This paper aimed to define two critical mechanical properties of leather—Young’s modulus and Poisson ratio—essential to the virtual simulation of the behaviour of the footwear uppers against the manufacturing operations of stitching and perforating. The following technological aspects were considered to analyse the materials from manufacturing conditions point of view: the number of layers (one layer and two layers), the nature of the materials used for uppers subgroups (calfskin-outer upper, sheep leather-lining, polyester knitted fabric-lining), the overlapping width in the stitching area, the number of parallel stitches (single stitch and double stitch), the punching interval and the type of perforations (simple and with eyelets), resulting in nine kinds of samples. Furthermore, the elasticity (Young’s modulus) and lateral contraction (Poisson’s ratio) were calculated during the tensile strength analysis performed on the SATRA STM 466 equipment. Both mechanical parameters are essential to simulate the behaviour of the virtual footwear prototypes in various conditions.

The objective of this study was to analyse the influence of materials and their position within the upper assembly on the behaviour of casual footwear using finite element simulation tools. The study was carried out on three models of casual footwear, which are identical in terms of design lines, varying only in the materials of the upper assembly, namely calfskin leather (M1), knitted fabric (M2), and combination of knitted fabric and calfskin leather (M3). The footwear models were designed according to the design constraints specific to casual footwear. The foot was reconstructed based on the shoe last obtained based on anthropometric data. Material definition, 3D models editing, setting up analysis conditions, and constraints were performed using the Ansys 17.2 software. Gait biomechanics were taken into account to define the loading model, force distribution, force values, and constraints. The study evaluates footwear behaviour in terms of directional deformation (Z axis), equivalent von Mises stress, and equivalent elastic strain distribution. This paper explores a methodology that has the potential to enhance the footwear design and manufacturing process, providing designers with information about the deformations and stress distribution on upper parts of the footwear product.

Footwear geometry plays an important role in determining mechanical performance, plantar load distribution, comfort, and foot stability during gait. Understanding how constructive design parameters influence foot biomechanics is essential for developing footwear that improves comfort while reducing excessive mechanical loading. Although various finite element studies have investigated insole and outsole design, midsole materials, and plantar pressure redistribution, comparatively little attention has been paid to the influence of upper construction parameters, particularly vamp opening configuration, on the biomechanical behaviour of feet and footwear. This study investigates how the opening amplitude of the vamp affects the biomechanical response of three constructive variants—medium (M1), wide (M2), and narrow (M3) vamp openings—developed on a common shoe last derived from anthropometric data. Finite element analysis was conducted using ANSYS 17.2, with 3D models built in Delcam Crispin ShoeMaker Pro 2015 R2 for the three loading scenarios. Total deformation and von Mises stress were extracted as primary output parameters for both the foot and footwear. The results indicate that wider vamp openings increase structural flexibility, with M2 recording the highest total deformation across multiple scenarios, whereas narrower openings generate elevated stress concentrations, particularly in loading scenario 2. The medium vamp opening (M1) demonstrated the most favourable stress distribution overall, with a maximum stress of 1.838 Megapascals (MPa). Validation against experimental plantar pressure data confirmed that loading scenario 3 follows the same plantar pressure distribution trend as in the biomechanical study. The results confirm finite element analysis as an effective computational tool for footwear design evaluation and indicate that vamp amplitude should be considered alongside material selection and geometry as a key variable influencing comfort, fit, and structural performance.