Fabrication of Bulk Functionally-Graded Syntactic Foams for Impact Energy Absorption

2012 ◽  
Vol 706-709 ◽  
pp. 711-716 ◽  
Author(s):  
Tadaharu Adachi ◽  
Masahiro Higuchi
Keyword(s):  
Theoretical Analysis ◽  
Energy Absorption ◽  
Functionally Graded ◽  
Fabrication Process ◽  
Syntactic Foams ◽  
Compression Tests ◽  
Matrix Resin ◽  
Local Fracture ◽  
Density Distributions ◽  
The Matrix

Function of functionally-graded (FG) foams as energy absorption material for impact was discussed on the basis of theoretical analysis, and fabrication process of the foams was proposed in the paper. The FG foams were found to be useful as impact absorber due to progressively local fracture or cushion in the theoretical analysis. Next the fabrication process of the FG foams was suggested. The graded dispersion of the micro-balloons was conducted before curing the matrix resin in the process. The density distributions in the FG foams were confirmed to be predicted by the numerical analysis on the basis of floating the micro-balloons. Finally, compression tests were carried out to evaluate mechanical properties.

Controlling of Distribution of Mechanical Properties in Functionally-Graded Syntactic Foams for Impact Energy Absorption

2012 ◽  
Vol 706-709 ◽  
pp. 729-734 ◽  
Author(s):  
Masahiro Higuchi ◽  
Tadaharu Adachi ◽  
Yuto Yokochi ◽  
Kenta Fujimoto
Keyword(s):  
Mechanical Properties ◽  
Density Distribution ◽  
Energy Absorption ◽  
Impact Energy ◽  
Volume Fraction ◽  
Functionally Graded ◽  
Syntactic Foams ◽  
Compression Tests ◽  
Density Distributions ◽  
Control Distribution

In the study, novel fabrication processes of functionally-graded (FG) syntactic foams were developed to control distribution of the mechanical properties in the FG foams for highly impact energy absorption. In order to control mechanical properties, the density distributions in FG foams were graded by floating phenomenon of the light-weight micro-balloons in matrix resin during curing process. The density distribution in the foam could be controlled by adjusting the average volume fraction and the turning procedure of the mold before grading the micro-balloons in the foam. The compression tests of the fabricated FG foams suggested that the foams had high absorption of impact energy since the foams collapsed progressively due to the grading of the density distribution.

Quasi-State Compressive Properties of Functionally Graded Aluminum Matrix Syntactic Foams

2021 ◽  
Vol 1035 ◽  
pp. 878-883
Author(s):  
Ming Ming Su ◽  
Mo Qiu Li ◽  
Thomas Fiedler ◽  
Hai Hao
Keyword(s):  
Volume Fraction ◽  
Hollow Spheres ◽  
Aluminum Matrix ◽  
Stir Casting ◽  
Functionally Graded ◽  
Small Range ◽  
Syntactic Foams ◽  
Compression Tests ◽  
Static Compression ◽  
Plateau Stress

The uniform aluminum matrix syntactic foams (SFs) were prepared by the stir casting method, with alumina hollow spheres (2-3 mm and 3-4 mm) and expanded glass (2-3 mm) as reinforcements, and ZL111 aluminum alloy as matrix. The functionally graded aluminum matrix syntactic foams (FG-SFs) were obtained by superimposing two uniform aluminum matrix syntactic foams. Quasi-static compression tests were performed. The plateau stress of FG-SFs containing only hollow spheres decreased slightly with increasing volume fraction of SF containing 3-4 mm hollow spheres. The FG-SFs containing 2-3 mm hollow spheres and 2-3 mm expanded glass showed the highest plateau stress. The energy absorption behavior of all samples fluctuated in a small range. The initial position of shear band depended on the volume fraction of uniform aluminum matrix syntactic foams, reinforcement type and size. The cracks always appeared first in the uniform aluminum matrix syntactic foams containing expanded glass.

