A Simple Design Formula to Estimate the Ultimate Strength of Stiffened Panels Under Bi-Axial Compression Mainly in Transverse Direction

2018 ◽  
Author(s):  
Yusuke Komoriyama ◽  
Daisuke Yanagihara
Keyword(s):  
Ultimate Strength ◽  
Axial Compression ◽  
Transverse Direction ◽  
Yield Condition ◽  
Stiffened Panel ◽  
Simple Design ◽  
Buckling Mode ◽  
Stiffened Panels ◽  
Design Formula ◽  
Collapse Behavior

Most of stiffened panels subjected to bi-axial compression mainly in transverse direction collapse with the buckling deformation of one times one half-wave in a local panel between longitudinal stiffeners and transverse frames. The authors defined this collapse mode as “local panel buckling mode”. In this study, the collapse behavior of the stiffened panel with local panel buckling mode is investigated in detail. Then, a simple design formula to estimate ultimate strength of a stiffened panel with local panel buckling mode is derived based on the collapse behavior. This formula is composed of a formula to predict the ultimate strength of a rectangular unstiffened panel subjected to uniaxial transverse compression, and the effects of stiffeners, bi-axial compression and von Mises yield condition are added to the formula. The ultimate strength calculated by the proposed formula is in good agreement with FEA results. Finally, the proposed formula is compared with an existing method and formulae used in the CSR-OT, CSR-BC and H-CSR. As a result, it is confirmed that the proposed formula has sufficient accuracy and high availability.

scholarly journals Experimental Study and Development of Design Formula for Estimating the Ultimate Strength of Curved Plates

2021 ◽  
Vol 11 (5) ◽  
pp. 2379
Author(s):  
Jeong-Hyeon Kim ◽  
Doo-Hwan Park ◽  
Seul-Kee Kim ◽  
Myung-Sung Kim ◽  
Jae-Myung Lee
Keyword(s):  
Aspect Ratio ◽  
Ultimate Strength ◽  
Large Deflection ◽  
Slenderness Ratio ◽  
Compressive Load ◽  
Element Analysis ◽  
Shipbuilding Industry ◽  
Design Formula ◽  
Deflection Analysis ◽  
Collapse Behavior

The curved plate has been extensively used as a structural member in many industrial fields, especially the shipbuilding industry. The present study investigated the ultimate strength and collapse behavior of the simply supported curved plate under a longitudinal compressive load. To do this, experimental apparatuses for evaluating the buckling collapse test of the curved plates was developed. Then, a series of buckling collapse experiments was carried out by considering the flank angle, slenderness ratio, and aspect ratio of plates. To examine the fundamental buckling and collapse behavior of the curved plate, elastoplastic large deflection analysis was performed using the commercial finite element analysis program. On the basis of both the experimental and FE analysis, the effects of the flank angle, slenderness ratio, and aspect ratio on the characteristics of the buckling and collapse behavior of the curved plates are discussed. Finally, the empirical design formula for predicting the ultimate strength of curved plates was derived. The proposed empirical formula is a good indicator for estimating the behavior of the curved plate.

Buckling/Ultimate Strength Evaluation for Continuous Stiffened Panel Under Combined Shear and Thrust

2016 ◽  
Author(s):  
Hiroaki Ogawa ◽  
Tomoki Takami ◽  
Akira Tatsumi ◽  
Yoshiteru Tanaka ◽  
Shinichi Hirakawa ◽  
...  
Keyword(s):  
Ultimate Strength ◽  
Fem Analysis ◽  
Strength Analysis ◽  
Stiffened Panel ◽  
Fe Modeling ◽  
Test Results ◽  
Strength Evaluation ◽  
Shear Buckling ◽  
Collapse Behavior ◽  
Good Agreement

In this study, FE modeling method for the buckling/ultimate strength analysis of a continuous stiffened panel under combined shear and thrust is proposed. In order to validate the proposed method, shear buckling collapse tests of a stiffened panel and FEM analysis are carried out. As the result of these, it is confirmed that the buckling collapse behavior and the ultimate strength estimated by the proposed method are in good agreement with the test results.

