Buckling analyses of double-shell octagonal lattice truss composite structures

2017 ◽  
Vol 52 (9) ◽  
pp. 1227-1237 ◽  
Author(s):  
Qianqian Sui ◽  
Changliang Lai ◽  
Hualin Fan
Keyword(s):  
Failure Mode ◽  
Composite Structures ◽  
Failure Modes ◽  
Local Buckling ◽  
Buckling Mode ◽  
One Dimensional ◽  
Load Carrying ◽  
Global Buckling ◽  
Buckling Failure ◽  
Equivalent Continuum

To reveal the compression failure modes of one-dimensional hierarchical double-shell octagonal lattice truss composite structures (DLTCSs), finite element modeling and equivalent continuum models were developed. DLTCS has three typical failure modes: (a) fracture of the strut, (b) global buckling, and (c) local buckling. Failure mode maps were constructed. It is found that column of long enough length will collapse at global buckling. When the column length decreases, the failure mode will turn to local buckling and strut fracture successively. Bay length greatly influences the buckling mode. Longer bay length could change the buckling mode from global buckling to local buckling. Compared with single-shell lattice truss composite structure, DLTCS has advantage in load carrying when the column fails at strut fracture or global buckling, while local buckling tolerance of DLTCS is smaller.

scholarly journals Comparative Investigation on the Failure Modes of Natural Kenaf/Epoxy Reinforced Composite Hexagonal Tubes

2016 ◽  
Vol 709 ◽  
pp. 7-10 ◽  
Author(s):  
M.F.M. Alkbir ◽  
S.M. Sapuan ◽  
A.A. Nuraini ◽  
Mohamad Ridzwan Ishak
Keyword(s):  
Failure Mode ◽  
Transverse Crack ◽  
Failure Modes ◽  
Epoxy Composite ◽  
Local Buckling ◽  
Comparative Investigation ◽  
Composite Tubes ◽  
Reinforced Composite ◽  
Buckling Failure ◽  
Mode Response

This study aims to investigate failure mode response of woven natural kenaf/epoxy composite hexagonal tubes subjected to an axial and lateral quasi-static crushing test. The hexagonal composite tubes were prepared by the hand lay-up technique using a variety of hexagonal angles 40ο, 50 ο, and 60 ο. The result showed that hexagonal composite tubes under an axial compression test exhibited few failure modes such as, the transverse crack failure mode . Splaying failure mode and local buckling failure mode respectively, whereas the tubes under lateral test only exhibited longitudinal fracture.

scholarly journals Numerical Simulation of Multi-Span Greenhouse Structures

Agriculture ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 499
Author(s):  
María S. Fernández-García ◽  
Pablo Vidal-López ◽  
Desirée Rodríguez-Robles ◽  
José R. Villar-García ◽  
Rafael Agujetas
Keyword(s):  
Matrix Method ◽  
Local Buckling ◽  
External Pressure ◽  
Climatic Conditions ◽  
Wind Loads ◽  
Buckling Modes ◽  
First Order ◽  
Global Buckling ◽  
Computational Fluid Dynamics Cfd ◽  
Buckling Failure

Greenhouses had to be designed to sustain permanent maintenance and crop loads as well as the site-specific climatic conditions, with wind being the most damaging. However, both the structure and foundation are regularly empirically calculated, which could lead to structural inadequacies or cost ineffectiveness. Thus, in this paper, the structural assessment of a multi-tunnel greenhouse was carried out. Firstly, wind loads were assessed through computational fluid dynamics (CFD). Then, the buckling failure mode when either the European Standard (EN) or the CFD wind loads were contemplated was assessed by a finite element method (FEM). Conversely to the EN 13031-1, CFD wind loads generated a suction in the 0–55° region of the first tunnel and a 60% reduction of the external pressure coefficients in the third tunnel was not detected. Moreover, the first-order buckling eigenvalues were reduced (32–57%), which resulted in the need for a different calculation method (i.e., elastoplastic analysis), and global buckling modes similar to local buckling shape were detected. Finally, the foundation was studied by the FEM and a matrix method based on the Wrinkler model. The stresses and deformations arising from the proposed matrix method were conservative compared to those obtained by the FEM.

The torsional buckling behaviour of shafts with transverse holes

2002 ◽  
Vol 37 (3) ◽  
pp. 247-258 ◽  
Author(s):  
W. S Robotham ◽  
T. H Hyde ◽  
E. J Williams ◽  
J. W Taylor
Keyword(s):  
Failure Modes ◽  
Peak Torque ◽  
Diameter Ratio ◽  
Elastic Buckling ◽  
Torsional Loading ◽  
Torsional Buckling ◽  
Buckling Mode ◽  
Shaft Length ◽  
Shaft Diameter ◽  
Buckling Failure

The paper presents the results of a parametric finite element study of the failure behaviour of shafts with a single row of transverse holes, subjected to torsional loading. The introduction of the holes reduces the peak torque at failure compared with the equivalent plain shaft and the reduction increases with increasing D/t (shaft diameter-wall thickness) ratio and d/D (hole diameter-shaft diameter) ratio and with the number of holes. Depending on the geometry used, either plastic collapse or elastic-plastic buckling failure modes can occur. For given values of n (number of holes) and D/t and d/D ratios, the failure torque varies by less than 5 per cent for L/D (shaft length-diameter) ratios in the range 0.6 to 4. The greatest reduction in the failure torque occurs when the D/t ratio is such that the number of circumferential lobes in the elastic buckling mode for the equivalent plain shaft is the same as the number of holes in the shaft.

