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Numerical Simulation of Response of SRC Columns Subjected to Blast Loading

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Transactions of Tianjin University 2006年第B09期12卷 126-131页

作者： SUN Jianyun li guoqiang LU Yong College of Civil Engineering Tongji University Shhnghai 200092China School of Civil and Environmental Engineering Nanyang Technological University Nanyang Avenue Singapore 639798 Singapore

The dynamic characteristics and failure modes of steel reinforced concrete (SRC) columns subjected to blast loading are complicated because of the transient stress wave in the SRC columns and the interaction between steel and concrete. This paper presents a numerical simulation of the response of SRC columns subjected to blast loading using hydrocode LS-DYNA. In the numerical model, a sophisticate concrete material model (the Concrete Damage Model) is employed with consideration of the strain rate effect and the damage accumulation. An erosion technique is adopted to model the spalling process of concrete. The possible failure modes of SRC columns are evaluated. It is observed that the failure of SRC columns subjected to blast load can generally be classified into three modes, namely, a direct failure in concrete body due to the stress wave, a transverse shear failure near the support sections due to the high shear force, and a flexural failure pertaining to large local and global deformation of the reinforcing steel.

关键词： blast steel reinforced concrete column failure mode concrete damage model

Metaheuristic-based inverse design of materials--A survey

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Journal of Materiomics 2020年第2期6卷 414-430页

作者： T.Warren liao guoqiang li Mechanical&Industrial Engineering Department Louisiana State UniversityBaton RougeLA70803USA

There is a growing interest in the inverse approach to material deign,in which the desired target properties are used as input to identify the atomic identity,composition and structure(ACS)that exhibit such *** an overview,this paper surveys and summarizes previous works in metaheuristicbased inverse design of various *** basics of metaheuristic-based inverse design of materials are presented,including feature identification(fingerprinting),machine learning of ACS→property models(forward design),metaheuristic algorithms for property→ACS predictions(inverse design),and experimental validations,with focus on inverse *** past studies are organized into a two-level hierarchy with how properties are predicted at the higher level,either by first principles,simulation,or machine learning model,and the number of target properties considered at the lower level,either one or more than *** uniqueness and limitation of previous research are discussed and several possible topics for future research are *** review intends to serve as the steppingstone/springboard for those interested in advancing this area of research.

关键词： Inverse design Materials Metaheuristics Machine learning Fingerprinting

Optimal design and dynamic impact tests of removable bollards

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Earthquake Engineering and Engineering Vibration 2017年第4期16卷 793-802页

作者： Chen Suwen liu Tianyi li guoqiang liu Qing Sun Jianyun State Key Laboratory for Disaster Reduction in Civil Engineering Shanghai 200092China College of Civil Engineering Tongji UniversityShanghai 200092China China State Construction Engineering Corp.Ltd.Beijing 101300China

Anti-ram bollard systems, which are installed around buildings and infrastructure, can prevent unauthorized vehicles from entering, maintain distance from vehicle-borne improvised explosive devices （VBIED） and reduce the corresponding damage. Compared with a fixed bollard system, a removable bollard system provides more flexibility as it can be removed when needed. This paper first proposes a new type of K4-rated removable anti-ram bollard system. To simulate the collision of a vehicle hitting the bollard system, a finite element model was then built and verified through comparison of numerical simulation results and existing experimental results. Based on the orthogonal design method, the factors influencing the safety and economy of this proposed system were examined and sorted according to their importance. An optimal design scheme was then produced. Finally, to validate the effectiveness of the proposed design scheme, four dynamic impact tests, including two front impact tests and two side impact tests, have been conducted according to BSI Specifications. The residual rotation angles of the specimen are smaller than 30~ and satisfy the requirements of the BSI Specification.

