Analytical and Numerical Study of Crushing of Syntactic Foams Under Uniaxial Compression

2008 ◽  
Author(s):  
Prabhakar Marur
Keyword(s):  
Finite Element ◽  
Uniaxial Compression ◽  
Numerical Study ◽  
Bulk Material ◽  
Hollow Spheres ◽  
Syntactic Foam ◽  
Particulate Composites ◽  
Syntactic Foams ◽  
The Matrix ◽  
Crushing Behavior

Syntactic foams are a class of particulate composites made with hollow microspheres dispersed uniformly in a matrix. By the inclusion of hollow spheres in the matrix, the bulk mechanical properties are improved by limiting the bending of cell edges and localization of inelastic deformation, which is the cause of failure in the case of low-density foams. For the general class of cellular materials, several analytical and experimental methods are available in the literature to characterize the material. In the case of syntactic foams, relatively few methods exist for the computation of effective elastic properties and methods for analyzing the crush behavior of the syntactic foams are rather limited. In this research, the quasi-static crushing behavior of syntactic foam under uniaxial compression is investigated using analytical and numerical methods. To better understand the bulk behavior of syntactic foam, a micromechanical study is conducted to analyze the crushing of hollow spheres in dilute concentration. Initially the stress fields around dilute concentration are derived using continuum mechanics principles and subsequently a limit analysis is performed. To gain further insight into the deformation fields and deformations of cell walls leading to densification, a finite element (FE) analysis is performed. Assuming a periodic repetition of a representative volume of the material would correspond to the bulk material, axisymmetric and 3D finite element models are developed. The numerical computations are compared with the analytical results obtained in this study, and with experimental data reported in the literature. Using the FE models, a parametric study is conducted to investigate the influence of microsphere strength and elastic mismatch between the matrix and the inclusions on the crush behavior of syntactic foam.

scholarly journals Predictive Computational Model for Damage Behavior of Metal-Matrix Composites Emphasizing the Effect of Particle Size and Volume Fraction

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2143
Author(s):  
Shaimaa I. Gad ◽  
Mohamed A. Attia ◽  
Mohamed A. Hassan ◽  
Ahmed G. El-Shafei
Keyword(s):  
Finite Element ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Particulate Composites ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Zone Method ◽  
Stress Strain ◽  
The Matrix

In this paper, an integrated numerical model is proposed to investigate the effects of particulate size and volume fraction on the deformation, damage, and failure behaviors of particulate-reinforced metal matrix composites (PRMMCs). In the framework of a random microstructure-based finite element modelling, the plastic deformation and ductile cracking of the matrix are, respectively, modelled using Johnson–Cook constitutive relation and Johnson–Cook ductile fracture model. The matrix-particle interface decohesion is simulated by employing the surface-based-cohesive zone method, while the particulate fracture is manipulated by the elastic–brittle cracking model, in which the damage evolution criterion depends on the fracture energy cracking criterion. A 2D nonlinear finite element model was developed using ABAQUS/Explicit commercial program for modelling and analyzing damage mechanisms of silicon carbide reinforced aluminum matrix composites. The predicted results have shown a good agreement with the experimental data in the forms of true stress–strain curves and failure shape. Unlike the existing models, the influence of the volume fraction and size of SiC particles on the deformation, damage mechanism, failure consequences, and stress–strain curve of A359/SiC particulate composites is investigated accounting for the different possible modes of failure simultaneously.

The Processing and Structure of Steel Matrix Syntactic Foams Prepared by Infiltration Casting

2018 ◽  
Vol 933 ◽  
pp. 129-135
Author(s):  
Quan Zhan Yang ◽  
Yan Peng Wei ◽  
Zhi Quan Miao ◽  
Peng Gao ◽  
Bo Yu
Keyword(s):  
Metal Matrix ◽  
Heat Insulation ◽  
Hollow Spheres ◽  
Syntactic Foam ◽  
Average Diameter ◽  
Steel Matrix ◽  
Syntactic Foams ◽  
Minimum Diameter ◽  
Microstructure Characteristics ◽  
Multifunctional Properties

