Tuesday  |  Salon 8  |  10:00 AM–10:20 AM

#19021–Monitoring the Interface Behaviour of Bolted Joints

Validating the localized nonlinear contact behaviour of a jointed structure is a challenging task. This is because monitoring the interface during a vibration cycle, to identify stick, slip and separation zones, without changing the interface, is very difficult. Total Internal Reflection has recently been used at Imperial College London to measure the interface conditions of simple, well controlled joints, where two transparent interfaces were illuminated via a laser and the reflected/transmitted light from the interface was recorded. The change in reflection/transmission can reveal localised contact zones and show their transition from stick to slip during a vibration cycle. This work applies the total internal reflection technique to more realistic lap-jointed structures. The structures investigated were based on the well-investigated Brake-Reuss beam, but manufactured from transparent PMMA to facilitate the novel testing approach. Bolt loads and excitation were well controlled via the use of instrumented bolts, and rigorous modal testing, and Total Internal Reflection measured using a high speed camera and expanded laser beam. For the first time, this has allowed for the production of a fuller picture of the contact conditions during the vibration cycle of a realistic jointed structure.

Tom Mace   Imperial College London
Tomas Moghadam   Cranfield University
Pushpa Pandey   Swansea University
Suzanna Gilbert   Brigham Young University