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| Study on Keys Influencing Optimization Effect of Rational Criterion Methods of Structural Optimization |
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Abstract Keys influencing optimization effect of rational criterion methods of structural optimization are correctness of criteria equation groups and astringency of iterative algorithm, these keys are dissectionally lucubrated. It is firstly pointed out that structural weight plays two ambivalent roles in structural optimization: As design resource, weight can improve structural performances; On the other hand, as structural load, weight may make structural performances bad. Criteria equation group of virtual work method has ignored derivatives of structural load to design variables, can not consider the other hand of ambivalent roles of structural weight, this ignoring can not be treated as a rational approximation. For aircraft, spacecraft, high-precision antenna, high-speed train, vehicle and machine etc., their structural main load is structural weight or inertial load, the result obtained through Virtual Work method is far away from the optimum solution. In Guide-weight method, the criteria equation groups of are strictly deduced, the limitation of Virtual Work method has been overcome, and its optimization result is improved greatly. Rational criteria methods come down to directly iterative solution of nonlinear criteria equation group, which is a fixed point mapping problem with strict convergence condition. The step factor method is often used to ensure iteration convergence. It can be proved that the step factors making iteration convergence must be existent. And theoretic value range and practical selection methods of step factors making iteration convergence has been educed and proposed. Optimization examples of a truss with 10 bars and two antenna structures can validate above contention.
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Received: 25 December 2012
Published: 28 February 2014
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2014, Vol. 35 
