F franklin j d powell a emami naeini feedback control

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: igenvalue calculations. Although the problem appears rather simplistic in nature, it is a severe test for linear irregular shaped elements where accurate bending mode frequencies are required. 2. Since the beam is free of any constraints, only one-half of the beam is required for modeling. Symmetry constraints are applied at the mid-length of the models. To obtain the desired bending mode (in the XY plane) all nodes at Z = 0 are constrained in the Z direction. Additionally, for the axial mode only, all nodes at Y = 0 are constrained in the Y direction. 3. For the axial mode case, Householder extraction is used with all UX degrees of freedom chosen as MDOFs. For the bending mode case, subspace extraction is used with shifted subspace to circumvent zero energy modes. 4. All load cases show good agreement in the prediction of the first axial natural frequency. This mode is simply linearly-varying longitudinal motion which is easily handled by both linear and quadratic elements. Irregular element shapes have only a minor effect on solution accuracy since axial motion is pre...
View Full Document

This note was uploaded on 12/09/2010 for the course DEPARTMENT E301 taught by Professor Kulasinghe during the Spring '09 term at University of Peradeniya.

Ask a homework question - tutors are online