Calculation of structural dynamic forces and stresses using mode acceleration

Blelloch, Paul

doi:10.2514/3.20475

Cited by 8 publications

(3 citation statements)

References 2 publications

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“…(51) the dynamicMD reduced-ordersolutions(corresponding to different load cases) {q(t )} are used together with the static adjoint solutions {p} (corresponding to different stresses). Because in the MA method the quasi-static problem (22) is solved with the full-order stiffness matrix for all time steps (right-hand sides), and because in the approximate reduced-order methods presented here this problem is solved in reduced order, considerablecomputational savings can be materialized.…”

Section: Dynamic Responsementioning

confidence: 99%

“…Instead, the insight gained to this point regarding stress-orientedorder reduction of the static problem can be used to obtain reduced-order dynamic stresses based on the MA method as follows: stress recovery in the MA method is based on the solution of a full-orderquasi-staticproblem with a dynamic right-hand side [Eqs. (13), (14), (22), and (23)]. …”

Section: Dynamic Responsementioning

confidence: 99%

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Reduced-Order Design-Oriented Stress Analysis Using Combined Direct and Adjoint Solutions

Livne

Blando

2000

AIAA Journal

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A new method for extracting accurate stress information from reduced-order structural and aeroelastic models is presented. The method has second-order accuracy when approximate reduced-order direct and adjoint solutions (based on different reduced-order bases) are used simultaneously to obtain approximate stresses. The method is applicable to both static and dynamiclinear analysis. A review of four common methods for structural model order reduction [two variants of the mode displacement method (standard mode displacement and the ctitious mass method), the mode acceleration method, and the Ritz vector method] identi es sources of dif culty and causes of errors in stress behavior sensitivity calculations. Considerations used for selection of the reduced-order direct and adjoint bases are discussed. A series of static and dynamic test cases is used to assess accuracy of the new method in an analysis mode. Accuracy studies of sensitivity calculations follow. We hope to contribute to the eld of design-oriented structural dynamics in terms of both insight and practice.

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Section: Dynamic Responsementioning

confidence: 99%

Section: Dynamic Responsementioning

confidence: 99%

Reduced-Order Design-Oriented Stress Analysis Using Combined Direct and Adjoint Solutions

Livne

Blando

2000

AIAA Journal

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“…First, the aeroservoelastic state-space equations must be formulated in a reduced modal space, in order for the computational cost of the Lyapunov solver to remain tractable. Stresses (and their sensitivities) are known 12,13 to be very difficult to accurately extract from modal approximations, as they converge slowly with mode number. Secondly, stress-based (or buckling-based) failure indices of interest, such as the von Mises stress, are nonlinear quadratic functions of the aerservoelastic state, complicating the formulation of a stochastic failure criterion from the covariance matrix.…”

Section: Introductionmentioning

confidence: 99%

Aeroservoelastic Optimization under Stochastic Gust Constraints

Stanford

2018

2018 Applied Aerodynamics Conference

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This work considers the aeroservoelastic optimization of a highly flexible transport aircraft wingbox with several control surfaces distributed along the trailing edge. The steady deflections of the control surfaces are designed to alleviate static maneuver loads, while the unsteady deflections are designed to alleviate stochastic continuous gust disturbances. Spatially-detailed unsteady stochastic stress and panel buckling constraints are formulated via modal acceleration, and by methods to locate the most-probable failure point along an equal-probability hypersurface. For the case considered here, it is found that the inclusion of such gust constraints during optimization presents a sizable structural mass penalty. In some cases, this mass penalty can be completely recovered with controlled gust load alleviation.

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Limited Experimental Displacement Data used for obtaining Full-Field Dynamic Stress Strain Information

Pingle

Avitabile

2011

Linking Models and Experiments, Volume 2

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Calculation of structural dynamic forces and stresses using mode acceleration

Cited by 8 publications

References 2 publications

Reduced-Order Design-Oriented Stress Analysis Using Combined Direct and Adjoint Solutions

Reduced-Order Design-Oriented Stress Analysis Using Combined Direct and Adjoint Solutions

Aeroservoelastic Optimization under Stochastic Gust Constraints

Limited Experimental Displacement Data used for obtaining Full-Field Dynamic Stress Strain Information

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