The document describes a study to develop a composite rubber armor that can resist high velocity bullets like those from AK-47 rifles. The study involved: 1) Preparing rubber composites with different carbon black and sulfur contents and testing their tensile strength and hardness. 2) Manufacturing shear thickening fluids (STFs) and impregnating aramid and carbon fabrics to strengthen them. 3) Simulating armor designs in ANSYS and testing designs with 14 STF-impregnated layers, finding the armor stopped 7.62mm bullets at 15m with 7.5mm back deformation. 4) Recommending further tests against different weapons and distances to validate effectiveness, and adding layers to reduce weight

1. Theoretical and Experimental
Study to Manufacture of Rubber
Composite Armor
Ahmed Ehsan Jassem
Supervised By
Prof. Mohammed Al-Maamori Asst. Prof. Ahmed Fadhil

2. General Type Body Armor
• Soft Body Armor
Consist of multiple layers of ballistic-resistant
materials. The arrangement of this layers influences
its overall performance of armor. Additional energy
is absorbed by each successive layer of material is
used to resist the bullet that has velocity less than
450 m/s
• Hard Body Armor
Consist of ceramics, compressed
laminate sheets, metallic plates or
composites that incorporate more than
one material. it is used to resist bullet
has high-velocity more than 450 m/s

3. The Aim of Research
Study and manufacture a third type armor by the American Society (NIJ) to resist AK-47 from cheap
materials and which can product in Iraq also have properties soft and hard armor, which resist high
velocity of the bullet and have the flexibility .

4. Plan of Work
The Best Result by
Simulation Compare with
Stander
Fiber Treatment for
Adhesion and Adhesion
Test
Preparation
Ebonite
Preparation
Rubber
Preparation
Ceramics
Test Tensile, Hardness and
Density
Ballistic Test
Numerical Analysis (Simulation)
Test SEM
Preparation of Aramid
fabric/ STF
Composites
Test Viscosity , G’ G’’
and SEM
Preparation of Shear
thickening fluids

5. Preparation of Rubber and Hard Rubber
The rubber was plasticizer by friction and the zinc oxide, citric acid
were then added. Then the black carbon ((N 115) has average
particles size 17-23 nm ) was added and then the batch was left for
24 hours after which the processing then adds the sulfur and the
accelerator to batch and also left a period of time in order to remove
the internal stresses resulting from the master batch, the ratio of
materials as it is shown in table, preparation of sheets of rubber
batched by the process of the vulcanization doing at conditions
temperature 165 oC and pressure 3 tons and time 15 minutes.

6. Preparation of Ceramics
Alumina was formed in the form of hexagons with a dimension of 2 cm length of the side
and thickness 2 mm, where the alumina was mixed with a small amount of PVA and
smelting aid and was first compressed by pressure 3 Tons and then burnt by temperature
1500 C and rate 4 temperatures every minute, to avoid the thermal stress in sample, the
final-shape of the sample that is shown in figure.

7. Preparation of STFs
Vacuum media
Grinding
Shear Thickening
Fluids (STFs)
Drying at 78 oC
PEG 400
STF Solution
Fume Silica
Nanoparticles
Ethyl Alcohol
Magnetic Stirrer at 3h
Sonication 5 h
Sonication 4 h

8. Preparation of Aramid Fabric/ STF Composites
Shear Thickening
Fluids (STFs) Ethyl Alcohol
STF Solution
STF impregnated
fabrics
Drying at 78 oC
Aramid and Carbon
fabric / STF
composites
Sonication 3h

9. Results and Discussion
 Tensile Test
0
20
40
60
80
100
120
140
160
180
200
15 20 25 30 35 40
Tensile
Strengh
(MPa)
Sulpher content (phr)
30 phr carbon black
26 phr carbon black
18 phr carbon black 0
0.2
0.4
0.6
0.8
1
1.2
15 20 25 30 35 40
Elastic
Modules
(GPa)
Sulpher content (phr)
The Relation Between Tensile Strength with Sulphur Content
at Deferent Concentration of Nano Carbon Black
The Relation Between Modulus with Sulphur Content at
Deferent Concentration of Nano Carbon Black

10.  Elongation & Toughness
The Relation Between Toughness and Sulphur
Content at Three Concentration of Nano Carbon
Black
0
20
40
60
80
100
120
140
160
180
15 20 25 30 35 40
Toughness
(MPa)
Sulpher content (phr)
0
50
100
150
200
250
300
18 20 22 24 26 28 30 32 34 36 38
Elogation
%
Sulpher content (phr)
The Relation Between Elongation and Sulphur
Content at Three Concentration of Nano Carbon
Black

11.  Hardness
90
92
94
96
98
100
102
104
15 20 25 30 35 40
Hardness
(Shore
D)
Sulpher Content (phr)
30 phr carbon…
The Relation of Hardness with Sulpher Concentration at 30 phr of
Nano Carbon Black

