Numerical analysis of energy absorption in expanded polystyrene foams

Abstract

The expanded polystyrene foam is widely used as a protective material in engineering applications where energy absorption is critical for the reduction of harmful dynamic loads. However, to design reliable protective components, it is necessary to predict its nonlinear stress response with a good approximation, which makes it possible to know from the engineering design analysis the amount of energy that a product may absorb. In this work, the hyperfoam constitutive material model was used in a finite element model to approximate the mechanical response of an expanded polystyrene foam of three different densities. Additionally, an experimental procedure was performed to obtain the response of the material at three loading rates. The experimental results show that higher densities at high loading rates allow better energy absorption in the expanded polystyrene. As for the energy dissipation, high dissipation is obtained at higher densities at low loading rates. In the numerical results, the proposed finite element model presented a good performance since root mean square error values below 9% were obtained around the experimental compressive stress/strain curves for all tested material densities. Also, the prediction of energy absorption with the proposed model was around a maximum error of 5% regarding the experimental results. Therefore, the prediction of energy absorption and the compressive stress response of expanded polystyrene foams can be studied using the proposed finite element model in combination with the hyperfoam material model.

Study of the mechanical properties and constitutive model of the roadbed rehabilitation polyurethane grouting materials under uniaxial compression

“…41,42 Studies on the mechanical properties of the porous polymer materials using the hyperfoam model are also reported. 43,44 Since the stress-strain curves of rubber and RHPU grouting materials are similar, 16,42 the hyperfoam model holds the potential in studying the mechanical properties of RHPU grouting materials, which, however, is not yet described. In addition, the equation form of the hyperfoam model is a polynomial containing exponential terms with at least three unknown parameters, 43 making it inconvenient for practical engineering applications.…”

“…The hyperfoam model has become the most commonly used model to study the mechanical properties of rubber materials 41,42 . Studies on the mechanical properties of the porous polymer materials using the hyperfoam model are also reported 43,44 . Since the stress–strain curves of rubber and RHPU grouting materials are similar, 16,42 the hyperfoam model holds the potential in studying the mechanical properties of RHPU grouting materials, which, however, is not yet described.…”

3D printed geometrically tessellated sheets with origami-inspired patterns

“…[19][20][21][22][23] There are also many parameters involved in the design of foam structures that can varied to change mechanical properties. For example, Rodriguez-Sanchez et al 24 studied how changes in the density of expanded polystyrene foam affect their energy absorption during compression testing to learn that higher density foams were more effective at absorbing energy at higher loading rates. Andena et al 25 characterized polymeric foams based on their microstructure, density, and the applied strain rate to determine the most effective models for predicting the mechanical behavior of foams.…”

Enhanced energy absorption characteristics of novel integrated hybrid honeycomb/polystyrene foam

“…For the inner helmet foam liner, EPS is one of the most commonly used material due to its excellent impact absorption capability. 9–12 The main purpose of this layer is to minimize the overall impact energy transferred to the cyclist’s head. In conventional helmets, the outer ABS shell absorbs only 10–15% of the impact energy while the remaining are absorbed by the EPS foam liner.…”