Solution of Ordinary Differential Equations in Gradient-Based Multidisciplinary Design Optimization

Hwang, John T ; Munster, Drayton W

关键词: DIFFERENTIAL EQUATIONS;    MULTIDISCIPLINARY DESIGN OPTIMIZATION;    RUNGE-KUTTA METHOD;    GRADIENTS;    DERIVATION;    DESIGN ANALYSIS;    NONLINEARITY;   

RP-ID  :  GRC-E-DAA-TN50163

学科分类：数值分析

美国|英语

来源: NASA Technical Reports Server

【 摘 要 】

A gradient-based approach to multidisciplinary design optimization enables efficient scalability to large numbers of design variables. However, the need for derivatives causes difficulties when integrating ordinary differential equations (ODEs) in models. To simplify this, we propose the use of the general linear methods framework, which unifies all Runge-Kutta and linear multistep methods. This approach enables rapid implementation of integration methods without the need to differentiate each one, even in a gradient-based optimization context. We also develop a new parallel time integration algorithm that enables vectorization across time steps. We present a set of benchmarking results using a stiff ODE, a non-stiff nonlinear ODE, and an orbital dynamics ODE, and compare integration methods. In a modular gradient-based multidisciplinary design optimization context, we find that the new parallel time integration algorithm with high-order implicit methods, especially Gauss-Legendre collocation, is the best choice for a broad range of problems.