Bøger af Nicolae Herisanu

This book presents peer-reviewed and selected papers from the 17th Conference on Acoustics and Vibration of Mechanical Structures (AVMS) held in Timisoara, Romania, on 26-27 May 2023. Internationally recognized experts share their knowledge and key findings in a broad range of topics related to acoustics and vibration of mechanical structures such as analytical, numerical and experimental techniques for noise and vibration problems, environmental and occupational noise and vibration, modelling, prediction and simulations of noise and vibration, noise and vibration control, noise and vibration attenuators. The book addresses application studies and fundamental studies as well, and it is meant for academics researchers and professionals, as well as Ph.D. students concerned with various fields of acoustics and vibration of mechanical structures.

This book presents the optimal auxiliary functions method and applies it to various engineering problems and in particular in boundary layer problems. The cornerstone of the presented procedure is the concept of ¿optimal auxiliary functions¿ which are needed to obtain accurate results in an efficient way. Unlike other known analytic approaches, this procedure provides us with a simple but rigorous way to control and adjust the convergence of the solutions of nonlinear dynamical systems. The optimal auxiliary functions are depending on some convergence-control parameters whose optimal values are rigorously determined from mathematical point of view. The capital strength of our procedure is its fast convergence, since after only one iteration, we obtain very accurate analytical solutions which are very easy to be verified. Moreover, no simplifying hypothesis or assumptions are made.The book contains a large amount of practical models from various fields of engineering such as classical and fluid mechanics, thermodynamics, nonlinear oscillations, electrical machines, and many more.The book is a continuation of our previous books ¿Nonlinear Dynamical Systems in Engineering. Some Approximate Approaches¿, Springer-2011 and ¿The Optimal Homotopy Asymptotic Method. Engineering Applications¿, Springer-2015.

The first chapter is introductory while the second chapter is devoted to a short history of the development of homotopy methods, including the basic ideas of the Optimal Homotopy Asymptotic Method.

This book presents and extends methods for solving different types of strong nonlinearities encountered in engineering systems. Each chapter introduces a distinct approximate method, accompanied by representative examples from various fields of engineering.