دانلود گزارش کارورزی و کار آموزی

چکیده : 

In this paper the exact stability stiffness matrix of an Euler–Bernoulli column in presence of an arbitrary

number of concentrated cracks is derived. The procedure for the evaluation of the stability stiffness

matrix is based on the exact closed form solution of the buckling modes of the multi-cracked column,

derived by the present authors in a previous paper. The knowledge of the exact stability stiffness matrix

of the multi-cracked beam allows the direct evaluation of the exact global stability stiffness matrix of

damaged frame structures. Furthermore, the exact evaluation of the buckling loads and the corresponding

buckling modes, consistent with the distributed parameter model, are obtained through the application

of the well-known Wittrick–Williams algorithm. The great advantage of the proposed approach is

that the degrees of freedom of the overall frame structure are exactly the same of the equivalent undamaged

structure irrespective of the number of the concentrated damages. A numerical application, aiming

at validating the exact solution of a framed structure, in presence of concentrated cracks, is reported. The

influence of multiple cracks on the critical load and the corresponding buckling mode of the frame under

study is assessed.