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CHAPTER IINTRODUCTION Background IssueThe development of millitary technology and military innovation in the tweentieth have grown so fast. As the result, many kinds of military innovation products have been appearing. One of them is ballistic vest and stab-resistant vest which made from kevlar.Up till now, the ballistic vest and stab-resistant vest material is synthetic para-aramid fiber which also known as kevlar that was invented by Stephanie Kwolek in 1964. Because of the globalizaton, the ways to produce the ballistic vest and stab-resistant vest have been being spreaded around the world to be used as the millitary personel protection.Although, synthethic para-aramid fiber has some advantages, it was cost very much depending on world market price (Yuhazri and Dan, 2008 : 1). On the other case, the budget of the production is rather expensive since the use of sulphate acid in the production is difficult. This extreme condition was needed to keep the high polymer didn’t solute in the solution during the synthesis and the stir. (M. Alaudin, 2007). Furthermore, a synthetic para-aramid fiber is a synthetic chemical elements that was non-biodegradable. As the consequences, expired kevlar must be recycling in order to keep the environment safe.Based on those problems, researcher would like to give solution by making alternative vest made from semi-organic composite material which uses coconut plant (Cocos nucifera) fiber as the main material. This plant have been known as “multipurpose plant” by Indonesian society. This plant also flourishes in tropical countries, especially in Indonesia. From that reason, research titled Stab-resistant and Ballistic Vest made from Coconut Fiber was done. Problem LimitationsIn this research, the problem limitations are the specification of vest, the production cost of vest, and the performance of vest to resist bullet impact and sharp object impact. Also, the result of this research is the comparison between four vest layer design performance. Problem StatementsBased on the background issue. The problems can be stated as follows :How to make stab-resistant and ballistic vest using coconut fiber as the main material ?How much money needed to make stab-resistant and ballistic vest made from coconut fiber ?Does stab-resistant and ballistic vest made from coconut fiber can defend a bullet impact for level IIA ballistic vest until it meets certain safety limitations ?Does stab-resistant and ballistic vest made from coconut fiber can defend a sharp point impact for level II stab-resistant vest until it meets certain safety limitations ? Research PurposesThe purposes of this research can be stated as follows :To make stab-resistant and ballistic vest using coconut fiber as the main materialTo compare the production cost of stab-resistant and ballistic vest made from kevlar with the production cost of stab-resistant and ballistic vest made from coconut fiber.To test the endurance of stab-resistant and ballistic vest made from coconut fiber from the level IIA bullet impact.To test the endurance of stab-resistant and ballistic vest made from coconut fiber from the level II sharp point impact The Benefit of ResearchThe benefit of research were shown below :For the government :Reduce the amount of money that the government spends to import or to make ballistic vest made from kevlar.Utilize coconut fiber to make them more valuable.For the researcher :Enrich scientific references in general, and for the particular purpose, it will help the other researchers who want to do a further research in ballistic vest.CHAPTER IILITERATURE STUDYBallistic VestBallistic vest is a kind of vest that is worn on body to absorb the kinetic energy of the bullet attack and then distribute it to the whole parts of the vest so that it can protect the users from a bullet attack and bomb flakes. The work of ballistic vest are by absorbing the kinetic energy of a bullet intensively and then smash it to the wide longitudinal section of the vest, so that the energy of the bullet will be no longer enough to break through the body (Basuki, 2014). However, it doesn’t mean that the use of ballistic vest can secure the user from the bullet attack entirely. By the time the bullet strike the ballistic vest, the vest will be deformed through it and it will give an effect of hit to the user. This effect can cause internal injury or even cracked bone. The limit of deformation into the body that is categorized as safe is 44 mm (Borneocom, 2013). If the ballistic vest deformed deeper than that number, the user can have a serious injury (Borneocom, 2013)Although, ballistic vest helps protect the user body. It doesn’t address threat from knives and sharply pointed instruments, which are different types of threat (National Institute of Justice, 2000).According to National Institute of Justice (NIJ) standard 0101.04, ballistic vest can be classified that can be seen below :Table 2.1.Ballistic Vest Level ClassificationLevelLevel ProtectionILR LRN bullet caliber .22 with nominal masses of 2,6 g impacting at a minimum velocity of 320 m/sFMJ RN bullet caliber .380 ACP with nominal masses of 6,2 