A relationship between progressive collapse and initial buckling for tubular structures under axial loading

2013 ◽  
Vol 75 ◽  
pp. 200-211 ◽  
Author(s):  
Jie Song ◽  
Yufeng Zhou ◽  
Fenglin Guo
Keyword(s):  
Progressive Collapse ◽  
Axial Loading ◽  
Tubular Structures

Progressive collapse behaviour of aluminium-composite bitubular energy absorbers subjected to axial loading

2021 ◽  
Author(s):  
D. Maneiah ◽  
A. Praveen Kumar ◽  
M. Shunmugasundaram ◽  
Debasish Mishra ◽  
D. Sravani
Keyword(s):  
Progressive Collapse ◽  
Axial Loading ◽  
Aluminium Composite ◽  
Energy Absorbers

scholarly journals Effect of geometric parameters and combined loading on stress distribution of tubular T-joints

Mechanika ◽  
2019 ◽  
Vol 25 (5) ◽  
pp. 350-356
Author(s):  
Samira Belhour ◽  
Hafida Kahoul ◽  
Ahmed Bellaouar ◽  
Sébastien Murer
Keyword(s):  
Axial Loading ◽  
Computation Time ◽  
Geometric Parameters ◽  
Combined Loading ◽  
Offshore Platforms ◽  
Tubular Structures ◽  
Stress Concentrations ◽  
Standard Samples ◽  
T Joints ◽  
Modeling And Analysis

Steel tubular structures are widely used in the construction of offshore platforms and T-type junctions are extensively used in this domain. The tubular members are welded, which generates significant stress concentrations at the edges. The stress levels reached in these critical places are used to assess lifetimes based on fatigue curves from tests conducted on standard samples. This study is devoted to the modeling and analysis of T-type welded tubular structures for the determination of hot spots stresses (HSS) at the chord/brace intersection, A numerical analysis was carried out to study the effect of a combined loading composed of an axial loading and a continuation of rational bending, that best assimilate real conditions, as well as the effect of normalized geometric parameters α, β, g on the distribution of stress concentration (area and values) of T-joints. The mechanical behaviour has been modeled in 2D using quadrangular and triangular thin-shell elements by the finite element method (FEM). It is the most appropriate approach because it considers all geometric complexities and singularities of the structure, while the efforts as well as the computation time are considerably reduced compared to an experimental study or to complex FE models implementing solid elements. In this study, we use the COMSOL-MULTIPHYSICS® software...

scholarly journals Comparative Analysis of Buckling Load of Circular and Corrugated Tubes by Utilizing Key Performance Indicators

2017 ◽  
Vol 22 (3) ◽  
pp. 789-797 ◽  
Author(s):  
Mohammad Reyaz Ur Rahim ◽  
S. Akhtar ◽  
P.K. Bharti
Keyword(s):  
Comparative Analysis ◽  
Cross Section ◽  
Performance Indicators ◽  
Axial Loading ◽  
Key Performance Indicators ◽  
Buckling Load ◽  
Tubular Structures ◽  
Engineering Designs

AbstractThe performance of buckling load of tubular structures under quasi-static axial loading is quite appreciable, numerous tubes of various cross-section have been extensively investigated and corrugated sections have been designed to further improve the performance. In this paper, a carefully designed set of key performance indicators (KPIs) is utilized to assess and compare the buckling load of circular and corrugated tubes. A series of diagrams related to KPIs with various parameters of tubes are presented to demonstrate the influence of sectional configuration on the performance of tubes as well as the effect of the material on the potential of the same. The work is inestimable to engineering designs and applications, and further studies on the buckling load of other configurations.

Crush Performance of Top-Hat Tubular Structures Considering Different Forming Conditions

2010 ◽  
Vol 139-141 ◽  
pp. 571-575
Author(s):  
Jian Hui Niu ◽  
Ping Zhu ◽  
Yong Jin Guo
Keyword(s):  
Axial Loading ◽  
High Strength ◽  
Absorption Capacity ◽  
Knife Edge ◽  
Tubular Structures ◽  
Thin Walled Structures ◽  
Collapse Mode ◽  
Bending Process ◽  
History Of ◽  
Forming Condition

The influence of forming condition on crash performance of thin-walled structures is investigated, in which high strength low alloy steel HSLA340 and dual phase steel DP590 are considered. Stamping and knife-edge-bending process were carried out respectively to form hat channels, and then, impact tests were performed on the spot-welded top-hat sections subjected to quasi-static and dynamic axial loading conditions to identify the forming effect on the crashworthiness. Regular progressive buckling (quasi-inextensional mode) was observed for knife-edge-bent specimens, while the stamped specimens showed peculiar collapse mode, especially, global instability existed for all the specimens under dynamic impacting and their energy absorption capacity was significantly reduced. The result demonstrates that for accurate assessing the structural performance detailed stamping history of sheet metal components should be taken into consideration.

