Modeling thermal expansion of a large area extrusion deposition additively manufactured parts using a non-homogenized approach

Interest in the use of large area extrusion deposition additive manufacturing (LAEDAM) to create tools for creation of composites is on the rise, due to its ability to create complex shapes rapidly. To ensure the parts created from the tool meet geometric standards, it is important to understand the thermal expansion of the printed part. Which is a challenge as LAEDAM imparts a non-uniform fiber orientation to the deposited material. A non-uniform fiber orientation in the deposited material creates a non-homogeneous cross section at a given position. Due to this heterogeneity, the coefficient of thermal expansion (CTE) also varies according to the position in the cross section. Previous modelling attempts of LAEDAM parts have employed a homogenized approach. This work experimentally characterizes CTE variations across the cross section of a bead using thermomechanical analysis and uses this as a non-homogenized input at the bead level for a finite element model. Predictions from this finite element model are then be compared to strain maps measured using 2-D digital image correlation of large-scale printed parts (127 mm cubes).