g impacting at a minimum velocity of 312 m/sIIAFMJ RN bullet caliber 9 mm with nominal masses of 8,0 g impacting at a minimum velocity of 332 m/sFMJ bullet caliber .40 S&W with nominal masses of 11,7 g impacting at a minimum velocity of 312 m/sIIFMJ RN bullet caliber 9 mm with nominal masses of 8,0 g impacting at a minimum velocity of 358 m/sJSP bullet caliber .357 Magnum with nominal masses of 10,2 g impacting at a minimum velocity of 427 m/sIIIAFMJ RN bullet caliber 9 mm with nominal masses of 8,0 g impacting at a minimum velocity of 427 m/sJHP caliber .44 Magnum with nominal masses of 15,6 g impacting at a minimum velocity of 427 m/sIIIFMJ bullet caliber 7,62 mm (U.S. Military designation M80) with nominal masses of 9,6 g impacting at a minimum velocity of 838 m/sIVAP bullet caliber 0.30 (U.S. Military designation M2-AP) with nominal masses of 10,8 g impacting at a minimum velocity of 869 m/sSource : National Institute of Justice standard-0101.04 Coconut FiberCoconut fiber or also named ‘Coir’ is a lignocellulosic natural fiber. Its obtained from the outer shell or husk of the Cocos nucifera (Coconut) plant. The individual fiber cells are narrow and hollow, with thick walls made of cellulose. They are pale when immature but later become hardened and yellowed as a layer of lignin is deposited on their walls (Harish, et al, 2008 : 45). It can have length 10-30 cm per piece and 12-24 μm in diameter. This fiber sticks on the middle layer of coconut and it must be cleaned first to get it. The Kind of Coconut FiberThere are two kinds of coconut fiber based on its maturity that can be seen below : Mature Brown Coconut FiberThis fiber can be found in the coconut fiber that has been riped. This fiber contain more lignin and less cellulose than fibers such as flax and cotton and are thus stronger but less flexible. (Harish, et al, 2008 : 45). It can have 10 – 20 μm in diameter. White Coconut FiberThis kind of coconut fiber can be found in the coconut which hasn’t been ripe yet. The characteristics of this fiber are soft, elastic, and weak at restraining tension. Since it is soft, this fiber is mainly used as the material of carpet or mattress.Mechanical Properties of Coconut FiberThe comparison between mechanical properties of coconut fiber and the other natural fiber materials can be seen below :Table 2.2.The Mechanical Properties Comparison between Coir and the other Natural Fiber materialsFiberDensity (g/cm3)Elongation (%)Tensile Strength (MPa)Young Modulus (GPa)Cotton1.5-1.63.0 - 10.0287-5975.5-12.6Jute1.3-1.461.5 – 1.8393-80010-30Flax1.4-1.51.2 – 3.2345-150027.6-80Hemp1.481.6550-90070Ramie1.52.0 – 3.8220-93844-128Sisal1.33-1.52.0 – 14400-7009.0-38.0Coir1.215.0 – 30.0175-2204.0-6.0Source : Chemical Treatments of Natural Fiber for Use in Natural Fiber-Reinforced Composites : A ReviewChemical Treatment of Coconut FiberThere are many ways to treat coconut fiber. One of the most used way to treat coconut fiber is by giving alkaline (NaOH) solution to coconut fiber that dissolved in water. This treatment removes a certain amount of lignin, wax, and oils covering the external surface of the fiber cell wall, depolymerizes cellulose and exposes the short length crystallities (Xue Li, et al, 2007 : 3).In this treatment, coconut fiber are given 5 % NaOH solution for a given period of time in room temperature. This treatment has two effects on the fiber : Increase surface roughnessIncrease the amount of cellulose exposed on the fiber surfaceJacob et al has treated sisal fiber with various NaOH percentage solution (0.5, 1, 2, 4, and 10 %. It’s reported that 4 % NaOH solution resulted maximum tensile strength at room temperature. The maximum NaOH solution that can be given to natural fiber reported by Mishra et al was 5 %. This is because at higher NaOH solution resulted damaging fiber that reduce its tensile strength Composite MaterialComposite material is a material made from two or more different material substances that known as reinforcement combined with resin that known as matrix with various proportion to get a material that has different properties with compiling material . It has done because of many reason. Such as, to lower the cost, to increase its mechanical properties, etc.Emad S. (2007) stated that there are some important factors that must be considered when designing FRC (Fiber-Reinforced Composite) as follows :Ratio of fiber length and diameterAmount of fiber.Orientation of the fiber.Emad S. (2007) also reported that the thinner fiber give more hardness and tensile strength than tougher fiber. The amount and the orientation of the fiber was reported that more fiber proportion than resin give more hardness and tensile strength than less fiber proportion. Fiber in form of woven roving also reported has more hardness and tensile strength than fiber in form of chopped strand mat.FiberglassThe Definition of FiberglassFiberglass is a liquid glass that is pulled into thin fiber with the diameter around 0,005 mm - 0,01 mm. This fiber can be twisted into threads or weaved into cloth. Then, it will be absorbed by resin to make it a strong material which is also resistant against corrosion.The History of FiberglassThe