Structural dynamic analysis for time response of bars and trusses using the generalized finite element method

the generalized finite element method (gfem) can be viewed as an extension of the finite element method (fem) where the approximation space is enriched by shape functions appropriately chosen. many applications of the gfem can be found in literature, mostly when some information about the solution is known a priori. this paper presents the application of the gfem to the problem of structural dynamic analysis of bars subject to axial displacements and trusses for the evaluation of the time response of the structure. since the analytical solution of this problem is composed, in most cases, of a trigonometric series, the enrichment used in this paper is based on sine and cosine functions. modal superposition and the newmark method are used for the time integration procedure. five examples are studied and the analytical solution is presented for two of them. the results are compared to the ones obtained with the fem using linear elements and a hierarchical finite element method (hfem) using higher order elements.