The Experts below are selected from a list of 9 Experts worldwide ranked by ideXlab platform
Siamak Talatahari - One of the best experts on this subject based on the ideXlab platform.
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charged system search for optimum grillage system design using the lrfd aisc code
Journal of Constructional Steel Research, 2010Co-Authors: Alavi Kaveh, Siamak TalatahariAbstract:Abstract Grillage systems are widely used in structures to cover large areas in bridge Decks, Ship hulls and floors. In this paper, the charged system search (CSS) algorithm is utilized to obtain the optimum design of grillage systems. This algorithm is inspired by the Coulomb and Gauss laws of electrostatics in physics and the governing laws of motion from Newtonian mechanics. The cross-sectional properties of beams are considered as the design variables. Comparison of the results with those of some previous studies shows the robustness of the new algorithm.
Alavi Kaveh - One of the best experts on this subject based on the ideXlab platform.
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charged system search for optimum grillage system design using the lrfd aisc code
Journal of Constructional Steel Research, 2010Co-Authors: Alavi Kaveh, Siamak TalatahariAbstract:Abstract Grillage systems are widely used in structures to cover large areas in bridge Decks, Ship hulls and floors. In this paper, the charged system search (CSS) algorithm is utilized to obtain the optimum design of grillage systems. This algorithm is inspired by the Coulomb and Gauss laws of electrostatics in physics and the governing laws of motion from Newtonian mechanics. The cross-sectional properties of beams are considered as the design variables. Comparison of the results with those of some previous studies shows the robustness of the new algorithm.
Philippe Rigo - One of the best experts on this subject based on the ideXlab platform.
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Vibration Assessment of the Beam Structures and Stiffened Panels
2008Co-Authors: Adrian Constantinescu, Philippe RigoAbstract:Nowadays, noise and vibration problems tend to become an important part of the design process in the automotive and naval industries. Vibrations often affect the passengers comfort, but more dangerously may damage the structure, embarked merchandise and equipments. A simple way to avoid vibrations is to prevent the resonance conditions. The paper presents a study about the vibration of beam structures and stiffened panels. The main application is to determine the eigenfrequencies of structures like platforms, trailer chassis and as well as stiffened shell beam assemblies. The research work covers analytical vibration modeling of 3D beam structures and 3D stiffened shells, as well as the finite element analyses necessary for the validation. The analysis combines the assumption of undamped free vibrations with the simple harmonic motion for the displacement. The 3D numerical model (6 degrees of freedom per node) uses Euler-Bernoulli beam equations in the axial, torsional and flexural cases. This modeling allows to easily take into account the concentrated masses distributed on the panel surface. This approach has been implemented in FORTRAN into a numerical module and will be integrated in the near future with the LBR-5 generic stiffened structure optimization tool. Key-Words: vibration, natural frequency, resonance, stiffened panel, concentrated mass, Lapack 1 General overview Vibrations acting into the mechanical systems can cause many problems at different levels such as mechanical and performance degradation. If we include the human factor, the study of the vibration becomes extremely important. The work presented in this paper is devoted only to the case of beams structures, stiffened panels, their assemblies, and other connected problems. For this type of structures the contact with the human beings are very limited. The most affected are the structural fatigue level and the functioning of the embarked installations. In addition of the marine engineering field (Decks, Ship tanks, offshore structures), the stiffened panels and beam structures are the base element of many other engineering domains. For example, taking the case of a platform vehicle equipped with a military shooting system, the resonant displacement of the platform can affect the fire precision. Imagine also an armored tank equipped with a balance-bridge damaged by the vibration during military actions. Another important application connecting the marine and vehicle fields refers to the dynamics vehicle/Ship-deck investigations. The experiences demonstrate that the dynamic interactions between the vehicles and the vessel deck (for example, a roll-on/roll-off RO-RO vessel with vehicle cargo) may be very different from that of static case. In this case, it was found that the vehicle cargoes can work as mass dumpers to reduce at least one mode shape response of the deck [1].
Gilbert Y. Grondin - One of the best experts on this subject based on the ideXlab platform.