extensively development of fiberglass started in 1930s. It was needed for the aviation industry and unintentionally in the years 1932 – 1935, the researchers in Owen, Illinois found resin to combine fiberglass with plastic. Since then, the fiberglass production grew so fast, but it was still for industrial matter, especially for the surface layer of industrial goods since it is light and strong. Until post-World War II era or approximately in 1950s, the use of fiberglass widened. It was used for sports equipment, telecommunication, shipping, pipe and bath-up making, etc.Even though today the use of fiberglass has been replaced by carbon fiber which is lighter and stronger, fiberglass is still in use since it’s cheaper than carbon fiber.Mechanical Properties of FiberglassThe strength of fiberglass is varied depends on its matrix filler and its reinforcements. The comparison between mechanical properties of fiberglass and the other materials can be seen below :Table 2.3.The Mechanical Properties Comparison between Fiberglass and the other materialsDecomposition Temperature( °C )427 – 482427 – 48285073015002542561493500Thermal Expansion Coefficient( 10-6/°F )-2.2-2.7+1.7+1.6+3.7----0.1Specific Tensile Strength( 106 in. )8.158.377.405.431.03.403.3610.76.93Break Elongation( % )3.62.45.44.82.018.314.53.51.4Modulus( 106 psi )10.216.312.410.5290.82.01732Tenacity( 103 psi )424435665500285143168375450Specific Density( lb/in.3 )0.0520.0520.0900.0920.2800.0420.0500.0350.065Kevlar 29Kevlar 49S-GlassE-GlassSteel WireNylon-66PolyesterHS PolyethyleneHigh-Tenacity CarbonSource : Kevlar Aramid Fiber Technical GuideTable 2.4.The Physical Properties of Various FiberglassPhysical PropertiesS-2-Glass2.46 g/cc1.5211056 °C816 °C766 °C4890 MPa86.9 GPa5.7 %R-Glass2.54 g/cc1.546952 °C736 °C4135 MPa85.5 GPa4.8 %AR-Glass2.70 g/cc1.562773 °C3241 MPa73.1 GPa4.4 %ECR-Glass2.72 g/cc1.579882 °C3445 MPa80.3 GPa4.8 %E-Glass2.58 g/cc1.558846 °C657 °C615 °C3445 MPa72.3 GPa4.8 %D-Glass2.11-2.14 g/cc1.465771 °C521 °C477 °C2415 MPa51.7 GPa4.6 %C-Glass2.52 g/cc1.533750 °C588 °C522 °C3310 MPa68.9 GPa4.8 %A-Glass2.44 g/cc1.538705 °C3310 MPa68.9 GPa4.8 %Density Refractive IndexSoftening PointAnnealing PointStruin PointTensile Strength at 23 °CYoung Modulus23 °CElongationSource : High Strength Glass FiberJeansJeans are popular sheets which can be used as fashion equipment among teenager which was invented by Jacob Davis and Levi Strauss in 1873. It is made from cotton which is weaven into cloth. There are many fashion equipment which made from jean sheets. Such as dressers, hat, jackets, belts, handbags, skirts, etc.There are also many styles and colors of jeans. One of the widely used in the world is blue jeans. Which are particularly identified with American Culture especially American Old West. The picture below shows blue jeans sheetPicture 2.1. : Blue jeans textureSource : EnergyKinetic energy is energy that associated with the state of the movement of an object (Halliday, Resnick, Walker, 2005 : 153). In classical mechanics, the kinetic energy of a point object (an object so small that its mass can be assumed to exist at one point), or a non-rotating rigid body depends on the mass of the body as well as its speed. The kinetic energy is equal to the mass multiplied by the square of the speed, multiplied by the constant 1/2. In formula form:Ek=12mv2Stab Resistance VestStab resistance vest is a kind of vest that protect the user against the sharp pointed object by absorbing its kinetic energy so it will be no longer penetrate user’s body. According to NIJ, Stab-resistant vest is classified by its definition that can be seen below :Edged Blade ClassThe one which is intended to deal with threats that might be expected on “the street” from high quality, commercialy machined edged knife blades. This class is referred to as the “Edged Blade” class. (NIJ, 2000).Spike ClassThe other protection class which is intended to deal with threats that might be expected in a corrections environment. Lower quality knife blades and spike style weapons that have been improvised from other materials typically characterize these threats. This class is referred to as the “Spike” class. (NIJ, 2000)Stab-Resistant Panel TestAccording to National Institute of Justice 0115.00 standard (2000), the stab-resistant test protocol requires the knife blade or spike to impact the armor test sample at two distinct energy levels. The first energy level, called “E1,” corresponds to the percentiles described above. At this condition, a maximum blade or spike penetration of 7 mm (0.28 in) is allowable. The penetration limit was determined through research indicating that internal injuries to organs would be extremely unlikely at 7 mm (0.28 in) of penetration. The test protocol then requires an overtest condition where the knife blade or spike kinetic energy is increased by 50 %. At this higher energy condition, called “E2,” a maximum blade or spike penetration of 20 mm (0.79 in) is allowable. This overtest is required to ensure that there is an adequate margin of safety in the armor design. The protection levels of stab-resistant vest can be seen below :Table 2.5.Stab resistant protection level strike