INFLUENCE OF THE FLEXIBLE INTERLAYER ON A 4D PRINTED SHAPE MEMORY ALLOY HYBRID COMPOSITE

This study compares an auxetic cellular structure to a conventional honeycomb structure when used as a flexible interlayer for shape-adaptive Shape Memory Alloy Hybrid Composites (SMAHC).

A SMAHC is a combination on material level of fiber reinforced plastics with shape memory alloy wires that provide actuation potential to the composite. Locating the SMA wires out of the neutral axis leads to bending deformation of the composite during heating. To optimize this deformation, a lever arm between the SMA and the neutral fiber of the base substrate is necessary. This lever arm can be introduced through an elastic intermediate layer.

The impact of various cellular geometries of this interlayer is experimentally investigated in this study. The SMAHC is manufactured via stereo lithography (SLA) in a 4D printing process, which enables the formation of structures with graded stiffness and the usage of UV curing material provides low processing temperatures to ensure the integration of a hybrid glass fibre-SMA textile preform into the composite structure.

This study involves an initial analysis of the component's shape deflection and actuation abilities, along with an evaluation of the heat distribution within the material caused by electric activation.