Deformation of Perforated Aluminium Plates under In-Plane Compressive Loading

2016 ◽  
Vol 710 ◽  
pp. 357-362
Author(s):  
Irene Scheperboer ◽  
Evangelos Efthymiou ◽  
Johan Maljaars
Keyword(s):  
Research Work ◽  
Compressive Loading ◽  
Local Buckling ◽  
Buckling Load ◽  
Structural Behaviour ◽  
Critical Buckling Load ◽  
Out Of Plane ◽  
The Difference ◽  
Ultimate Resistance ◽  
Multiple Holes

Aluminium plates containing a single hole or multiple holes in a row are recently becoming very popular among architects and consultant engineers in many constructional applications, due to their reduced weight, as well as facilitating ventilation and light penetration of the buildings. However, there are still uncertainties concerning their structural behaviour, preventing them from wider utilization. In the present paper, local buckling phenomenon of perforated aluminium plates has been studied using the finite element method. For the purposes of the research work, plates with simply supported edges in the out-of-plane direction and subjected to uniaxial compression are examined. In view of perforations, circular cut-outs and the total cut-out size has been varied between 5 and 40% of the total plate area. Moreover, different perforation patterns have been investigated, from a single, central cut-out to a more refined pattern consisting of up to 25 holes equally distributed over the plate. Regarding the material characteristics, several aluminium alloys are considered and compared to steel grade A36 on plates of different slenderness. For each case the critical (Euler) buckling load and the ultimate resistance has been determined.A study into the boundary conditions of the plate showed that the restrictions at the edges parallel to the load direction have a large influence on the critical buckling load. Restraining the top or bottom edge does not significantly influence the resistance of the plate.The results showed that the ultimate resistance of aluminium plates containing multiple holes occurs at considerably larger out-of-plane displacement as that of full plates. For very large total cut-out, a plate containing a central hole has a larger resistance than a plate with equal cut-out percentage but with multiple holes. The strength and deformation in the post-critical regime, i.e. the difference between the critical buckling load and the ultimate resistance, differs significantly for different number of holes and cut-out percentage.

Pasternak effect on the buckling of embedded single-walled carbon nanotubes using non-local cylindrical shell theory

2011 ◽  
Vol 225 (12) ◽  
pp. 3045-3059 ◽  
Author(s):  
A Ghorbanpour Arani ◽  
M Mohammadimehr ◽  
A R Saidi ◽  
A Arefmanesh ◽  
Q Han
Keyword(s):  
Cylindrical Shell ◽  
Shell Theory ◽  
Buckling Load ◽  
Spring Constant ◽  
Single Walled Carbon Nanotube ◽  
Critical Buckling Load ◽  
Single Walled Carbon ◽  
Non Local ◽  
The Difference ◽  
Walled Carbon Nanotubes

In this article, the buckling analysis of a single-walled carbon nanotube using the non-local cylindrical shell theory under general loading embedded on the Winkler- and Pasternak-type foundations is presented. The effect of the surrounding elastic medium such as the Winkler-type spring constant and the Pasternak-type shear constant is taken into account in the present formulations. The non-local and local critical buckling loads are obtained under general loading such as the axial compression, lateral pressure, and torsional loading, and it is concluded from the results that the non-local critical buckling load under general loading is lower than the local critical buckling load. It is seen that the Winkler-type spring constant and Pasternak-type shear constant increase the non-local critical buckling load under general loading, therefore the difference between the presence and the absence of the Pasternak-type shear constant is large.

scholarly journals Improving the Structural Behavior of Tied-Arch Bridges by Doubling the Set of Hangers

2020 ◽  
Vol 10 (23) ◽  
pp. 8711
Author(s):  
Juan Manuel García-Guerrero ◽  
Juan José Jorquera-Lucerga
Keyword(s):  
Buckling Load ◽  
Structural Behavior ◽  
Wind Loading ◽  
Structural Systems ◽  
Critical Buckling Load ◽  
Out Of Plane ◽  
Arch Bridges ◽  
Transversal Stiffness ◽  
Single Set ◽  
General Reduction