关键词： removable anti-ram bollards optimal design orthogonal design method dynamic impact test

Structural characterization and strengthening mechanism of forsterite nanostructured scaffolds synthesized by multistep sintering method

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Journal of Materials Science & Technology 2018年第12期34卷 2263-2270页

作者： Fariborz Tavangarian Abbas Fahami guoqiang li Mohammadhassan Kazemi Anoosha Forghani Mechanical Engineering Program School of ScienceEngineering and TechnologyPennsylvania State University Department of Mechanical Engineering Texas A&M University Department of Mechanical and industrial Engineering Louisiana State University Department of Mechanical and Aerospace Engineering University at Buffalo Department of Biomedical Engineering Millennium Science ComplexPennsylvania State UniversityUniversity Park

In this study, highly porous forsterite scaffolds with interconnected porosities were synthesized using multi-step sintering(MSS) method. The starting powder was nanosized forsterite, which was synthesized from talc and magnesium carbonate powders. The phase composition, average particle size and morphology of the produced forsterite powder were characterized by X-ray diffraction technique(XRD) and transition electron microscopy(TEM). Forsterite scaffolds were produced by foamy method using polymeric sponges. MSS process including three steps was used to efficiently sinter the forsterite nanopowders without destroying the initial porous structure of polymeric sponges. The results showed that MSS technique is an efficient and appropriate procedure to produce highly porous forsterite scaffolds with pore size in the range of 100-300 μm. The compressive strength, compressive modulus and porosity of C12 specimen(sintered at 1650℃ for 1 h with subsequent annealing at 1000℃ for 1000 min) was 1.88 MPa, 29.2 MPa, and 72.4%, respectively, which is very close to that of cancellous bone. The approach studied in this research can be developed for other nanostructure ceramics to produce highly porous scaffolds with interconnected porosities for load bearing applications.

关键词： Forsterite Multi-step sintering Scaffolds Porosity

Evaluation of redundancy-based system: a model checking approach

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Science China(Information Sciences) 2018年第6期61卷 241-243页

作者： ling FANG Chunyan MU Zhuo CHENG guoqiang li Institute of Technology Innovation Hefei Institutes of Physical Science Chinese Academy of Sciences School of Computing Teesside University State International S&T Cooperation Base of Networked Supporting Software Jiangxi Normal University School of Software Shanghai Jiao Tong University

Dear editor,Functional redundancy is a key and well-known fault tolerance scheme for which there are functionally equivalent versions that can rescue a system from execution failure and improve its reliability with **... 详细信息

关键词： NVP RB a model checking approach Evaluation of redundancy-based system

Sarcocinerenoids A—J,Eight Rare Capnosane-Type and Two New Cage-Type Cembranoids with Promoting Angiogenesis Activity from the South China Sea Soft Coral Sarcophyton cinereum

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Chinese Journal of Chemistry 2024年第8期42卷 815-822页

作者： Yue Mi Yanan Yang Xuli Tang Xiao Han guoqiang li Key Laboratory of Marine Drugs Chinese Ministry of EducationSchool of Medicine and PharmacyOcean University of ChinaQingdaoShandong266003 China Laboratory of Marine Drugs and Biological Products National Laboratory for Marine Science and TechnologyQingdaoShandong266235 China College of Chemistry and Chemical Engineering Ocean University of ChinaQingdaoShandong266100 China

Backgroundand Originality Content,Cembranoids are a structurally diverse class of diterpenoids commonly occurring in marine and terrestrial organisms.(+)-Cembrene was the first reported cembranoid diterpenoid discovered in 1962,l and more than 1400 cembranoid diterpenoids have been identified in the last six decades,[2]Cembranoids are characterized by a 14-membered carbocyclic ring,an isopropyl group and three methyl groups,which form their core carbon *** processes such as oxidation,oxidative rearrangements and transannular cyclizations occur in organisms,leading to the formation of distinctive specialized metabolites such as epoxide,lactone,ester,furan,pyrane and other ringbased cembranoids.[2-3]

关键词： Soft coral Sarcophyton cinereum Capnosane-type cembranoids Absolute configurations Activities Natural products NMR spectroscopy liquid chromatography X-raydiffraction Chiral resolution

