Mechanical Behavior of Composite Beams Considering Nonlinear Shear Stiffness of Clustered Studs

Duo Liu,Ding Zhou,Bohai Ji,Wenqin Deng,Shang Zha,Jiandong Zhang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.4

Clustered studs are suitable for use in prefabricated steel-concrete composite beams. As a kind of shear connector, clustered studs have a non-negligible influence on the mechanical behavior of structures. Based on the theory of elasticity, prefabricated composite beams investigated via laminated plane stress problem. The load-slip curves of the shear connectors are linearly processed, and through iterative calculations, the displacement and stress distribution functions of prefabricated composite beams are obtained. Then, a model test is carried out on the positive bending moment section of prefabricated composite beams. A sampling method with front segments controlled by the load and back segments controlled by the slip is adopted. This method provides a better rate of convergence and higher accuracy than those of other methods. The test results show that when the load is small and the composite beam is in the elastic stage, the slope of the load-slip curve can be used as the shear stiffness of the clustered studs. When the load is large and the composite beam enters the plastic stage, the nonlinear shear stiffness of the studs must be considered to obtain a high-precision solution.

어학 : 중국의 한어신사 보급도연구

유다리 ( Duo Li Liu ) 한국중국학회 1998 國際中國學硏究 Vol.1 No.-

Novel Structural Composite Yarns Spun with Harmonic Migrations of Filaments

Duo Xu,Hang Fan,Wangwang Yang,Keshuai Liu,Weilin Xu 한국섬유공학회 2022 Fibers and polymers Vol.23 No.6

A novel structural composite yarn was fabricated by periodically forcing filaments with harmonic migrations toenhance the cooperativity between filaments and staple fibers. The geometrical principle of yarn structure variations causedby harmonic migrations of filaments was theoretically analyzed, then demonstrated the influences of filament’s positions ondifferent shapes of the composite spinning-triangle zone. Further, the novel structural composite yarn structure was comparedto the seven models of composite yarns which were established with different filament’s positions, showing a varied filamenthelical structure to capture and then lock internal and external staple fibers, distinguishing that other composite yarns inliterature. Then, a synergetic eccentric device was employed to oscillate two filaments to conduct confirmatory tests. Theonline observations of the dynamic spinning-triangle zone were technically applied to evaluate the filaments’ harmonicmigrations. Furthermore, the yarn structural variations were caused by various geometrical configurations. Experimentalresults exhibited that the novel structural composite yarn had relatively fewer hairiness, medium irregularity, and strengthafter comparisons with other composite yarns. Altogether, the cyclically harmonic migrations of filaments were promising asan efficient and novel method for control the configurations between filaments and staple fibers.

Applying the statistical experimental method to evaluate the process conditions of TiO_2 nanotube arrays by anodization method

Rui Liu,Ching-Shieh Hsieh,Wein-Duo Yang,Liang-Sheng Qiang,Jian-Fu Wu 한국물리학회 2011 Current Applied Physics Vol.11 No.6

Vertically oriented TiO_2 nanotube arrays were successfully produced by the anodization technique in NH_4F/H_3PO_4 electrolyte. The structure and morphology were characterized by X-ray diffraction (XRD)and field emission scanning electron microscopy (FE-SEM). It is found that TiO_2 nanotube arrays annealed at 500 ℃ containing 100% anatase phase and entirely converted into rutile at 800 ℃. The response surface methodology (RSM) and Box-Behnken design were applied to find the optimal factor conditions in production of TiO_2 nanotube arrays. Based on the results in preliminary experiments, we selected anodization time, anodization voltage and NH4F concentration as the key factors to investigate their effects on responses. The regression models were built by fitting the experimental results with a second-order polynomial. By using the regression models, the optimal factor conditions were obtained as follows: anodization time of 300 min; anodization voltage of 15.39 V; NH_4F concentration of 0.50 M. Corresponding to the optimal factor conditions, the predicted average length and diameter of nanotube array were 1429 nm and 33 nm, respectively. Confirmation experiments using the optimized conditions were performed: TiO_2 nanotube arrays were obtained with an average tube length of 1420 nm and average tube diameter of 36 nm. The experimental results are in good agreement with the predicted results.

