Experimental and numerical investigation of wear behavior at overlapping area in CFRP/Ti laminated single-lap bolted joint

Interfacial wear resulting from vibration loads is one of the primary causes of bolted joint failure. This paper conducted an experimental and numerical study on the wear behavior at the overlapping area in CFRP/Ti-alloy bolted joint and revealed the influences of normal load, wear amplitude and loading frequency. The evolution of friction coefficients (COFs), wear surface morphologies, wear volumes and energy wear rates were analyzed to characterize the wear mechanism qualitatively and quantitatively. The major wear mode changes from abrasive wear to adhesive wear as the normal load increases, and the primary damage mechanism under higher normal load (100 N) is material crushing. The interfacial slip state transitions from partial slip to full slip with the increase of wear amplitude. The 'bearing lubrication' provided by carbon debris is the primary mechanism to reduce the wear rate at higher wear amplitude (200 mu m). Thermal softening of CFRP is the main mechanism responsible for the formation of transfer film during higher frequency (100 Hz) loading. A finite element model (FEM) considering variable COFs is established based on the energy wear approach and adaptive grid technique, which predicts the wear volume, wear depth and surface morphology. The predication results are consistent with the experimental results.