the-art of SOEC research progress in electrothermal catalysis and key materials and provide a future perspective.

关键词： Electrocatalysis Solid oxide electrolysis cell Cathode Anode Electrolyte

Strength behavior and collapse of spatial-reticulated structures under multi-support excitation

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Science China(Technological Sciences) 2011年第6期54卷 1624-1638页

作者： ye JiHong ZHANG ZhiQiang CHU ye Key Laboratory of C & PC Structure of Ministry of Education Southeast University Nanjing 210096 China

Under strong shocks,long-span spatial-latticed structures may collapse due to dynamic instability or strength *** elasto-plastic dynamic behaviors of three spatiallatticed structures,including two double-layer cylindrical shells and a spheri-cal shell used for the 2008 Olympic Games in Beijing,were quantitatively examined under multi-support excitation(MSE) and uniform support excitation(USE).Numerical analyses described several important parameters such as the peak acceleration and displacement responses at key joints,the number and distribution of plastic elements,and the deformation of the shell at the moment of *** of the analysis revealed the features and the failure mechanism of the spatial-latticed structures under MSE and *** both scenarios,the double-layer reticulated shell collapsed in the "overflow" mode,collapse was govrned by the number of invalid plastic elements rather than the total number of plastic elements,and the collapse of the structure began with damage to certain local regions near the *** comparing the numbers and distributions of the plastic members under MSE to those under USE,it was observed that the plastic members spread more sufficiently and the internal forces were more uniform under MSE,especially for lower apparent velocities in *** to the effects of pseudo-static displacement,the stresses in members near supports under MSE were higher than those under *** regions are prone to failure during earthquakes and deserve special attention in the seismic design of reticulated structures.

关键词： multiple support excitation(MSE) uniform support excitation(USE) elastic-plastic time history analysis spatial-latticed structure strength failure

Adaptive Control With Guaranteed Transient Behavior and Zero Steady-State Error for Systems With Time-Varying Parameters

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IEEE/CAA Journal of Automatica Sinica 2022年第6期9卷 1073-1082页

作者： Hefu ye Yongduan Song Chongqing Key Laboratory of Autonomous Systems Institute of Artificial IntelligenceSchool of AutomationChongqing UniversityChongqing 400044China IEEE

It is nontrivial to achieve global zero-error regulation for uncertain nonlinear *** underlying problem becomes even more challenging if mismatched uncertainties and unknown time-varying control gain are involved,yet certain performance specifications are also *** this work,we present an adaptive control method,which,without the persistent excitation(PE)condition,is able to ensure global zero-error regulation with guaranteed output performance for parametric strict-feedback systems involving fast time-varying parameters in the feedback path and input *** development of our control scheme benefits from generalized-dependent and-dependent functions,a novel coordinate transformation and“congelation of variables”*** theoretical analysis and numerical simulation verify the effectiveness and benefits of the proposed method.

关键词： Adaptive control global property guaranteed performance uncertain nonlinear systems

The Stability of Traveling Waves with Non-critical Speeds for Some Competition Systems

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Acta Mathematicae Applicatae Sinica 2010年第4期26卷 643-652页

作者： ye Zhao Department of Mathematics and Physics Beijing Institute of Petrolchemical-TechnologyBeijing 102617China

This paper is concerned with some quasilinear cross-diffusion systems which model competing species in mathematical *** detailed spectral analysis,each traveling wave solution with non-critical speed is proved to be l... 详细信息

关键词： traveling waves asymptotic stability spectral analysis

Stressed Lattice Creating New Electric Field for Photoelectrocatalysis

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Chemical Research in Chinese Universities 2020年第4期36卷 725-726页

作者： ye Jinhua National Institute for Materials Science 1-1 NamikiTsukubaIbaraki 305-0044Japan

To improve the water splitting performance of photoelectrode,Wang's group borrowed the lithiation mechanism of Li-ion battery to create ordered lattice strain in the *** stressed lattice induced by Li-jon inser-tion generates a polarized electric field in the bulk,which greatly improves the bulky charge separation and transfer capability and remarkably promotes the photoelectrocatalytic water *** work paves a new avenue for photo electrochemical water splitting towards efficient solar hydrogen *** related work was published in Nature Communications on May 1,2020.

关键词： battery splitting Lattice