Experimental Study on the Motion Process of Radial Retractable Roof Structures

JinYu Lu,Jie Liao,Gan-Ping Shu,Tao Zhang 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.4

In recent years, the use of retractable roofs is increasing to meet the demand of holding big-scale events. This article introduces a class of radial retractable roofs based on the foldable bar structure (FBS) mechanism. A radial retractable roof structure whose moveable section consisted of 6 segments and 6 rigid linkages was designed with appropriate parameters. An experimental study of a radial retractable roof was carried out. A scale model with a 3 metre diameter was constructed to study the roof deflection and vibration during the deployment process under four different load cases. Furthermore, based on the multi-flexible body dynamics theory, an ADAMS-ANSYS co-simulation was applied to simulate the motion process of the radial retractable roof structure. The experimental results were consistent with the numerical simulations. This indicates that the dynamic and fluctuation phenomena of structural behaviour are universal. The structural vibration was increased with the increase of external loads, and the vibration amplitude increased significantly when the roof was starting and braking. With the closing of the movable roof, the deflection of the fixed roof increased significantly. In the motion process, the bending moment of the fixed roof gradually increases, while that of the moving roof varies little. Vertical vibration is significant in the motion process by reason of the complex wheel-rail contact.

Experimental Study and Numerical Simulation on Steel Plate Shear Walls with Non-uniform Spacing Slits

JinYu Lu,XuDong Qiao,Jie Liao,Yi Tang 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.4

Numerous experimental and finite element studies have shown that steel plate shear walls with slits have several beneficial characteristics, such as good ductility and excellent energy dissipation capacity, which make them a feasible lateral load resisting and energy dissipation system for high-rise buildings in high seismic regions. The width of the flexural links between slits has a significant effect on the mechanical behavior and hysteretic performance of steel plate shear walls with slits. This paper presented two kinds of steel plate shear walls with non-uniform spacing slits (SPWNS) and investigated their performance under low-cycle loading based on tests and finite element software. The study mainly focused on the ultimate bearing capacity, the lateral stiffness, the energy dissipation capacity and the ductility of SPWNS. The results from numerical analysis and test study were compared with each other. The ultimate bearing capacity and the lateral stiffness of traditional steel plate shear walls with uniform spacing slits (SPWUS) were similar to that of SPWNS. In contrast, the ductility and the energy dissipation capacity of SPWUS were much higher.

Experimental Study on Low Cyclic Loading Tests of Steel Plate Shear Walls with Multilayer Slits

JinYu Lu,Shunji Yu,XuDong Qiao,Na Li 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.4

A new type of earthquake-resisting element that consists of a steel plate shear wall with slits is introduced. The infi ll steel plate is divided into a series of vertical fl exural links with vertical links. The steel plate shear walls absorb energy by means of in-plane bending deformation of the fl exural links and the energy dissipation capacity of the plastic hinges formed at both ends of the fl exural links when under lateral loads. In this paper, fi nite element analysis and experimental studies at low cyclic loadings were conducted on specimens with steel plate shear walls with multilayer slits. The eff ects caused by varied slit pattern in terms of slit design parameters on lateral stiff ness, ultimate bearing capacity and hysteretic behavior of the shear walls were analyzed. Results showed that the failure mode of steel plate shear walls with a single-layer slit was more likely to be out-of-plane buckling of the fl exural links. As a result, the lateral stiff ness and the ultimate bearing capacity were relatively lower when the precondition of the total height of the vertical slits remained the same. Diff erently, the failure mode of steel plate shear walls with multilayer slits was prone to global buckling of the infi ll steel plates; more obvious tensile fi elds provided evidence to the fact of higher lateral stiff ness and excellent ultimate bearing capacity. It was also concluded that multilayer specimens exhibited better energy dissipation capacity compared with single-layer plate shear walls.

