Structural behaviour modelling of bolted joints in composite laminates subjected to cyclic loading

The structural behaviour of bolted joints of composite laminates for aerospace applications was modelled comparing the shape, amplitude and phase of stress-strain cycles. This study proposes a model for the bolted joints resulting in a typical load-displacement curve, under cyclic loading, significantly affected by hysteretic effects. From the data gathered through the experimental activities, a constitutive relationship between strain and stress was proposed, starting from simple physical models. The assumption of a rigid shift between the laminates was used to correlate load and displacement curves in the different phases of the load cycle. The hysteretic behaviour was attributed to friction phenomena and interpreted using damping coefficients characterizing the global dynamic response of the structural joint.