Shearography is a non-destructive testing technique that provides full-field surface strain characterization. Previous inspection of flat objects or simple geometric shapes has been reported. However, real-life objects especially in aerospace, transport, or cultural heritage are not flat, but their inspection with shearography is of interest for both hidden defect detection and material characterization. Accurate strain measurement of a highly curved or free-form surface needs to be performed by combining in-line object shape measuring and processing of the shearography data in 3D. Previous research has not provided a general solution for that. This paper presents a new approach of 3D shape shearography which is based on the integration of a structured light projector for in-line shape measuring with 3D shearography. For the experimental part, a 3D shape shearography system prototype was developed and its performance was evaluated with a cylinder specimen loaded by internal pressure and compared with strain gauges.

Reliable measurement of a deflection magnitude refers to one of the most important tasks in floating dry dock operation. Current and accurate information about the deflection can prevent structural damage and failure by activating alarms and on-board deflection compensation systems. This paper describes the development of a deflection measuring system for floating dry docks. The measuring system is capable of measuring the actual deflection of a dock structure in real-time and fully automatic mode. The system consists of a set of reference marks based on light emitting diodes and a measurement unit with two oppositely directed camera-based channels. The measurement unit is placed in the middle of a wing deck of the dock. The measurement unit and the reference marks are aligned along the wing deck. The accuracy of deflection measurement of ±1.5mm in the range of ±150 mm for the docks in length more than 100 m was achieved during laboratory tests. The system resistance to harsh environment (salt fog, temperature gradient, high humidity, etc.) and the ability to perform measurements in 24/7 regime was proved through field tests at a floating dry dock in operation.