抄録
When a both-ends-clamped beam whose volume is constant is subjected to a concentrated load, it is known that we can get the actual most suitable form by the optimality criteria only under a certain specific condition that a load is on central part of the span. But, the most suitable form is supposed to exist at a condition except for the above as well. So, in this research, when a both-ends-clamped beam is subjected to a concentrated load, we optimize the structural form under the condition of volume constancy as a mere minimization of the displacement by GA(the genetic algorithm).