| Summary: | 碩士 === 國立中興大學 === 機械工程學系 === 85 === This thesis deals with optimum design of headstocks with three
different shapes. The design purpose is to minimize the
deflection of workpieces at cutting point. Each kind of
headstock is subjected to two load case. The first load case
includes the cutting force and the second load case combines the
cutting force and the thermal effects. Heat generation is due to
friction which is resulted from bearing revolution. The quantity
of heat generated is calculated by the formula given by bearing
manufactures. Design variables are the shape of headstock, the
size of headstock, the stiffnesses of bearings, locations of
bearings,locations of fins,and the size of fins. These variables
include integer and continuous varilables. Because genetic
algorithm has the ability of global search and dealing with
mixed-variable problems, it is chosen to be the solver. The
finite element model used in this thesis is created by MSC/PATRN
and alayzed by MSC/NASTRAN. Each example which represents one
specific shape is solved twice by the two load cases mentioned
previsously. The validity and difference of the results are
checked and discussed. The optiimun results of the three
different-shape headstocks are compared and the best one is
determined.
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