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Stiffened steel plates under combined compression and bending
Journal of Constructional Steel Research, 2003Co-Authors: I.a. Sheikh, A.e. Elwi, Gilbert Y. GrondinAbstract:Abstract This paper presents part of a series of investigations of the behaviour of steel plates stiffened with tee-shape stiffeners and loaded with axial compressive forces with or without bending moments. These elements typically form bridge Decks, Ship hulls, Ship Decks and heavy haul equipment walls. Earlier work by the authors validated a non-linear large deformation-finite strain elasto-plastic finite element model by comparison of the model with the results of sophisticated full-scale physical experimental trials under different load combinations. A parametric study carried out using the finite element model is presented in the following. The study deals with the response of stiffened plate elements under combined uniaxial compression and bending moment. The parameters investigated were the transverse slenderness of the plate, the slenderness of the web and flange of the stiffener, the ratio of torsional slenderness of the stiffener to the transverse slenderness of the plate, and the stiffener to plate area ratio. Average magnitude residual stresses and initial imperfections were assumed. The parametric study indicated that the plate transverse flexural slenderness is the most influential parameter affecting both the strength and behaviour of stiffened steel plates for all the failure modes observed under combined compression and bending. The ratio of stiffener torsional slenderness to plate transverse flexural slenderness, β 4 , affected both the strength and behaviour of only the stiffened plates failing by stiffener tripping. A comparison of the numerical analysis results with American Petroleum Institute and Det Norske Veritas design guidelines indicates that the guidelines predict stiffened steel plate capacity with various degrees of success, depending on the governing mode of failure.
Adrian Constantinescu - One of the best experts on this subject based on the ideXlab platform.
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Vibration Assessment of the Beam Structures and Stiffened Panels
2008Co-Authors: Adrian Constantinescu, Philippe RigoAbstract:Nowadays, noise and vibration problems tend to become an important part of the design process in the automotive and naval industries. Vibrations often affect the passengers comfort, but more dangerously may damage the structure, embarked merchandise and equipments. A simple way to avoid vibrations is to prevent the resonance conditions. The paper presents a study about the vibration of beam structures and stiffened panels. The main application is to determine the eigenfrequencies of structures like platforms, trailer chassis and as well as stiffened shell beam assemblies. The research work covers analytical vibration modeling of 3D beam structures and 3D stiffened shells, as well as the finite element analyses necessary for the validation. The analysis combines the assumption of undamped free vibrations with the simple harmonic motion for the displacement. The 3D numerical model (6 degrees of freedom per node) uses Euler-Bernoulli beam equations in the axial, torsional and flexural cases. This modeling allows to easily take into account the concentrated masses distributed on the panel surface. This approach has been implemented in FORTRAN into a numerical module and will be integrated in the near future with the LBR-5 generic stiffened structure optimization tool. Key-Words: vibration, natural frequency, resonance, stiffened panel, concentrated mass, Lapack 1 General overview Vibrations acting into the mechanical systems can cause many problems at different levels such as mechanical and performance degradation. If we include the human factor, the study of the vibration becomes extremely important. The work presented in this paper is devoted only to the case of beams structures, stiffened panels, their assemblies, and other connected problems. For this type of structures the contact with the human beings are very limited. The most affected are the structural fatigue level and the functioning of the embarked installations. In addition of the marine engineering field (Decks, Ship tanks, offshore structures), the stiffened panels and beam structures are the base element of many other engineering domains. For example, taking the case of a platform vehicle equipped with a military shooting system, the resonant displacement of the platform can affect the fire precision. Imagine also an armored tank equipped with a balance-bridge damaged by the vibration during military actions. Another important application connecting the marine and vehicle fields refers to the dynamics vehicle/Ship-deck investigations. The experiences demonstrate that the dynamic interactions between the vehicles and the vessel deck (for example, a roll-on/roll-off RO-RO vessel with vehicle cargo) may be very different from that of static case. In this case, it was found that the vehicle cargoes can work as mass dumpers to reduce at least one mode shape response of the deck [1].
