Parametric analysis on diagonal bracing joints connected with self-tapping screw

Zhenhua Xu,Guoliang Bai,Biao Liu,Jiarui Li,Yifan Yang 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.41 No.1

In this paper, a three-dimensional finite element model (FEM) was established to study the performance of sliding resistance on the diagonal bracing joints of prefabricated steel frame (PSF) connected with self-tapping screw. In addition, the load-displacement curves of the joints were well verified by the test results, and a parametric study was conducted using the validated models to investigate the effect of steel grade, thickness of the tapped plate, the margin of bolt hole, the end and the central distance of bolt hole. The results showed that with the increase of steel grade, thickness of the tapped plate and the distance of the bolt holes, the anti-slide stiffness and the ultimate bearing capacity of the joint were significantly improved. It was recommended that steel grade should be Q345, Q390 or above. It was advisable to take the thickness of the tapped plate at 0.7d0 ~ 1.0d0, take the margin of bolt hole at 1.2d0 ~ 1.6d0, the central and the end distance of bolt hole should be greater than 2.0d0 and 1.2d0, respectively. The results could provide reference for engineering design.

(PhIO)n Mediated Annulations of Aromatic Aldehyde N-Acylhydrazones for the Synthesis of 1,3,4-Oxadiazoles

Zhenhua Shang,Jing Ha,Xiao Tao,Longpeng Xu,Qing Liu,Pan Wang 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.6

Crack behaviour of top layer in layered rocks

Chang, Xu,Ma, Wenya,Li, Zhenhua,Wang, Hui Techno-Press 2018 Geomechanics & engineering Vol.16 No.1

Open-mode cracks could be commonly observed in layered rocks. A concept model is firstly used to explore the mechanism of the vertical cracks (VCs) in the top layer. Then the crack behaviour of the two-layer model is simulated based on a cohesive zone model (CZM) for layer interfaces and a plastic-damage model for rocks. The model indicates that the tensile stress normal to the VCs changes to compression if the crack spacing to layer thickness ratio is lower than a threshold. The results indicate that there is a threshold for interfacial shear strength that controls the crack patterns of the layered system. If the shear strength is lower than the threshold, the top layer is meshed by the VCs and interfacial cracks (ICs). When the shear strength is higher than the threshold, the top layer is meshed by the VCs and parallel cracks (PCs). If the shear strength is comparative to the threshold, a combining pattern of VCs, PCs and ICs for the top layer can be formed. The evolutions of stress distribution in the crack-bound block indicate that the ICs and PCs can reduce the load transferred for the substrate layer, and thus leads to a crack saturation state.

(PhIO)_n Mediated Annulations of Aromatic Aldehyde N-Acylhydrazones for the Synthesis of 1,3,4-Oxadiazoles

Shang, Zhenhua,Ha, Jing,Tao, Xiao,Xu, Longpeng,Liu, Qing,Wang, Pan Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.6

Robust Stochastic Sampled-data-based Output Consensus of Heterogeneous Multi-agent Systems Subject to Random DoS Attack: A Markovian Jumping System Approach

Hongjie Ni,Zhenhua Xu,Jun Cheng,Dan Zhang 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.7

This paper addresses the robust stochastic sampled-data-based output feedback (SSDBOF) consensuscontroller design for a network of continuous-time heterogeneous multi-agent systems (MASs) in the presence ofdenial-of-service (DoS) attack. Under the mild assumption that the sampling instant is stochastically triggered andsatisfies the Markov property, a homogeneous Markovian jump system (MJS) method is introduced that is capable ofmodeling the stochastic sampled-data-based control system. Furthermore, the randomly occurring Deny-of-Service(DoS) attack problem is also taken into account due to the existence of potential adversary that tries to block thecommunication channels. A novel discrete-time stochastic Markovian system model is first introduced that enablesus to deal with the stochastic sampling and random DoS attack phenomena in a unified framework. Then byadopting the decoupling scheme, some sufficient conditions are proposed such that all the outputs of the followingagents can track the output of the leading agent, and the prescribed H∞ performance level is also guaranteed. Inour work, the SSDBOF consensus controller design method is transformed to a feasibility problem subject to thelinear matrix inequality (LMI) constraints. The theoretical results are finally applied to solve the position trackingproblem of a network of vehicle systems

Thermo-mechanical analysis of angular contact ball bearing

Wei Bian,Zhenhua Wang,Juntang Yuan,Weiwei Xu 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.1

The thermal-mechanical character, which is difficult to ensure because of the lack of a corresponding theory and tool, has a significanteffect on the dynamics of bearings. It even leads to a sudden failure of bearings in a working situation. In this research, a thermal deformationmodel was established, based on the analysis of temperature effect on the basic size of angular contact ball bearing. And thetransmission from rolling size to bearing axial stiffness was explicit. On the basis of the variation of Hertz contact stiffness and thechange of initial contact angle of angular contact ball bearing caused by temperature rise, a “Thermo- mechanical” model of bearing wasproposed. According to this model, using the corresponding calculation procedure programmed by MATLAB, the effect of bearing temperatureon the axial stiffness has been studied. And the correctness of this model was verified with experiments. Some design suggestionshave been made for the decision of bearing preload: to prevent the bearing failure caused by overheating.

