An Explicit Constitutive Reconstruction Framework for Mechanical Characterization of Miniaturized 3D‐Printed Specimens

Accurate constitutive characterization of miniaturized tensile specimens is challenging because grip‐to‐grip displacement measurement includes deformation from both the gauge and shoulder sections, leading to systematic errors in the measured stress–strain response. Existing compliance‐correction methods are limited to linear elastic characterization and require multiple specimen geometries, whereas inverse finite element methods (iFEM) reconstruct nonlinear constitutive behavior at substantial computational cost. Here, an explicit constitutive reconstruction framework that accurately recovers the intrinsic nonlinear stress–strain response from a single tensile test using only grip‐to‐grip displacement measurements was presented. The proposed method sequentially reconstructs the constitutive response through incremental tangent modulus updating, transforming constitutive reconstruction from an inverse optimization problem into an explicit sequential solution. A progressive three‐stage validation was conducted comprising self‐consistency across different gauge lengths, analytical comparison with the regression‐based compliance correction method, and numerical benchmarking against the published iFEM. The proposed method reduced the intergroup constitutive variation from 18.8% to 2.1%, reconstructed Young's modulus within 4.4% error against the regression method, and achieved a maximum error below 4.8% relative to iFEM while reducing computation time from approximately 40 min to 0.75 s per specimen. The proposed framework provides an accurate and computationally efficient approach for constitutive characterization of miniaturized specimens.