**Preface to "Reliability of Mechatronic Systems and Machine Elements: Testing and Validation"**

Advanced and complex systems require technologies and methodologies to develop mechatronic systems in an efficient and effective way. In addition to the design of these systems, testing and validation activities are a key challenge in product development. These activities ensure the functionality and reliability of the system.

The papers in this Special Issue are intended to support the analysis and design of advanced mechatronic systems and are aimed at scientists and engineers in the fields of product development, reliability engineering, dynamics and control engineering.

The guest editors would like to express their sincere appreciation to all the authors who contributed to this Special Issue.

> **Thomas Gwosch and Sven Matthiesen** *Editors*