energiesProtection Level“E1” Strike Energy (J)“E2” Overtest Strike Energy (J)124 ± 0.5036 ± 0.60233 ± 0.6050 ± 0.70343 ± 0.6065 ± 0.80Source : National Institute of Justice standard-0115.00 Synthetic ResinSynthetic resin is a human-made liquid or solid materials that are used as the matrix of composite material. There are two kinds of synthetic resin according the effect of heat to its mechanical properties that can be seen below :Thermoplastic ResinThermoplastic resin is a kind of resin that are reversible between solid state and liquid state without any significantly effect to its mechanical properties. The example of thermoplastic resin is acrylic, nylon, polyethylene, polystyrene, etc.Thermosetting ResinThermosetting resin is a kind of resin that significantly reduces its mechanical properties when its form changed from solid state to liquid state. Because of this, thermosetting resin considered as irreversible polymer. There are three most widely used thermosetting resin that can be seen below :Polyester ResinPolyester resins are the most widely used resin systems, particularly in the marine industry (Cripps, 2014). It is formed by the reaction of dibasic organic acids and polyhydric alcohols. The picture below shows the typical polyester resin chemical structure.Picture 2.2 : Polyester resin chemical structureSource : are two principles types of polyester resin used as standard laminating system. First is Orthophthalic polyester resin which economical value to many people. Second is Isophthalic polyester resin which is more water resistance than Orthophthalic polyester resin although its more expensive.For use in molding, polyester resin must be added addition solution. Mainly, catalyst to hardening the polyester resin.Davallo et al (2010) was conducted research with orthophthalic polyester resin type with curing agent cobalt octoate accelerator that was allowed to react at 25°C. Its mechanical properties was reported that can be seen below :Table 2.6.Mechanical Properties of Orthophthalic Polyester Resin cured with agent Cobalt Octoate AcceleratorTensile ParameterStress at failure (MPa)Modulus (GPa)Strain at failure (%)63 ± 2.01.0 ± 0.404.7 ± 0.20Flexural ParameterStress at failure (MPa)Modulus (GPa)Strain at failure (%)78 ± 1.44.0 ± 0.51.8 ± 0.30Fracture ParameterFracture Toughness(MPa m0.5)Fracture Energy (J m-2)0.3090Source : Mechanical properties of unsaturated polyester resin.Vinylester ResinVinylester resin are similar in their molecular structure to polyesters (Cripps, 2014). But the reactive sites only being positioned at the end of the molecular chains. As the result, vinylester resin become tougher and more water resistant than polyester resin. The picture below shows the typical vinylester resin chemical structure.Picture 2.3. : Vinylester resin chemical structureSource : ResinEpoxy resin are a family of thermoset plastic material which do not give off reaction product when they cure and so have low cure shrinkage (Manoj and Singla, 2010). The epoxy resin are generally manufactured by reacting epichlorohydrin with bisphenol (Manoj and Singla, 2010).Epoxy resin is tougher than vinylester resin and capable for long-working time but its more expensive and longer time to hardening than vinylester resin. Its also has higher viscosity than polyester resin.When used as the matrix material, epoxy resin must be added curing agent, often referred as catalyst, hardener, or activator to hardening the epoxy resin and diluent/thinner to reduce its viscosity.Manoj and Singla (2010) was conducting research about the effect of fly ash to the mechanical properties of epoxy resin. Epoxy resin was mixed with the hardener with the proportion 10 : 1 at room temperature for 24 hours. It was reported that the addition of fly ash can increase its compressive strength but reduce its impact strength. Glass fiber was used as the reinforcement of epoxy resin and it was reported that glass fiber can increase both compressive strength and impact strength.Emad (2010) was observed the effect of hardener to the epoxy resin Epikote 828 (DGEBA) cured with diaminodiphenyl-methane (DDM) on its mechanical properties ( with the ratio of hardener : epoxy is 24 : 1, 27 : 1, 30 : 1, 34 : 1. It was reported that the highest value of impact strength, young modulus, ultimate tensile strength, break elongation, hardness, flexural, compression, and bending strength was the epoxy mixture which has the ration of hardener : epoxy is 30 : 1. HypothesesBased on the mechanical properties of fiberglass comparing to kevlar. It can be seen that s-glass fiber cloth has higher tenacity than kevlar, cheaper, and more common to the society. Based on the mechanical properties of natural material. It can be seen that coconut fiber has the highest break elongation. So, the researchers state some hypotheses as follow :Fiberglass cloth function is to absorb kinetic energy of the impact, either bullet or sharp point impact and change bullet shape to be wider area surface. So, the friction between stab-resistant and ballistic panel can be increased.Coconut fiber function is to distribute the kinetic energy of the impact, either bullet or sharp point impact, slowly decreases