Experimental Investigation on Steel-Plate-Masonry Composite Column Compressive Behavior

2011 ◽  
Vol 255-260 ◽  
pp. 591-595 ◽  
Author(s):  
Deng Hu Jing ◽  
Shuang Yin Cao ◽  
Hai Tao Zhou
Keyword(s):  
Carrying Capacity ◽  
Failure Modes ◽  
Steel Plate ◽  
Local Buckling ◽  
Epoxy Adhesive ◽  
Critical Cross Section ◽  
Load Carrying Capacity ◽  
Large Space ◽  
Composite Column ◽  
Load Carrying

The steel-plate-masonry composite structure is an innovative type of structural scheme popular in masonry structures with load-bearing walls removed for a large space. A total of 4 column specimens under static loading were tested to mainly study the failure modes, load-carrying capacity, and strain distribution in the critical cross-section. Results show that the composite columns started an initial failure from local buckling of the steel plate located between binding bolts; the main factors influencing load-carrying capacity included thickness of the steel plate, type of injected material, and initial column eccentricity; the working performance of the composite column with epoxy adhesive was better than that with cement grout; and re-distribution of compressive stress existed in the steel plates of the column. Also, the ratio of service load-carrying capacity to ultimate capacity of the steel-plate-masonry composite column is about 70%.

Laboratory tests of ice interaction with steel booms

1996 ◽  
Vol 23 (2) ◽  
pp. 560-566 ◽  
Author(s):  
G. W. Timco ◽  
A. M. Cornett
Keyword(s):  
Failure Mode ◽  
Laboratory Tests ◽  
Failure Modes ◽  
Quantitative Information ◽  
Ice Thickness ◽  
Test Program ◽  
Buckling Failure ◽  
River Loads ◽  
St Lawrence River ◽  
Ice Control

A test program was carried out to study the interaction of ice with sections of ice-control booms. Two different boom shapes and four different boom sizes were tested. The results indicate that there can be several different failure modes for the ice during the interaction. Particularly high loads were obtained when the ice failed in a buckling failure mode. To minimize the ice-induced loads, the boom must be designed to prevent this failure mode and induce flexural failures in the ice. This note presents quantitative information on the loads measured for different boom shapes and sizes, and for different ice thickness. The results can be used to help optimize the design of a suitable boom for ice control. Key words: ice, ice control, ice booms, St. Lawrence River, loads, forces, design.

scholarly journals Ultimate Limit Design of Strengthened Steel Columns by Mortar-Filled FRP Tubes

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Jian Hou ◽  
Li Song
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Load Capacity ◽  
Local Buckling ◽  
Ultimate Load Capacity ◽  
Composite Columns ◽  
Steel Columns ◽  
Frp Tube ◽  
Frp Tubes ◽  
Ultimate Limit

The present study investigated the various failure modes of strengthened steel columns by mortar-filled fiber-reinforced polymer (FRP) tubes to analytically formulate the ultimate capacities of these steel columns. A simple and effective method, wherein a mortar-filled FRP tube was sleeved outside the steel member, was also formulated to enhance the buckling resistance capacity of compressed steel members. In addition, to facilitate the connection of the column to other structural members, the length of the sleeved mortar-filled FRP tubes is less than that of the original steel columns. Theoretical analyses were also performed on the critical sections of such composite columns at their ultimate states to identify their potential failure modes, such as FRP-tube splitting at the ends or on the insides of wrapped areas, local buckling at the steel ends of transition zones, and global buckling of the composite columns. The corresponding ultimate capacity of each failure mode was then analytically formulated to characterize the critical failure mode and ultimate load capacity of the columns. The current theoretical results were compared with those from literature to validate the applicability of the developed ultimate limit design approaches for FRP-mortar-steel composite columns.

scholarly journals Cyclic Load Test and Finite Element Analysis of NOVEL Buckling-Restrained Brace

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5103
Author(s):  
Robel Wondimu Alemayehu ◽  
Youngsik Kim ◽  
Jaehoon Bae ◽  
Young K. Ju
Keyword(s):  
Finite Element ◽  
Parametric Study ◽  
Cyclic Load ◽  
Failure Modes ◽  
Slenderness Ratio ◽  
Load Test ◽  
American Institute ◽  
Element Analysis ◽  
Global Buckling ◽  
Buckling Failure