In tied-arch bridges with a single arch, the deck is usually suspended from the arch by means of a single set of cables, pinned at both ends and anchored to the centerline, using either vertical or Nielsen-type hanger arrangements. When properly designed, this layout can significantly reduce forces and deflections under loads that are symmetrical with respect to the plane of the arch. However, it does not contribute to the support of nonsymmetrical loads, such as eccentric loads distributions or wind loading, and does not reduce the sensibility of the arch to out-of-plane buckling. Thus, this paper studies how a cable arrangement composed of two sets of lateral hangers, attached to both edges of a deck, can be very suitable to address these problems. Firstly, it is demonstrated that the structural behavior under symmetrical loads improves with respect to the bridge with centered hangers. Secondly, it is shown how nonsymmetric loads are partially carried by structural systems (such as the transversal stiffness both of the arch and the deck) that would remain inactive for tied-arch bridges with centered hangers, leading to a general reduction in the forces and the deflections of the bridge and in the critical buckling load of the arch.

scholarly journals GUI FOR VIBRATION PREDICTIONS DURING RTB OF A SERVICED HELICOPTER

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Kothara Srinivasa Rao ◽  
A.Gopala Krishna
Keyword(s):  
Linear Regression ◽  
Multiple Linear Regression ◽  
Regression Models ◽  
Research Work ◽  
Rotor System ◽  
Rotor Blades ◽  
Main Rotor ◽  
Out Of Plane ◽  
The Difference ◽  
Flight Regimes

Vibrations on helicopter induced in Main Rotor System and Tail Rotor System due to in plane unbalanced masses and out of plane rotation of rotor blades. Rotor Track and Balance (RTB) of helicopter is performed to reduce vibrations of helicopter. Number of vibration flights will increase if RTB is not optimised. Main Rotor and Tail Rotor vibrations can be reduced by predicting the vibrations prior to flight using Multiple Linear Regression and Analysis of Variance (MLR & ANOVA). The Inputs for the Multiple Linear Regression would be in terms of mass changes, track changes and tab changes based on established sensitivities of these Inputs and cross sensitivities between them. The outputs are vibration changes of Main Rotor / Tail Rotor. Change in vibrations is the difference between the vibration values of two successive flights / ground runs. For Main Rotor, there are 12 inputs to adjust 2 outputs (MR Lateral and MR Vertical), for Tail Rotor, there are 8 inputs to adjust 2 outputs (TR Radial and TR Axial) for satisfactory vibrations during ground run, HOGE and two steady speed forward flight regimes. In this Research work, three types of Regression Models for Main Rotor System and Two types of Regression Models for Tail Rotor System were made to predict the vibrations of helicopter prior to ground run or flight. The Regression Coefficients were evaluated using MatLab and models were generated. ANOVA is performed for regression models and found satisfactory. The Coefficient of Regression (Multiple-R / R 2 ) values obtained are more than 0.9. The results of the regression indicated that the model was a significant predictor of vibration changes. Graphical User Interface (GUI) using Regression Models is made for vibration predictions of Main Rotor and Tail Rotor Vibrations of Serviced helicopter. This research work recommends for the implementation of Multiple Linear Regression and its applications for vibration predictions of Serviced helicopters to reduce vibration fl

Out-of-Plane Secondary Bifurcation Buckling Behavior of Elastic Circle Pipe Arch

2011 ◽  
Vol 462-463 ◽  
pp. 271-276
Author(s):  
Yu Zhi He ◽  
Chang Yun Liu ◽  
Zhen Hua Hou ◽  
Guang Kui Zhang ◽  
Xing Hua Chen ◽  
...  
Keyword(s):  
Buckling Load ◽  
Concentrated Load ◽  
Carry Capacity ◽  
Distributed Load ◽  
Uniformly Distributed Load ◽  
Bifurcation Buckling ◽  
Out Of Plane ◽  
Calculation Results ◽  
Secondary Bifurcation ◽  
The Difference

