Showing papers by "Gasser Abdelal published in 2017"

Web crippling behaviour of cold-formed steel channel sections with web holes subjected to Interior-one-flange loading condition-part I: experimental and numerical investigation

Abstract: Web openings are increasingly used in cold-formed steel beam members of buildings to facilitate ease of services. In this paper, a combination of tests and non-linear finite element analyses is used to investigate the effect of such holes on web crippling under the interior-one-flange (IOF) loading condition; the cases of both flange fastened and flange unfastened to the bearing plate are considered. The results of 61 web crippling tests are presented, with 18 tests conducted on channel sections without web openings and 43 tests conducted on channel sections with web openings. In the case of the tests with web openings, the hole was either located centred beneath the bearing plate or having a horizontal clear distance to the near edge of the bearing plate. A good agreement between the tests and finite element analyses was obtained in term of both strength and failure modes.

Web crippling behaviour of cold-formed steel channel sections with web holes subjected to interior-one-flange loading condition – Part II: parametric study and proposed design equations

Abstract: A parametric study of cold-formed steel sections with web openings subjected to web crippling under interior-one-flange (IOF) loading condition is undertaken, using finite element analysis, to investigate the effects of web holes and cross-sections sizes. The holes are located either centred beneath the bearing plate or with a horizontal clear distance to the near edge of the bearing plate. It was demonstrated that the main factors influencing the web crippling strength are the ratio of the hole depth to the depth of the web, the ratio of the length of bearing plate to the flat depth of the web and the location of the holes as defined by the distance of the hole from the edge of the bearing plate divided by the flat depth of the web. In this study, design recommendations in the form of web crippling strength reduction factor equations are proposed, which are conservative when compare with both the experimental and finite element results.

A Multiphysics Simulation Approach for Efficient Modeling of Lightning Strike Tests on Aircraft Structures

Abstract: A numerical approach is proposed and demonstrated for efficient modeling of the thermal plasma behavior present during a lightning strike event. The approach focuses on events with timescales from microseconds to milliseconds and combines the finite element method, magnetohydrodynamics, and similitude theory. Similitude theory is used to scale the problem to require considerably less computing resource. To further reduce the computational burden and to resolve the numerical difficulty of simulating the nearly zero electrical conductivity of air at room temperature, an approach based on cold-field electron emissions is introduced. Simulations considering turbulent flow have been considered, modeling a test configuration from literature designed to inspect composite material performance and applying an aerospace standard test profile (Waveform-B). Predicted peak temperatures (of the order of ~40 000 K) and pressures (of the order of 0.1–0.2 MPa) suggest that the pressure loading during a Waveform-B event will have a minimal effect on composite material damage.