## 1 Introduction
[13] proposed a numerical approach for simulating the SPIF process of polypropylene sheets at room temperature using a modified viscoplasticity based on overstress (VBO) model. The model was calibrated using experimental data from tensile, relaxation, and creep tests conducted at various strain rates and previous strain levels. Implementation of the VBO model was carried out via a Fortran subroutine that described the material's constitutive behaviour within the simulation framework. Finite element simulations showed good agreement with experimental results, accurately predictingboth the final geometry and thickness distribution of the formed parts. The findings confirm the effectiveness of the modified VBO model in capturing deformation behaviour and identifying mechanical defects during SPIF, thereby offering a robust foundation for optimising polymer sheet incremental forming processes. The finite element method was also used to simulate the two-point incremental forming (TPIF) process of woven fabric composite sheet [14]. In this paper, the authors propose a combined experimental-numerical study that combines incremental forming with autoclave treatment, aiming to reduce costs and production time for small batches. To prevent viscous friction and material damage, a metal-fibre-metal (MFM) sandwich configuration was used. Metal sheets were actually only used to protect the fabric on both sides. The analysis using the finite element method was performed in the Pam-Form software. To validate the numerical model, the section profiles, peripheral contours and shear strain distribution between experiments and simulations were compared. Another comparative, numerical-experimental study was conducted by [PERSON] et al. [15]. They analysed the mechanical behaviour of 1.8 mm thick polycarbonate (PC) sheets subjected to the SPIF process. The authors manufactured rectangular square cup parts at variable wall angles (15\({}^{\circ}\), 30\({}^{\circ}\), 45\({}^{\circ}\), 60\({}^{\circ}\)). Numerical simulations conducted using Abaqus enabled the assessment of forming forces and the distribution of Von Mises stresses, showing strong agreement with experimental results. Additionally, fracture energy was determined from force-displacement curves, offering valuable insights into the material behaviour during the SPIF process. [PERSON] et al. developed a coupled thermomechanical model for simulating the SPIF process of polymer sheets [16]. The numerical model employs an explicit formulation in Abaqus, integrating J2 plasticity with isotropic hardening and temperature-dependent material behaviour to simulate the deformation of thermoplastics such as PVC, PC, and HDPE. Experimental validation showed a prediction error of less than 11% for the vertical forming force. The study underscored the critical influence of finite element type and size, as well as material modelling, on simulation accuracy and computational efficiency. The finite element model effectively predicted temperature distribution, final geometry, and sheet thinning, serving as a reliable tool for optimising the SPIF process in polymers. This study offers a practical balance between accuracy and computational cost, without relying on complex rheological models. An advanced robotized approach to the SPIF process for polymer sheets, with a particular focus on PVC was presented by [PERSON] et al. [17]. A novel forming tool, integrating ultrasonic vibrations and localised laser heating, was developed to enhance material formability and reduce friction during processing. Thermal and mechanical behaviours during SPIF process were analysed using finite element method (FEM) simulations conducted in Ansys. The simulations effectively predicted temperature distribution and material deformation. Experimental trials validated the simulation results, showing strong agreement between predicted and actual displacements. Thermal imaging and displacement sensors provided real-time monitoring of the forming process.