The out-of-plane secondary bifurcation buckling load-displacement equilibrium paths of the elastic circle pipe arch with and without out-of-plane brace at the top of the arch are traced using a new numerical tracing strategy. The out-of-plane secondary bifurcation buckling loads of the arch with the same sections and different rise-span ratios are obtained under the concentrated load at the top of the arch and the full span uniformly distributed load, which are compared with out-of-plane linear buckling load and in-plane primary buckling load. The calculation results show: for the same section circle pipe arches without the out-of-plane brace and under the concentrated load at the top the arch, the out-of-plane secondary buckling load is always less than the in-plane primary buckling load and the out-of-plane buckling will occur before the in-plane primary buckling. The out-of-plane secondary bifurcation buckling load of the arch with 0.2 rise-span ratio is the biggest. The bigger the rise-span ratio is, the bigger the difference between out-of-plane and in-plane buckling load. When the arch is subjected to full span uniformly distributed load, the out-of-plane buckling will also occur before the in-plane primary buckling and the out-of-plane secondary bifurcation buckling load of the arch with 0.4 rise-span ratio is the biggest. The difference between out-of-plane and in-plane buckling load of the arch with 0.2 rise-span ratio is the biggest. For the circle pipe arch with the out-of-plane brace at the top of the arch, the out-of-plane buckling load of the arch with 0.4 rise-span ratio is the biggest under the two load conditions. The brace can raise the out-of-plane buckling load significantly especially for the arch with big rise-span ratio and under full span load. The out-of-plane buckling will occur before the in-plane primary buckling when the arch is under full span uniformly distributed load. The out-of-plane buckling will occur before the in-plane primary buckling only when the arch is under concentrated load and the rise-span ratio of the arch is less than 0.3. No matter there is or not brace for the arch, the ultimate load carry capacity of the arches increase a little bit after the out-of-plane secondary buckling occurs.

Numerical Simulation Analysis on Buckling Load of Large Combined Cylindrical Shells

2008 ◽  
Author(s):  
Zhiping Chen ◽  
Ming Zeng ◽  
Chu-Lin Yu ◽  
Jinping Zhu
Keyword(s):  
Numerical Simulation ◽  
Hoop Stress ◽  
Simulation Analysis ◽  
Cylindrical Shells ◽  
Great Influence ◽  
Buckling Load ◽  
Critical Buckling Load ◽  
Buckling Behavior ◽  
The Difference ◽  
Almost All

To comply with the uniform-strength theory, almost all large tanks are made by welding unequal-thickness cylindrical shell courses together. This structure can be considered as a kind of geometry imperfection of tank walls, which has a great influence on buckling behavior and critical load of tank walls. To obtain the related critical buckling load and to verify the effect regularity on bulking due to hoop stress in various combined unequal-thickness cylindrical shells, the numerical simulation was adopted to analyze the buckling behavior with different loads. The results show that the characteristic factors of unequal-thickness structure can reduce the critical buckling load significantly, such factors as shell layers and the difference in thickness of adjacent shell courses are the most dominant.

Critical buckling load of paper honeycomb under out-of-plane pressure

2005 ◽  
Vol 18 (3) ◽  
pp. 141-150 ◽  
Author(s):  
Li-Xin Lu ◽  
Ya-Ping Sun ◽  
Zhi-Wei Wang
Keyword(s):  
Buckling Load ◽  
Critical Buckling Load ◽  
Out Of Plane ◽  
Paper Honeycomb

Research on the Dynamic Buckling Characteristics of Carbon Fiber Composite Honeycomb Panel under Out-of-Plane Impact Load

2014 ◽  
Vol 1004-1005 ◽  
pp. 492-496
Author(s):  
Ming Jun Fan
Keyword(s):  
Carbon Fiber ◽  
Failure Load ◽  
Impact Load ◽  
Fiber Composite ◽  
Dynamic Buckling ◽  
Buckling Load ◽  
Carbon Fiber Composite ◽  
Critical Buckling Load ◽  
Out Of Plane ◽  
Honeycomb Panel

This paper aims at studying the dynamic buckling characteristic of the fiber composite honeycomb under out-of-plane impact load. It was found that: with the increasing of the wall thickness, both the critical buckling load and the critical failure load of the composite honeycomb will decrease gradually. By increasing the wall aspect, the critical buckling load will decrease, while the critical failure load will increase. However, when the aspect reaches to 3.5,both the above two kinds of load are no longer sensitive to the variation of it.

