3D laser scanning and DIC in structural testing: state‐of‐the‐art, best practice and effective use

3D laser scanning and digital image correlation (DIC), two novel techniques capable of non-contact, full-field measurements of surface geometry and deformations respectively, have emerged and gained increasing applications in structural engineering research. The aim of the present study is to provide a state-of-the-art review and best-practice guidance on 3D laser scanning and DIC in the context of structural testing, and to introduce their main applications and advantages in physical experiments on metallic structures. For 3D laser scanning, the basic principles and general applications are firstly introduced. Laser scanning of a generic structural steel sample is subsequently described as a case study to demonstrate the workflow, with recommendations provided on the best practice. 3D laser scanning has been utilised in structural experiments for determining dimensional parameters, examining surface topography, characterising geometric imperfections of different forms and representing true geometry in finite element modelling, examples of which, along with corresponding data analysis methods, are provided and discussed. For DIC, following an initial review, the procedure for setting up a stereo DIC system in a stub column test is subsequently presented, where recommendations are provided on the setup, speckle pattern, execution and data processing. Example applications of DIC in various types of structural experiments, ranging from material tests to geometric imperfection measurements, structural element tests and structural system tests, are subsequently presented, and the advantages offered by DIC over conventional measurement methods are discussed. 3D laser scanning and DIC provide structural researchers with deeper insights into the geometric properties and behaviour of metallic structures in physical experiments, and the presented work will help to facilitate the broader and more effective use of these techniques among peer researchers.