scholarly journals Functionally-Graded Metallic Syntactic Foams Produced via Particle Pre-Compaction

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 314 ◽  
Author(s):  
Thomas Fiedler ◽  
Nima Movahedi ◽  
Lucas York ◽  
Steffen Broxtermann
Keyword(s):  
Syntactic Foam ◽  
Functionally Graded ◽  
Syntactic Foams ◽  
Compression Tests ◽  
Graded Materials ◽  
Static Compression ◽  
X Ray Imaging ◽  
Foam Properties ◽  
A356 Aluminum ◽  
Particle Beds

This paper introduces a novel functionally graded metallic syntactic foam. The investigated foams are manufactured while using infiltration casting where molten A356 aluminum flows into the interstitial voids of packed expanded perlite (EP) particle beds. The partial pre-compaction of particle beds enables the creation of distinct and reproducible density gradients within the syntactic foam. In this study, the samples are produced using four gradually increasing compaction forces and are compared to non-compacted samples. X-ray imaging is used to detect the resulting spatial variation of foam density. In addition, quasi-static compression tests are performed to determine the mechanical foam properties. The results suggest that particle pre-compaction is an efficient tool for tailoring the density and mechanical properties of these novel functionally graded materials.

Thermal expansion and dynamic mechanical analysis of epoxy matrix–borosilicate glass hollow particle syntactic foams

2017 ◽  
Vol 54 (3) ◽  
pp. 463-481 ◽  
Author(s):  
Steven Eric Zeltmann ◽  
Brian Chen ◽  
Nikhil Gupta
Keyword(s):  
Thermal Expansion ◽  
Dynamic Mechanical Analysis ◽  
Borosilicate Glass ◽  
Coefficient Of Thermal Expansion ◽  
Hollow Microsphere ◽  
Mechanical Analysis ◽  
Syntactic Foams ◽  
Matrix Resin ◽  
Dynamic Mechanical ◽  
The Matrix

Syntactic foams are commonly fabricated with sodalime–borosilicate glass hollow microsphere fillers, which are susceptible to degradation after long-term or high temperature moisture exposure. In comparison, borosilicate glass hollow particles offer higher degradation resistance to moisture, lower thermal expansion, and higher softening temperature. This work explores borosilicate glass hollow microspheres for use as fillers in syntactic foams and studies their thermophysical properties. The coefficient of thermal expansion over the temperature range 35–90℃ was observed to decrease from 62.4 μ/K for the matrix resin to a minimum of 24.3 μ/K for syntactic foams, representing higher thermophysical stability of syntactic foams. Theoretical models are used to conduct parametric studies and understand the correlation between material parameters and coefficient of thermal expansion of syntactic foams. The dynamic mechanical analysis results show that the storage modulus of syntactic foams increases with increasing glass hollow microsphere wall thickness and with decreasing glass hollow microsphere volume fraction in the glassy region at 40℃. The β-relaxation of the matrix resin found at 66.1 ± 2.0℃ was suppressed in the majority of syntactic foams, further improving the stability around typical application temperatures.

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.

AN EXPERIMENTAL STUDY ON THE BEHAVIOUR OF GLASS FILLED POLYPROPYLENE AND POLYETHYLENE COMPOSITE PIPES UNDER QUASI-STATIC AXIAL LOADING

2015 ◽  
Vol 74 (10) ◽  
Author(s):  
H. H. Ya ◽  
H. EL-Sobky
Keyword(s):  
Energy Absorption ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Axial Loading ◽  
Fibre Volume ◽  
Compression Tests ◽  
Local Fracture ◽  
Polyethylene Composite ◽  
The Difference ◽  
Composite Pipes