Compared to concrete or mortar-filled Buckling-Restrained Braces (BRBs), all-steel BRBs provide weight and fabrication time reductions. In particular, all-steel buckling braces with H-section cores are gaining attention in cases where large axial strength is required. In this paper, an all-steel BRB, called NOVEL (Noise, CO2 emission, Vibration, Energy dissipation and Labor), is presented. It comprises an H-section core encased in a square casing, and its behavior was studied through full-scale subassembly and brace tests, followed by a finite element parametric study. Two failure modes were observed: global buckling and flange buckling of the H-section core, which occurred in test specimens with Pcr/Py ratios of 1.68 and 4.91, respectively. Global buckling occurred when the maximum moment in the casing reached its yielding moment, although the test specimens had sufficient stiffness to prevent global buckling. Failure by core flange buckling occurred at a core strain of 1.2%. The finite element parametric study indicated that adjusting the width-to-thickness ratio of the core flange is more feasible than stiffening the flange or adjusting the unconstrained-length end stiffeners. The value of 5.06 was the minimum flange slenderness ratio that provided a stable hysteresis to the end of the loading protocol of the American Institute of Steel Construction standard.

Designing Hierarchical IsoTruss Column Based on Controlling Multi-Buckling Behaviors

2021 ◽  
Author(s):  
Changliang Lai ◽  
Qianqian Sui ◽  
Hualin Fan
Keyword(s):  
Finite Element ◽  
Parametric Design ◽  
Local Buckling ◽  
Fe Model ◽  
The Finite Element Method ◽  
Buckling Modes ◽  
Buckling Behavior ◽  
Global Buckling ◽  
Buckling Failure ◽  
Theoretical Analyses

To develop large-span but ultralight lattice truss columns, a hierarchical IsoTruss column (HITC) was proposed. The multi-buckling behavior of the axially compressed HITC was analyzed by the finite element method (FEM) using a parametric approach in the framework of ANSYS parametric design language (APDL). It was demonstrated that the program enables efficient generation of the finite element (FE) model, while facilitating the parametric design of the HITC. Using this program, the effects of helical angles and brace angles on the buckling behavior of the HITC were investigated. Depending on the helical angles and brace angles, the HITCs mainly have three buckling modes: the global buckling, the first-order local buckling and the second-order local buckling. Theoretical multi-buckling models were established to predict the critical buckling loads. Buckling failure maps based on the theoretical analyses were also developed, which can be useful in preliminary design of such structures.

scholarly journals Strengthening of Hollow Square Sections under Compression Using FRP Composites

2014 ◽  
Vol 2014 ◽  
pp. 1-19 ◽  
Author(s):  
M. C. Sundarraja ◽  
P. Sriram ◽  
G. Ganesh Prabhu
Keyword(s):  
Failure Modes ◽  
Deformation Behaviour ◽  
Three Dimensional ◽  
Local Buckling ◽  
Experimental Results ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
Load Carrying ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

The feasibility study on carbon fibre reinforced polymer (CFRP) fabrics in axial strengthening of hollow square sections (HSS) was investigated in this paper. CFRP was used as strips form with other parameters such as the number of layers and spacing of strips. Experimental results revealed that the external bonding of normal modulus CFRP strips significantly enhanced the load carrying capacity and stiffness of the hollow sections and also reduced the axial shortening of columns by providing external confinement against the elastic deformation. The increase in the CFRP strips thickness effectively delayed the local buckling of the above members and led to the inward buckling rather than outward one. Finally, three-dimensional nonlinear finite element modeling of CFRP strengthened hollow square sectionswas created by using ANSYS 12.0 to validate the results and the numerical results such as failure modes and load deformation behaviour fairly agreed with the experimental results.

scholarly journals BEHAVIOUR OF CFST MEMBERS UNDER COMPRESSION EXTERNALLY REINFORCED BY CFRP COMPOSITES

2013 ◽  
Vol 19 (2) ◽  
pp. 184-195 ◽  
Author(s):  
M. C. Sundarraja ◽  
G. Ganesh Prabhu
Keyword(s):  
Failure Modes ◽  
Axial Stress ◽  
Constant Width ◽  
Local Buckling ◽  
Steel Tube ◽  
Reinforced Polymer ◽  
Load Carrying ◽  
Externally Bonded ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

This research is aimed at investigating the structural improvements of concrete filled steel tubular (CFST) sections with normal strength concrete externally bonded with fibre reinforced polymer (FRP) composites. For this study, compact mild steel tubes were used with the main variable being FRP characteristics. Carbon fibre reinforced polymer (CFRP) fabrics was used as horizontal strips (lateral ties) with several other parameters such as the number of layers and spacing of strips. Among twenty one columns, eighteen were externally bonded by CFRP strips having a constant width of 50 mm with a spacing of 20 mm and 40 mm and the remaining three columns were unbounded. Experiments were undertaken until column failure to fully understand the influence of FRP characteristics on the compressive behaviour of square CFST sections including their failure modes, axial stress-strain behaviour, and enhancement in load carrying capapcity. It was found that the external bonding of CFRP strips provides external confinement pressure effectively and intended to delay the local buckling of steel tube and also to improve the load carrying capacity further.

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