A scheme for imposing constraints and improving conditioning of structural stiffness matrices

作者：Martin F; Benavent Climent A^*; Gallego R

来源：International Journal for Numerical Methods in Biomedical Engineering, 2010, 26(9): 1117-1124.

DOI：10.1002/cnm.1181

• computer analysis
• stiffness method
• constraints
• condition number
• building frames

This paper presents a scheme for incorporating kinematic constraints ( rod constraint, diaphragm constraint) in beam-type finite element models. The formulation employs minimization using Lagrange multipliers and does not require the arrangement of the coefficient matrix. Unlike the classical formulation-which imposes the constraints after assembling the global stiffness matrix of the structure-in the proposed scheme the constraints are applied twice: first to the stiffness matrix of the individual elements before assembly and then to the global stiffness matrix of the structure after assembly. As a result, the condition number of the coefficient matrix is remarkably reduced. The validity of the proposed scheme is demonstrated through numerical examples.

• 出版日期2010-9