Controlled Mechanical Anisotropy in 3D‐Printed Thermoplastic Elastomeric Composites

The present work explores the use of acrylonitrile butadiene styrene (ABS) + thermoplastic elastomer (TPE) core–shell composite filaments to enable additive manufacturing of soft structures with tunable mechanical response. It investigates the effect of core/shell ratio of the filament, and raster orientation via printing, to control the mechanical anisotropy of 3D‐printed structures. Load frame experiments demonstrate control over a wide range of tensile modulus (50–2200 MPa) and flexural modulus (50–2600 MPa), by varying the number and sequence of 0°, ±45°, and 90° raster orientations (plies) within 16‐layer test coupons. Asymmetric (with respect to the sample mid‐plane) ply stacks are shown to exhibit a bending response that is sensitive to bending direction. Segmented designs, in which print orientation is varied along the length of a test coupon, are fabricated and exhibit localized bending. Analytical composite laminate theory and finite element simulations are shown to capture the broad trends in mechanical response for these 3D printed soft composites, although these models overpredict structural stiffness as ABS volume fraction increases due to strain localization and softening in the TPE phase.