53/58:153 Lecture 23 Fundamental of Vibration ______________________________________________________________________________ - 1 - Lecture 23: Finite element method: vibrations of trusses Reading materials: Section 9.2 1. Plane truss element In terms of local coordinates or Assume that there is no distributed force.53/58:153 Lecture 23 Fundamental of Vibration ______________________________________________________________________________ - 2 - Degree of freedom Nodal forces In terms of global coordinates where Equations of motion53/58:153 Lecture 23 Fundamental of Vibration ______________________________________________________________________________ - 3 - Finally, where Or53/58:153 Lecture 23 Fundamental of Vibration ______________________________________________________________________________ - 4 - Example Element 153/58:153 Lecture 23 Fundamental of Vibration ______________________________________________________________________________ - 5 - Element 253/58:153 Lecture 23 Fundamental of Vibration ______________________________________________________________________________ - 6 - Element 353/58:153 Lecture 23 Fundamental of Vibration ______________________________________________________________________________ - 7 - Element 453/58:153 Lecture 23 Fundamental of Vibration ______________________________________________________________________________ - 8 - Element 5 Element 653/58:153 Lecture 23 Fundamental of Vibration ______________________________________________________________________________ - 9 - Boundary conditions Equations of motion53/58:153 Lecture 23 Fundamental of Vibration ______________________________________________________________________________ - 10 - 2. Space truss element53/58:153 Lecture 23 Fundamental of Vibration ______________________________________________________________________________ - 11