Use of particle tracking velocimetry in timber material and connection testing

Particle tracking velocimetry (PTV) is a quantitative field measuring technique originally developed to track and measure the velocity of individual particles in fluid flows. In this study, PTV was applied for the first time in three different experimental studies in the field of structural timber engineering: (1) dowel embedment testing in cross laminated timber (CLT), (2) large-scale dowelled CLT connection testing, (3) material testing of small clear wood and laminated veneer lumber (LVL). The suitability of PTV was first assessed by comparing the PTV displacements to those obtained by potentiometers. Furthermore, the behaviour of the timber substrate was analysed with PTV in both embedment and large-scale connection tests. It was found that PTV was able to not only accurately measure dowel displacements, but also capture crack growth in the timber and compute the resulting displacement and strain fields in the dowel embedment area. Lastly, PTV was applied to small clear specimen testing to capture brittle fracture in shear, tension perpendicular to the grain, and in cleavage. This study demonstrated that PTV is able to provide reliable contact-free high-resolution measurements of displacement and strain fields on exposed timber surfaces and capture failure mechanisms such as brittle fractures and crack growth.