The Experts below are selected from a list of 9 Experts worldwide ranked by ideXlab platform
Amin Zare - One of the best experts on this subject based on the ideXlab platform.
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exact dynamic Stiffness Matrix for flexural vibration of three layered sandwich beams
Journal of Sound and Vibration, 2005Co-Authors: William Paul Howson, Amin ZareAbstract:Abstract An exact dynamic Member Stiffness Matrix (exact finite element), which defines the flexural motion of a three-layered sandwich beam with unequal faceplates, is developed from the closed form solution of the governing differential equation. This enables the powerful modelling features associated with the finite element technique to be utilised, including the ability to account for nodal masses, spring support Stiffnesses and non-classical boundary conditions. However, such a formulation necessitates the solution of a transcendental eigenvalue problem. This is accomplished using the Wittrick–Williams algorithm, which enables the required natural frequencies to be converged upon to any required accuracy with the certain knowledge that none have been missed. The accuracy of the method is confirmed by comparison with three sets of published results and a final example indicates its range of application.
Yuxin Liu - One of the best experts on this subject based on the ideXlab platform.
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hybrid Member Stiffness Matrix accounting for geometrical nonlinearity and Member inelasticity in semi rigid frameworks
Engineering Structures, 2009Co-Authors: Yuxin LiuAbstract:Abstract This article presents the derivation of a generic Stiffness Matrix for steel Members accounting for the combined influence of P –delta effects, Member shear deformation, inelasticity, semi-rigid connection, and joint damage. Member Stiffness coefficients accounting for rotational Stiffness degradation are derived using the modified moment distribution method. The displacement method is applied to derive the Member Stiffness coefficients due to translational Stiffness degradation, and the force method is utilized to obtain the axial Stiffness coefficients caused by normal axial Stiffness degradation. Incorporating the derived Member Stiffness Matrix into the conventional Matrix displacement method, a computational procedure with increment loading steps is achieved for the nonlinear analysis of steel frameworks subjected to normal and/or abnormal loadings. Example case studies are carried out to illustrate the progressive collapse behaviour of two steel frameworks under abnormal loadings. Results show that the effect of damage to joints may considerably affect the local response of damaged structures, but its effect on the global loading capacity is insignificant. A building framework designed in a non-seismic zone is less robust against progressive collapse than that designed in a seismic zone.
William Paul Howson - One of the best experts on this subject based on the ideXlab platform.
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exact dynamic Stiffness Matrix for flexural vibration of three layered sandwich beams
Journal of Sound and Vibration, 2005Co-Authors: William Paul Howson, Amin ZareAbstract:Abstract An exact dynamic Member Stiffness Matrix (exact finite element), which defines the flexural motion of a three-layered sandwich beam with unequal faceplates, is developed from the closed form solution of the governing differential equation. This enables the powerful modelling features associated with the finite element technique to be utilised, including the ability to account for nodal masses, spring support Stiffnesses and non-classical boundary conditions. However, such a formulation necessitates the solution of a transcendental eigenvalue problem. This is accomplished using the Wittrick–Williams algorithm, which enables the required natural frequencies to be converged upon to any required accuracy with the certain knowledge that none have been missed. The accuracy of the method is confirmed by comparison with three sets of published results and a final example indicates its range of application.
Frank E Weisgerber - One of the best experts on this subject based on the ideXlab platform.
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torsion constant for Matrix analysis of structures including warping effect
International Journal of Solids and Structures, 1996Co-Authors: Mohammed Z Ahmed, Frank E WeisgerberAbstract:Abstract In this research, an effective torsion constant, Jeff, for a wide-flanged Member with different warping restraint conditions at the ends is developed. In order to derive Jeff, the boundary conditions for different warping restraint conditions at the ends, as imposed by the use of different types of connections in steel structures, are employed in the general equation of torsional rotation, o. This effective torsion constant can be used directly instead of the St Venant torsion constant, J, in the conventional Member Stiffness Matrix. The use of Jeff will account for the effect of warping when using the commercial computer programs which employ either a 6 x 6 Member Stiffness Matrix for grid or a 12 x 12 Member Stiffness Matrix for space frame. A table for factor F, which is the ratio of Jeff to J, is presented for different Member properties and warping restraint conditions for the easy and rapid torsional analysis of structures composed of wide-flanged Members by the Matrix method. The solutions of a sample grid problem using Jeff are compared with well known solutions to demonstrate its application.
Mohammed Z Ahmed - One of the best experts on this subject based on the ideXlab platform.
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torsion constant for Matrix analysis of structures including warping effect
International Journal of Solids and Structures, 1996Co-Authors: Mohammed Z Ahmed, Frank E WeisgerberAbstract:Abstract In this research, an effective torsion constant, Jeff, for a wide-flanged Member with different warping restraint conditions at the ends is developed. In order to derive Jeff, the boundary conditions for different warping restraint conditions at the ends, as imposed by the use of different types of connections in steel structures, are employed in the general equation of torsional rotation, o. This effective torsion constant can be used directly instead of the St Venant torsion constant, J, in the conventional Member Stiffness Matrix. The use of Jeff will account for the effect of warping when using the commercial computer programs which employ either a 6 x 6 Member Stiffness Matrix for grid or a 12 x 12 Member Stiffness Matrix for space frame. A table for factor F, which is the ratio of Jeff to J, is presented for different Member properties and warping restraint conditions for the easy and rapid torsional analysis of structures composed of wide-flanged Members by the Matrix method. The solutions of a sample grid problem using Jeff are compared with well known solutions to demonstrate its application.