Elastic Foundation Beam Solution of Tensile Flexible Retaining Wall

Xu Jianqiang,Xu Jiangbo,Yang Xiaohua,Yan Zhaobai,Li Haiping,Wang Huoming,Tan Ling,Fei Dongyang,Li Jianguo,Luo Yongzhen 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.2

The application of fl exible retaining walls in foundation pit engineering is gradually increasing. At present, many practical engineering problems need to be solved. This article takes a corrugated steel retaining wall with tensile reinforcement, for example, assuming that it is an elastic foundation beam model. A typical vertical thin layer unit is taken on the retaining wall for analysis. It uses the waveform integration method to calculate the moment of inertia, deriving the diff erential equation of fl exural deformation of corrugated steel retaining wall and establishing the theoretical formula for deformation of corrugated steel retaining wall under fi lling pressure behind the wall. Finally, a FLAC3D model was established to simulate the deformation of corrugated steel retaining walls in practical engineering, and the fi nal numerical simulation results were consistent with the theoretical formula. Thus, providing a theoretical basis for the deformation of such fl exible retaining structures.

Static analysis of a radially retractable hybrid grid shell in the closed position

Jianguo Cai,Chao Jiang,Xiaowei Deng,Jianfeng Zhao,Yixiang Xu 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.18 No.6

A radially retractable roof structure based on the concept of the hybrid grid shell is proposed in this paper. The single-layer steel trusses of the radially foldable bar structure are diagonally stiffened by cables, which leads to a single-layer lattice shell with triangular mesh. Then comparison between the static behavior between the retractable hybrid grid shell and the corresponding foldable bar shell with quadrangular mesh is discussed. Moreover, the effects of different structural parameters, such as the rise-to-span ratio, the bar cross section area and the pre-stress of the cables, on the structural behaviors are investigated. The results show that prestressed cables can strengthen the foldable bar shell with quadrangular mesh. Higher structural stiffness is anticipated by introducing cables into the hybrid system. When the rise-span ratio is equal to 0.2, where the joint displacement reaches the minimal value, the structure shape of the hyrbid grid shell approaches the reasonable arch axis. The increase of the section of steel bars contributes a lot to the integrity stiffness of the structure. Increasing cable sections would enhance the structure stiffness, but it contributes little to axial forces in structural members. And the level of cable prestress has slight influence on the joint displacements and member forces.

Spatial-Temporal Distribution of Soil Salt Crusts in the Taklimakan Desert Highway Shelterbelt of Northwest China

Jianguo Zhang,Xinwen Xu,Jiaqiang Lei,Ying Zhao,Shengyu Li 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Non-linear stability analysis of a hybrid barrel vault roof

Jianguo Cai,Ya Zhou,Yixiang Xu,Jian Feng 국제구조공학회 2013 Steel and Composite Structures, An International J Vol.14 No.6

This paper focuses on the buckling capacity of a hybrid grid shell. The eigenvalue buckling, geometrical non-linear elastic buckling and elasto-plastic buckling analyses of the hybrid structure were carried out. Then the influences of the shape and scale of imperfections on the elasto-plastic buckling loads were discussed. Also, the effects of different structural parameters, such as the rise-to-span ratio, beam section, area and pre-stress of cables and boundary conditions, on the failure load were investigated. Based on the comparison between elastic and elasto-plastic buckling loads, the effect of material non-linearity on the stability of the hybrid barrel vault is found significant. Furthermore, the stability of a hybrid barrel vault is sensitive to the anti-symmetrical distribution of loads. It is also shown that the structures are highly imperfection sensitive which can greatly reduce their failure loads. The results also show that the support conditions pose significant effect on the elasto-plastic buckling load of a perfect hybrid structure.

Geometry and Mechanical Behaviour of Radially Retractable Roof Structures During the Movement Process

Jianguo Cai,Yuhang Zhou,Yifeng Zhu,Yixiang Xu,Jin Zhang 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.3

In this paper, the kinematic characteristic of the radially retractable roof structure was firstly discussed and the motion boundary of the system was also studied. The results show that the diameter of the outer boundary of the system increases firstly and then decreases when the roof is open. Moreover, the numerical study of the structural behavior of the retractable roof with radial foldable bars and circumferential foldable bars was carried out, respectively. It can be found the latter one has a better structural behavior. Then the mechanical behaivor of the system during the motion was also investigated. Finally, a loop linkage based on a special scissor-like element was proposed to support the retractable roof.

