| Summary: | 博士 === 國立臺灣大學 === 造船工程學系 === 82 === A constraint with fuzzy information is called a fuzzy
constraint. Some mutual-conflicting objectives may also exist
in an optimal design problem. For the design problem with fuzzy
constraint, based on the decision-making model proposed by
Bellman and Zadeh, an multi-objective fuzzy optimization
technique is proposed and used to find the best compromise
solution to the conflicting objective functions rationally.
First, a membership function is used to describe the satisfied
grade for the fuzzy constraint,and then to find the interval of
possible optimum value for each objective function. Secondly,
the interval of each objective function is converted into a
membership function. Finally, a multi-objective problem with
fuzzy constraint can be transformed into a conventional single
objective problem. A reliable and efficient algorithm based on
the sequential quadratic programming(SQP) method is developed
and used to solve above single objective problem. In this
thesis, the characteristics of the vibration absorber with a
small mass ratio in a two masses dynamic system is studied by
using the multi-objective fuzzy optimzation technique. A case
which a control force acting between the main syetem and
absorber is introduced, the dynamic effect due to this
parameter is also studied. To obtain the minimum dynamic
response of the main system and absorber simultaneously is
self-conflicting. Thus, the best compromise solution is
obtained by using the multi-objective fuzzy optimization
technique. The design parameters of an active and passive
absorber is also optimized. Finally,a simple dynamic model of
3-D structure is used to xamine the problem encountered in the
two masses model.
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