Effects of Initial Geometric Imperfection on Stability of Single-Layer Reticulated Shell

2011 ◽  
Vol 368-373 ◽  
pp. 276-279
Author(s):  
Fei Hua Zheng ◽  
Jin Song Lei ◽  
Wen Zhi Yin
Keyword(s):  
Finite Element ◽  
Shell Structure ◽  
Single Layer ◽  
Initial Imperfection ◽  
Limited Capacity ◽  
Geometric Imperfection ◽  
Finite Element Software ◽  
Initial Geometric Imperfection ◽  
Overall Stability ◽  
The Stability

The stability of reticulated shell is a key issue for single-layer reticulated shell. In the paper, a single-layer arch-supported shell structure was analyzed by finite element software MIDAS. The eigenvalue buckling analysis and the geometric nonlinear overall stability analysis with initial imperfection of the model which carried two different load combinations were studied too. At the same time, the influences on the stability of the shell structure were researched. The results showed that the shell structure was sensitive to the initial imperfection. Under different load combinations, the instability of modes and limited capacity of stability are different in the shell structure.

Analysis of the Member Buckling Influence to the Stability of Single-Layer Lattice Dome

2014 ◽  
Vol 578-579 ◽  
pp. 8-15
Author(s):  
Teng Fei Ma ◽  
Jiang Wang ◽  
Hui Zhou ◽  
Zhen Wu Wang ◽  
Zong Yun Mo ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Single Layer ◽  
Systematic Analysis ◽  
Geometric Imperfection ◽  
Initial Geometric Imperfection ◽  
Overall Stability ◽  
The Stability

Stability analysis is a key proplem for single layer lattice dome structures. single layer lattice dome structures before the overall instability of member instability may exist, but in the current single layer lattice dome structures stability analysis considering the influence of single layer lattice dome structures node defects only without considering the influence of the member buckling.Considering the initial geometric imperfection of single layer lattice dome structures in this paper, on the basis of initial defects of member with initial bending simulation, and the single layer lattice dome structures is different to weaken the position of member and make the member buckling before single layer lattice dome structures overall instability, systematic analysis of the member buckling effect on the overall stability of the single layer lattice dome structures.

Determination of collapse moment of different angled pipe bends with initial geometric imperfection subjected to in-plane bending moments

2021 ◽  
pp. 095440622199640
Author(s):  
Manish Kumar ◽  
Pronab Roy ◽  
Kallol Khan
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Circular Cross Section ◽  
Initial Imperfection ◽  
Bend Angle ◽  
Bending Moments ◽  
Element Analysis ◽  
Geometric Imperfection ◽  
Initial Geometric Imperfection

From the recent literature, it is revealed that pipe bend geometry deviates from the circular cross-section due to pipe bending process for any bend angle, and this deviation in the cross-section is defined as the initial geometric imperfection. This paper focuses on the determination of collapse moment of different angled pipe bends incorporated with initial geometric imperfection subjected to in-plane closing and opening bending moments. The three-dimensional finite element analysis is accounted for geometric as well as material nonlinearities. Python scripting is implemented for modeling the pipe bends with initial geometry imperfection. The twice-elastic-slope method is adopted to determine the collapse moments. From the results, it is observed that initial imperfection has significant impact on the collapse moment of pipe bends. It can be concluded that the effect of initial imperfection decreases with the decrease in bend angle from 150∘ to 45∘. Based on the finite element results, a simple collapse moment equation is proposed to predict the collapse moment for more accurate cross-section of the different angled pipe bends.

Analysis of Nonlinear Buckling of a Long-Span Elliptic Paraboloid Suspended Dome Structure

2013 ◽  
Vol 639-640 ◽  
pp. 191-197 ◽  
Author(s):  
Zheng Rong Jiang ◽  
Kai Rong Shi ◽  
Xiao Nan Gao ◽  
Qing Jun Chen
Keyword(s):  
Single Layer ◽  
Buckling Mode ◽  
Nonlinear Buckling ◽  
Elliptic Paraboloid ◽  
Geometric Imperfection ◽  
Long Span ◽  
Initial Geometric Imperfection ◽  
Dome Structure ◽  
Unsymmetrical Loading ◽  
The Stability

The suspended dome structure, which is a new kind of hybrid spatial one composed of the upper single layer latticed shell and the lower cable-strut system, generally has smaller rise-to-span ratio, thus the overall stability is one of the key factors to the design of the structure. The nonlinear buckling behavior of an elliptic paraboloid suspended dome structure of span 110m80m is investigated by introducing geometric nonlinearity, initial geometric imperfection, material elastic-plasticity and half-span distribution of live loads. The study shows that the coefficient of stable bearing capacity usually is not minimal when the initial geometric imperfection configuration is taken as the first order buckling mode. The unsymmetrical loading distribution and the material nonlinearity might have significant effects on the coefficient. The structure is sensitive to the changes of initial geometric imperfection, and the consistent mode imperfection method is not fully applicable to the stability analysis of suspended dome structure.

