104th NIA CFD Seminar Topic: Sensitivity analysis of flexible multibody systems with application to rotor dynamics

Speaker: Alfonso Callejo Speaker Bio: Alfonso Callejo graduated in Industrial Engineering from the University of Navarra in 2008 and obtained a Master’s Degree in Mechanical Engineering from the Technical University of Madrid in 2010. He obtained a Ph.D. in Mechanical Engineering at the University Institute for Automobile Research in 2013, entitled “Dynamic Response Optimization of Vehicles through Efficient Multibody Formulations and Automatic Differentiation Techniques”. During his Ph.D., he conducted research at the Motion Research Group of the University of Waterloo. In 2013 he joined the National Institute for Aviation Research at Wichita State University. From 2014 to 2016 he was a Postdoctoral Fellow at McGill University’s Centre for Intelligent Machines. Dr. Callejo is currently an Asst. Research Scientist at the University of Maryland. His research interests are in the areas of Efficient Multibody Formulations, Flexible Multibody Systems and Sensitivity Analysis. Abstract: The combination of analysis and optimization methods in mechanical engineering, also known as design optimization, has great potential in product development. In turn, robust sensitivity analyses that provide reliable and efficient objective function gradients play a key role in design optimization. This paper presents a discrete adjoint method for the sensitivity analysis of flexible mechanical systems. The ultimate goal is to be able to relate the physical properties of beam cross-sections to the dynamic behavior of the system, which is key to design realistic flexible elements. The underlying flexible multibody formulation is one that supports large-amplitude motion, beams with sophisticated composite cross-sections, and kinematic joints. A summary of the kinematic and dynamic foundations of the forward equations is presented first. Then, a discrete adjoint method, along with meaningful examples and validation, is presented. The method has proven to provide accurate and reliable sensitivities. Additional information, including the webcast link, can be found at the NIA CFD Seminar website: http://www.hiroakinishikawa.com/niacfds/index.html