The behaviour of extruded glass fibre reinforced thermoplastic pipes under axial crushing load was investigated experimentally. It was envisaged that the difference between the axial and hoop moduli and strengths as well as the volume fraction would influence the mode of collapses and energy absorption. The ability to vary the moduli and the fibre volume fraction provides means of controlling the collapse mode in order to optimize specific energy absorption. Axial compression tests were performed on glass filled Polypropylene (GPP) and glass filled Polyethylene (GPE) composite pipes. The samples were chosen with a variety of fibre volume fraction (Vf = 5% to 20% and average angle of orientation 15θ">  = 50o to 80o) to evaluate the effect of anisotropy and Vf to the collapse modes when subjected to axial static loading. The results from the experiments revealed that typical axial and hoop modulus (Ea and 15Eθ"> ) of GPP and GPE pipes increased with increasing of 15θ">  from 55 15°">  to 75 15°">  and decreased gradually in between 75 15°">  to 80 15°"> . The axial modulus was increased constantly with the increase of Vf from 5 % to 20 %. However, the hoop modulus is the highest at 5% Vf, decreases significantly at 10%, and gradually increases at 20%. It is noticed that, the GPP and GPE pipes contain higher Vf and 15θ"> , collapsed in brittle failure mode (fragmentation), whereas those with less Vf and 15θ">  angle, collapsed in non-axis-symmetric (diamond) mode with the local fracture while the local fracture disappeared with lower fibre contents.

scholarly journals Compressive Properties of Functionally Graded Bionic Bamboo Lattice Structures Fabricated by FDM

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4410
Author(s):  
Zhou Wen ◽  
Ming Li
Keyword(s):  
Mechanical Properties ◽  
Energy Absorption ◽  
Honeycomb Structure ◽  
Absorption Capacity ◽  
Functionally Graded ◽  
Honeycomb Lattice ◽  
Lattice Structures ◽  
Compression Tests ◽  
Uniform Lattice ◽  
Static Compression

Bionic design is considered a promising approach to improve the performance of lattice structures. In this work, bamboo-inspired cubic and honeycomb lattice structures with graded strut diameters were designed and manufactured by 3D printing. Uniform lattice structures were also designed and fabricated for comparison. Quasi-static compression tests were conducted on lattice structures, and the effects of the unit cell and structure on the mechanical properties, energy absorption and deformation mode were investigated. Results indicated that the new bionic bamboo structure showed similar mechanical properties and energy absorption capacity to the honeycomb structure but performed better than the cubic structure. Compared with the uniform lattice structures, the functionally graded lattice structures showed better performance in terms of initial peak strength, compressive modulus and energy absorption.

Dynamic compression of functionally-graded metal syntactic foams

2020 ◽  
pp. 113308
Author(s):  
Nima Movahedi ◽  
Matej Vesenjak ◽  
Lovre Krstulović-Opara ◽  
Irina V. Belova ◽  
Graeme E. Murch ◽  
...  
Keyword(s):  
Dynamic Compression ◽  
Functionally Graded ◽  
Syntactic Foams

Impact Properties of Syntactic Foams and Effect of Microballoon Wall Thickness

2006 ◽  
Author(s):  
Tien-Chih Lin ◽  
Nikhil Gupta
Keyword(s):  
Impact Strength ◽  
Total Energy ◽  
Energy Absorption ◽  
Volume Fraction ◽  
Impact Testing ◽  
Syntactic Foams ◽  
Lower Strength ◽  
Impact Properties ◽  
Different Types ◽  
Pendulum Impact

Hollow particle (microballoon) filled polymeric composites, called syntactic foams, are tested for impact properties in the present work. Izod type pendulum impact testing is carried out on eight types of foams, which are made of four types of microballoons used in volume fractions of 0.5 and 0.6. Variation in the volume fraction of microballoons leads to a difference in the total energy absorbed during fracture of different types of foams. Results show that syntactic foams containing microballoons of lower density show lower impact strength because of the lower strength of these microballoons. An increase in microballoon volume fraction leads to decreased energy absorption and strength.

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