Parametric Analysis on Flexural Capacity of Flange-Plate Connections Considering Prying Force

2010 ◽  
Vol 163-167 ◽  
pp. 3-10
Author(s):  
Yuan Qing Wang ◽  
Liang Zong ◽  
Yong Jiu Shi
Keyword(s):  
Finite Element ◽  
Parametric Analysis ◽  
Axial Loading ◽  
Loading Capacity ◽  
Tubular Structures ◽  
Flexural Capacity ◽  
Effect Factors ◽  
Finite Element Program ◽  
Axial Tension ◽  
Plate Connections

Within construction industry developing rapidly in domestic, long span buildings and high-rise buildings emerge in endlessly. Steel tubular structures are increasingly widely used for its unique advantages. Thanks to the situation, flange-plate connections become more and more popular as an important solution of splicing steel tubular structures. The connections provide easy and fast installation，nice shape, simple constitution for tubular structures without the need for welding. Typical loading situations include axial tension force and moment for flange-plate connections. The loading capacity under axial tension was studied by many scholars. Unfortunately, study on flexural capacity of flange-plate connections is limited. This situation limits the generalization of the nice connections. As can be seen from the review on flange-plate connections, there is no doubt that doing research on flexural capacity of flange-plate connections is necessary. Previous studies on axial loading capacity of flange-plate connections can provide helpful options of research for this work. One of the options is to observe the prying forces caused by flange-plates’ deformation, for prying is an important influencing factor on axial loading capacity of flange-plate connections which can reduce capacity of the connection. It is same as axial loading case that prying forces exists in the tensile region of flange-plate connections under bending moment, and they should be paid attention because they can reduce the flexural capacity of the connections with no doubt. This paper addresses on four basic kinds of flange-plate connection’s flexural capacity and is developed by means of finite element method with finite element program ANSYS. Related FE models are established and checked compared with experimental results. Based on the reliable FE models, the subsequent analysis especially studies on the effect factors of prying force in the tensile region of connection in the tensile region of connection. The corresponding parametric analysis is developed, including the thickness of flange-plate, the ratio of outer and inner diameter of flange-plate, material property of bolts, etc. Finally the key effect factors are found. The conclusions from this paper can provide references for Engineering Design.

Labelling of non-A, non-B hepatitis infected chimpanzee hepatocytes with nuclease-gold conjugates

1984 ◽  
Vol 42 ◽  
pp. 250-251
Author(s):  
G. D. Gagne ◽  
M. F. Miller ◽  
D. A. Peterson
Keyword(s):  
Endoplasmic Reticulum ◽  
Experimental Infection ◽  
Uranyl Acetate ◽  
Type I ◽  
Cellular Injury ◽  
Type Ii ◽  
Tubular Structures ◽  
Type Iii ◽  
Type Iv ◽  
Infected Chimpanzee

Experimental infection of chimpanzees with non-A, non-B hepatitis (NANB) or with delta agent hepatitis results in the appearance of characteristic cytoplasmic alterations in the hepatocytes. These alterations include spongelike inclusions (Type I), attached convoluted membranes (Type II), tubular structures (Type III), and microtubular aggregates (Type IV) (Fig. 1). Type I, II and III structures are, by association, believed to be derived from endoplasmic reticulum and may be morphogenetically related. Type IV structures are generally observed free in the cytoplasm but sometimes in the vicinity of type III structures. It is not known whether these structures are somehow involved in the replication and/or assembly of the putative NANB virus or whether they are simply nonspecific responses to cellular injury. When treated with uranyl acetate, type I, II and III structures stain intensely as if they might contain nucleic acids. If these structures do correspond to intermediates in the replication of a virus, one might expect them to contain DNA or RNA and the present study was undertaken to explore this possibility.

Complex Vesicles, Microtubules, and Cytoplasmic Filaments in the Endothelial Cells of Normal Dog Aorta

1968 ◽  
Vol 26 ◽  
pp. 172-173
Author(s):  
C. N. Sun ◽  
J. J. Ghidoni
Keyword(s):  
Electron Microscopy ◽  
Endothelial Cells ◽  
Cross Sections ◽  
Functional Significance ◽  
Tubular Structures ◽  
Aldehyde Fixation ◽  
Cytoplasmic Filaments

Endothelial cells in longitudinal and cross sections of aortas from 3 randomly selected “normal” mongrel dogs were studied by electron microscopy. Segments of aorta were distended with cold cacodylate buffered 5% glutaraldehyde for 10 minutes prior to being cut into small, well oriented tissue blocks. After an additional 1-1/2 hour period in glutaraldehyde, the tissue blocks were well rinsed in buffer and post-fixed in OsO4. After dehydration they were embedded in a mixture of Maraglas, D.E.R. 732, and DDSA.Aldehyde fixation preserves the filamentous and tubular structures (300 Å and less) for adequate demonstration and study. The functional significance of filaments and microtubules has been recently discussed by Buckley and Porter; the precise roles of these cytoplasmic components remains problematic. Endothelial cells in canine aortas contained an abundance of both types of structures.

Replication of Internal Biological Surfaces

1972 ◽  
Vol 30 ◽  
pp. 308-309
Author(s):  
J. A. Nowell ◽  
J. Pangborn ◽  
W. S. Tyler
Keyword(s):  
Da Vinci ◽  
Leonardo Da Vinci ◽  
Rat Lung ◽  
Tubular Structures ◽  
Cerebral Ventricles ◽  
Internal Surfaces ◽  
Biological Surfaces ◽  
Dog Kidney ◽  
Lung And Kidney ◽  
Scanning Electron

Leonardo da Vinci in the 16th century, used injection replica techniques to study internal surfaces of the cerebral ventricles. Developments in replicating media have made it possible for modern morphologists to examine injection replicas of lung and kidney with the scanning electron microscope (SEM). Deeply concave surfaces and interrelationships to tubular structures are difficult to examine with the SEM. Injection replicas convert concavities to convexities and tubes to rods, overcoming these difficulties.Batson's plastic was injected into the renal artery of a horse kidney. Latex was injected into the pulmonary artery and cementex in the trachea of a cat. Following polymerization the tissues were removed by digestion in concentrated HCl. Slices of dog kidney were aldehyde fixed by immersion. Rat lung was aldehyde fixed by perfusion via the trachea at 30 cm H2O. Pieces of tissue 10 x 10 x 2 mm were critical point dried using CO2. Selected areas of replicas and tissues were coated with silver and gold and examined with the SEM.

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