12. AdhesiveFiber – Rubber
The Tensile Strength of Kevlar Fiber with Rubber before and after Treatment of
Fibers

13. Shear Thickening Fluid
 Viscosity
The Change of Viscosity with Shear Rate by Change Concentration of Fume
Silica (5-35 wt %)
Sample
Critical shear
rate 1/s
Viscosity at
critical shear
(Pa.s)
Max.
(Pa.s)
PEG 5 % 213 0.362 0.375
PEG 10% 91 0.917 1.263
PEG 15% 85 23.801 31.614
PEG 20% 41 51.244 66.573
PEG 25% 31 15.0.2 55.594
PEG 30% 22 23.245 181.80
PEG 35% 15 43.433 5620

14. Hydrocluster theory Order disorder theory

15.  Dynamic Shear Rheology
Dynamic properties of PEG 35% Dynamic properties of PEG 30%

16.  San Electron Microscopy (SEM)
SEM Images of Neat Kevlar Fabric at Different Magnifications
a) 1300 X, b) 100x
a b

17. SEM Images of Neat Carbon Fabric at Different Magnifications
a) 100 X, b) 41x
a b

18. Numerical Simulation (Ansys)
A simulation was performed by using the Ansys program's (Explicit Dynamics) project to test
the ballistics to approximate the results and shorten time, the difficulty of applying them in
practice due to not availability of equipment lab. And the amount of losses reduces in materials
as well as knowing the number of layers that serve the correct application. Many experiments
have been done to get better results and we will show the most important ones.

19. The best arrangement for layers by Ansys is shown
It consists of three main parts, the first part
contains ceramic and alternating layers of fiber
Kevlar and rubber, the second part is the
composite consist of the Kevlar and carbon fabrics
with STFs and the third part is the supporting
layer of the previous layer consisting of the
Ebonite, the Rubber A is rubber content 18 phr
sulfur, 30 phr carbon black, Rubber B is rubber
content 24 phr sulfur, 30 phr carbon black, the
Ebonite is rubber content 28 phr sulfur, 30 phr
carbon black.

20. The Deformation of Armor Plate Have (Rubber-Ceramic-Ebonite-5 Multilayer Rubber Kevlar-14
STFsKevlar And Carbon Layers-Ebonite), A) Side and Front views of Armor Plate. B) Chart
Deformation of Plate
a
b
Def.
time

21. Front and Side of views of armor plate and Chart Deformation of Plate have (Rubber-Ceramic-
Ebonite-5 Multilayer Rubber Kevlar-14 STFsKevlar And Carbon Layers-Ebonite) at velocity
840 m/s
time
Def.

22. Front and Side of views of armor plate and Chart Deformation of Plate have (Rubber-Ceramic-Ebonite-5
Multilayer Rubber Kevlar-14 STFsKevlar And Carbon Layers-Ebonite) at velocity 940 m/s
time
Def.

23. Front and Side of views of armor plate and Chart Deformation of Plate have (Rubber-Ceramic-Ebonite-5 Multilayer
Rubber Kevlar-14 STFsKevlar And Carbon Layers-Ebonite) at velocity 1040 m/s
time
Def.

24. Front and Side of views of armor plate and Chart Deformation of Plate have (Rubber-Ceramic-Ebonite-5 Multilayer
Rubber Kevlar-14 STFsKevlar And Carbon Layers-Ebonite) at velocity 1240 m/s
time
Def.

25. Ballistic Test
A field test was conducted on the plate containing 14
layers of STFs at a distance between of 15 m and
velocity 838 m/s. The results showed that ability of
plate to resist the penetration, where, when shock of
single bullet in to the plate the amount of back
deformation is 7.5 mm and when shock of double
bullet in to plate at same the location the amount of
back deformation is 11.3 mm, which is within the
permissible limits of (NIJ) where the possible limit to
back deformation is 44 mm .
Position of
double bullet
Position of single
bullet
A
B

26. Conclusions
The following points can be concluded from the present work:
1. The ability of the rubber to absorb the shock from high-speed extruded objects after adjusting in the rubber masterbatch.
2. Preparation of Shear thickening fluid armor and proofing its ability to strength the fibers to use it in armor.
3. Arrive the correct arrangement of the layers in plate armor and the ability of armor plate to stop the caliber bullet 7.62 x39 mm
from the rifle Ak-47 and by distance 15 m.
4. The back deformation amount of the plate is a very good value 7.5mm compared with the constants that is used in the armor
industry 4cm.
5. The arrival of armor with very good characteristics compared to available armors, as the total weight (3.75 kg) of the present
armor while the USA armor (3.5 kg) and Iraqi armor (15 kg).
6. The cost of its production is appropriate and equal to 150 thousand ID compared to that of armor USA that is equal to 350
thousand ID.
7. Through Numerical simulation (Ansys) estimated to endure a speed of the same type of bullet 1240 ms, therefore has a safety
factor of more than 20%.
8. The materials that is used are simple and available in Iraq.

27. Recommendations
Below are some recommendations for future studies:
1. preparation more samples and re-examination practically again, but with different distances and
different types of weapons, to determine the effectiveness of armor with different types of
weapons.
2. Add some materials that more reduce the weight of rubber while retaining the properties of
rubber.
3. Add a layer to the back of the plate from silicon rubber in order to give more comfort for the
user.

32. Thank You for
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