Nonlinear Analysis of Single-Layer Reticulated Spherical Shells Under Static and Dynamic Loads

2004 ◽  
Vol 10 (5) ◽  
pp. 731-754 ◽  
Author(s):  
Q. S. Li ◽  
J. M. Chen
Keyword(s):  
Geometrical Nonlinearity ◽  
Three Dimensional ◽  
Single Layer ◽  
Dynamic Responses ◽  
Space Structures ◽  
Equilibrium Equations ◽  
Tangent Stiffness Matrix ◽  
Nonlinear Equilibrium ◽  
Element Technique ◽  
Updated Lagrangian

A nonlinear finite element technique is developed for analyzing the nonlinear static and dynamic responses as well as the nonlinear stability of single-layer reticulated shells under external loads, in which the nonlinear three-dimensional beam elements are employed. Using the updated Lagrangian formulation, we derive a tangent stiffness matrix of three-dimensional beam element, considering the geometric nonlinearity of the element. Moreover, the modified Newton-Raphson method is employed for the solution of the nonlinear equilibrium equations, and the Newmark-β method is adopted for determining the seismic response of single-layer reticulated shells. An improved arc-length method, in which the current stiffness parameter is used to reflect the nonlinear degree of such space structures, is presented for determining the load increment for the structural stability analysis. In addition, an accurate incremental method is developed for computing the large rotations of the space structures. The developed approach is presented in matrix form, which is particularly convenient for developing a computer program. Numerical examples are presented to illustrate the application of the present method and to investigate the effects of the geometrical nonlinearity of the space structures.

scholarly journals Experimental Studies of Single-Layer Reticulated Domes with Isolated Supports

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Guibo Nie ◽  
Kun Liu
Keyword(s):  
Seismic Behavior ◽  
Damping Ratio ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Single Layer ◽  
Shaking Table ◽  
Dynamic Responses ◽  
Shaking Table Tests ◽  
Isolation Effects ◽  
Reticulated Domes

To study the seismic behavior of a single-layer reticulated dome subjected to severe earthquakes, a series of shaking table tests were conducted for this paper. Seismic responses including the acceleration, displacement, and strains gathered at the members and nodes were discussed. The dynamic characteristics, including structure frequencies and damping ratio, were obtained through the results under the input excitation of white noise and the fast sine sweeping with different amplitudes. Various isolation devices usually installed in the upper portion of the structures have been widely used to reduce the dynamic responses for more than three decades. However, these isolation devices deal mostly with either horizontal isolation or vertical isolation, which is not applicable for synchronous isolation in both horizontal and vertical isolation. Therefore, an innovative isolated support for three-dimensional isolation was invented. In order to understand the earthquake-isolation effects of a single-layer reticulated dome with the isolated support, a series of shaking table tests were conducted. The dynamic behavior of the structure was then investigated and discussed using the acceleration and displacement responses of the tested structures with or without the isolated supports. The experimental results show that the isolated support invented in this study had a remarkable earthquake-isolation action in both horizontal and vertical isolation.

On the deflected configuration of a slender elastic rod subject to parallel terminal forces and moments

1995 ◽  
Vol 449 (1936) ◽  
pp. 337-349 ◽  
Keyword(s):  
Cross Section ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Cartesian Coordinate System ◽  
Elastic Rod ◽  
Equilibrium Equations ◽  
Elastic Deformations ◽  
Nonlinear Equilibrium ◽  
Cartesian Coordinate ◽  
Nonlinear Elastic

This paper investigates the three-dimensional configurations of a slender elastic rod of uniform circular cross-section subject to parallel terminal forces and moments. The nonlinear, equilibrium equations for the rod are established for a Cartesian coordinate system and solved analytically without linearization. Consequently, the results are applicable for large nonlinear elastic deformations.

