To reduce emissions of pollutants, automotive and aerospace industries are seeking new solutions to create lighter structures. Extreme lightweight structures can today be obtained by using high-performance composites based on continuous fibers and polymeric matrices. Assembling composite parts is however still a challenge that often jeopardizes the performance of primary structure today, because of its extreme sensitivity to the quality of the substrate preparation that can largely modify the intrinsic performance of the joint. More important for us, the failure of adhesive joints is often unstable: the joint behaves well until the development of a catastrophic crack that would propagate throughout the whole joint. This is not the case only for composite-to-composite bonding in structural applications, but for many tape-based solutions across the board, especially in the healthcare sector where life expectation and stability of bonded joints is essential.
Our objective is here to introduce new strategies to equip by design adhesive interfaces with crack arrest features. From a practical point of view, we are manipulating the R-curve of the interface by introducing non-local dissipative mechanisms, such as bridging, that will add to the classical cohesive energy of the adhesive.(strength and toughness) between the adhesive layer and the substrate. We present here different techniques to manipulate the bond and interface morphology, either by additive or substrative engineering, and demonstrate how this results in large enhancement of the effective properties of the joints.
These morphological modifications pave the way for new families of micro structured joints and tapes that would overperform compared to existing technologies, without changing the material system but only its spatial distribution.
References:
Physical Sciences and Engineering Division, KAUST