A LUMPED-MASS MODEL FOR THE DYNAMIC ANALYSIS OF THE SPATIAL BEAM-LIKE LATTICE GIRDERS

✍ Scribed by J.-S WU; M HSIEH; C.-L LIN

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 541 KB
• Volume: 228
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1006/jsvi.1999.2414

✦ Synopsis

A method is presented to replace the distributed mass of each bay of a spatial beam-like lattice girder by 24 lumped masses, half of the latter being located at the upper plane and the other half at the lower one of the bay respectively, where the correct magnitude and location of each lumped mass are determined according to the actual arrangement of all the members constituting the bay. Based on the locations of the 24 lumped masses, the coe$cients associated with the &&masses'' translating in the xN , yN and zN directions and those associated with the &&mass moment of inertias'' rotating about the xN -, yN -, and zN -axis for the e!ective mass matrix of a bay-equivalent (continuum) beam are calculated. Numerical results show that the presented lumped-mass model together with the e!ective sti!ness matrix of the bayequivalent beam derived on the assumption that the cross-sections at both ends of each bay remain plane after deformation will give more accurate natural frequencies for the multi-bay spatial X-braced, Pratt or Warren beam-like lattice girders. Besides, the presented lumped-mass model is available for various transverse side-length ratios R ?@ and longitudinal side-length ratios R ?* .