This study introduces a novel computational framework for designing and analyzing highly flexible, stochastic lattice structures using 3D Voronoi tessellations. This design replicates the stochastic cellular morphology of porous foams while allowing precise control over structural parameters, which offers great versatility for engineering applications such as lightweight construction, energy dissipation, and acoustic insulation. A computational design methodology is developed, including additive manufacturing, mechanical testing, and numerical modeling. First, the mechanical behavior of 3D-printed materials is examined under cyclic tension using a visco-hyperelastic constitutive model, which is then integrated into nonlinear finite element simulations incorporating large deformations and contact interactions. Numerical simulations are validated against experimental compression tests under cyclic loading, showing strong agreement, particularly for relative densities ranging from 6 to 18%. Strain responses at 20% and 60% compression were analyzed at 2 to 50 mm/min deformation rates. Furthermore, the stress distribution exhibited heterogeneity during initial buckling and the plateau phase due to randomly oriented struts. However, as the load increased and strain reached 0.6, stress distribution became more uniform, marking the onset of densification, and suggesting that stochastic lattices may offer mechanical advantages such as smoother energy absorption compared to regular cellular structures. By bridging computational modeling with experimental validation, this work enhances the understanding of highly deformable lattice structures, enabling optimized engineering designs. Graphical abstract

This paper focuses on FEM simulation model of pneumatic spring implemented into cushioning of a car seat. This spring is a part of a device which ensures controlled change pressure distribution in contact zone between car seat and passenger. This spring made up from silicone and foam parts and from the tape. In this article, the material properties of these materials are experimentally investigated in order to get parameters for their mathematical models implemented in FEM software MSC.Marc. The simulation of the spring is then carried out with changing internal pressure.

The inverse dynamics method is applied to the investigation of dynamical behavior of a parallel manipulator. The substructure technique is used for creating a differential-algebraic system of equations that describes motion of the Stewart-Gough platform. The system of equations is modified into a...

In this article, an attempt was made to model the body of a person moving in a passive manner (movement forced by another person) in a wheelchair. For this purpose, the Wan–Schimmels model was modified by 4 DOF, supplementing it with the weight of the wheelchair and a polyurethane cushion. The study was designed to test the effectiveness of utilizing a polyurethane cushion to reduce the whole-body vibration acting on a person while moving in a wheelchair. The study used a rheological model of polyurethane (PU) foam with concentrated parameters. Harmonic and random vibration analysis was carried out for this model. At the same time, the model with 5 DOF seems to be sufficient to describe vibrations transmitted to wheelchair users. The model presented in this paper can become a tool for future analysis of vibrations of people of different weights, moving passively on various types of wheelchairs on surfaces whose irregularities can be given by an appropriate form of kinematic excitation. The approach used in this study is likely to be useful in selecting a wheelchair and seat cushion so as to counteract and minimize vibrations perceived by humans.

We would like to thank Bernardo-Filho et al