Geometric distortion remains a major obstacle to achieving high dimensional accuracy in laser powder bed fusion (LPBF), especially for complex thin-walled components with heterogeneous structural constraint. In this study, a finite element simulation-driven geometric compensation strategy was applied and validated for an LPBF-fabricated winged annular funnel structure (WAFS). A transient thermo-mechanically coupled finite element model was established to predict the distortion behavior during fabrication and validated by 3D scanning measurements, showing good agreement in both global deformation trend and local distribution characteristics. The simulation results indicated that the distortion of the WAFS was dominated by the combined constraint effect of the wing-like features and the baseplate, resulting in a non-uniform and symmetric deformation pattern. Based on the validated displacement field, an inverse-mapping method was used to construct a compensated geometry for re-fabrication. The compensated WAFS exhibited a substantially reduced deformation level, and the overall geometric distortion was reduced by more than 85% after a single compensation iteration. The present results demonstrate that finite element simulation-driven geometric compensation provides an efficient and practical route for improving the dimensional accuracy of the investigated WAFS, while reducing dependence on repeated trial-and-error optimization.

Unsupported and weakly supported overhang features remain a critical challenge in laser powder bed fusion (LPBF) due to their strong susceptibility to geometric degradation, residual stress accumulation, and part distortion. In this study, bridge-shaped structures with four different arch sizes are fabricated to systematically investigate geometry-dependent macroscopic forming quality, stress evolution, and distortion behavior. Experimental results show that increasing arch size leads to progressive thickness reduction at the arch bottom and eventual overhang closure loss, indicating a monotonic deterioration in geometric fidelity. A thermo-mechanically coupled finite element model is developed and calibrated using 3D scanning measurements of warpage, achieving a maximum deviation below 0.03 mm between predicted and measured displacements. Numerical analyses reveal that larger arch sizes promote local heat accumulation and reduced cooling rates beneath the arch, which reduce the instantaneous load-bearing capacity of the material and increase its susceptibility to downward deformation. Meanwhile, arch size significantly influences the establishment of structural continuity and stress transfer during printing; incomplete closure in large arches interrupts load-bearing paths and alters stress redistribution at intermediate stages, whereas similar stress evolution trends are observed once geometric continuity is achieved. These findings demonstrate that arch closure acts as a key structural transition controlling stress transmission and distortion development during LPBF, thereby providing mechanistic insight into geometry-induced defects and offering quantitative guidance for the design of unsupported features in additively manufactured components.

Laser beam powder bed fusion (PBF-LB) enables the fabrication of complex rotational metallic components for aerospace applications, such as engine exhaust nozzles and combustion liners, but the localized thermal cycles inherent to the process often lead to residual stress accumulation and geometry-dependent distortion, particularly in low-stiffness and open structures. This study investigates the thermo-mechanical response of three representative 316L stainless steel rotational geometries—dumbbell-shaped, cylindrical, and drum-shaped—in both closed and open configurations using a transient, fully coupled thermo-mechanical finite element model validated by high-resolution three-dimensional deformation measurements. The results reveal pronounced geometry- and size-dependent distortion mechanisms: for closed structures, the drum-shaped geometry exhibits the largest radial contraction and stress concentration due to its larger characteristic size and lower stiffness, with a maximum deformation of approximately 0.14 mm, whereas the dumbbell-shaped and cylindrical geometries show smaller and more uniform deformations of about 0.09 mm and 0.12 mm; open configurations experience substantially amplified distortion, with both the magnitude and vertical location of bulging governed by geometric stiffness and substrate constraint, and the open drum-shaped structure reaching a maximum displacement of approximately 1.6 mm. These findings clarify how geometric size and stiffness control stress relaxation and shape stability in PBF-LB-fabricated rotational components and provide transferable guidance for geometry-informed design and distortion mitigation in high-precision additive manufacturing.

Multi-laser powder bed fusion (PBF-ML) enables efficient fabrication of large components but introduces spatially heterogeneous thermal histories near inter-laser overlap zones. However, how global thermal-input variables and local thermal-path variations jointly affect defect evolution, microstructure, and mechanical response in geometrically constrained Ti-6.5Al-3.5Mo-1.5Zr-0.3Si (TC11) structures remains unclear. Here, TC11 arch structures were fabricated by varying laser power, scanning speed, overlap-zone position, and interlayer rotation and characterized by tensile testing, optical metallography, Scanning Electron Microscope (SEM), and fractography. Increasing laser power from 170 to 290 W increased Yield Strength (YS) and Ultimate Tensile Strength (UTS) from 955 and 1228 MPa to 1259 and 1463 MPa, respectively, while Elongation (EL) decreased from 14.7% to 3.1%. Increasing the scanning speed from 1050 to 1450 mm/s produced the opposite strength–ductility trend, whereas overlap-zone position had limited influence on strength and 67° interlayer rotation produced moderate improvements. Defect count and area fraction did not always vary synchronously, while semi-quantitative SEM analysis revealed microstructural coarsening with increasing laser power and refinement with increasing scanning speed. These results show that global thermal-input variables primarily govern the overall strength–ductility and microstructural-scale responses, whereas local thermal-path variables mainly regulate spatial defects and microstructural heterogeneity.