Bio-based Epoxy Thermoset Containing Stilbene Structure with Ultrahigh T<SUB>g</SUB> and Excellent Flame Retardancy

Guangming Lu,Xuezhen Wang,Na Teng,Jingyuan Hu,Liyue Zhang,Jinyue Dai,Yongjia Xu,Sakil Mahmud,Xiaoqing Liu 한국고분자학회 2021 폴리머 Vol.45 No.4

Bio-based epoxy resins with an ultrahigh glass transition temperature (Tg) and excellent flame retardancy are critical for developing sustainable polymers. Herein, a novel trifunctional epoxy monomer triglycidyl ether of resveratrol (TGER) was synthesized from renewable resveratrol. The chemical structure of TGER was confirmed by Fourier transform infrared (FTIR), ¹H, and <SUP>13</SUP>C nuclear magnetic resonance (NMR) spectroscopy which was then reacted with 4,4’-diaminodiphenylmethane (DDM) to form resin. The obtained resin was evaluated in terms of flame retardance and thermal properties. The resultant TGER-DDM 240 resin shows excellent flame-retardant properties, presenting a residual char of 42.5% at 800 ℃, limiting oxygen index (LOI) of 31.2%, and flammability rating of V-0 in UL94 test. Moreover, the resin possesses an ultrahigh Tg at 294 ℃. This work provides a facile method for preparing high-performance flame-retardant epoxy resin from a renewable resource.

Progressive Collapse Behavior of Large-span Truss String Structures Subjected to Cable Failure

Haiying Zhang,JinYu Lu,Xiaolong Wu,Na Li 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.4

Cables play an important role in truss string structures, and their sudden failure can lead to massive damage and even collapse of the structures. This paper studies the dynamic response of a 72 m span truss string structure, the progressive collapse numerical simulation of the structure is carried out under different load conditions, the displacement and force responses of the structure after cable failure are investigated, the dynamic amplification factor is calculated, and the collapse mechanism is revealed. The effect of individual factor changes on the structural response is analyzed and compared. Results showed that after cable failure, the stress state of the upper truss changed from an arch to a simply supported beam, when reaching collapse load, the structure collapsed within 5s instead of reaching new equilibrium positions. Moreover, the structure with stiffer elastic support exhibited higher resistance to collapse. The critical member of the truss, which first buckled under compression, shifted from the mid-span to the lower chord at the end, leading to rapid structural collapse. Increasing the cable's cross-sectional area can hardly reduce the structure's dynamic response. However, when the instantaneous failure time of the cable exceeded 0.1s, a significant alleviation of the structure's dynamic response was observed.

Flexural Behavior of Anchor Horizontal Boundary Element in Steel Plate Shear Wall

Ying Qin,JinYu Lu,Li-Cheng-Xi Huang,Shi Cao 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.3

Steel plate shear walls (SPSWs) have been increasingly used in lateral load resisting system since the post-buckling strength of web plates was realized and considered in practical design. Diagonal tension field is formed in the web plate to resist the lateral force induced by winds and earthquakes. The force is anchored by the surrounded horizontal boundary elements (HBEs) and vertical boundary elements (VBEs) and eventually transferred to the ground. Therefore, the response of HBEs, especially anchor HBEs, is essential to ensure that SPSWs could exhibit the required strength, ductility, and energy dissipation capacity. This paper presents the results of theoretical studies into the flexural behavior of the anchor HBEs of SPSWs and can be regarded as an extension to the previous work by Qu and Bruneau (2011) and Qin et al. (2017). The boundary effect was considered to reflect the actual stress state at the HBE-to-VBE connection, which assembled the method by Qin et al. (2017). Furthermore, more proper distributions of the vertical component of tension field for the positive and negative flexure cases, respectively, were proposed comparing to the work by Qu and Bruneau (2011). The hand calculation approach for the plastic flexural capacity of the anchor HBEs was given by the summation of the contributions from the flanges and the web. The developed equations are compared with previous data and good agreement was found between them. Meanwhile, comprehensively discussions are conducted to evaluate the influence of key parameters on the flexural behavior of anchor HBE. It was found that the plastic flexural capacity of anchor HBE decreases from unity to the minimum as a result of the increase in shear force, axial force and vertical stresses. Moreover, the flexural response of anchor HBE is most vulnerable to the change in shear force. This indicates that boundary effect is significantly important and cannot be ignored in the analysis. The research in this paper provides basis for the capacity design of anchor HBE.