Metal matrix syntactic foams are consisting of metal matrix and hollow spheres in closely or randomly packed, which own multifunctional properties with lightweight, damping, heat insulation, energy absorption and have a vast application prospect. Steel matrix can extend the potential of syntactic foams as a materials class to several new fields of application. In this paper, the hollow alumina spheres were introduced into the steel matrix by infiltration casting, the minimum diameter of hollow spheres for infiltration is analyzed in theory, the steel matrix syntactic foams were successfully prepared, which contain two different sphere types with average diameter sizes 3.97mm and 4.72mm, and the average densities of syntactic foams were calculated to be 4.39 (spheres occupy 43.7% of the volume) and 3.74 g/cm3 (spheres occupy 52.1% of the volume), respectively. The microstructure characteristics of the steel matrix syntactic foam were analyzed by means of scanning electron microscopy and energy spectrum.

scholarly journals Hysteretic Behavior of Random Particulate Composites by the Stochastic Finite Element Method

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2909 ◽  
Author(s):  
Damian Sokołowski ◽  
Marcin Kamiński
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cyclic Stretch ◽  
Hysteretic Behavior ◽  
Particulate Composites ◽  
Strain History ◽  
Stochastic Finite Element Method ◽  
Stochastic Finite Element ◽  
The Matrix ◽  
Element Method

Hysteretic behavior of random particulate composite was analyzed using the stochastic finite element method and three independent probabilistic formulations, i.e., generalized iterative stochastic perturbation technique of the tenth order, Monte-Carlo simulation, and semi-analytical method. This study was based on computational homogenization of the representative volume element (RVE), and its main focus was to demonstrate an influence of random stress in constitutive relation to the matrix on the deformation energies stored in the effective (homogenized) medium. This was done numerically for an increasing uncertainty of random matrix admissible stress with a Gaussian probability density function, for which the relations to the energies of the entire composite were approximated via the weighted least squares method algorithm. This composite was made of two phases, a hyper-elastic matrix exhibiting hysteretic behavior and a linear elastic spherical reinforcing particle located centrally in the RVE. The RVE was subjected to a cyclic stretch with an increasing amplitude, and computations of deformation energies were carried out using the finite element method system ABAQUS. A stress–strain history of the homogenized medium has been presented for the extreme and for the mean mechanical properties of the matrix to illustrate the random hysteresis of the given composite. The first four probabilistic moments and coefficients of the RVE deformation energy were determined and have been presented in addition to the input statistical scattering of the admissible stresses.

Structure Properties Relationship Studies of Vinyl Ester Hybrid Syntactic Foam

2021 ◽  
pp. 368-394
Author(s):  
Pravin R. Kubade ◽  
Amol N. Patil ◽  
Hrushikesh B. Kulkarni
Keyword(s):  
Vinyl Ester ◽  
Syntactic Foam ◽  
Fracture Mechanisms ◽  
Syntactic Foams ◽  
Static Compression ◽  
Molding Method ◽  
Deformation And Fracture ◽  
The Matrix ◽  
Fly Ash Cenosphere ◽  
Izod Impact

Syntactic foam is the porous composite produced by mixing prefabricated hollow spherical particle into the matrix. Syntactic foams are used as energy absorption sandwich core for several applications like marine, automotive, and aerospace. In this work, low density hollow glass microspheres are hybridized with fly ash cenosphere in Bisphenol-A epoxy-based vinyl ester matrix. Hybrid syntactic foams is created with 60% total filler content. Within these hybrid systems internal composition of two fillers were varied in a step of 25 vol% with respect to each other. Hybrid syntactic foams are prepared by the hand lay-up (molding) method. The physical characterization parameter contains density and matrix porosity whereas tensile, quasi-static compression, flexural (3-point bending), Izod impact, and micro Vickers hardness are grouped as mechanical characterization parameters. Scanning electron microscopy was performed on fractured surfaces to examine deformation and fracture mechanisms related with each loading condition.

scholarly journals Notch (In)Sensitivity of Aluminum Matrix Syntactic Foams

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 574 ◽  
Author(s):  
Attila Szlancsik ◽  
Bálint Katona ◽  
Dóra Károly ◽  
Imre Orbulov
Keyword(s):  
Fracture Toughness ◽  
Crack Opening ◽  
Matrix Material ◽  
Hollow Spheres ◽  
Aluminum Matrix ◽  
Syntactic Foams ◽  
Complex Investigation ◽  
Pressure Infiltration ◽  
Three Point Bending ◽  
The Matrix