An Accurate Method to Estimate Traffic Matrices from Link Loads for QoS Provision

Wang, Xingwei,Jiang, Dingde,Xu, Zhengzheng,Chen, Zhenhua The Korea Institute of Information and Commucation 2010 Journal of communications and networks Vol.12 No.6

Effective traffic matrix estimation is the basis of efficient traffic engineering, and therefore, quality of service provision support in IP networks. In this study, traffic matrix estimation is investigated in IP networks and an Elman neural network-based traffic matrix inference (ENNTMI) method is proposed. In ENNTMI, the conventional Elman neural network is modified to capture the spatio-temporal correlations and the time-varying property, and certain side information is introduced to help estimate traffic matrix in a network accurately. The regular parameter is further introduced into the optimal equation. Thus, the highly ill-posed nature of traffic matrix estimation is overcome effectively and efficiently.

magnetostratigraphy, 26Al-10Be, Yx02 borehole, tectonic evolution, Daxing Uplift, Beijing Sub-plain

Fubing He,Xiwei Xu,Fang Tian,Zhenhua Liu,Yueze Zhang,Lingyan Bai,Yubin Cui,Kai Wang,Wenzhi Niu,Jingbo Ni,Xiaoyong Liu,Mengmeng Cao 한국지질과학협의회 2024 Geosciences Journal Vol.28 No.2

The buried Daxing Uplift connects the Beijing Sag and Dachang Sag, which is the critical tectonic unit for understanding the structural evolution of the Beijing Sub-plain and its linkages to regional tectonics. This study combines paleomagnetic, 26Al-10Be isochron dates and sedimentary analyses from a new borehole (Yx02) in the northeastern Beijing Sub-plain to shed fresh light on regional tectonic processes and the sedimentary history since the Pliocene. The main findings are as follows: (1) the Daxing Uplift had formed three depositional episodes: alluvial-fan, lacustrine-delta, and alluvial-fan sedimentation since the Cenozoic; (2) The borehole records the Brunhes, Gauss normal chron, and the Matuyama, Gilbert reversed chron in the Daxing Uplift, the corresponding depths are 0–148.9 m, 148.9–315.0 m, 315.0–520.5 m and 520.5–650 m; (3) An important tectonic event started in ~4.3 Ma, disintegrated NE-trending basin and range terrain, reactivated the NW-trending Nankou-Sunhe fault, and formed Shunyi fault in Beijing Sub-plain. Sedimentation occurs exclusively in the Beijing Sag and the northeastern Daxing Uplift during ~4.3–1.77 Ma; (4) During ~1.77–1.07 Ma, a transition from an extension to a strike-slip occurred, and is described not only in a progressively higher increase of the overall deposition rate, but also in a decrease of the relative deposition disparity between sags and uplifts. Since then, the Beijing Sub-plain has been shaped, associated with an overall subsidence depression in the Bohai Bay Basin. This work enhances our understanding of the formation and evolution of the Beijing Sub-plain, the division of tectonic episodes, and the initiation time of the latest tectonic movement in the break-up region, North China Craton, since the Neogene.

An Accurate Method to Estimate Traffic Matrices from Link Loads for QoS Provision

Xingwei Wang,Dingde Jiang,Zhengzheng Xu,Zhenhua Chen 한국통신학회 2010 Journal of communications and networks Vol.12 No.6

Effective traffic matrix estimation is the basis of efficient traffic engineering, and therefore, quality of service provision support in IP networks. In this study, trafficmatrix estimation is investigated in IP networks and an Elman neural network-based traffic matrix inference (ENNTMI) method is proposed. In ENNTMI,the conventional Elman neural network is modified to capture the spatio-temporal correlations and the time-varying property, and certain side information is introduced to help estimate traffic matrix in a network accurately. The regular parameter is further introduced into the optimal equation. Thus, the highly ill-posed nature of traffic matrix estimation is overcome effectively and efficiently.

Thermostability of Monolithic and Reinforced Al-Fe-V-Si Materials

He, Yiqiang,Qiao, Bin,Wang, Na,Yang, Jianming,Xu, Zhengkun,Chen, Zhenhua,Chen, Zhigang The Korean Society for Composite Materials 2009 Advanced composite materials Vol.18 No.4

Al-Fe-V-Si alloys reinforced with SiC particles were prepared by multi-layer spray deposition technique. Both microstructures and mechanical properties including hardness and tensile properties development during hot exposure process of Al-8.5Fe-1.3V-1.7Si, Al-8.5Fe-1.3V-1.7Si/15 vol% $SiC_P$ and Al-10.0Fe-1.3V-2Si/15 vol% $SiC_P$ were investigated. The experimental results showed that an amorphous interface of about 3 nm in thickness formed between SiC particles and the matrix. SiC particles injected silicon into the matrix; thus an elevated silicon concentration was found around $\alpha-Al_{12}(Fe,\;V)_3Si$ dispersoids, which subsequently inhibited the coarsening and decomposition of $\alpha-Al_{12}(Fe,\;V)_3Si$ dispersoids and enhanced the thermostability of the alloy matrix. Moreover, the thermostability of microstructure and mechanical properties of Al-10.0Fe-1.3V-2Si/15 vol% $SiC_P$ are of higher quality than those of Al-8.5Fe-1.3V-1.7Si/15 vol% $SiC_P$.