This work investigates the effects of high-temperature curing processes on the stress-strain and failure responses of additively manufactured aligned discontinuous fiber-reinforced composites (DFRCs). A micromechanical framework is used for finite element simulation of damage and failure in the three-dimensional (3-D) representation of the DFRCs under mechan- ical and thermal loadings. Accurate constitutive equations are utilized to explicitly consider the fibers, matrix, and fiber/matrix interfaces within the composite’s microstructure. The coupled thermo-mechanical analysis available on the commercial nonlinear finite element software ABAQUS is used to accurately simulate the response of the studied DFRC when exposed to different curing temperatures and mechanical loading. All material and geometrical parameters of the microstruc- tural representation are defined based on a recently developed 3-D printed aligned discontinuous fiber-reinforced thermosetting polymer. The curing-induced thermal residual stresses and damage are then simu- lated and validated against the experimental data. The effects of different curing processes on the initiation and propagation of different dam- age types and on the stress-strain response up to and including final failure are predicted. Also, the impact of the perfect versus cohesive interfacial bonding on the DFRC’s performance is examined. This work 1 Springer Nature 2021 L ATEX template 2 The effects of curing process on the damage behavior of ... reveals that the DFRCs’ responses are significantly affected when resid- ual thermal stresses due to curing are considered, providing guidance for better design, manufacturing, and analysis of such composites. Keywords: Finite element simulation, additive manufacturing, carbon fiber-reinforced thermosetting composites, curing process, thermal residual stress, damage, failure 1 Introduction Recent advancements in developing thermoset polymer composition and injec- tion technologies have enabled the additive manufacturing of discontinuous fiber-reinforced composites (DFRCs) with highly aligned fibers (e.g., [1–4]). One of these techniques uses the direct write method, where material melting is not required for printing thermosetting polymers, and the entire structure is printed at room temperature. Thermal curing is then applied, sometimes even up to the temperature of 220◦C, in a secondary process to achieving 100% degree of cure [4]. The secondary process for thermal curing simplifies the entire manufacturing procedure and reduces the dependence of the mechanical prop- erties on thermal printing history, and spatial heating path [2, 4]. However, the curing process still induces residual thermal stresses due to the mismatch in the coefficients of thermal expansion (CTE) during heating and cooling from the curing temperature to room temperature. The residual stresses can be high enough to initiate microcracks and damage prior to mechanical load- ing. The microcracks then coalesce, leading to the formation of macrocracks, reducing the overall strength, and consequently compromising the composite’s performance (e.g., [5–7]). Therefore, it is critical to understand and accurately predict residual thermal stresses’ influence on the composite’s performance. Residual thermal stresses in carbon fiber-reinforced composites (CFRCs) have been investigated by various experimental, analytical, and computa- tional methodologies. Destructive and non-destructive experimental techniques were conducted to investigate the effects of residual thermal stresses [8–10]. However, such techniques are too complicated, expensive, and incapable of quantitatively demonstrating the influence of the residual stresses on the dam- age initiation and propagation in composites. Moreover, these residual stresses at the macro-scale have been predicted by the classical laminate theory or other analytical methods [11–15]. Nonetheless, analytical methods cannot calculate the stress, strain, and damage fields at micro- and meso-scales [16, 17]. There- fore, computational techniques, such as finite element methods (FEMs), are necessary to calculate the residual thermal stress and strain at the micro-scale, leading to precise predictions of stress concentration, deformation, damage onset, and propagation. FEMs have been extensively utilized to study residual thermal stresses in CFRCs in the literature (e.g., [5–7, 18–24]). Most of these works examined Springer Nature 2021 L ATEX template The effects of curing process on the damage behavior of ... 3 the effect of the curing-induced residual stresses on the transverse response of CFRCs through two-dimensional (2-D) simulations. Among the literature, Yuan et al. [22] used three-dimensional (3-D) micromechanical models to inves- tigate the effects of temperature and macro residual stresses on the evolution of micro residual stresses, but not on damage initiation and evolution. Moreover, in most of these works, the influence of fiber/matrix interfaces on the compos- ite’s performance has been neglected. Several studies had emphasized on the critical effect of fiber/matrix interface properties on the response of CFRCs (e.g., [25, 26]). Among the above works,