Structural Design and Analysis of Aluminum Dome for Caofeidian Coal Storage

2016 ◽  
Vol 710 ◽  
pp. 396-401 ◽  
Author(s):  
Ze Chao Zhang ◽  
Hong Bo Liu ◽  
Xiao Dun Wang ◽  
Xiang Yu Yan ◽  
Jing Hai Yu ◽  
...  
Keyword(s):  
Finite Element ◽  
Aluminum Alloys ◽  
Three Dimensional ◽  
Single Layer ◽  
Element Model ◽  
Internal Force ◽  
Structural Deformation ◽  
Mode Analysis ◽  
Finite Element Software ◽  
The Stability

The upper part of Caofeidian coal storage was approximately hemispherical aluminum shell, covered with aluminum alloys plate. The capsule was made of aluminum alloys material, and its span was 125 meters. In the design, according to TEMCOR joint, we used the finite element software MIDAS to build the accurate geometry models and calculation models of aluminum alloys single layer latticed dome structures. By the combination of constant loads, live loads, snow load, wind load, temperature effect and other working conditions, we summarized the consumption of aluminum of the structures, and studied the structural internal force, structural deformation and structural stiffness. In addition, the X and Y two different direction seismic dynamic load was applied to the structure. The structural seismic performance under two kinds of modes were studied through the structure mode analysis of the vibration frequency. The vierendeel dome and single layer dome were controlled by the stability. ANSYS three-dimensional frame element model were set up, and the eigenvalue buckling analysis was carried out. By the geometrical nonlinear finite element method, combining with initial imperfections and material nonlinear, we found out the stability coefficient and the weak parts of the structure.

Parameter Analysis on Stability of a Suspendome

2005 ◽  
Vol 20 (2) ◽  
pp. 115-124 ◽  
Author(s):  
Zhi-Hua Chen ◽  
Yang Li
Keyword(s):  
Structural Parameters ◽  
Engineering Application ◽  
Single Layer ◽  
Parameter Analysis ◽  
Space Structures ◽  
Buckling Mode ◽  
Geometric Imperfection ◽  
Stability Performance ◽  
Initial Geometric Imperfection ◽  
The Stability

As a kind of hybrid space structures, the suspendome system increases the stiffness and improves the stability of the original dome system by the appropriate use of prestressing cables. Based on the engineering application of suspendome in Tianbao Center (completed in China, 2002), the present paper concentrates on the stability performance of the suspendome with a span of 35.4m using different structural parameters, including the rise-span ratio, magnitude and level settings of initial prestressing in cables, connection rigidity and boundary support condition. Stability performances including buckling mode, critical loads and sensitivity to initial geometric imperfection are studied in detail, and contrast analyses with the corresponding singly-layer shells are carried out to study the superiorities of the suspendome over the single-layer shell. Some valuable conclusions are drawn for practical design.

scholarly journals Influence of welding deformation on anti-collapse performance of single-layer reticulated shell structures with prestressed cables

2021 ◽  
Vol 2045 (1) ◽  
pp. 012018
Author(s):  
Y Q Fu ◽  
X D Yang ◽  
H D Zhang ◽  
Y M Wang
Keyword(s):  
Finite Element ◽  
Shell Structure ◽  
Single Layer ◽  
Shell Structures ◽  
Welding Deformation ◽  
Finite Element Software ◽  
Reticulated Shell Structure ◽  
Prestressed Cable

Abstract In this paper, the ABAQUS finite element software is used to model and analyze the single-layer reticulated shell structure. And the method of removing the constraints of key components is used to analyze the anti-continuous collapse performance of this reticulated shell structure under the action of geometric defects and welding deformation. Welding deformation is mainly caused by welding and prestressed cable tensioning of single-layer reticulated shell. The results show that the removal of the key columns under the reticulated shell will lead to the continuous collapse of the upper part, which leads to the continuous collapse of the whole structure, and the welding deformation can make the continuous collapse of the whole reticulated shell more obvious. Thus determining the influence of geometric defects and temperature shrinkage deformation on the anti-continuous collapse performance.

scholarly journals Stability analysis of composite I-shaped masonry reinforced retaining wall

