Michell (1904) derived his well-known optimality criteria for trusses in the context of unequal permissible stresses in tension and compression. For the same design constraints, Hemp (1973) and the author (e.g. 1989) have obtained optimality conditions which are different from those of Michell, and also lead, in general, to different, and lighter trusses. The reasons for this contradiction are examined and it is found that for unequal permissible stresses Michell's optimality conditions are only valid for a highly restricted class of support conditions.
ASJC Scopus subject areas
- Civil and Structural Engineering