scholarly journals Effects of plies orientations and initial geometric imperfections on buckling strength of a composite stiffened panel

2018 ◽  
Vol 191 ◽  
pp. 00008
Author(s):  
Ikram Feddal ◽  
Abdellatif Khamlichi ◽  
Koutaiba Ameziane
Keyword(s):  
Stiffened Panel ◽  
Buckling Mode ◽  
Element Analysis ◽  
Geometric Imperfections ◽  
Stiffened Panels ◽  
Specific Strength ◽  
Euler Buckling ◽  
Buckling Behavior ◽  
Composite Stiffened Panel ◽  
Strength And Stiffness

The use of composite stiffened panels is common in several activities such as aerospace, marine and civil engineering. The biggest advantage of the composite materials is their high specific strength and stiffness ratios, coupled with weight reduction compared to conventional materials. However, any structural system may reach its limit and buckle under extreme circumstances by a progressive local failure of components. Moreover, stiffened panels are usually assembled from elementary parts. This affects the geometric as well as the material properties resulting in a considerable sensitivity to buckling phenomenon. In this work, the buckling behavior of a composite stiffened panel made from carbon Epoxy Prepregs is studied by using the finite element analysis under Abaqus software package. Different plies orientations sets were considered. The initial distributed geometric imperfections were modeled by means of the first Euler buckling mode. The nonlinear Riks method of analysis provided by Abaqus was applied. This method enables to predict more consistently unstable geometrically nonlinear induced collapse of a structure by detecting potential limit points during the loading history. It was found that plies orientations of the composite and the presence of geometric imperfections have huge influence on the strength resistance.

A Benchmark Study of ISO 18072-2 on the Stiffened Panel Ultimate Strength

2011 ◽  
Author(s):  
Paul A. Frieze ◽  
Martino Abbattista ◽  
Mirella Vallascas ◽  
Jeom K. Paik
Keyword(s):  
Ultimate Strength ◽  
Structural Reliability ◽  
Close Correlation ◽  
Stiffened Panel ◽  
Stiffened Panels ◽  
The Public ◽  
Benchmark Study ◽  
Wide Range ◽  
Non Linear ◽  
Complete Set

The paper presents a major benchmarking exercise to demonstrate the accuracy of the formulations for the ultimate strength of stiffened panels that had been proposed for inclusion in ISO TS 18072-2. The complete set of formulations addressed the ultimate strength of plates, hull girders and support members, in particular, transverse frames and webs. The stiffened panel strength formulations have been in the public domain for some time and represent the most comprehensive set yet published. Their potential application is to a wide range of structural forms, e.g. floating dock gates, caissons, bridge decks, FPSOs, etc, and as such have much to recommend for other than just ship structures. The benchmark study presents comparisons between two implementations of the formulations and the results of non-linear FEA. The structures analysed represent a range of different stiffened panels with varying overall dimensions, plate dimensions and stiffener shapes, in particular, flats, angles and Tees. Close correlation is generally realized but where differences arise, these are readily related to the approximations used in developing the strength formulations. The comparisons between the strength formulations and non-linear FEA results provides the basis for quantifying statistical uncertainties in the formulations which can be used in subsequent structural reliability analysis and partial resistance factor derivation.

Comparison of Numerical Results With Experiments on the Ultimate Strength of Long Stiffened Panels

2011 ◽  
Author(s):  
Mingcai Xu ◽  
C. Guedes Soares
Keyword(s):  
Numerical Analysis ◽  
Test Results ◽  
Buckling Mode ◽  
Geometric Imperfections ◽  
Geometric Nonlinearities ◽  
Stiffened Panels ◽  
Initial Imperfections ◽  
Linear Buckling ◽  
Initial Geometric Imperfections ◽  
Collapse Behavior

The behavior of long stiffened panels are simulated numerically and compared with test results of axial compression until collapse, to investigate the influence of the stiffener’s geometry. The material and geometric nonlinearities are considered in the simulation. The initial geometric imperfections, which affect the collapse behavior of stiffened panels, are also analyzed. The initial imperfections are assumed to have the shape of the linear buckling mode. Four types of stiffeners are made of mild or high tensile steel for bar stiffeners and mild steel for ‘L’ and ‘U’ stiffeners. To produce adequate boundary conditions at the loaded edges, three bays stiffened panels were used in the tests and in the numerical analysis.

