A common technique for alleviating stresses in overlap joints in aircraft industry is by designing tolerances for the rivet holes. It is shown that optimal tolerances can be obtained by means of a linear programming algorithm. When generalizing the concept to the retrofit of existing trusses by means of optimal clearances the basic problem becomes nonlinear. The reason is that we do not know the signs of the optimal forces in the truss with clearances. When using the nominal signs, clearances will always improve the situation but the solution is not guaranteed to be optimal. When ignoring the sign in the formulation, optimal solutions can be obtained but often also non-feasible solutions. In this paper the problem for optimal clearances is replaced by a problem for optimal stiffnesses. It is shown that a stress-ratio type method converges rapidly on the correct signs. With these signs a standard linear programming routine produces the optimal clearances. The approach is illustrated with examples of truss beams.

purchase the full-text of this paper (price £20)

go to the previous paper
go to the next paper
return to the table of contents
return to the book description
purchase this book (price £78 +P&P)