The Earthquake Engineering Online Archive

A Modal Analysis of Finite Deformation Enhanced Strain Finite Elements

Armero, Francisco

UCB/SEMM-1996/03, Dept. of Civil and Environmental Engineering, University of California, Berkeley, 1996-02, 21 p. (500 C23 96-03)

Presents closed-form expressions for the eigenvalues and eigenvectors of enhanced strain finite elements in finite strain conditions. An undistorted square element under uniaxial tension/ compression is considered in the calculations. The material model is given by a general compressible Ogden hyperelastic model. It is shown that models exhibiting negative axial stiffness in tension lead to negative stiffness of the transversal hourglass mode.

Available online: http://nisee.berkeley.edu/documents/SEMM/SEMM-96-03.pdf (1 MB)