Stress and Strain Recovery of Laminated Composite Doubly-Curved Shells and Panels Using Higher-Order Formulations

2014 ◽  
Vol 624 ◽  
pp. 205-213 ◽  
Author(s):  
Erasmo Viola ◽  
Francesco Tornabene ◽  
Nicholas Fantuzzi
Keyword(s):  
Differential Quadrature Method ◽  
Three Dimensional ◽  
Single Layer ◽  
Laminated Composite ◽  
Higher Order ◽  
Equilibrium Equations ◽  
Analysis And Design ◽  
Generalized Differential ◽  
Doubly Curved ◽  
Laminated Composite Shells

The present paper investigates the static behaviour of doubly-curved laminated composite shells and panels. A two dimensional Higher-order Equivalent Single Layer approach, based on the Carrera Unified Formulation (CUF), is proposed. The differential geometry is used for the geometric description of shells and panels. The numerical solution is calculated using the generalized differential quadrature method. The through-the-thickness strains and stresses are computed using a three dimensional stress recovery procedure based on the shell equilibrium equations. Sandwich panels are considered with soft cores. The numerical results are compared with the ones obtained with a finite element code. The proposed higher-order formulations can be used for solving elastic problems involved in the first stage of any scientific procedure of analysis and design of masonry structures.

Dynamic Stability Analysis of Single-Layer Lattice Dome Considering Member Imperfections

2014 ◽  
Vol 1044-1045 ◽  
pp. 629-632 ◽  
Author(s):  
Shang Qi Wang ◽  
Jun Lin Wang ◽  
Shu Li Zhao ◽  
Jian Heng Sun
Keyword(s):  
Stability Analysis ◽  
Dynamic Stability ◽  
Three Dimensional ◽  
Single Layer ◽  
Space Structures ◽  
Important Research ◽  
Research Project ◽  
Stability Behavior ◽  
Beam Method ◽  
Geometrical Imperfections

Dynamic stability analysis is a very important research project in the space structures. Up to now, in most researches, the imperfections of members are not included in the dynamic stability analysis for the single-layer lattice domes. In this paper, using multiple-beam method to simulate the initial bending deformation of the members, the dynamic stability behavior of a Kiewitt-8 single-layer lattice dome under three dimensional earthquake actions is analyzed by considering the member imperfections and the initial geometrical imperfections. The influence of member imperfections to the dynamic stability behavior of the structure is investigated.

Characterization of a monolayer graphitic structure

1994 ◽  
Vol 52 ◽  
pp. 760-761
Author(s):  
X. Lin ◽  
X. K. Wang ◽  
V. P. Dravid ◽  
J. B. Ketterson ◽  
R. P. H. Chang
Keyword(s):  
Three Dimensional ◽  
Single Layer ◽  
Synthesis Process ◽  
Graphitic Structure ◽  
Positive Gaussian Curvature ◽  
Graphitic Sheet ◽  
Structural And Electronic Properties ◽  
New Material ◽  
Hexagonal Network

For small curvatures of a graphitic sheet, carbon atoms can maintain their preferred sp2 bonding while allowing the sheet to have various three-dimensional geometries, which may have exotic structural and electronic properties. In addition the fivefold rings will lead to a positive Gaussian curvature in the hexagonal network, and the sevenfold rings cause a negative one. By combining these sevenfold and fivefold rings with sixfold rings, it is possible to construct complicated carbon sp2 networks. Because it is much easier to introduce pentagons and heptagons into the single-layer hexagonal network than into the multilayer network, the complicated morphologies would be more common in the single-layer graphite structures. In this contribution, we report the observation and characterization of a new material of monolayer graphitic structure by electron diffraction, HREM, EELS.The synthesis process used in this study is reported early. We utilized a composite anode of graphite and copper for arc evaporation in helium.

Macroorganisation and flexibility of thylakoid membranes

2019 ◽  
Vol 476 (20) ◽  
pp. 2981-3018 ◽  
Author(s):  
Petar H. Lambrev ◽  
Parveen Akhtar
Keyword(s):  
Light Harvesting ◽  
Current Knowledge ◽  
Three Dimensional ◽  
Photosynthetic Apparatus ◽  
Dynamic Responses ◽  
State Transitions ◽  
Photochemical Quenching ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Light Harvesting Complex Ii

Abstract The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.

scholarly journals Mastering of NIL Stamps with Undercut T-Shaped Features from Single Layer to Multilayer Stamps

