ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

3aSA10. Direct global stiffness matrix method for thin cylindrical shell dynamics.

Mark A. Hayner

J. Robert Fricke

MIT, Rm. 5-435, 77 Massachusetts Ave., Cambridge, MA 02139

This paper introduces the direct global stiffness matrix (DGSM) method for analyzing the dynamics of cylindrical shells with axial symmetry. The dynamic stiffness matrix of a straight, circular cross-section cylindrical element is formulated in terms of ring forces and displacements at each end on a per circumferential mode basis. The stiffness matrix is based on an exact wave-type solution of the thin shell Donnell equations. More complicated shell systems are analyzed by assembling any number of cylindrical elements. For example, a cylinder with a gradual variation in radius may be modeled by a series of shell elements welded together at their ends. Total system dynamics are found at any given frequency by inverting the global system matrix formed from the individual stiffness element matrices and summing over circumferential mode number. Results for a test case are presented to demonstrate and verify the implementation. [Research sponsored by ONR.] [sup a)]E-mail: