Title

Design of Optimum Structures for Dynamic Loads

Description

An optimization method for the minimum weight design of structures subjected to dynamic loads is presented. The method is called designing in the dynamic mode. The dynamic mode may be a single natural mode of the structure or a linear combination of a set of natural modes depending on the spatial distribution and dynamic characteristics of the forcing function. An optimality criterion for minimum weight structures in the dynamic mode is derived. It is based on the strain energy and kinetic energy of the individual elements. A recursion relation for attaining the optimality criterion is also derived. The natural frequencies are obtained by using the Sturm Sequence property in conjunction with a bisection procedure. The normal modes are determined by inverse iteration . A step by step procedure for the optimum design under dynamic response constraints is presented. It includes a method for determining the modes that predominate in the dynamic response. Some examples of design are presented to illustrate the method.

Creator

Venkayya, V. B.

Khat, N. S.

Tischler, V. A.

Taylor, R. F.

Abstract

An optimization method for the minimum weight design of structures subjected to dynamic loads is presented. The method is called designing in the dynamic mode. The dynamic mode may be a single natural mode of the structure or a linear combination of a set of natural modes depending on the spatial distribution and dynamic characteristics of the forcing function. An optimality criterion for minimum weight structures in the dynamic mode is derived. It is based on the strain energy and kinetic energy of the individual elements. A recursion relation for attaining the optimality criterion is also derived. The natural frequencies are obtained by using the Sturm Sequence property in conjunction with a bisection procedure. The normal modes are determined by inverse iteration . A step by step procedure for the optimum design under dynamic response constraints is presented. It includes a method for determining the modes that predominate in the dynamic response. Some examples of design are presented to illustrate the method.

Corporate Author

Air Force Flight Dynamics Laboratory

Report Number

AFFDL TR 71-160 p. 619-658

Report Availability

Full text available

Publisher

Wright-Patterson Air Force Base, OH : Air Force Flight Dynamics Laboratory, Air Force Systems Command and Air Force Institute of Technology, Air University

Date

1973

Type

article

Date Issued

1973-12

Provenance

Bombardier/Aero

Distribution Classification

1

Distribution Conflict

No

DTIC Record Exists

No

Format

1 online resource (40 pages) : ill.

Extent

40

Identifier

AD0785968

Is Part Of

Proceedings of the Third Conference on Matrix Methods in Structural Mechanics: Proceedings of the Conference held at Wright-Patterson Air Force Base, Ohio 19-21 October 1971