its velocity, and to reduce blunt trauma to the user. Stab-resistant and ballistic vest made from coconut fiber can resist level IIA bullet impact and level II sharp point impact.Stab-resistant and ballistic vest made from coconut fiber can be alternative protection vest that cheaper, semi-organic, and easier to be made than ballistic vest made from para-aramid synthetic.CHAPTER IIIRESEARCH METHODOLOGYResearch MethodsThis research uses Research and Development (R&D) methods which focuses on cycle (R&D) as the background of development and the action of perfecting of effectiveness and efficiency of the tool prototype being developed. Besides, there will be made four models of prototype layers and each of its effectiveness and efficiency will be tested.The development and the act of perfecting effectiveness and efficiency of those four types of prototypes will be selected based on how effective and efficient they are.3.2. Research ProceduresThis research procedures use ADDIE (Analysis-Design-Develop-Implement-Evaluate) model. It was developed by Molenda (2003: 34 – 37) with a little modification on its procedure. As follows :Problem searching and analysis related to ballistic and stab-resistant vest.Study the literature about coconut fiber as the alternative material of ballistic and stab-resistant vest to solve the problems.Form four kinds of alternative ballistic and stab-resistant vest layer design made from several different combination of composite materials.Implement those four layer designs.Test the endurance of those four layers to resist bullet impact and sharp point object pare the total specification of those four layers. Development will be made in the layer which has highest effectiveness and posing the report.Illustration 3.1. R&D methods procedure in the research “Stab-Resistant and Ballistic Vest made from Coconut Fiber.”3.3. Research Time and PlaceThis research was done in stages and continuos as R&D cycle between the end of December 2013 until the end of April 2014. This research was done in several different places, the researcher’s home, the library of SMAN 3 Semarang, Dian Kartika tennis court, PERBAKIN’s Shoot field, Forensic Laboratory of Police Academy Semarang, Mr. Suroso’s Workshop, and Infantry Battalion 400 Raider Shoot field.Table 3.1.Previous research activitiesResultZig zag material arrangement is the strongest material arrangementPressured panel with the thickness 2,5 cm and mass 1,7 kg successfully resist level I bullet impactLevel IIA bullet still can penetrate old ballistic panel.Level I bullet still can penetrate new ballistic panel which has the thickness 1,15 cm and mass 700 gTreated coconut fiber, More glass fiber reinforcement, Epoxy resin, and coconut fiber structure can improve panel performanceIndependent variableComposite material arrangementPanel Pressure-Coconut FiberFiberglass -Fiberglass and Resin typeCoconut Fiber and Jean sheetResearch purposeTo know the strongest composite material arrangementTo produce a ballistic panel that can resist level I bullet impact (lead bullet)To test the resistance of old ballistic panel from level IIA bullet impact (FMJ)To produce ballistic panel that can resist level I bullet impact with less thickness and massesTo identify the other variable that may improve panel performanceTo produce panel that can resist level II sharp point impact and level IIA bullet impactPeriod timeDecember 2013– January 2014January 2014 – February 2014February 2014March 2014 – April 2014April 2014April 20143.4. Ballistic Test MethodsBallistic tests of those four layers designs are done in the Headquarter of Infantry Battalion Yonif 400/Raider and Forensic Laboratory of Police Academy with M1911 pistol handgun chambered for the 0.45 ACP cartridge and Revolver Colt Police Positive Special chambered for the 0.38 S&W Special. The bullets are fired from the distance 5 m for 0.45 ACP and 5 m and 1,5 m for 0.38 S&W Special from the panel. Plywoods with the thickness 2 mm have been used as backing material of the panel. The inside deformation of plywoods caused by bullet impact will be measured. If the deformation still less than 44 mm, it will be considered successfully resist the bullet impact.3.5. Stab Test MethodsStab test of those four layer designs is done in the Headquarter of Infantry Battalion Yonif 400/Raider with Edged Blade class. The impact is done manually by the human power. Ply woods with the thickness 2 mm have been used as backing material of the panel. The inside deformation of plywood caused by sharp point impact will be measured. If the deformation still less than 7 mm, it will be considered successfully resist the bullet impact.3.6. Instrument and MaterialsThe instruments and the materials that are needed can be read as follows :Fiber Cloth SW 220B-90A S-Glass 5 m2Fiber Cloth EW SC100 E-Glass 5 m2Jean sheet 3 m2Mature Brown Coconut Fiber 1 kgChopped Strand Mat Coconut Fiber 5 m2 with the thickness 1 cmNaOH crystal 1 kgPolyester Resin 157 5 kgEpoxy Resin and Hardener each of them 1 kgCatalyst 100 ccDiluent EPD Z8 1 kgWorkshop pressure toolsBrushRollerbrushMica film plastic Abutai sheet 1 m2Zinc sheet 1 m2Armor vest (without panel)Mass scales with