Abstract
This paper presents the thermal effects on the damage initiation and
growth in the CFRP (Carbon Fiber Reinforced Polymer) composite plate of
the hybrid metal-composite multi-bolted joints. A fully 3D finite
element model, incorporating all possible nonlinearities as geometric,
in-plane lamina shear strains, lamina elastic properties reduction and
friction-based contact is developed to anticipate the temperature
gradient effects on the strength and failure modes of metal-composite
multi-bolted joints. A PDA (Progressive Damage Analysis) material model
which accounts for lamina nonlinear shear strains, Hashin-type failure
criteria and strain-based continuum degradation rules was developed
using the UMAT user subroutine in Nastran (MSC. Software Inc.)
commercial software. In order to validate the temperature effects on the
failure modes of the joint with protruding and countersunk bolts,
experiments were conducted using the SHM (Structural Health Monitoring)
technique in the temperature controlled chamber. The results showed that
the temperature effects on damage initiation and failure modes has to be
taken into account in the design process in order to fructify the high
specific strength of the composites. Experimental results were quite
accurately predicted by the PDA material model, which proved to be
computational efficient and can predict failure propagation and damage
mechanism in hybrid metal-composite multi-bolted joints.