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Abstract
In this report two different iterative methods to solve structural weight optimization problems are implemented and compared. The first method is based on the so called ”fully stressed design” concept and will be called the FSD method. The second method is based on calculating the derivatives (or gradients) of the constraint functions at given iteration points and will be called the derivative method or the gradient method.
The first problem for which the two methods are compared is the problem of minimizing the weight of 3-‐dimensional beam structures subject to constraints on maximal stress in each beam.
The beam structures are exposed to given statical load conditions. The first part of this report deals with this problem and the results of tests on a car model are presented.
The second part of the report deals with the problem of minimizing the weight of shell structures subject to constraint on stresses and displacements under given statical load conditions. Again the two general methods above are implemented and used. Test results are compared for a number of shell structures and load conditions.
In general both of these methods work rather well for both of these problems. However, the derivative (or gradient) method seems to be somewhat more reliable than the FSD method.