Compressive Tests on Long Continuous Stiffened Panels

2008 ◽  
Author(s):  
Jose´ Manuel Gordo ◽  
C. Guedes Soares
Keyword(s):  
Mild Steel ◽  
Ultimate Strength ◽  
Axial Compression ◽  
Stiffened Panels ◽  
Series Of Experiments ◽  
Very High ◽  
Compressive Tests

Results are presented of 8 tests on long stiffened panels under axial compression until collapse. The specimens are three bay panels with associated plate made of very high tensile steel S690. Four different configurations are considered for the stiffeners, which are made of mild or high tensile steel for bar stiffeners and mild steel for ‘L’ and ‘U’ stiffeners. The influence of the stiffener’s geometry on the ultimate strength of the stiffened panels under compression is analyzed. This series of experiments belong to an extended series of tests that include short and intermediate panels which allows analyzing the effect of space framing on the strength of stiffened panels.

Experimental and Numerical Study on Six- Point Bending Test of a Composite Stiffened Panel

2011 ◽  
Vol 328-330 ◽  
pp. 1309-1312
Author(s):  
Qiang Ye ◽  
San San Xiao ◽  
Pu Hui Chen
Keyword(s):  
Cohesive Zone Model ◽  
Numerical Study ◽  
Bending Test ◽  
Stiffened Panel ◽  
Zone Model ◽  
Buckling Mode ◽  
Stiffened Panels ◽  
Shell Elements ◽  
Composite Stiffened Panel ◽  
Post Buckling

A six-point bending test was presented to simulate skin/stiffener debonding under anti-symmetrical loading conditions. A novel rig was design via which the anti-symmetrical bending deformations can be forced on to the specimens. Experimental study on six-point bending test of composite stiffened panels of T700/QY8911 was done by using this rig. The tests are numerically analyzed using the finite element code ABAQUS, modeling the entire stiffened panel by shell elements, and investigating the progressive delamination by means of the cohesive zone model. The results of numerical analyses are compared to the experimental ones in terms of load-displacement curves and debonding positions between skin and stringer. The experimental and numerical resulits show that the anti-symmetrical bending deformation is the main factor which results in the asymmetrical propagation of the debonding between the skin and the stiffener. The failure mechanisms of the test are similar to the ones which induces skin/stiffener debonding during post-buckling in the anti-symmetrical buckling mode.

Probabilistic Assessment of Stiffened Panel Strength: An Interactive Tool Using PROBAN and PULS

2010 ◽  
Author(s):  
Hadi Amlashi ◽  
Torfinn Ho̸rte ◽  
Eivind Steen ◽  
Jon Kippenes
Keyword(s):  
Ultimate Strength ◽  
Probability Distributions ◽  
Ship Design ◽  
Probabilistic Methods ◽  
Computational Time ◽  
Stiffened Panel ◽  
Probabilistic Assessment ◽  
Limit States ◽  
Stiffened Panels ◽  
Safety Margins

To achieve an economic and reliable ship design, the ship structure has to be designed with adequate safety margins. This can be accomplished by a reliability-based limit states design approach, in which probabilistic methods are used to guide the development of the design criteria. A tool is developed to probabilistically assess the capacity distribution of the stiffened panels. A Monte Carlo simulation scheme, which samples a number of probability distributions, has been applied using PROBAN (DNV) which interactively utilizes PULS (DNV) as an efficient ultimate strength prediction tool for plated panels. It is demonstrated that this tool can successfully link the two internationally recognized programs, i.e. PROBAN and PULS for probabilistic assessment of stiffened panel’s ultimate strength. The results demonstrate that the suitability of the assumed distribution for the strength can be assessed with relatively little computational time, where the yield stress and imperfection sizes are treated as random variables. Such results are very informative and useful for further development of existing safety format ensuring a safe, economic and reliable ship design.

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