Offshore support and naval vessels operate in complex and hazardous environments facing the risk of impact from falling objects, collisions and projectiles. Accurate impact localization is essential to guarantee safety of the individuals, the environment and the asset.

This thesis explores the feasibility of impact localization on steel plates and stiffened panels by utilizing the information carried by the stress waves generated during impacts. These waves propagate along the surface of the structure as Guided Ultrasonic Waves (GUW). The inherent time reversibility and spatial reciprocity properties of the wave equations allow the use of Time Reversal (TR) process of the recorded wave signals to localize impacts.

The study combines experimental testing with an analytical framework. Small scale controlled impact experiments were performed in the Structures Laboratory at TU Delft while large scale tests were conducted onboard a Shoalbuster vessel at DAMEN Shipyards in Gorinchem, allowing the assessment of the scalability and robustness of the method. Acoustic Emissions (AE) were generated through Pencil Lead Breaks (PLBs) and instrumented hammer impacts. TR was implemented virtually in the frequency domain using an analytical propagation formulation that models dispersion and wave amplitude decay due to geometric spreading. The novelty of the present research lies in extending the analytical TR framework from plates to stiffened panels by removing the effect of stiffeners in back-propagation. This is achieved by introducing a scalar Transmission Coefficient (Tc) into the analytical model.

In the small scale experiments two configurations were tested, a plate and a stiffened plate with a stiffener located at the midspan, both measuring 400 x 400 mm². The average localization error for the plate ranged from 11 to 15 mm, while stiffened panel tests showed slightly higher errors in the order of 12 to 23 mm, depending on the impact type. Larger errors were observed for the instrumented hammer impacts. In the large scale tests, a 7500 x 2000 mm² area was monitored. Localization accuracy decreased due to increased structural complexity, including variable plate thickness, multiple stiffeners, and high acoustic noise from parallel steel work activity. A mean localization error of 662 mm was achieved, demonstrating the method’s scalability and potential for real world application.

These results confirm that TR of GUW is a feasible method for impact localization across different scales. The developed methodology shows potential for extension to composite materials and towards a complete impact identification framework that includes impact severity estimation, contributing to the development of integrated Structural Health Monitoring (SHM) systems capable of detecting, localizing, and quantifying structural impacts.