DYNAMIC ANALYSIS OF AN SIR MODEL WITH STOCHASTIC PERTURBATIONS

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International Journal of Biomathematics 2013年第6期6卷 63-77页

作者： ZHENJIE liU JINliANG WANG YALAN XU guoqiang li Department of Mathematics Harbin University Harbin Heilongjiang 150086 P. R. China School of Mathematical Science Heilongjiang University Harbin Heilongjiang 150080 P. R. China

In this paper, we present a differential infectivity SIR epidemic model with modified saturation incidences and stochastic perturbations. We show that the stochastic epidemic model has a unique global positive solutio... 详细信息

关键词： Epidemiological model Ito's formula stochastic Lyapunov function asymptotic behavior.

ZenLDA: Large-Scale Topic Model Training on Distributed Data-Parallel Platform

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Big Data Mining and Analytics 2018年第1期1卷 57-74页

作者： Bo Zhao Hucheng Zhou guoqiang li Yihua Huang the National Key Laboratory for Novel Software Technology Nanjing University Collaborative Innovation Center of Novel Software Technology and Industrialization Microsoft Research Huawei Technologies Co. Ltd.

Recently, topic models such as Latent Dirichlet Allocation(LDA) have been widely used in large-scale web mining. Many large-scale LDA training systems have been developed, which usually prefer a customized design from top to bottom with sophisticated synchronization support. We propose an LDA training system named ZenLDA, which follows a generalized design for the distributed data-parallel platform. The novelty of ZenLDA consists of three main aspects:(1) it converts the commonly used serial Collapsed Gibbs Sampling(CGS) inference algorithm to a Monte-Carlo Collapsed Bayesian(MCCB) estimation method, which is embarrassingly parallel;(2)it decomposes the LDA inference formula into parts that can be sampled more efficiently to reduce computation complexity;(3) it proposes a distributed LDA training framework, which represents the corpus as a directed graph with the parameters annotated as corresponding vertices and implements ZenLDA and other well-known inference methods based on Spark. Experimental results indicate that MCCB converges with accuracy similar to that of CGS, while running much faster. On top of MCCB, the ZenLDA formula decomposition achieved the fastest speed among other well-known inference methods. ZenLDA also showed good scalability when dealing with large-scale topic models on the data-parallel platform. Overall, ZenLDA could achieve comparable and even better computing performance with state-of-the-art dedicated systems.

关键词： latent Dirichlet allocation collapsed Gibbs sampling Monte-Carlo graph computing large-scale machine learning

Stability analysis of Alfvén eigenmodes in China Fusion Engineering Test Reactor fully non-inductive and hybrid mode scenarios

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Plasma Science and Technology 2021年第4期23卷 21-29页

作者： Wenjun YANG guoqiang li Xueyu GONG Xiang GAO Xiaoe li University of South China Hengyang 421001People’s Republic of China Institute of Plasma Physics Chinese Academy of SciencesHefei 230031People’s Republic of China

In this paper, NOVA/NOVA-K codes are used to investigate the stability of Alfvén eigenmodes(AEs) in the China Fusion Engineering Test Reactor(CFETR). Firstly, the stability of AEs excited by energetic alpha particles is investigated. For the fully non-inductive scenario, it is found that all AEs are stable, and the least stable toroidal mode number is n= 8. However, for the hybrid mode scenario, it is found that many AEs are unstable, and the least stable toroidal mode numbers are n= 7, 8. Secondly, the effect of energetic alpha-particle parameters and beam ions on AE stability is also presented. The threshold of the least stable AE is about βcrit,α = 1.12%,crit,less than the value of alpha-particle beta(βα=1.34%). The result demonstrates that the AEs excited by alpha particles are weakly unstable. The effect of the beam ions on AE stability is found to be very weak in CFETR.

关键词： energetic particle Alfven eigenmode NOVA/NOVA-K CFETR