Dynamic analysis of a cylindrical boom based on Miura origami

Jianguo Cai,Ya Zhou,Xinyu Wang,Yixiang Xu,Jian Feng 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.28 No.5

The dynamic behavior of the deployment and folding process of a foldable boom based on the Miura origami pattern is investigated in this paper. Firstly, mechanical behavior of a single storey during the motion is studied numerically. Then the deployment and folding of a multi-storey boom is discussed. Moreover, the influence of the geometry parameters and the number of Miura-ori elements n on the dynamic behavior of the boom is also studied. Finally, the influence of the imperfection on the dynamic behavior is investigated. The results show that the angles between the diagonal folds and horizontal folds will have great effect on the strains during the motion. A bistable configuration can be obtained by choosing proper fold angles for a given multi-storey boom. The influence of the imperfection on the folding behavior of the foldable mast is significant.

Modified Wettability of Micro-structured Steel Surfaces Fabricated by Elliptical Vibration Diamond Cutting

Jianguo Zhang,Andreas Rosenkranz,Junjie Zhang,Jiang Guo,Xiaoqing Li,Xiao Chen,Junfeng Xiao,Jianfeng Xu 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.5

Hardened steel is an important material related to the development of modern industry branches. In order to satisfy the adhesion strength as well as the corrosion and wear resistance under extreme conditions, the modification of the wettability of hardened steel has become an important scientific topic. As micro/nano-structured surfaces play an essential role to induce advanced functional surfaces with wettability control, this contribution aims at presenting the feasibility of micro/nano sculpturing of hardened steels by elliptical vibration diamond cutting. The influence of the fabricated micro/nano structures on the resulting wettability is discussed and related to the contact line density as well as asperity heights. In this regard, it has been verified that a pitch value of 12 μm and structural height of 500 nm are the preferred structural parameters to increase the hydrophobicity of the textured steel specimens.

Nonlinear stability analysis of a radially retractable hybrid grid shell in the closed position

Jianguo Cai,Qian Zhang,Youbao Jiang,Yixiang Xu,Jianfeng Zhao,Xiaowei Deng 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.24 No.3

The buckling capacity of a radially retractable hybrid grid shell in the closed position was investigated in this paper. The geometrically non-linear elastic buckling and elasto-plastic buckling analyses of the hybrid structure were carried out. A parametric study was done to investigate the effects rise-to-span ratio, beam section, area and pre-stress of cables, on the failure load. Also, the influence of the shape and scale of imperfections on the elasto-plastic buckling loads was discussed. The results show that the critical buckling load is reduced by taking account of material non-linearity. Furthermore, increasing the rise-tospan ratio or the cross-section area of steel beams notably improves the stability of the structure. However, the cross section area and pre-stress of cables pose negligible effect on the structural stability. It can also be found that the hybrid structure is highly sensitive to geometric imperfection which will considerably reduce the failure load. The proper shape and scale of the imperfection are also important.

An Improved Flux Estimator for Gap Flux Orientation Control of DC-Excited Synchronous Machines

Xu, Yajun,Jiang, Jianguo The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2

Flux estimation is a significant foundation of high-performance control for DC-excited synchronous motor. For almost all flux estimators, such as the flux estimator based on phase locked loop (PLL), DC drift causes fluctuations in flux magnitude. Furthermore, significant dynamic error may be introduced at transient conditions. To overcome these problems, this paper proposes an improved flux estimator for the PLL-based algorithm. Filters based on the generalized integrator are used to avoid flux fluctuation problems caused by the DC drift at the back electromotive force. Programmable low-pass filters are employed to improve the dynamic performance of the flux estimator, and the cutoff frequency of the filter is determined by the dynamic factor. The algorithm is verified by a 960V/1.6MW industrial prototype. Simulation and experimental results show that the proposed estimator can estimate the flux more accurately than the PLL-based algorithm in a cycloconverter-fed DC-excited synchronous machine vector control system.

Nonparametric comparison of recurrent event processes based on panel count data

Da Xu,Jianguo Sun,Dehui Wang 한국통계학회 2016 Journal of the Korean Statistical Society Vol.45 No.2

Recurrent event processes arise in many fields including medical follow-up studies and reliability experiments and many procedures have been developed in the literature for their comparison nonparametrically (Cook and Lawless, 2007; Sun and Zhao, 2013). However, most of them are for either the complete data situation where one observes recurrent event data or the incomplete data situation where one observes panel count data with the same observation process. There also exist a couple of nonparametric comparison procedures for the panel count data situation that allow unequal observation processes, but apply only to limited situations. In this paper, we discuss the latter situation for both univariate and multivariate panel count data and propose a new type of nonparametric procedures that apply to more general situations. The proposed test statistics are shown to have asymptotic normal distributions, and an extensive simulation is conducted and suggests that they work well in practical situations. An application is also provided.