Matrix algorithm for structural modification based upon the parallelelement concept

This paper deals with the reduction of the computer time needed to perform arithmetical operations for the structural analysis consisting of an original solution of a complex redundant structure, followed by a number of consecutive modifications. A matrix algorithm is derived in the paper for this purpose from the so-called parallel element method and discussed in connection with the Force or Displacement methods used for the original solution. This algorithm is compared with the so-called "initial strain" method of modification. Computer time for all the algorithms is evaluated showing the parallel element algorithm as much more economic than the initial strain approach for a larger number of consecutive modifications. Computer accuracy tests are reported and two numerical examples are provided. Applications are pointed out for structural optimization, nonlinear analysis and computeraided design.

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