Sensors and Instrumentation, Aircraft/Aerospace and Energy Harvesting, Volume 7: Proceedings of the 39th IMAC, A Conference and Exposition on Structural Dynamics, 2021, the seventh volume of nine from the Conference brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on fundamental and applied aspects of Shock & Vibration, Aircraft/Aerospace, Energy Harvesting & Dynamic Environments Testing including papers on: Alternative Sensing & AcquisitionActive ControlsInstrumentationAircraft/Aerospace & Aerospace Testing Techniques Energy Harvesting