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Item type:Publication, Access status: with files , A network‐based approach to identifying key components in structural vibrationsModeling the dynamics of systems with many interacting components, such as robots, wind turbines, and trusses, remains challenging today. These systems often display complex oscillatory responses to external inputs, and harmful vibrations might be excited along with the desired motion. Understanding the relative importance of individual components or systems aspects to the overall system dynamics could be a vital step towards focused design and maintenance efforts. This work proposes a network‐based approach to studying the dynamics of a mechanical system by representing the system as a network of coupled oscillators, where each node corresponds to a machine component and each link denotes a physical connection, such as a weld or bolt. Inspired by studies of dynamics in biological and social networks, we show how network measures can be used to predict the importance of a single oscillator, or component, for shaping the overall dynamics. We further demonstrate under which conditions these conclusions are possible, and where the metrics fail. This study hopes to contribute to the broader field of network‐based methods in engineering and yield insights that help focus design and maintenance efforts in the future.Publicationtype: Journal Article21 7 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Wave propagation in non‐uniform media by linear expansion of the refraction lawThe propagation of mechanical waves in an unbounded, non‐uniform medium can be described by using curvilinear coordinates centered at the source position. The Frenet coordinate system, with origin on a point riding a wave, is used as a basis for the curvilinear coordinates. In this way a principal coordinate stating the evolution of the wave field and running along a ray, orthogonally to the successive wave fronts, is determined. A linear expansion of the refraction law at the rider point connects the gradient of the speed of sound field to the curvatures of the wave path and of the wave front. We use this connection in developing a numerical solution for the wave field, after recalling recent developments about the historical determination of the refraction law.Publicationtype: Journal Article17 7 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Numerical modeling of inertial particles in three‐dimensional fluid flowThe motion of inertial particles in a fluid is modeled by the Maxey–Riley–Gatignol equation (MaRGE). The MaRGE contains an integral term that arises due to the viscous diffusion of vorticity in the fluid around the particle. Because it makes MaRGE difficult to solve numerically, the integral term is often neglected or approximated, despite its demonstrated importance for obtaining realistic trajectories. There are some studies that propose algorithms to solve the full MaRGE numerically for two dimensional flows fields. For simple flows like a vortex, analytical solutions exist that can serve as test cases to verify implementations. However, in most practical applications, fluids will be three dimensional. This article extends a multi‐step algorithm proposed by Daitche to the three‐dimensional case. Based on an approach by Candelier et al., it derives an analytical solution for a particle moving in a three‐dimensional vortex while being subject to gravity. Numerical examples compare empirical and theoretical convergence orders and demonstrate order reduction in particular for particles with non‐zero relative initial velocity.Publicationtype: Journal Article59 49