minimum scale 25 gramThree plywood layers with the thickness 2 mmScissorRuler Raffia string with the length 6 m3.7. The Ways of Making3.7.1. First Panel Design with Polyester ResinIn this panel design, polyester resin mixture is produced every layers are made because polyester resin mixture is hardening faster than the other thermosetting resin. The proportion of polyester resin and catalyst based by volume that meet 90 : 1. The coconut fiber in this panel design is in form of discontinue random-oriented fiber and chemically treated with NaOH crystal that dissolved into water. The thickness in this panel design is controlled to be not more than 1,2 cm.3.7.1.1. S-Glass Fiber Cloth ArrangementCutting 6 layer of s-glass fiber cloth with the width 24 cm x 24 cm.Spray motor kit to the zinc layer to avoid polyester resin stick to the zinc layer. Mixing polyester resin 77 cm3 with catalyst in certain proportion.Brushing polyester resin mixture to s-glass fiber cloth with brush.Pick one layer of s-glass fiber cloth and then, put it on the brushed s-glass fiber cloth.Repeating step 4 and 5 to get three separate composite layers. Each layer consist of two s-glass fiber cloth.Coconut Fiber Preparation and ArrangementBefore used as composite material of the panel, 1 kg of coconut fiber was soaked in the water that consist of 0,9% NaOH solution for 5 hours. Then, treated coconut fiber is dried in sunlight for 4 hours. The arrangement of treated coconut fiber as composite material can be seen below :Leveling polyester resin mixture in the backside of first composite s-glass fiber cloth with the certain proportion.Leveling coconut fiber in the backside of first composite s-glass fiber cloth.Pressing both of them with the workshop pressure tools for 3 minutes.Releasing the pressure tools. Then, leveling the polyester resin mixture in the backside of coconut fiber.Putting the second layer of composite s-glass fiber cloth in the backside of coconut fiber.Pressing again them for about 5 minutes.Repeating step 1 until 6 to get a panel that consist of three composites of s-glass fiber cloth layer and three composites of coconut fiber layer.Second Panel Design with Epoxy ResinIn this panel design, epoxy resin, together with hardener and thinner are used as the matrix material. S-glass fiber cloth layer quantity are increased into 32 layers that separated into two composite layers. The coconut fiber in this panel design is in form of chopped strand mat (continuos fibre-reinforced) and chemically untreated. The proportion of reinforcement with matrix based by weight is controlled to be maximum 5 : 6 and the proportion of epoxy resin, hardener, and thinner based by weight is controlled to be 9 : 9 : 2. Abutai sheet is used in the manufacture of this panel to decrease the proportion of matrix material to the reinforcement material.3.7.2.1. S-Glass Fiber Cloth ArrangementCutting 32 layers of s-glass fiber cloth with the width 15 cm x 15 cm.Put a layer of mica film in the top of the zinc layer.Mixing 54 gram of epoxy resin with hardener and thinner in certain proportion.Brushing epoxy mixture with brush to the top of mica film layer.Putting a layer of s-glass fiber cloth in the top of brushed mica film layer.Leveling a layer of s-glass fiber cloth layer with rollerbrush.Repeating the same way as step 4 until step 6 to the another layer of s-glass fiber cloth to get a composite layer which consist of 16 layers of s-glass fiber clothCutting 4 layers of abutai sheet with the width 15 cm x 15 cm.Putting 2 layers of abutai sheet in the top of a composite layer.Pressing the composite layer by workshop pressure tool for 4 hours.Repeating step 7 until 10 to get two composites layer which each layer consist of 16 s-glass fiber cloth layers.Coconut Fiber ArrangementIn this panel design, untreated coconut fiber is in form of chopped strand mat (continuos fibre-reinforced) with the thickness 1 cm that is supplied from Cilacap city. The proportion of chopped strand mat coconut fiber reinforcement to the epoxy resin matrix based by weight is controlled to be not more than 1 : 2. Epoxy resin matrix consist of hardener and thinner with the proportion based by weight 20 : 30 : 5. The coconut fiber arrangement can be seen below :Cutting 4 layers of chopped strand mat coconut fiber with the width 15 cm x 15 cm.Putting a layer of mica film in the top of zinc sheet.Mixing 35 gram of epoxy resin with the hardener and thinner in certain proportion.Brushing epoxy mixture with brush to the top of mica film layer.Putting a layer of chopped strand mat coconut fiber in the top of mica film layer.Brushing epoxy mixture with brush to the top of chopped strand mat coconut fiber.Putting an another layer of chopped strand mat coconut fiber to the top of first chopped strand mat coconut fiber.Brushing epoxy mixture to the top of second chopped strand mat coconut fiber and the surface area of composite s-glass fiber cloth layer.Putting s-glass fiber cloth layer in the top of second chopped strand mat coconut fiber.Repeating the same way as step 4 until step 9 to get a panel that consist of 32 layers of s-glass fiber cloth composite material and 4 layers of coconut fiber composite material.Pressing the panel for 38 hoursThird Panel Design with Epoxy ResinIn this panel design, epoxy resin, together with hardener and thinner are used as the matrix material. S-glass fiber cloth layer quantity are 28 layers that separated into two composite layers. 