This book contains selected and expanded contributions presented at the 15th Conference on Acoustics and Vibration of Mechanical Structures held in Timisoara, Romania, May 30-31, 2019. The conference focused on a broad range of topics related to acoustics and vibration, such as analytical approaches to nonlinear noise and vibration problems, environmental and occupational noise, structural vibration, biomechanics and bioacoustics, as well as experimental approaches to vibration problems in industrial processes. The different contributions also address the analytical, numerical and experimental techniques applicable to analyze linear and non-linear noise and vibration problems (including strong nonlinearity) and they are primarily intended to emphasize the actual trends and state-of-the-art developments in the above mentioned topics. The book is meant for academics, researchers and professionals, as well as PhD students concerned with various fields of acoustics and vibration of mechanical structures.