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In the event of a crash involving a car, its seats, together with their backrests and head supports, ensure the safety of the passengers. The filling material used for such a car seat is normally made of polyurethane foam. To simulate the behaviour of the seat assembly during a crash, the material characteristics of the seat-filling foam should be appropriately modelled. The purpose of this paper is to present a method, with which the proper parameter values of the selected material model for the seat-filling foam can be easily determined.

In the study, an experiment with the specimen from seat-filling foam was carried out. The results from this experiment were the basis for the determination of the parameter values of the low-density-foam material model, which is often used in crash-test simulations. Two different numerical optimisation algorithms – a genetic algorithm and a gradient-descent algorithm – were coupled with LS-DYNA explicit simulations to identify the material parameters.

The paper provides comparison of two optimisation algorithms and discusses the engineering applicability of the results.

This paper presents an approach for the identification of the missing parameter values of the highly non-linear material model, if these cannot be easily determined directly from experimental data.

Metal foams are a structural and functional composite materials that have received wide attention due to their specific structures and properties. The aim of this study is to investigate the mechanical properties of syntactic foam by using expanded silica gel with the spacer technique.

In this research paper, the vacuum casting production method was used to produce metal syntactic foams including AlSi12 and AlSi8Cu3 matrix and expanded silica gel fillers with diameters of 2–4.75 mm and 4.75–5.6 mm.

As a result of the study, it was observed that as the foam densities increased, the compressive strength values of the samples increased due to the increasing volume fraction of the metallic matrix. Samples with the AlSi12 matrix showed higher compressive strength than samples with the AlSi8Cu3 matrix.

The originality of the study is the comparison of two different main matrix alloys (AlSi12 and AlSi8Cu3) and different pores using expanded silica gel.

Auxetics metamaterials show high performance in their specific characteristics, while the absolute stiffness and strength are much weaker due to substantial porosity. This paper aims to propose a novel auxetic honeycomb structure manufactured using selective laser melting and study the enhanced mechanical performance when subjected to in-plane compression loading.

A novel composite structure was designed and fabricated on the basis of an arrowhead auxetic honeycomb and filled with polyurethane foam. The deformation mechanism and mechanical responses of the structure with different structural parameters were investigated experimentally and numerically. With the verified simulation models, the effects of parameters on compression strength and energy absorption characteristics were further discussed through parametric analysis.

A good agreement was achieved between the experimental and simulation results, showing an evidently enhanced compression strength and energy absorption capacity. The interaction between the auxetic honeycomb and foam reveals to exploit a reinforcement effect on the compression performance. The parametric analysis indicates that the composite with smaller included angel and higher foam density exhibits higher plateau stress and better specific energy absorption, while increasing strut thickness is undesirable for high energy absorption efficiency.

The results of this study served to demonstrate an enhanced mechanical performance for the foam filled auxetic honeycomb, which is expected to be exploited with applications in aerospace, automobile, civil engineering and protective devices. The findings of this study can provide numerical and experimental references for the design of structural parameters.

The purpose of this paper is to investigate the preparation and the flexural property of hollow glass microspheres (HGMs) filled resin-matrix composites, which have been widely applied in deep-sea fields.

The composites with different contents of HGMs from 47 to 57 Wt.% were studied. The voids in syntactic foams and their flexural properties were investigated.

The results showed that the voids quantity increased because of the increment of HGM content, whereas the exural strength and the exural modulus decreased. The fracture mechanism of the composites was also investigated by scanning electron microscope, which indicated that the composites failed by the crack extending through the microspheres.

The advantages of HGMs with similar hollow spheres will be further investigated in a future research.

Results demonstrated that the properties of the composite might be tailored for specific application conditions by changing the HGM volume fraction.

The HGM filled resin-matrix composite materials have their unique properties and significant application potential. In this work, the resin-HGM composites were synthesized by mechanically mixing defined quantities of HGMs into epoxy resin, by which a kind of syntactic foams with good flexural properties could be obtained.

This monograph eschews the view that packaging is an exclusively marketing tool, or for that matter the concern of the distribution function alone. The author insists that a total systems view should be taken of the multiple purposes which the pack must meet. This poses very real problems for at least three levels—the conceptual acceptance of the proposition, its interpretation into operational terms, and implementation/control of the packaging activity. This discussion is intended for all directors of companies with a substantial recurrent expenditure in packaging as well as for members of the distribution function itself. Accordingly, it takes a managerial rather than a technical view of packaging. It stresses the critical importance of the state of goods on arrival with the customer; the aesthetics and sales power of packaging; the informative role of the pack; issues of unitisation; handling problems at all stages in the channel; and the ecological/environmental aspects in contemporary society. At each juncture, sensible plans of action are proposed.

