Experimental and computational investigation of the thermo-mechanical response of PLA-APHA blend: A comparative study using FDM schemes and FEA

What the paper says

• A hybrid experimental-computational framework is developed for FDM-printed PLA-PHA bio-composites. • Finite element analysis (ANSYS) APDL and MATLAB (element birth and death method) are integrated for process-aware simulation. • Experimental tensile testing and computational modeling are used to validate thermo-mechanical behavior. • Layer height variation is shown to significantly influence stress distribution and mechanical properties. • The implicit scheme-based prediction enables accurate modeling of layer-wise deposition and stress evolution in biopolymers. Fused deposition modeling (FDM) of biodegradable polymer blends, such as PLA/APHA, introduces complex thermo-mechanical behaviors that demand precise simulation to optimize print quality and performance. This study presents a coupled thermal-structural modeling approach for simulating PLA/APHA specimens using ANSYS Mechanical APDL and MATLAB-based finite difference analysis. A transient, layer-by-layer deposition model was developed using element birth-death techniques in APDL to simulate actual FDM processes at two layer heights: 0.1 mm and 0.15 mm. Simultaneously, MATLAB simulations employed the implicit Backward-Time Central-Space (BTCS) scheme to solve the heat conduction equation with high stability and accuracy. Both approaches effectively captured the steep thermal gradients and post-deposition cooling behavior, which are known to significantly impact internal stress development. The simulation revealed residual thermal stresses up to ∼12 MPa, found primarily along boundaries due to convective cooling. These stresses correlated with measured warping and dimensional deviations, emphasizing the role of thermal contraction in the final part quality. Notably, thinner layers (0.1 mm) resulted in quicker cooling and reduced interlayer diffusion time, while thicker layers (0.15 mm) retained heat longer but showed higher stress concentrations due to increased mass and contraction. Validation against experimental results demonstrated excellent agreement, with less than 8% error across both the temperature and stress metrics. These findings confirm the robustness of the dual-simulation methodology and offer insights into the influence of layer height on bonding, stress buildup, and warping. This research highlights the practical application of simulation-driven process optimization in additive manufacturing and establishes a reliable predictive model for PLA/APHA components produced via FDM.