On the plane geometry design method of the loop-free hyperbolic single-layer cable structures

Renjie Liu,Jiajia Cao,Hang Zhao,Su-Duo Xue,Guangyong Wang,Jin Liang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.10

The plane geometry design of the cable-net structure is the basis for the form-finding and structural design. The loop-free single-layer cable-net structure is a new cable-net scheme, but due to its special and complex shape, it is difficult to determine its plane geometry according to architectural requirements. In this paper, the moving support node method is proposed, which can quickly get the plane geometry of a loop-free single-layer cable-net structure. The form-finding is proceeded based on the existing small elastic modulus method. There are two constraints when using the moving support node method. One is that the projection of all cables is straight line, and the other is that the distance between the two cables of each support node and the inner boundary of the target is equal. The aim is to minimize the sum of the distances from all cables to the inner boundary of the target. Using the plane geometry control parameters and the plane coordinates of the support nodes as decision variables, the plane geometry closest to the target inner and outer boundaries is get through optimization analysis. According to the derivation of the formula, the plane projection shape of a loop-free single-layer cable-net structure is mainly related to three parameters, including the number of supports, the difference between the node numbers of the supports at both ends of each cable, and the target curve equations of the inner and outer boundaries. Finally, taking the roof structure of Linyi Olympic Stadium as an instance, the feasibility of the plane geometry design method of the loop-free single-layer cable-net structures based on the moving support node method is verified.

Concept Proposal and Feasibility Verification of the Annular Crossed Cable-Truss Structure

Su-Duo Xue,Renjie Liu,Xiongyan Li,Marijke Mollaert 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.4

A new concept for improving the robustness of pre-stressed spatial structures was introduced. The purpose of this concept is to avoid existing key elements by creating an alternative load path for every structural member. With this new concept, the Annular Crossed Cable-Truss Structure was proposed. How to defining the target geometry, force-finding, and designing connections for the Annular Crossed Cable-Truss Structure were illustrated by means of designing an experimental set-up. Feasibility of the structure, including self-weight, structural stiffness, and structural adaptability in asymmetric load arrangement, was discussed based on experimental results. The results show that the Annular Crossed Cable-Truss Structure can have a light self-weight, reasonable structural stiffness, and acceptable adaptability in asymmetric load arrangement. It is concluded that the Annular Crossed Cable-Truss Structure is a feasible pre-stressed spatial structure.

Gefitinib Alone or with Concomitant Whole Brain Radiotherapy for Patients with Brain Metastasis from Non-small-cell Lung Cancer: A Retrospective Study

Zeng, Yin-Duo,Zhang, Li,Liao, Hai,Liang, Ying,Xu, Fei,Liu, Jun-Ling,Dinglin, Xiao-Xiao,Chen, Li-Kun Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.3

Background: Gefitinib, a tyrosine kinase inhibitor (TKI) of epidermal growth factor receptor (EGFR), is used both as a single drug and concurrently with whole brain radiotherapy (WBRT) the standard treatment for brain metastases (BM), and is reported to be effective in a few small studies of patients with BM from non-small-cell lung cancer (NSCLC). However, no study has compared the two treatment modalities. This retrospective analysis was conducted to compare the efficacy of gefitinib alone with gefitinib plus concomitant WBRT in treatment of BM from NSCLC. Methods: We retrospectively reviewed 90 patients with BM from NSCLC who received gefitinib alone (250mg/day, gefitinib group) or with concomitant WBRT (40Gy/20f/4w, gefitinib-WBRT group) between September 2005 and September 2009 at Sun Yat-Sen University Cancer Center. Forty-five patients were in each group. Results: The objective response rate of BM was significantly higher in gefitinib-WBRT group (64.4%) compared with gefitinib group (26.7%, P<0.001). The disease control rate of BM was 71.1% in gefitinib-WBRT group and 42.2% in gefitinib group (P=0.006). The median time to progression of BM was 10.6 months in gefitinib-WBRT group and 6.57 months in gefitinib group (P<0.001). The median overall survival(OS) of gefitinib-WBRT and gefitinib alone group was 23.40 months and 14.83 months, respectively (HR, 0.432, P=0.002). Conclusion: Gefitinib plus concomitant WBRT had higher response rate of BM and significant improvement in OS compared with gefitinib alone in treatment of BM from NSCLC.