This study aims to generate different three-dimensional (3D) foam models using computer tomography (CT) scan and solid continuum techniques. The generated foam models were used to study deformation mechanism and the elastic-plastic behaviour with the existing experimental foam behaviour.

CT scan model was generated by combing 2D images of foam in MIMICS software. Afterwards, it was imported in ABAQUS/CAE software. However, solid continuum model was generated in ABAQUS/CAE software by using crushable foam properties. Then, the generated foam models were sets boundary conditions for a compression test.

CT scans capture the actual morphology of foam sample which may directly an image based finite element foam model. The sectional views of both the models were used to observe deformation mechanism on compression. The real compressive behaviour of foam was visualised in CT-Scan foam model. It was observed that CT-scan model was the more accurate modelling method than crushable foam model.

The internal structure of foam is very complex and difficult to analyse. Therefore, CT-scanning may be the accurate method for capturing the macro-level detailing of foam structure. A CT-scan foam model can be used for multiple times for mechanical analysis using a simulation software, which may reduce the manufacturing and the experimental cost and time.

This paper attempts to cover the thermal processes in syntactic metal foams. Regularshaped cubic closed‐cell structures with spherical pores are investigated by means of the finite element method. Based on the numerical modelling of the microstructure, the effective macroscopic thermal properties are evaluated. Different relative densities (0.95 ‐ 0.5) and different base materials (aluminium and iron) are considered. Furthermore, the influence of the geometry, i.e. spherical ‐ cubical for 3D and circular ‐ rectangular for 2D models, is investigated. The focus is on such cellular materials where the transport of heat is dominated by solid conduction and thermal radiation; contributions from gaseous conduction and convection are neglected.

The efficiency of fractional derivative and hereditary combined approach in modeling viscoelastic behavior of soft foams was successfully addressed in Elfarhani et al. (2016a). Since predictions obtained on flexible polyurethane foam (FPF) type A (density 28 kg m⁻³) were found very promoting, the purpose of this paper is to apply the approach basing on two other types of foams. Both soft polyurethane foams type B of density 42 kg m⁻³ and type C of density 50 kg m⁻³ were subjected to multi-cycles compressive tests.

The total foam response is assumed to be the sum of a non-linear elastic component and viscoelastic component. The elastic force is modeled by a seven-order polynomial function of displacement. The hereditary approach was applied during the loading half-cycles to simulate the short memory effects while the fractional derivative approach was applied during unloading cycles to simulate the long memory effects. An identification methodology based on the separation of the measurements of each component force was developed to avoid parameter admixture problems.

The proposed model reveals good reliability in predicting the responses of the two considered flexible foams. Predictions as measurements establish that residual responses were negligible compared to elastic and viscoelastic damping responses.

The development of a new combined model reveals good reliability in predicting the responses of the two polyurethane foams type A and B.

Most new developments are hailed as revolutionizing their sector of industry, either for the attractiveness of their economics or for the new applications made possible for an established process or material. One recently introduced process which would seem capable of living up to the claims made for it is the sandwich moulding process for plastics, invented by ICI.

The purpose of this paper is to cover an experimental investigation of the impulse response of the foam-mass system (FMS) to unveil some of the foam dynamic behavior features needed to optimize the impact comfort of seat-occupant system. The equation of motion of the studied system is modeled as a sum of a linear elastic, pneumatic damping and viscoelastic residual forces. An identification methodology based on two separated calibration processes of the viscoelastic parameters was developed.

The viscoelastic damping force representing the foam short memory effects was modeled through the hereditary formulation. Its parameters were predicted from the free vibrational response of the FMS using iterative Prony method for autoregressive–moving–average model. However, the viscoelastic residual force resulting in the long memory effects of the material was modeled with fractional derivative term and its derivative order was predicted from previous cyclic compression standards.

The coefficients of the motion law were determined using closed form solution approach. The predictions obtained from the simulations of the impulse and cyclic tests are reasonably accurate. The physical interpretations as well as the mathematical correlations between the system parameters were discussed in details.

The prediction model combines hereditary and fractional derivative formulations resulting in short and long physical memory effects, respectively. Simulation of impulse and cyclic behavior yields good correlation with experimental findings.