2020 ◽  
Vol 198 ◽  
pp. 02032
Author(s):  
Wu Yuedong ◽  
Zhang Lei ◽  
Xu Nan ◽  
Lui Jian
Keyword(s):  
Numerical Simulation ◽  
Retaining Wall ◽  
Single Layer ◽  
Earth Pressure ◽  
Horizontal Displacement ◽  
Finite Element Software ◽  
The Earth ◽  
Overall Stability ◽  
The Stability ◽  
Reinforced Retaining Wall

Based on the actual project, the influence of geogrid on the stability of the retaining wall of the single-layer masonry reinforced retaining wall is studied through field test and finite element software ABAQUS numerical simulation. The influence of geogrid on the stability of the retaining wall was determined by analyzing the changes in the pressure of the backfill, the displacement of the retaining wall and the strain of the geogrid, and changing the length and spacing of the geogrid through the controlled variable method. The results show that the geogrid can limit the horizontal displacement of the soil, balance the earth pressure, and improve the overall stability of the retaining wall. By increasing the length of the geogrid and reducing the distance of the geogrid, the design of the retaining wall is optimized, which has good economic and time benefits.

scholarly journals Stability charts based on the finite element method for underground cavities in soft carbonate rocks: validation through case-study applications

2019 ◽  
Vol 19 (10) ◽  
pp. 2079-2095 ◽  
Author(s):  
Michele Perrotti ◽  
Piernicola Lollino ◽  
Nunzio Luciano Fazio ◽  
Mario Parise
Keyword(s):  
Finite Element ◽  
Safety Margin ◽  
Structural Elements ◽  
The Finite Element Method ◽  
Geometrical Features ◽  
Overall Stability ◽  
Underground Cavities ◽  
The Stability ◽  
Rock Mechanical Properties

Abstract. The stability of man-made underground cavities in soft rocks interacting with overlying structures and infrastructures represents a challenging problem to be faced. Based upon the results of a large number of parametric two-dimensional (2-D) finite-element analyses of ideal cases of underground cavities, accounting for the variability both cave geometrical features and rock mechanical properties, specific charts have been recently proposed in the literature to assess at a preliminary stage the stability of the cavities. The purpose of the present paper is to validate the efficacy of the stability charts through the application to several case studies of underground cavities, considering both quarries collapsed in the past and quarries still stable. The stability graphs proposed by Perrotti et al. (2018) can be useful to evaluate, in a preliminary way, a safety margin for cavities that have not reached failure and to detect indications of predisposition to local or general instability phenomena. Alternatively, for sinkholes that already occurred, the graphs may be useful in identifying the conditions that led to the collapse, highlighting the importance of some structural elements (as pillars and internal walls) on the overall stability of the quarry system.

Optimal Design of the Large-Diameter Spinning Torispherical Head

2012 ◽  
Vol 544 ◽  
pp. 194-199
Author(s):  
Di Zhang ◽  
Shui Ping Sheng ◽  
Zeng Liang Gao
Keyword(s):  
Finite Element ◽  
Optimal Design ◽  
Large Diameter ◽  
General Purpose ◽  
Design Tool ◽  
Crown Area ◽  
Finite Element Software ◽  
The Stability

Two important parameters of torispherical head that are (interior radius of spherical crown area) and r (interior radius of transition corner) have been optimized by the module of the large general-purpose finite-element software ANSYS, targeting the strength and stability of the head. This paper provides an optimized torispherical head, which improves the stability of the edge of the head with acceptable strength of the head. The procedure is generally applicable as a design tool for optimal design.

Study on the Complete Equivalent Initial Imperfection of High Formwork Supporting Frame with Pulley-Clip Style

2011 ◽  
Vol 368-373 ◽  
pp. 3052-3056
Author(s):  
Wei Jun Yang ◽  
Yong Da Yang
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Initial Imperfection ◽  
Influential Factors ◽  
Horizontal Load ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Finite Element Software ◽  
Supporting Frame

New full hall scaffolds with pulley-clip style formwork support system is adopted in the concert hall of Changsha. This paper presents the concept of the complete equivalent initial imperfection according to the characteristics of too many influential factors on the high formwork supporting frame，then makes the complete equivalent initial imperfectione equivalent to assumed equivalent horizontal load in order to ensure the safety of the frame. At the same time, it gets a three-dimensional model by the general finite element software ANSYS 10.0. Based on the results of experiment and finite element analysis, it gets the recommended value of assumed equivalent horizontal load. The study on the high formwork supporting frame with pulley-clip style provides some reference for other similar projects.

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