Ultimate Strength Of Stiffened Panels Research Articles

Empirical formulae assessment of ultimate strength for perforated stiffened panels under longitudinal compression

The present paper studies the influence of cut-outs of local plates on the ultimate strength of stiffened panels based on the tests and numerical simulations. Four intact and perforated stiffened panels subjected to uniaxial compression loads were tested firstly. The initial imperfections of the specimens have been measured before testing, which were used in the FE (finite element) analysis. The tensile tests are used to determine the properties of material. The experimental results are used to verify the modelling technology of FE models. Based on the numerical simulations, the parametric studies with various configurations including the initial twisting distortion, boundary condition and the dimensions of opening are performed to investigate their influences on the collapse behaviours of the stiffened panels. It is found that the residual ultimate strength of perforated stiffened panel mainly depends on the transverse length of opening. Using numerical database, the empirical formulae of ultimate strength of perforated stiffened are developed.

A study on the residual ultimate strength of continuous stiffened panels with a crack under the combined lateral pressure and in-panel compression

In this study, the effects of the crack on the residual ultimate strength of a continuous stiffened panel with a crack under the combined lateral pressure and in-panel compression are investigated numerically. Based on the fact that the extent of model should be sufficient to analyze the surrounding structure, a two-span (1/2 + 1+1/2) model is modeled. Periodic and symmetric boundary conditions are used to calculate the ultimate strength of stiffened panels with a crack, a Plug-in that can be executed in ABAQUS has been developed using Python language. The accuracy of the advanced model is verified, and the influences of various parameters on the ultimate strength reduction rate of a continuous stiffened panel with a crack are comprehensively investigated. The results of the investigation showed that crack location was very important in the evaluation of the residual ultimate strength of a stiffened panel with a crack, and in particular, the cracks under the stiffener have a great influence on the ultimate strength reduction rate of the stiffened panel. Finally, a prediction equation capable of predicting the ultimate strength reduction rate of continuous stiffened panels with a crack is proposed and verified for its accuracy.

Effect of a central dent on the ultimate strength of narrow stiffened panels under axial compression

This paper studies the effect of a central dented imperfection on the load carrying capacity of stiffened panels considering the residual stress caused by the indentation, and identifying the type of boundary conditions to adopt for a model to be used in an experimental programme for damaged panels. A quasi-static nonlinear finite element analysis is used to simulate the production of the local dent, followed by an ultimate strength analysis of the stiffened panels under uniaxial compressive load. The structural plastic strain causes the residual stress and the dent, which are included in the ultimate strength analysis of the stiffened panels under compressive load. To prescribe appropriately the boundary conditions for the central span of stiffened panels, two and three spans models are adopted in the FE analyses. The effects of residual stress, geometric range and dent depth on the ultimate strength of the stiffened panels with a central dented imperfection are investigated using nonlinear quasi-static finite-element analysis.

Influence of Model Geometry and Boundary Conditions on the Ultimate Strength of Stiffened Panels Under Uniaxial Compressive Loading

The aim of this paper is to determine an appropriate configuration of the boundary conditions and geometric model to calculate the ultimate strength of a continuous stiffened panel under compressive loading in the finite element (FE) analysis. The 1 + 1 spans model with periodical symmetric boundary conditions is proposed to be used in the FE analysis, whose results are compared with the 1/2 + 1 + 1/2 span model with periodical symmetric and symmetric boundary condition, and the 1/2 + 1 + 1 + 1/2 span model with symmetric boundary conditions. The effects of the continuity of the stiffened panel with different geometric models and boundary conditions on its collapse mode are investigated. A beam tension test has been used to define the true stress-strain relationship in the FE analysis. The two-span model, either 1 + 1 or 1/2 + 1 + 1/2, with periodical symmetric conditions give a reasonable FE modeling, which can consider both odd and even number half waves and, thus, have the smallest model uncertainty.

Ultimate strength of stiffened panels with cutouts under uniaxial compression

An approximate method based on strut approach to predict the ultimate strength of simply-supported stiffened panels with initial imperfections and square cutouts, subjected to uniaxial compression is presented. The reduction in stiffness of the plate between stiffeners is considered by using an ‘effective width concept’. Tests are reported on welded stiffened steel panels with varying plate slenderness ratio and column slenderness ratio. Based on the experimental investigations and the proposed method, the influence of square openings, extending the full width between stiffeners, on the ultimate strength of stiffened panels is evaluated.