Monotonic and cyclic torsion of vat-photopolymerized tough resin: characterization of governing parameters and ultraviolet post-curing effects

作者：Hamed Sadaghian, Saeed Khodadoost, Sahand Khalilzadehtabrizi, Masood Farzam · 发表于：Rapid Prototyping Journal · 年份：2026 · DOI：10.1108/rpj-08-2025-0416 · 研究领域：Epoxy Resin Curing Processes、Polymer composites and self-healing、Mechanical Behavior of Composites

Purpose This study aims to address the absence of research on the torsional behavior of vat-photopolymerized (VPP) resin polymers, particularly under cyclic and reversed cyclic loading. No systematic investigations have previously examined the cyclic torsional response of VPP-ultraviolet (UV)-LED specimens. The aim is to establish reliable experimental data, evaluate the influence of UV post-curing and propose simplified constitutive models for numerical simulations. Design/methodology/approach Seventy-five Anycubic UV Tough resin specimens were fabricated in a vertical orientation and post-cured for 0, 60, 120, 180 and 240 min. Monotonic, cyclic, and reversed cyclic torsion tests were performed at a constant rate until failure. Torque–revolution data were converted into shear stress–strain curves, from which shear modulus, peak shear stress, energy absorption and torsional rigidity were quantified. Logistic regression was applied to predict parameter evolution, and normalized multilinear models were developed to represent shear stress–strain envelopes for different torsional regimes. Findings Results showed that UV post-curing improved stiffness, strength and energy absorption, with the most significant gains up to 180 min. All specimens failed in a ductile manner, with more than 90% of strain energy absorbed in the plastic range. Compared with monotonic tests, cyclic and reversed cyclic torsion reduced ultimate strain but preserved high ductility. Damage indices confirmed p...