Aluminum alloy (Al99.5 or AlSi12)-based metal matrix syntactic foams (MMSFs) were produced by pressure infiltration with ~65 vol % Globocer filler (33 wt % Al2O3, 48 wt % SiO2, 19 wt % Al2O3∙SiO2). The infiltrated blocks were machined by different geometry tools in order to produce notched samples. The samples were loaded in three-point bending, and the loading force values were recorded against the cross-head displacements and the crack opening displacements. To measure up the notch sensitivity and toughness of the MMSFs, the fracture energies and the fracture toughness values were determined. The results showed that the mentioned quantities are needed to describe the behavior of MMSFs. The fracture energies were shown to be notch-sensitive, while the fracture toughness values were dependent only on the matrix material and were insensitive to the notch geometry. The complex investigation of the fracture surfaces revealed strong bonding between the hollow spheres and the Al99.5 matrix due to a chemical reaction, while this bonding was found to be weaker in the case of the AlSi12 matrix. This difference resulted in completely different crack propagation modes in the case of the different matrices.

Strength Analysis of Syntactic Foams Using a Three-Dimensional Continuum Damage Finite Element Model

2015 ◽  
Vol 82 (2) ◽  
Author(s):  
Yejie Shan ◽  
Guodong Nian ◽  
Qiang Xu ◽  
Weiming Tao ◽  
Shaoxing Qu
Keyword(s):  
Finite Element ◽  
Tensile Strength ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Syntactic Foam ◽  
Interfacial Strength ◽  
Strength Analysis ◽  
Failure Behavior ◽  
Fe Model ◽  
Syntactic Foams

The failure behavior of the syntactic foams is investigated based on a three-dimensional (3D) micromechanical finite element (FE) model, by varying the volume fraction, the wall thickness of the hollow particles, and the interfacial strength. The maximum principal stress criterion is adopted to determine the state (damaged or undamaged) for both interface and matrix. Material property degradation is used to describe the mechanical behavior of those damaged elements. The current model can reasonably predict the tensile strength of the syntactic foams with high volume fractions (40%–60%). The failure mechanism of the syntactic foam under uniaxial tension is captured by analyzing the stress–strain curves and the contours of damaging evolution process. Results from the quantitative simulations demonstrate that the tensile strength of the syntactic foam can be improved effectively by enhancing the interfacial strength.

scholarly journals Investigation of Bimodal Aluminium Matrix Syntactic Foams Filled with Ceramic Hollow Spheres

2020 ◽  
Vol 13 (1) ◽  
pp. 110-113
Author(s):  
Borbála Leveles ◽  
Alexandra Kemény ◽  
Imre Norbert Orbulov
Keyword(s):  
Metal Foam ◽  
Mechanical Energy ◽  
Matrix Material ◽  
Hollow Spheres ◽  
Volume Ratio ◽  
Syntactic Foams ◽  
The Matrix ◽  
Static Mechanical ◽  
Specific Mechanical Energy ◽  
Energy Absorbing

AbstractIn this study bimodal A413 matrix syntactic foams filled with ceramic hollow spheres (CHSs) were produced and examined by computer tomography (CT) and quasi-static mechanical testing to determine the mixing properties of the hollow spheres and the strength of the metal foam. Two hollow spheres of different nominal diameters (d1 = 2.4 mm and d2 = 7.0 mm) were used in equal volume ratio. The produced metal foams have a density of 1.61±0.03 g/cm3, with smaller inclusions and some defective hollow spheres in the structure. The foams have an average compressive strength of 120 MPa and a specific mechanical energy absorbing capacity of 43.5 J/cm3. As a result of the upsetting tests, the matrix material is separated from the CHSs, breaking the connection between them.

