A Numerical Study on Mechanical Behavior of Composite Metal Foam

This report presents a numerical study on the mechanical behavior of composite metal foam (CMF), an innovative material developed using gravity casting. The study investigates the energy absorption capabilities of CMF under static compression using ANSYS analysis, revealing its superior performance compared to conventional metal foams. Microstructural examinations explore the development of diverse phases at the steel-aluminum interface and their impact on bending behavior during compression. The report also addresses the influence of elevated strain rates on energy absorption. The methodology encompasses materials processing, structural analysis, and quasi-static/dynamic compression testing using the Split Hopkinson Pressure Bar. Results detail the structural and mechanical properties derived from simulations, providing insights into the potential benefits of CMF in various applications. The document is contributed by a student and available on Desklib, a platform offering study tools and resources for students.

A Numerical Study on Mechanical Behavior of Composite Metal Foam 1
A Numerical Study on Mechanical Behavior of Composite Metal Foam
Student Name
Student Number
A report submitted for
300598Master Project 2
In partial fulfilment of the requirements for the degree of Course Name
Supervisor Name
School of Computing, Engineering and Mathematics
Western Sydney University
Month Year

A Numerical Study on Mechanical Behavior of Composite Metal Foam 2
ABSTRACT
(CMF) Composite Metal Foam, which is an innovative material that belongs to the level
of complex and advanced porous and cellular materials, has for the first time been developed
through the use of gravity casting technique at the North Carolina State University. This
particular substance is composed of steel void spherical objects and a matrix of solid alloy made
of aluminum. The absorbed energy activities of the substance undergoing static compression
force was experimented on and studied well. Results obtained through ANSYS analysis shows
that Composite Metal Foam has a superior absorption of energy capacity compared to that of
supplementary monetarily accessible foams of metal developed through the use of similar
materials as well as hold a bigger capacity to ratio of the density. This micro-structural
examination of the substance was utilized for learning and reporting on the development of
diverse stages at the interface of the structural steel and aluminum and the outcome on the
bending activities of the metal foam during the forces of compression. The impact of elevated
rates of strain and strength are noted, the rise of the absorption of the energy of the compound
foam of metal illustrations seen varies over thirty times when contrasted against the value of
100% aluminum foams and more than twice that of 100% steel foams.

A Numerical Study on Mechanical Behavior of Composite Metal Foam 3
ACKNOWLEDGEMENTS
I would like to convey my sincere gratitude for all the many hours of help I received from the
technical and subordinate staff as well as from fellow students. An important thank you goes
towards our project supervisor, XXXX whose unfailing input in inspiring encouragement and
contributions, aided me to organize my project and ideas especially in the write up of this report.
Moreover, I would as well like to recognize with a lot of thanks the critical role of the XXXX
who provided the go ahead to utilize all necessary apparatus and equipment and the essential
materials for the completion of the job. A special gratitude goes to my group mates, namely;
XXXX who tirelessly aided me to gather the components and gave countless ideas and
contributions towards the task.
Last although not least, a big thankyou goes to the project leader, XXXX whose invaluable input
could not go without being mentioned. He/she provided his/her complete support in directing the
group to achieve its goals. I need to be grateful for the leadership provided by other project
coordinators as well as the judging panels specifically during the project presentation phase that
has sharpened our presentation proficiency with credit to their advises and comments.

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TABLE OF CONTENTS
ABSTRACT....................................................................................................................................2
ACKNOWLEDGEMENTS............................................................................................................3
TABLE OF CONTENTS...............................................................................................................4
LIST OF TABLES..........................................................................................................................5
LIST OF FIGURES.......................................................................................................................6
NOMENCLATURE........................................................................................................................7
ABBREVIATIONS.........................................................................................................................8
CHAPTER I: INTRODUCTION...................................................................................................9
CHAPTER II: Literature Review................................................................................................12
Steel foam characteristics......................................................................................................13
Structural applications for metallic foams............................................................................14
Non-structural applications for metallic foams....................................................................16
Steel foam manufacturing processes..................................................................................16
Powder metallurgy..............................................................................................................19
Hollow spheres....................................................................................................................20
Lotus-type.............................................................................................................................20
Macroscopic properties..........................................................................................................21
Experimentally measured structural properties..................................................................23
Testing procedures.................................................................................................................25
Computational models............................................................................................................26
Testing requirements..............................................................................................................26
CHAPTER III: METHODOLOGY..............................................................................................28
Materials and Processing......................................................................................................28
Structural Analysis..................................................................................................................30
ANSYS Simulation..................................................................................................................30
Quasi-Static and Dynamic Compression Testing Procedure...........................................31
Split Hopkinson Pressure Bar...............................................................................................31

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CHAPTER IV: RESULTS...........................................................................................................33
Structural Properties...............................................................................................................33
Mechanical Properties............................................................................................................38
CHAPTER V: DISCUSSION.....................................................................................................40
CHAPTER VI: CONCLUSION..................................................................................................41
References...................................................................................................................................43

