Structural Modification by Perturbation Method

The proposed method is based upon an assumption that any kind of modification may be reduced to an addition of a certain number of new elements to the structure to be modified. The matrix operations algorithm adopting the force method is derived and yields the effect of an arbitrary modification on the stress-strain state of the modified structure. The algorithm eliminates the necessity of repetition of the solution of compatibility equations for the original structure if already solved. The obtained results are especially simple in application if the whole computation procedure is planned from the very beginning in a way so as to include the possibility of later modifications. The method is briefly compared with the initial strain approach and its applicability for calculating the effect of structural element nonlinearity is pointed out.