Nonlinear wind-induced instability of orthotropic plane membrane structures

Liu, Changjiang,Ji, Feng,Zheng, Zhoulian,Wu, Yuyou,Guo, Jianjun Techno-Press 2017 Wind and Structures, An International Journal (WAS Vol.25 No.5

The nonlinear aerodynamic instability of a tensioned plane orthotropic membrane structure is theoretically investigated in this paper. The interaction governing equation of wind-structure coupling is established by the Von $K\acute{a}rm\acute{a}n's$ large amplitude theory and the D'Alembert's principle. The aerodynamic force is determined by the potential flow theory of fluid mechanics and the thin airfoil theory of aerodynamics. Then the interaction governing equation is transformed into a second order nonlinear differential equation with constant coefficients by the Bubnov-Galerkin method. The critical wind velocity is obtained by judging the stability of the second order nonlinear differential equation. From the analysis of examples, we can conclude that it's of great significance to consider the orthotropy and geometrical nonlinearity to prevent the aerodynamic instability of plane membrane structures; we should comprehensively consider the effects of various factors on the design of plane membrane structures; and the formula of critical wind velocity obtained in this paper provides a more accurate theoretical solution for the aerodynamic stability of the plane membrane structures than the previous studies.

Nonlinear wind-induced instability of orthotropic plane membrane structures

Changjiang Liu,Feng Ji,Zhoulian Zheng,Yuyou Wu,Jianjun Guo 한국풍공학회 2017 Wind and Structures, An International Journal (WAS Vol.25 No.5

he nonlinear aerodynamic instability of a tensioned plane orthotropic membrane structure is theoretically investigated in this paper. The interaction governing equation of wind-structure coupling is established by the Von Kármán\'s large amplitude theory and the D\'Alembert\'s principle. The aerodynamic force is determined by the potential flow theory of fluid mechanics and the thin airfoil theory of aerodynamics. Then the interaction governing equation is transformed into a second order nonlinear differential equation with constant coefficients by the Bubnov-Galerkin method. The critical wind velocity is obtained by judging the stability of the second order nonlinear differential equation. From the analysis of examples, we can conclude that it\'s of great significance to consider the orthotropy and geometrical nonlinearity to prevent the aerodynamic instability of plane membrane structures; we should comprehensively consider the effects of various factors on the design of plane membrane structures; and the formula of critical wind velocity obtained in this paper provides a more accurate theoretical solution for the aerodynamic stability of the plane membrane structures than the previous studies.

Selection of Potential Virulence Factors Contributing to Streptococcus suis Serotype 2 Penetration into the Blood-Brain Barrier in an In Vitro Co-Culture Model

( Hongtao Liu ),( Seng Zhu ),( Yingying Sun ),( Na Li ),( Jingmin Gu ),( Changjiang Sun ),( Xin Feng ),( Wenyu Han ),( Jianxia Jiang ),( Liancheng Lei ) 한국미생물 · 생명공학회 2017 Journal of microbiology and biotechnology Vol.27 No.1

Meningitis caused by Streptococcus suis serotype 2 (S. suis 2) is a great threat to the pig industry and human health. Virulence factors associated with the pathogenesis of meningitis have yet to be clearly defined, even though many potential S. suis 2 virulence factors have been identified. This greatly hinders the progress of S. suis 2 meningitis pathogenesis research. In this study, a co-culture blood-brain barrier (BBB) model was established using primary porcine brain microvascular endothelial cells and astrocytes, and the whole genome library of S. suis 2 was constructed using phage display technology. Finally, a total of 14 potential virulence factors contributing to S. suis 2 adherence to and invasion of the BBB were selected by analyzing the interactions between the phage library and the co-culture model. Twelve of these factors have not been previously reported in meningitis-related research. The data provide valuable insight into the pathogenesis of S. suis 2 meningitis and potential targets for the development of drug therapies.

High-Strength Model Material Production for Structural Plane Replica and Its Shear Testing

Feng Ji,Changjiang Liu,Yu Zhang,Luobing Zheng,Kai Pan,Xun Tan 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.1

Shear strength parameters (c, φ) of a structural plane are the key factors for the stability assessment of rock masses. The shear strength parameters are obtained by a structure plane shear test carried out in laboratory. However, it is difficult to obtain test samples with the same surface morphology and to remove the effect of surface irregularity from test results. Based on the similarity principle and orthogonal test, this paper presents a new model preparation method for structural planes using a high-strength mold mixture material. Firstly, the original morphology of the structural plane is recorded by in situ measurement using a laser device and then the mold of the structural plane is reproduced using a 3D printer. Subsequently, a mix proportion test of the high-strength mold material is conducted using the orthogonal test, and the model of the structural plane is prepared by pouring this high-strength mixture material into the 3D mold. Ultimately, the shear strength parameters of this high-strength structural plane replica are obtained using a shear box test in the laboratory. The proposed method has particular advantages such as the preparation of multiple replicas for structure planes and the ability to obtain repeatable results.

Nonlinear aerodynamic stability analysis of orthotropic membrane structures with large amplitude

Zhoulian Zheng,Yunping Xu,Changjiang Liu,Xiaoting He,Weiju Song 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.37 No.4

The aerodynamic stability of orthotropic tensioned membrane structures with rectangular plane is theoretically studied under the uniform ideal potential flow. The aerodynamic force acting on the membrane surface is determined by the potential flow theory in fluid mechanics and the thin airfoil theory in aerodynamics. Then, based on the large amplitude theory and the D'Alembert's principle, the interaction governing equation of wind-structure is established. Under the circumstances of single mode response, the Bubnov-Galerkin approximate method is applied to transform the complicated interaction equation into a system of second order nonlinear differential equation with constant coefficients. Through judging the stability of the system characteristic equation, the critical divergence instability wind velocity is determined. Finally, from different parametric analysis, we can conclude that it has positive significance to consider the characteristics of orthotropic and large amplitude for preventing the instability destruction of structures.