8 layers of jeans sheets are added as reinforcement composite material to reduce s-glass fiber cloth layer quantity and to decrease its total price. The coconut fiber in this panel design is in form of chopped strand mat (continuos fibre-reinforced) and chemically untreated. The proportion of reinforcement with matrix based by weight is controlled to be maximum 5 : 6 and the proportion of epoxy resin, hardener, and thinner based by weight is controlled to be 2 : 1 : 2. Abutai sheet is used in the manufacture of this panel to decrease the proportion of matrix material to the reinforcement material.3.7.3.1. S-Glass Fiber Cloth and Jeans Sheet ArrangementCutting 28 layers of s-glass fiber cloth and 8 layers of jeans sheet with the width 15 cm x 15 cm.Putting a layer of mica film in the top of zinc layer.Mixing 105,6 gram of epoxy resin with hardener and thinner in certain proportion.Brushing epoxy mixture with brush to the top of mica film layer.Putting a layer of s-glass fiber cloth in the top of brushed mica film layer.Leveling a layer of s-glass fiber cloth layer with rollerbrush.Repeating the same way as step 4 until 6 to get 3 layers of s-glass fiber cloth.Putting a layer of jean sheet in the top of s-glass fiber cloth composites.Leveling a layer of jean sheet with rollerbrush.Brushing epoxy mixture with brush to the top of jean sheet.Putting a layer of s-glass fiber cloth in the top of jean sheet.Leveling a layer of s-glass fiber cloth with rollerbrush.Repeating the same way until get two separated composite layers with each composite layer consist of 14 layers of s-glass fiber cloth and 4 layers of jean sheet.Cutting four layers of abutai sheet with the width 15 cm x 15 cm.Putting four layers of abutai sheet in the top of each separated composite layer. Each separated composite layer will be putted 2 layers of abutai sheetPressing both of two separated composite layers with the workshop pressure tool for 4 hours.Coconut Fiber ArrangementIn this panel design, untreated coconut fiber is in form of chopped strand mat (continuos fibre-reinforced) with the thickness 1 cm that is supplied from Cilacap city. The proportion of chopped strand mat coconut fiber reinforcement to the epoxy resin matrix based by weight is controlled to be not more than 1 : 2. Epoxy resin matrix consist of hardener and thinner with the proportion based by weight 20 : 30 : 5. The ways of arrangement is as same as coconut fiber arrangement in the second panel design.Fourth Panel Design with Epoxy ResinIn this panel design, epoxy resin, together with hardener and thinner are used as the matrix material. S-glass fiber cloth layer quantity are decreased to be only 16 layers that separated into two composite layers. 10 layers of jeans sheets and 10 layers of E-glass fiber cloth layers are added as reinforcement composite material to reduce s-glass fiber cloth layer quantity and to decrease its total price. The coconut fiber in this panel design is in form of chopped strand mat (continuos fibre-reinforced) and chemically untreated. The proportion of reinforcement with matrix based by weight is controlled to be maximum 5 : 6 and the proportion of epoxy resin, hardener, and thinner based by weight is controlled to be 2 : 1 : 1. Abutai sheet is used in the manufacture of this panel to decrease the proportion of matrix material to the reinforcement material.3.7.4.1.S-Glass, E-Glass Fiber Cloth, and Jeans Sheet ArrangementCutting 16 layers of s-glass fiber cloth, 10 layers of e-glass fiber cloth, and 10 layers of jeans sheets with the width 15 cm x 15 cm.Putting a layer of mica film in the top of zinc sheet.Mixing 150 gram of epoxy resin with hardener and thinner in certain proportion.Brushing epoxy mixture with brush to the top of mica film.Putting a layer of s-glass fiber cloth to the top of mica film.Leveling a layer of s-glass fiber cloth with rollerbrush.Repeating the same way as step 4 until 6 to the e-glass fiber cloth and jeans sheet with the repeating order to get two separated composite materials. Each composite material consist of 8 layers of s-glass fiber cloth, 5 layers of e-glass fiber cloth, and 5 layers of jeans sheet. The top of the panel consist of 3 layers of s-glass fiber cloth.Cutting 4 layers of abutai sheet with the width 15 cm x 15 cmPutting 2 layers of abutai sheet in the the top of each separated composite materials layer.Pressing both of two separated composte materials layer with the workshop pressure tool for 4 hours.Coconut Fiber ArrangementIn this panel design, untreated coconut fiber is in form of chopped strand mat (continuos fibre-reinforced) with the thickness 1 cm that is supplied from Cilacap city. The proportion of chopped strand mat coconut fiber reinforcement to the epoxy resin matrix based by weight is controlled to be not more than 1 : 2. Epoxy resin matrix consist of hardener and thinner with the proportion based by weight 20 : 30 : 5. The ways of