Syntactic foam under compressive stress: Comparison of modeling predictions and experimental measurements

2020 ◽  
pp. 0021955X2094311
Author(s):  
Baptiste Paget ◽  
Matthieu Zinet ◽  
Philippe Cassagnau
Keyword(s):  
Syntactic Foam ◽  
Model Parameters ◽  
Syntactic Foams ◽  
Compression Tests ◽  
Confined Compression ◽  
Model Predictions ◽  
Soft Shell ◽  
The Matrix ◽  
The Relationship ◽  
Critical Buckling Pressure

Syntactic foams are composite materials consisting in the association of hollow particles, called “microspheres” and a polymer matrix. The use of soft shell microspheres confers to the foam interesting properties but in return increases significantly its compressibility. Therefore, understanding and predicting the relationship between pressure and volume change is a crucial issue for the development of this type of material. The present study focuses on a high void fraction syntactic foam made with soft shell polymer microspheres embedded in a polyurethane matrix. Compression tests are performed using a capillary rheometer and a PVT accessory for the hydrostatic compression, and a more conventional apparatus for the confined compression. The experimental results are compared with De Pascalis’s pressure/volume model predictions, using Fok and Allwright’s model to determine the critical buckling pressure of the microspheres. The model proves to be fairly accurate at low pressure and high pressure, despite a notable deviation in the mid-pressure range. The influence of key model parameters such as microsphere size distribution and microsphere and matrix elastic properties is investigated. It is shown that the reinforcement of the matrix seems to be the only efficient way to limit the compressibility of such a syntactic foam.

Microstructure and Compressive Properties of Al/Al2O3 Syntactic Foams

2018 ◽  
Vol 933 ◽  
pp. 174-181 ◽  
Author(s):  
Ming Ming Su ◽  
Han Wang ◽  
Kai Yan Li ◽  
Hai Hao
Keyword(s):  
Hollow Spheres ◽  
Shear Bands ◽  
Syntactic Foam ◽  
Aluminum Matrix ◽  
Strain Curve ◽  
Stir Casting ◽  
Low Density ◽  
Syntactic Foams ◽  
Compressive Properties ◽  
Continuous Contact

Metal matrix syntactic foams with relativity low density (2.03 g/cm3) were prepared by stir casting method. The syntactic foam is comprised of alumina hollow spheres with a diameter range of 1.0-1.5 mm as reinforcement and ZL111 aluminum alloy as matrix. Calcium particles are used to increase the viscosity of the melt to ensure that low density hollow spheres are immersed in the melt. Microstructure characteristics and quasi-static compressive properties of syntactic foams were studied. The hollow spheres were uniformly distributed in the aluminum matrix, and the interface between them was in continuous contact. Compressive stress-strain curve exhibits three distinct stages of deformation: (i) the linear elastic stage; (ii) the plateau area; (iii) final densification stage. The compression strength and plateau stress are 85 MPa and 75 MPa, respectively. The main reasons for the sample failure are the collapse of hollow spheres and the formation of multiple shear bands.

Effect of Wall Thickness of Hollow Sphere on the Stress Distribution of Random Hollow Sphere Syntactic Foam

2014 ◽  
Vol 670-671 ◽  
pp. 630-633
Author(s):  
Zhuo Chen ◽  
Zhou Zhou ◽  
Bing Yan Jiang
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Wall Thickness ◽  
Hollow Sphere ◽  
Maximum Stress ◽  
Volume Fraction ◽  
Hollow Spheres ◽  
Syntactic Foam ◽  
Element Model ◽  
Spatial Arrangement

This paper addresses elastic analysis based on 3D finite element model for hollow sphere structures. In finite element models, which were analyzed under pressure of 1MPa, volume fraction of hollow spheres is kept at 30%, and hollow spheres are randomly located in the matrix. Five types of hollow sphere are used to form the model. All the types of hollow spheres have 60μm particle sizes, but different wall thicknesses. A comparison in stress distribution between the hollow sphere and matrix is made, which shows that in composites containing thin-walled hollow particles the maximum stress is located in the inner surface of particle wall, whereas increasing the wall thickness of hollow spheres results in getting some part of matrix around hollow spheres involved in energy absorption. Moreover, the location of the maximum stress in matrix related closely to the spatial arrangement of the particles. The study provides an insight into the micro structural performance of syntactic foam under load.

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