## 1 Introduction
Measured and simulated deflections of the end of the bar throughout printing were qualitatively similar [64]. [PERSON] and [PERSON] [65] modeled a pyramid of ABS using a SC-TMA. The ABS was modeled as thermoviscoelastic with properties from the literature [65]. The size of the model was reduced by using quarter symmetry [65]. Simulated versus measured final displacements along one line of the structure were within roughly 10% [65]. [PERSON] et al. [11] created a simulation tool in ABAQUS AM that includes the effects of thermoviscoelasticity and crystallization. The tool was tested by simulating the printing of plates and rings made of short carbon-reinforced polyphenyline sulfide [11]. Material properties were determined using experimentation and micromechanical modeling. Comparisons between experiment and simulation of the curvature of the plate and deformation of the ring were within 7% [11]. Though this model is accurate, it is also very computationally expensive, with a simulation of an autoclave mold taking around 11 h with two computers, each with 10 cores and 128 GB of RAM [11]. To accurately simulate the printing of a large 3D-printed part, the height of an element must be at most the bead height, which is typically on the order of millimeters or perhaps centimeters. This limits the size of traditional solid elements resulting in meshes with many elements. Further, because of complex geometries and/or printing paths, models can rarely take advantage of symmetry. Model runs on the order of hours or more makes a comprehensive exploration of a part design space impractical using available FEA-based SC-TMA strategies and tools, motivating the development of more computationally efficient models. There has been some work on speeding up thermal simulations of small [66; 67] or large [67; 68] parts, using, for example, mesh merging [66], modified beam elements [67] or a one-dimensional model [68]. [PERSON] and [PERSON] [69] developed a discrete event simulation thermal model and modeled the printing of a \"miniature... ashtrav model\" made of PLA or ABS. The authors then used the model as part of a SC-TMA of a large-scale culvert outlet diffuser printed with PLA reinforced with wood flour, simulated using a visco-elastic-plastic material model [9]. Viscous plastic deformations due to self-weight (no thermal shrinkage) were calculated using a finite element model, which were then used to predict whether the print will fail or not [9]. [PERSON] and [PERSON] also developed a different model to simulate the printing of a 0.5 m \(\times\) 0.5 m \(\times\) 0.5 m open top box made of carbon fiber-reinforced ABS [70]. The material is assumed to be orthotropic and its properties are not dependent on temperature [70]. A SC-TMA is written in MATLAB, using a fourth-order Runge-Kutta finite difference approximation with mesh merging for the thermal simulation and finite element analysis using CLT with solid hexahedral elements for the structural simulation [70]. Thermal stresses begin to develop once an element cools to below its glass transition temperature and self-weight is ignored [70]. Though there has been some work performed on computationally efficient SC-TMA of large scale FDM, the vast majority of prior work has focused on advancing thermal simulations. Available continuum structural models rely on brick elements that do not accurately capture bead geometry and make it challenging, if not impossible, to simulate imperfect bond at interfaces between beads. Such models also require a large number of elements to discretize each bead, resulting in models that quickly become computationally intractable. Further, the simulation of part-bed separation and other complex boundary conditions is challenging with solid models. In the big picture, the ongoing aim of this work is to develop a beam-element-based, computationally efficient structural model of large 3D-printed parts to determine residual stresses and deformations developed during printing.