A new SDOF method of one-way reinforced concrete slab under non-uniform blast loading

Wei Wang,Duo Zhang,Fangyun Lu,Ruichao Liu 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.46 No.5

A new effective model for calculation of the equivalent uniform blast load for non-uniform blast load such as close-in explosion of a one-way square and rectangle reinforced concrete slab is proposed in this paper. The model is then validated using single degree of freedom (SDOF) system with the experiments and blast tests for square slabs and rectangle slabs. Test results showed that the model is accurate in predicting the damage level on the tested RC slabs under the given explosive charge weight and stand-off distance especially for close-in blast load. The results are also compared with those obtained by conventional SDOF analysis and finite element (FE) analysis using solid elements. It is shown that the new model is more accurate than the conventional SDOF analysis and is running faster than the FE analysis.

Behavior of Cantilever Composite Girder Bridges with CSWs under Eccentric Loading

Wenqin Deng,Duo Liu,Zongqing Peng,Jiandong Zhang 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.10

A study on the torsion and distortion properties of the cantilever single-box three-cell composite girder bridge with corrugated steel webs (CSWs) is carried out based on experimental testing and finite element model analysis. Firstly, the mechanical characteristics such as the deformation, longitudinal warping normal stress were investigated based on a double cantilever girder model test. Secondly, the influence of parameters such as girder height, box width and corrugated steel web thickness on the warping stress of cantilever composite girder with CSWs under eccentric load were analyzed based on the finite element model. Finally, the eccentric load effect of the composite bridge with CSWs at the maximum cantilever construction stage under different load combinations was analyzed based on a finite element model of the real bridge. The results show that the longitudinal warping strain of the CSWs is significantly smaller than that of the top and bottom concrete slabs under eccentric loading due to the accordion effect. The maximum warping normal stress occurs at the corners of the bottom concrete slab. The additional shear stress of the steel webs distributes uniformly along the girder height, and the additional stress of the web on the loading side is clearly greater than that at the middle. The finite element parameter analysis results show that the height and width have a significant influence on the warping stress of single box three-cell composite girder with CSWs, and the thickness of CSWs has almost no effect. In practical engineering, the warping stress of the bottom slab accounts for approximately 20% of the bending stress when the self-weight is considered. Therefore, it is not trivial to consider the influence of the warping normal stress of a concrete slab and the additional shear stress of the CSWs in the design and calculation of this type of bridge.

Arge aurora Wei sp. nov. (Hymenoptera, Argidae) from China with a key to East Asian species of Arge nipponensis group

Wan Siying,Wu Duo,Niu Gengyun,Liu Ting,Wei Meicai 한국곤충학회 2022 Entomological Research Vol.52 No.1

Arge nipponensis group is proposed for 12 East Asian species. A key to species of this group is provided. Arge aurora Wei, sp. nov., a widespread species in China is described. It has been misidentified as Arge nipponensis Rohwer, 1910 in China since 1927. Arge nipponensis Rohwer is removed from the faunal list of China. The ovipositor and genitalia of A. nipponensis are described and figured for the first time. The geographic distribution analysis indicated that geographical barriers were probably the key to the distribution of A. aurora and A. nipponensis.