Eirikur Jonsson

Eirikur Jonsson
University of Michigan | U-M · Department of Aerospace Engineering

Doctor of Philosophy

About

21
Publications
8,060
Reads
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208
Citations
Citations since 2016
17 Research Items
204 Citations
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Publications

Publications (21)
Article
Full-text available
Dynamical systems often exhibit limit cycle oscillations (LCOs), self-sustaining oscillations of limited amplitude. LCOs can be supercritical or subcritical. The supercritical response is benign, while the subcritical response can be bi-stable and exhibit a hysteretic response. Subcritical responses can be avoided in design optimization by enforcin...
Article
Full-text available
Derivatives of eigenvalues and eigenvectors with respect to design variables are required for gradient-based optimization in many engineering design problems. However, for the generalized and standard eigenvalue problems with general complex and non-Hermitian coefficient matrices, no method can accurately compute the eigenvalue and eigenvec-tor der...
Conference Paper
Full-text available
View Video Presentation: https://doi.org/10.2514/6.2022-3357.vid The next-generation aircraft are trending towards more flexible wings that make them more prone to flutter, or more general, limit cycle oscillation (LCO). Thus, when conducting a multidisciplinary design optimization (MDO) using the gradient-based method, computing the LCO derivative...
Conference Paper
Full-text available
When designing aircraft, avoiding dynamic aeroelastic instabilities such as flutter is a key requirement. One way to meet this requirement is to use a multidisciplinary design optimization subject to a flutter constraint. To date, flutter-constrained design optimizations have used geometrically linear models, that do not accurately predict flutter...
Preprint
Full-text available
Limit cycle oscillations (LCO) can be supercritical or subcritical. The supercritical response is benign, while the subcritical response can be destructive. It is desirable to avoid subcritical responses by enforcing LCO stability through design optimization constraints. However, there is a need for a computational approach that can model this inst...
Article
Full-text available
Eigenvalue and eigenvectors are essential metrics to characterize dynamic system behavior and stability. When performing gradient-based design optimization, derivatives of these metrics are required. Analytic forward algorithmic differentiation (FAD) for a self-adjoint generalized eigenproblem has been a useful technique. However, reverse algorithm...
Conference Paper
Full-text available
Higher-aspect-ratio lightweight wings can make aircraft more energy efficient thanks to induced drag reduction. Because such wings exhibit large deflections, affecting the flutter onset, design optimization using linear flutter analysis is inadequate. To address this issue, we develop a framework for including a geometrically nonlinear flutter cons...
Article
Full-text available
Flutter and limit cycle oscillation (LCO) are important phenomena that need to be considered in aircraft design. Previous harmonic-balance-based flutter and LCO prediction methods either have low linear convergence rates or require expensive Newton steps to achieve quadratic convergence. In this paper, we propose a preconditioned, Jacobian-free, co...
Presentation
Full-text available
Develop coupled Newton--Krylov time spectral flutter solver and coupled adjoint solver. The corresponding conference paper is with the same title and with the following DOI: 10.2514/6.2019-3549.
Article
Full-text available
Flutter is a dynamic aeroelastic instability driven by the interaction of inertial, elastic, and aerodynamic forces. It is an undesirable phenomenon in aircraft because it causes divergent oscillations that may lead to structural damage or failure, performance and ride comfort degradation, or loss of control. If flutter is discovered at the aircraf...
Presentation
Full-text available
This is a presentation for the following conference paper https://doi.org/10.2514/6.2019-2354
Conference Paper
Full-text available
Flutter onset characteristic are an important consideration in commercial airliner design. Previous work with high-fidelity aerostructural optimization has shown a tendency for optimization algorithms to produce unrealistically high span designs, particularly when maximizing range or minimizing fuel burn, in an effort to maximize aerodynamic effici...
Article
This chapter describes an efficient aerodynamic design optimization methodology for wings in transonic flow. The approach replaces a computationally expensive high-fidelity computational fluid dynamic model (CFD) in an iterative optimization process with a corrected polynomial approximation model constructed by a cheap low-fidelity CFD model. The o...
Chapter
Rising fuel prices and inefficient fishing gear are hampering the fishing industry. Any improvements of the equipment that lead to reduced operating costs of the fishing vessels are highly desirable. This chapter describes an efficient optimization algorithm for the design of trawl-door shapes using accurate high-fidelity computational fluid dynami...
Conference Paper
Rising fuel prices and inefficient fishing gear are hampering the fishing industry. Any improvements of the equipment that lead to reduced operating costs of the fishing vessels are highly desirable. In this paper, we present a two-dimensional computational uid dynamic (CFD) model to analyse the hydrodynamic performance of trawl-doors, i.e., wings...
Conference Paper
This paper presents an effcient aerodynamic design optimization methodology for wings in transonic flow. The approach replaces a computationally expensive high-fidelity CFD model in an iterative optimization process with a corrected polynomial approximation model constructed by a cheap low-fidelity CFD model. The output space mapping tech- nique is...

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Projects

Projects (2)
Project
Develop MDO framework for dynamical systems and control including linear stability, LCO stability, bifurcation stability, and optimal control problems. We attempt to apply the adjoint method, and reverse-mode algorithmic differentiation to develop a series of efficient derivative computation methods for those dynamical system problems.
Archived project
Algorithm and implementation of time spectral-based flutter analysis and optimization.