Alternative approximation concepts for space frame synthesis

The objective of this work is to demonstrate the efficiency and applicability of the optimization algorithm using a multivariate spline approximation. In the present algorithm, based on the function values and first-order derivatives of the constraints available at the intermediate points of optimization, an explicit approximation of constraint functions is created by using the least squares spline algorithm. The nonlinearity of the function is adaptively updated using feedback information from the previous two iterations for finding the order of spline approximation. In addition, constraint deletion and design variable linking concepts are employed in solving the approximate problem by using the quasianalytical sequential quadratic programming and dual methods. The behavior constraints include stresses, displacements, and local buckling in the optimum design of frame structures. To demonstrate the broad applicability of the optimization algorithm, the cross-sectional dimensions are directly selected as the design variables for frame problems having thin-walled rectangular and tube cross-sectional members, and the cross-sectional areas are selected as design variables for an /-section problem.

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“…The initial design and side constraints are given in Ref. 8, and the initial volume is 32,393.4 in. 3 .…”

Section: Numerical Examples and Comparisonsmentioning

confidence: 99%

“…The details on stress and buckling evaluation points and the initial design and side constraints are given in Ref. 8; the initial weight is 1220.78 kg. The final cross-sectional dimensions are listed in Table 1, and the iteration history is shown in Table 2.…”

Section: Numerical Examples and Comparisonsmentioning

confidence: 99%

Optimal design of frame structures using multivariate spline approximation

Wang

Grandhi

1994

AIAA Journal

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“…(1-3) is a complex nonlinear mathematical programming problem that precludes direct solution attempts even in the absence of time parametric constraints. 14 The composite objective function design problem contained in Eqs. (1)(2)(3) can be specialized to a weight minimization problem by deleting E(d,t) from Eq.…”

Section: Optimum Design Problem Statementmentioning

confidence: 99%

Control augmented structural synthesis with transient response constraints

Manning¹,

Schmit

1990

AIAA Journal

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An integrated approach to the optimum design of control augmented structural systems is presented in which structural variables and control variables are changed simultaneously during the design process. Constraints are imposed on peak transient dynamic displacements and accelerations, and control system effort. Side constraints imposed on structural member sizes and control system thresholds and actuator output forces insure the generation of physically meaningful designs. Example problems are presented that illustrate the benefits of simultaneous treatment of both the structural design variables and the control design variables.

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“…-u U:X (4)(5)(6)(7)(8)(9)(10)(11)(12) where R is the maximum response ratio rounded down to the nearest tenth c then R = .6). …”

Section: Subscriptsmentioning

confidence: 99%