Studies on seismic performance of the new section steel beam-wall connection joint

Weicheng Su,Jian Liu,Changjiang Liu,Chiyu Luo,Weihua Ye,Yaojun Deng 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.88 No.5

This paper introduces a new hybrid structural connection joint that combines shear walls with section steel beams, fundamentally resolving the construction complexity issue of requiring pre-embedded connectors in the connection between shear walls and steel beams. Initially, a quasi-static loading scheme with load-deformation dual control was employed to conduct low-cycle repeated loading experiments on five new connection joints. Data was acquired using displacement and strain gauges to compare the energy dissipation coefficients of each specimen. The destruction process of the new connection joints was meticulously observed and recorded, delineating it into three stages. Hysteresis curves and skeleton curves of the joint specimens were plotted based on experimental results, summarizing the energy dissipation performance of the joints. It's noteworthy that the addition of shear walls led to an approximate 17% increase in the energy dissipation coefficient. The energy dissipation coefficients of dog-bone-shaped connection joints with shear walls and cover plates reached 2.043 and 2.059, respectively, exhibiting the most comprehensive hysteresis curves. Additionally, the impact of laminated steel plates covering composite concrete floors on the stiffness of semi-rigid joint ends under excessive stretching should not be disregarded. A comparison with finite element analysis results yielded an error of merely 2.2%, offering substantial evidence for the wide-ranging application prospects of this innovative joint in seismic performance.

Nonlinear aerodynamic stability analysis of orthotropic membrane structures with large amplitude

Zheng, Zhoulian,Xu, Yunping,Liu, Changjiang,He, Xiaoting,Song, Weiju Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.37 No.4

The aerodynamic stability of orthotropic tensioned membrane structures with rectangular plane is theoretically studied under the uniform ideal potential flow. The aerodynamic force acting on the membrane surface is determined by the potential flow theory in fluid mechanics and the thin airfoil theory in aerodynamics. Then, based on the large amplitude theory and the D'Alembert's principle, the interaction governing equation of wind-structure is established. Under the circumstances of single mode response, the Bubnov-Galerkin approximate method is applied to transform the complicated interaction equation into a system of second order nonlinear differential equation with constant coefficients. Through judging the stability of the system characteristic equation, the critical divergence instability wind velocity is determined. Finally, from different parametric analysis, we can conclude that it has positive significance to consider the characteristics of orthotropic and large amplitude for preventing the instability destruction of structures.

Effect of Sea Buckthorn Leaves on Inosine Monophosphate and Adenylosuccinatelyase Gene Expression in Broilers during Heat Stress

Zhao, Wei,Chen, Xin,Yan, Changjiang,Liu, Hongnan,Zhang, Zhihong,Wang, Pengzu,Su, Jie,Li, Yao Asian Australasian Association of Animal Productio 2012 Animal Bioscience Vol.25 No.1

The trial was conducted to evaluate the effects of sea buckthorn leaves (SBL) on meat flavor in broilers during heat stress. A total 360 one-day-old Arbor Acre (AA) broilers (male) were randomly allotted to 4 treatments with 6 replicates pens pretreatment and 15 birds per pen. The control group was fed a basal diet, the experimental group I, II and III were fed the basal diet supplemented with 0.25%, 0.5%, 1% SBL, respectively. During the 4th week, broilers were exposed to heat stress conditions ($36{\pm}2^{\circ}C$), after which, muscle and liver samples were collected. High performance liquid chromatography (HPLC) was performed to measure the content of inosine monophosphate (IMP); Real-Time PCR was performed to determine the expression of the ADSL gene. The results showed that the content of breast muscle IMP of group I, II and III was significantly increased 68%, 102% and 103% (p<0.01) compared with the control, respectively; the content of thigh muscle IMP of group II and III was significantly increased 56% and 58% (p<0.01), respectively. Additionally, ADSL mRNA expression in group I, II and III was increased significantly 80%, 65% and 49% (p<0.01) compared with the control, respectively. The content of IMP and expression of ADSL mRNA were increased by basal diet supplemented with SBL, therefore, the decrease of meat flavor caused by heat stress was relieved.

Solution Method and Application Verification of the K-curve as a Highway Transition Curve

Bing-hong Pan,Changpeng Wen,Kaiming Wang,Changjiang Liu,Linqi Chen 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.7

Because of the singular form and low flexibility of the clothoid as a highway transition curve in highway horizontal alignment, the K-curve, whose ratio of the chord-tangent angle to the tangential angle at any point is fixed, was proposed in a previous work, including the corresponding parametric equations and basic characteristics, and its high flexibility and various shapes were proved. Here, the application and verification of the K-curve in highway alignment is further studied. The solution methods of the K-curve for different connections are given. Through theoretical calculations and specific real-world examples, the geometric positions and lateral forces of the K-curve and the clothoid under different connection conditions are compared. The results show that the difference between the K-curve and clothoid in the above two aspects under a straight line-to-circle connection is greater than that under a circle-to-circle connection as an egg curve, and although the lateral force coefficient of the K-curve is smaller than that of the clothoid, the K-curve suffers from rapid change in the lateral force coefficient and a higher lateral acceleration change rate. Finally, the application conditions of the K-curve for highway alignment design are given with consideration of the centrifugal acceleration change rate.