Flexural behavior of beams in steel plate shear walls

Ying Qin,JinYu Lu,Li-Cheng-Xi Huang,Shi Cao 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.23 No.4

Steel plate shear wall (SPSW) system has been increasingly used for lateral loads resisting system since 1980s when the utilization of post-buckling strength of SPSW was realized. The structural response of SPSWs largely depends on the behavior of the surrounded beams. The beams are normally required to behave in the elastic region when the SPSW fully buckled and formed the tension field action. However, most modern design codes do not specify how this requirement can be achieved. This paper presents theoretical investigation and design procedures of manually calculating the plastic flexural capacity of the beams of SPSWs and can be considered as an extension to the previous work by Qu and Bruneau (2011). The reduction in the plastic flexural capacity of beam was considered to account for the presence of shear stress that was altered towards flanges at the boundary region, which can be explained by Saint-Venant’s principle. The reduction in beam web was introduced and modified based on the research by Qu and Bruneau (2011), while the shear stress in the web in this research is excluded due to the boundary effect. The plastic flexural capacity of the beams is given by the superposition of the contributions from the flanges and the web. The developed equations are capable of predicting the plastic moment of the beams subjected to combined shear force, axial force, bending moment, and tension fields induced by yielded infill panels. Good agreement was found between the theoretical results and the data from previous research for flexural capacity of beams.

Strength of Double Skin Steel-Concrete Composite Walls

Ying Qin,Gan-Ping Shu,Shenggang Fan,JinYu Lu,Shi Cao,Jian-Hong Han 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.2

Double skin steel-concrete composite walls have been increasingly used in civil engineering applications. However, the advantages of these walls have not been fully recognized due to the lack of appropriate technical guidelines for capacity design. In this paper, the local buckling strength of steel plate were firstly reviewed in terms of specifications incorporated in several modern codes. A methodology to predict the strength of steel plate with restraint of both concrete and shear studs was proposed based on the explicit solution for local buckling of steel plate in composite shear walls subjected to uniform axial compression and with elastically rotational restraint at loaded and unloaded edges. The results were compared with various previous experimental data and good agreement was observed. Furthermore, the load carrying capacity of composite walls was derived from the superposition of the contribution of steel plate and concrete. The predicted values from the proposed equations, together with the resulted determined from modern codes, were compared with the experimental results. It was found that both the proposed method and JEAG 4618 offer reasonable predictions while AISC 360 and KEPIC-SNG always underestimate the actual values.

Enhanced separation for paraffin wax using CO2-responsive emulsions based on switchable hydrophilicity solvents

Jie Qi,Xiaojiang Li,Xin Lv,Yang Ge,Jinyu Wang,Hongsheng Lu 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.110 No.-

Wax precipitation leads to destructive harms in the exploitation and transportation of petroleum. Solventtreatments can remove paraffin wax easily but the separation of solvent relying on distillation is admittedinefficient. Aiming at enhancing the separation and recovery performance of paraffin wax, CO2-responsive emulsion (SHS/W emulsion) based on switchable hydrophilicity solvents (SHS) is adopted. Since the paraffin wax is dissolved, emulsified, and dispersed by SHS/W emulsion, SHS/W emulsion exhibitsbetter removal performance than SHS. The paraffin wax is recovered effectively upon introducingCO2, which attributes to the transformation of SHS from hydrophobic to hydrophilic state. Comparedwith the SHS system, the recovery of paraffin wax is improved obviously by introducing surfactantSpan80. Owing to the deprotonation of SHS by bubbling N2 and heating, 77.6% SHS is recycled after recoveringparaffin wax. Here, the recycled SHS can be used to realize the removal of paraffin wax again. Thus,it is a promising and alternative strategy for realizing the sustainable and rapid removal of paraffin wax inthe petroleum industry.

Active current-limiting control to handle DC line fault of overhead DC grid

MENG Zhou,WANG Xiang,WENPING Zuo,WEIXING Lin,JINYU Wen,RUIZHANG Yang,BINYE Ni,XIAOJUN Lu 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

To handle with the DC line faults in a DC grid, this paper proposed an active current-limiting controller for hybrid MMC. With this active current-limiting control strategy, the requirement of interruption current of DCCB will be significantly decreased, and the investment of DC grid will be reduced obviously. Firstly, the control architecture of active current-limiting controller is disclosed. To avoid the overvoltage of submodule capacitors during DC fault, a dynamic limiter for the reference value of the DC current controller is proposed. To decrease the peak of fault current, the feedforward controller of DC voltage is put forward. The decoupling controllability of the AC/DC voltage of hybrid MMC is disclosed. The currentlimiting mechanism of the active current-limiting controller is analysis. Then, the validity of the active current-limiting control strategy is verified by RTDS.