Buckling Analysis of a Taper-Taper Adhesive-Bonded Composite Joint

2002 ◽  
Author(s):  
Jack E. Helms ◽  
Guoqiang Li ◽  
Su-Seng Pang
Keyword(s):  
Analytical Model ◽  
Ritz Method ◽  
Compressive Loading ◽  
Beam Theory ◽  
Buckling Load ◽  
Transverse Displacement ◽  
Laminated Beam ◽  
Critical Buckling Load ◽  
Composite Joint ◽  
Bonded Composite

An analytical model of the behavior of an adhesive-bonded taper-taper composite joint under axial compressive loading has been developed using the Ritz Method. The model was based on laminated beam theory. A Fourier series was used to represent the transverse displacement variable and the Ritz method was used to derive an eigenvalue equation for adhesively bonded taper-taper composite joint. The smallest eigenvalue is the critical buckling load. Finite element analyses were performed on two unidirectional laminated beam joints with various taper angles to verify the analytical model. The effect of varying the taper angle, adhesive thickness and adhesive modulus on the critical buckling load were investigated analytically.

scholarly journals Comparison of Fracture Resistance in Thermal and Self-Curing Acrylic Resins—An In Vitro Study

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1234
Author(s):  
António Sérgio Silva ◽  
Aurora Carvalho ◽  
Pedro Barreiros ◽  
Juliana de Sá ◽  
Carlos Aroso ◽  
...  
Keyword(s):  
Fracture Resistance ◽  
Research Work ◽  
Testing Machine ◽  
In Vitro Study ◽  
Dimensional Accuracy ◽  
Acrylic Resin ◽  
Thermosetting Resins ◽  
Acrylic Resins ◽  
The Difference

Thermal and self-curing acrylic resins are frequently and versatilely used in dental medicine since they are biocompatible, have no flavor or odor, have satisfactory thermal qualities and polishing capacity, and are easy and fast. Thus, given their widespread use, their fracture resistance behavior is especially important. In this research work, we comparatively analyzed the fracture resistance capacity of thermo and self-curing acrylic resins in vitro. Materials and Methods: Five prosthesis bases were created for each of the following acrylic resins: Lucitone®, ProBase®, and Megacryl®, which were submitted to different forces through the use of the CS® Dental Testing Machine, usually mobilized in the context of fatigue tests. To this end, a point was defined in the center of the anterior edge of the aforementioned acrylic resin bases, for which the peak tended until a fracture occurred. Thermosetting resins were, on average, more resistant to fracture than self-curable resins, although the difference was not statistically significant. The thermosetting resins of the Lucitone® and Probase® brands demonstrated behavior that was more resistant to fracture than the self-curing homologues, although the difference was not statistically significant. Thermosetting resins tended to be, on average, more resistant to fracture and exhibited the maximum values for impact strength, compressive strength, tensile strength, hardness, and dimensional accuracy than self-curing resins, regardless of brand.

scholarly journals Spin-ice physics in cadmium cyanide

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chloe S. Coates ◽  
Mia Baise ◽  
Adrian Schmutzler ◽  
Arkadiy Simonov ◽  
Joshua W. Makepeace ◽  
...  
Keyword(s):  
Dipole Moments ◽  
Interaction Strength ◽  
Magnetic Interaction ◽  
Energy Scale ◽  
Spin Ice ◽  
Structural Behaviour ◽  
Geometric Frustration ◽  
Cadmium Cyanide ◽  
The Difference ◽  
Increased Strength

AbstractSpin-ices are frustrated magnets that support a particularly rich variety of emergent physics. Typically, it is the interplay of magnetic dipole interactions, spin anisotropy, and geometric frustration on the pyrochlore lattice that drives spin-ice formation. The relevant physics occurs at temperatures commensurate with the magnetic interaction strength, which for most systems is 1–5 K. Here, we show that non-magnetic cadmium cyanide, Cd(CN)2, exhibits analogous behaviour to magnetic spin-ices, but does so on a temperature scale that is nearly two orders of magnitude greater. The electric dipole moments of cyanide ions in Cd(CN)2 assume the role of magnetic pseudospins, with the difference in energy scale reflecting the increased strength of electric vs magnetic dipolar interactions. As a result, spin-ice physics influences the structural behaviour of Cd(CN)2 even at room temperature.

Sign in / Sign up

Export Citation Format

Share Document