A Finite Element Java Program for Stability Analysis of Pre-Cracked Beam-columns

The anticipated paper reports the findings of a study on the stability analysis of pre-cracked beam-columns using the finite element method and a newly developed java code. First, a stiffness reduction parameter αSUB>1, which reduces the stiffness of the beam-column due to pre-crack, is calculated. The calculated stiffness parameter is then used to modify the stiffness of existing beam element as EI(1-αSUB>1), so that when αSUB>1=1, the beam-column has completely failed. For now a well known beam element for flexural buckling analysis is modified by the introduction of the stiffness parameter. Here only the elastic stiffness is modified. The geometric stiffness is not affected therefore it is not modified. The elastic and geometric stiffness matrices are assembled into a global eigen value matrix equation which is solved using an inverse power method of matrix iteration. An object oriented program in java is developed for the solution of matrix Eigen-value equations by first transforming the matrix equations into a standard form ready for iteration by the inverse power method. The results of the present study using the proposed java code compare well with those using analytical or finite element methods using procedural codes mainly Fortran codes. It is concluded that java-programming language holds a great potential as a candidate for future engineering analysis tool and that a stiffness reduction parameter αSUB>1 proposed herein can be used as a structural health monitoring parameter as a failure indicator.