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 956
Author(s):  
Philipp Taus ◽  
Adrian Prinz ◽  
Heinz D. Wanzenboeck ◽  
Patrick Schuller ◽  
Anton Tsenov ◽  
...  
Keyword(s):  
Electron Beam Lithography ◽  
Nanoimprint Lithography ◽  
Silicon Oxide ◽  
Three Dimensional ◽  
Single Layer ◽  
Fabrication Technology ◽  
Large Area ◽  
Structural Colors ◽  
Biomimetic Structures ◽  
Morpho Butterfly

Biomimetic structures such as structural colors demand a fabrication technology of complex three-dimensional nanostructures on large areas. Nanoimprint lithography (NIL) is capable of large area replication of three-dimensional structures, but the master stamp fabrication is often a bottleneck. We have demonstrated different approaches allowing for the generation of sophisticated undercut T-shaped masters for NIL replication. With a layer-stack of phase transition material (PTM) on poly-Si, we have demonstrated the successful fabrication of a single layer undercut T-shaped structure. With a multilayer-stack of silicon oxide on silicon, we have shown the successful fabrication of a multilayer undercut T-shaped structures. For patterning optical lithography, electron beam lithography and nanoimprint lithography have been compared and have yielded structures from 10 µm down to 300 nm. The multilayer undercut T-shaped structures closely resemble the geometry of the surface of a Morpho butterfly, and may be used in future to replicate structural colors on artificial surfaces.

scholarly journals Homogeneous 2D and 3D alignment of cardiomyocyte in dilated cardiomyopathy revealed by intravital heart imaging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kiyoshi Masuyama ◽  
Tomoaki Higo ◽  
Jong-Kook Lee ◽  
Ryohei Matsuura ◽  
Ian Jones ◽  
...  
Keyword(s):  
Heart Failure ◽  
Dilated Cardiomyopathy ◽  
Cardiac Dysfunction ◽  
Three Dimensional ◽  
Single Layer ◽  
Specific Pattern ◽  
Two Dimensional ◽  
Heart Imaging ◽  
Novel Method ◽  
2D And 3D

AbstractIn contrast to hypertrophic cardiomyopathy, there has been reported no specific pattern of cardiomyocyte array in dilated cardiomyopathy (DCM), partially because lack of alignment assessment in a three-dimensional (3D) manner. Here we have established a novel method to evaluate cardiomyocyte alignment in 3D using intravital heart imaging and demonstrated homogeneous alignment in DCM mice. Whilst cardiomyocytes of control mice changed their alignment by every layer in 3D and position twistedly even in a single layer, termed myocyte twist, cardiomyocytes of DCM mice aligned homogeneously both in two-dimensional (2D) and in 3D and lost myocyte twist. Manipulation of cultured cardiomyocyte toward homogeneously aligned increased their contractility, suggesting that homogeneous alignment in DCM mice is due to a sort of alignment remodelling as a way to compensate cardiac dysfunction. Our findings provide the first intravital evidence of cardiomyocyte alignment and will bring new insights into understanding the mechanism of heart failure.

scholarly journals Vibration characteristics of triple-gear-rotor system in compressed air energy storage under variable torque load

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042098705
Author(s):  
Xinran Wang ◽  
Yangli Zhu ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xuehui Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
Rotor System ◽  
Dynamic Responses ◽  
System Response ◽  
Rotating Speed ◽  
Torque Load ◽  
Set Up ◽  
Two Stages

This paper focuses on the effects of the off-design operation of CAES on the dynamic characteristics of the triple-gear-rotor system. A finite element model of the system is set up with unbalanced excitations, torque load excitations, and backlash which lead to variations of tooth contact status. An experiment is carried out to verify the accuracy of the mathematical model. The results show that when the system is subjected to large-scale torque load lifting at a high rotating speed, it has two stages of relatively strong periodicity when the torque load is light, and of chaotic when the torque load is heavy, with the transition between the two states being relatively quick and violent. The analysis of the three-dimensional acceleration spectrum and the meshing force shows that the variation in the meshing state and the fluctuation of the meshing force is the basic reasons for the variation in the system response with the torque load. In addition, the three rotors in the triple-gear-rotor system studied show a strong similarity in the meshing states and meshing force fluctuations, which result in the similarity in the dynamic responses of the three rotors.

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