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LIST OF TABLES
Table 1: Steel foam characteristics................................................................................................15
Table 2: Steel foam manufacturing processes...............................................................................20
Table 3: Table of material properties as extracted from selected publications.............................24
Table 4: Properties of steel............................................................................................................27
Table 5: Contents of the 316L stainless steel balls, LC (Low carbon) steel balls, and Al
(Aluminum) alloy (A356)..............................................................................................................30
Table 6: Chemical composition and physical properties of hollow spheres and the matrix
material..........................................................................................................................................30

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LIST OF FIGURES
Figure 1: Typical stress–strain curve for metal foams in compression.........................................16
Figure 2: Compressive yield strength versus normalized elastic modulus of various types of steel
foams..............................................................................................................................................25
Figure 3: Tables showing Alternating Stress Mean Stress, Strain Life parameters, Isotropic
Elasticity and Isotropic Relative Permeability..............................................................................35
Figure 4: Mesh...............................................................................................................................35
Figure 5: Mesh...............................................................................................................................36
Figure 6: Analysis..........................................................................................................................36
Figure 7: Analysis settings.............................................................................................................37
Figure 8: Analysis settings.............................................................................................................37
Figure 9: Model (A4) > Static Structural (A5) > Loads................................................................38
Figure 10: Equivalent stress...........................................................................................................38
Figure 11: Simulation showing the equivalent stress....................................................................39
Figure 12: Depicts meshing of the metal composite spheres........................................................40
Figure 13: Shows total deformation..............................................................................................40

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NOMENCLATURE
σ = sigma

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ABBREVIATIONS
EPSs - Expanded Polystyrene Spheres
LC - Low Carbon steel
CMFs - Composite Metal Foams
ANSYS - ANalysis SYStems

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CHAPTER I: INTRODUCTION
Metal forms are a unique type of materials with special physical, thermalcellular,
mechanical, acoustic, and electrical properties and a porous structure. They demonstrate a
structure with low values of density and high levels of stiffness, strength, sound absorption, high
energy of impact capacity, heat expulsion, and fire dissipation. These metal forms can be utilized
as foundation for sandwich plates, as firmer in shell configurations to buckle the blocks, for the
sake of the energy sucking parts in vehicle crumple zones and as effective exchangers of heat to
reduce heat generated by high power electronics (Adler, Standke, and Stephani, 2004). These
materials can be utilized in structural functions due to their high strength to density ratio,
excellent structural stability and sturdiness when compared to that of other foams or in absorbing
of energy and explosion safety purposes due to their energy absorption capacity in any path and
direction at low through modest levels of stress contrasted against bulk metals. Upon collision,
metal foams lose form plastically at a comparatively level of stress over an expansive area of
strain, while absorbing all the kinetic force prior to reaching densification.
The metal foams’ mechanical performance was determined to be greatly affected by the
characteristics of the foams like cell shape, cell size, cell connectivity, and cell wall width
(thickness). The present metal foam development methods can solely control the size of the cell
to a certain degree (Angel, Bleck, and Scholz, 2004). The curvy deformations of the cell wall
width, cell walls, and the non-homogeneous size and shape of the cells lead to tainted and
degraded mechanical performance making it hard to forecast the material’s failure and
performance. These distortions can be surmounted by integrating executed void balls in metal
foams. The executed spheres of the metal void have a homogenous cell shape, size, and wall
width and can be crammed into a solid collection of structure of foam. The metal void spheres

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are developed by covering EPSs (expanded polystyrene spheres) using a technique that uses
suspended metal powder. This takes place as the perfectly round objects move violently through
a surface that has been fluidized. This type of movement gives a homogenous outside layer on
the round objects (spheres) and permits almost immediate liquid drying.
The spheres that have been coated are exposed to heat to pyrolyze the binding agent and
the expanded polystyrene spheres, pursued by coalescing of the metal dust particles to produce a
shell that is dense. These rounded substances (spheres) can be coalesced to produce a void ball
structure or they can alternatively be left as single spheres to be utilized in other manufacturing
functions. This compound metal foam has gains in isotropy, mechanical characteristics, and
uniformity that allow for homogeny in the designs developed in technical applications (Ikeda,
Nakajima, and Aoki, 2005). 316L stainless steel and LC (low carbon) steel void perfect balls
were used in the development of CMFs (composite metal foams). CMF testing delves into the
physical, mechanical, and microstructural characteristics of the Aluminum stainless steel and
Aluminum-Low Carbon steel composite metal foams through the use of different methods
including compression and micro hardness testing, and through the use of ANSYS and suggests
a relation among the microstructure of the metal foam, the development temperature, and the
material’s mechanical performance during loading.
Compression tests of the Quasi-static type indicates an even deformation activity without
the occurrence of centralized collapse bands, which results in a great plateau rigidity in the range
of 50 to 150 MPa which depends on the substance properties and processing methods. CMFs
(Composite metal foams) have also been subjected to testing widely in compression-compression
forces, unloading-loading compression forces, and four-point bending forces. Nevertheless, their
performance at greater loading speeds has never been subjected to testing. Exclusive of a lone