Aeroelastic Loads and Sensitivity Analysis for Structural Loads Optimization

D'Vari, Ron; Baker, Myles L.

doi:10.2514/2.2421

Cited by 7 publications

(4 citation statements)

References 6 publications

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“…Next to Lockheed, work was also done at Boeing, e.g. by D'Vari and Baker [15] presenting an aeroelastic integrated loads subsystem. A framework used at Airbus and DLR is VarLoads, literature can be found by Kier et al [16,17] or Scharpenberg et al [18].…”

Section: Literature Reviewmentioning

confidence: 99%

Parametric aeroelastic modeling, maneuver loads analysis using CFD methods and structural design of a fighter aircraft

Voß

Klimmek

2023

Aerospace Science and Technology

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Section: Literature Reviewmentioning

confidence: 99%

Parametric aeroelastic modeling, maneuver loads analysis using CFD methods and structural design of a fighter aircraft

Voß

Klimmek

2023

Aerospace Science and Technology

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“…The drive to include gust response in integrated control/structure aeroservoelastic synthesis of actively controlled airplanes motivated development of PSD response sensitivity equations 9 as well as alternative state-space analysis and sensitivity techniques. 10−16 The state-space formulation becomes attractive when methods of modern control system modeling and design are used for aeroservoelastic synthesis.…”

Section: Nomenclaturementioning

confidence: 99%

Quadratic Stress Failure Constraints for Structures Under Combined Steady and Random Excitation

Engelsen

Livne

2004

AIAA Journal

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Constraint functions are formulated and their analytical sensitivities are derived for multiaxial states of stress arising in actively controlled airplane structures from combined maneuver loads and random gust responses. The stress failure criteria of von Mises for isotropic materials and Tsai-Wu for composite materials are considered. These criteria are nonlinear in nature and involve interactions between the multiaxial stress components. The gust response is based on random gust analysis using state-space mathematical models and statistical properties of gusts in the atmosphere. The covariance matrix of the stress components at a point is used to define a quadratic surface representing stress combinations of equal probability. It is shown how a single critical stress combination can be determined analytically for all stress combinations on the equal-probability stress surface. Analytic sensitivities of the resulting stress constraint with respect to design variables are derived. A constraint function approximation is also derived to reduce computational effort in an approximation-concepts-based optimization strategy. The constraint, analytic sensitivities, and approximations are then integrated into a multidisciplinary aeroservoelastic optimization capability, and results for a large flexible commercial transport airplane are presented.Nomenclature [A] = matrix with terms a i j {b}, c = coefficients determining the constraint function in normalized coordinates [C] = covariance matrix of the gust stress components due to a design gust velocity U σ [C 1 ] = covariance matrix of the gust stress components due to a unit design gust velocity [C ( p)] = covariance matrix variation with a design variable p [F], {f } = matrix and vector defining the quadratic failure criterion g = constraint function g = constraint function used to determine the critical stress vector h( ) = function value [I ] = identity matrix L = Lagrangian N k = total number of design variables p = design variable p k = kth design variable p( ) = probability density function {q} = vector of normalized coordinates s xx , s yy , s xy = stress components {s} = stress vector {s g } = stresses due to gust {s 1 } = mean stresses

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“…In fact, several authors have addressed the need to center, at the core of airplane design, the accurate and efficient computation of loads. Firstly, with the purpose of finding an optimal design with minimum weight, and secondly, to create a leaner industrial process [1,3,9]. With new environmental regulations on their way, new aircraft configurations must be explored.…”

Section: Background and Motivationmentioning

confidence: 99%

“…A classical approach, though computationally expensive, is to estimate sensitivity derivatives. This methodology was used in the 90's, where, in some instances, the mode shapes were considered constant through the optimization to simplify the calculation [9,[37][38][39].…”

Section: Literature Reviewmentioning

confidence: 99%

High Fidelity and Efficient Computations of Dynamic Loads for Multidisciplinary Design Optimization of Flexible Transport Aircraft

Nieto¹

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The current state-of-the-art design optimization of airframes is tightly wounded to its loads analyses as the process is usually conducted employing a deterministic set of critical load cases. The sheer number of scenarios required to estimate the critical loading conditions prevent these two processes from integrating, obstructing the development of a Multidisciplinary Design Optimization (MDO) framework. In this thesis, the problem of high fidelity and efficient estimation of critical dynamic aeroelastic loads is addressed, as a first step, towards the development of an integrated MDO platform for airframes at preliminary and detailed design stages. The method is based on the Kriging metamodeling technique along with the Latin Hypercube scheme for initial sampling and the expected improvement function for subsequent selection of sample points, known formally as the Efficient Global Optimization (EGO) algorithm. Furthermore, different inexpensive metrics, based on the concept of modal contribution factors, are investigated to serve as indicators to determine if a substantial change in the loads has occurred during the design optimization cycle, triggering the requirement for the re-exploration of the loads design space. A case study is presented to evaluate the performance of the proposed methodology versus a full factorial search. A reduction of 84% was achieved in the total time of execution employing the proposed methodology.

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Aeroelastic Loads and Sensitivity Analysis for Structural Loads Optimization

Cited by 7 publications

References 6 publications

Parametric aeroelastic modeling, maneuver loads analysis using CFD methods and structural design of a fighter aircraft

Parametric aeroelastic modeling, maneuver loads analysis using CFD methods and structural design of a fighter aircraft

Quadratic Stress Failure Constraints for Structures Under Combined Steady and Random Excitation

High Fidelity and Efficient Computations of Dynamic Loads for Multidisciplinary Design Optimization of Flexible Transport Aircraft

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