coconut fiber arrangement is as same as coconut fiber arrangement in the second panel design.Reporting MethodsThis research uses qualitative reporting methodology to report stab test and quantitative reporting methodology to report the specification of panel specimen, production cost, price comparison, and ballistic test in form of table that can be seen below:The Specification of Panel SpecimenNumberObserved aspectInformation1.Width2.Mass3.ThicknessProduction CostThe production cost of the panel specimen is in width 27 cm x 27 cm and included all cost materials that are needed to produce stab-resistance and ballistic vest. MaterialQuantityCostS-Glass Fiber ClothE-Glass Fiber ClothJeans SheetPolyester Resin & CatalystEpoxy ResinHardenerThinnerCoconut FiberArmor vest (without panel)Total PricePrice ComparisonLevel ProtectionPanel SpecimenCost (Rp)First Panel DesignSecond Panel DesignThird Panel DesignFourth Panel DesignIIAPara-Aramid PanelBallistic TestPanel SpecimenPenetration Depth (mm)Backing Material Deformation (mm)First Panel DesignSecond Panel DesignThird Panel DesignFourth Panel DesignCHAPTER IVRESULT AND DISCUSSION Panel SpecimenThe First Panel SpecimenThe First Panel Specimen SpecificationThe specification of the first panel specimen layer design can be seen below :Table 4.1.The specification of the first panel specimen layer designNumberObserved aspectInformation1.Width27 cm x 27 cm2.Mass700 grams3.Thickness1,15 cmThe photo of the first panel specimen can be seen below :Photo 4.1. : The first panel specimenThe illustration layers of the first panel specimen can be seen below :Illustration 4.1. : First Panel Layers SpecimenDescription :2 layers of composite s-glass fiber posite of chemically treated coconut fiber in form of discontinuos random-oriented fiber.The First Panel Specimen Production CostThe first panel specimen production cost is given in form of table that can be seen below :Table 4.2.The production cost of first panel specimenMaterialQuantityCostS-Glass Fiber Cloth6 layers x 2Rp. 111.536,00E-Glass Fiber Cloth-Jeans Sheet-Polyester Resin & Catalyst(77 cm3 ; 0,85 cm3) x 2Rp. 5982,00 ; Rp.22,00Epoxy Resin-Hardener-Thinner-Coconut Fiber75 grams x 2Rp. 7.000,00Armor vest (without panel)1Rp. 90.000,00Total PriceRp. 124.630,00The Second Panel SpecimenThe Second Panel Specimen SpecificationThe specification of the second panel specimen layer design can be seen below :Table 4.3.The specification of the second panel specimenNumberObserved aspectInformation1.Width15 cm x 15 cm2.Mass450 gram3.Thickness1,35 cmThe photo of the second panel specimen can be seen below :Photo 4.2. : The second panel specimenThe illustration layers of the second panel specimen can be seen below :Illustration 4.2. : Second panel layer specimenDescription :1.a.16 layers of composite s-glass fiber cloth with the proportion of reinforcement with matrix is 2 : 3 with the thickness 3,75 mm.1.b.16 layers of composite s-glass fiber cloth with the proportion of reinforcement with matrix is 1 : 2 with the thickness 4, 89 mm.2.2 layers of composite untreated chopped strand mat coconut fiber with the thickness 2,4 mm.The second panel layer photo can be seen below :Photo 4.3. : The second panel layer photoThe Second Panel Specimen Production CostThe second panel specimen production cost is given in form of table that can be seen below :Table 4.4.The production cost of second panel specimenMaterialQuantityCostS-Glass Fiber Cloth32 layers x 2Rp. 594.864,00E-Glass Fiber Cloth-Jeans Sheet-Polyester Resin & Catalyst-Epoxy Resin288,36 grams x 2Rp. 43.254,00Hardener345,06 grams x 2Rp. 51.759,00Thinner67,23 grams x 2Rp. 20.437,92Coconut Fiber4 layers x 2Rp. 8748,00Armor vest (without panel)1Rp. 90.000,00Total PriceRp.809.062,92The Third Panel SpecimenThe Third Panel Specimen SpecificationThe specification of the third panel specimen layer design can be seen below :Table 4.5.The specification of the third panel specimenNumberObserved aspectInformation1.Width15 cm x 15 cm2.Mass500 gram3.Thickness1,74 cmThe photo of the third panel specimen can be seen below :Photo 4.4. : The third panel specimenThe illustration layers of the third panel specimen can be seen below :Illustration 4.3. : Third panel layer specimen Description :1.posite material consist of 14 layers of s-glass fiber cloth and 4 layers of jeans sheet with the the proportion of reinforcement with matrix is 127 : 73 with the thickness 6,00 mm.1.posite material consist of 14 layers of s-glass fiber cloth and 4 layers of jeans sheet with the proportion of reinforcement with matrix is 127 : 73 with the thickness 6,15 mm.2.2 layers of composite untreated chopped strand mat coconut fiber with the thickness 2,6 mm.The third panel layer photo can be seen below :Photo 4.5. : The third panel layer photoThe Third Panel Specimen Production CostThe third panel specimen production cost is given in form of table that can be seen below :Table 4.6.The production cost of third panel specimenMaterialQuantityCostS-Glass Fiber Cloth28 layers x 2Rp. 520.506,00E-Glass Fiber ClothJeans Sheet8 layers x 2Rp. 6318,00Polyester Resin & Catalyst-Epoxy Resin454,4424 grams x 2Rp. 68.166,36Hardener340,6212 grams x 2Rp. 51.093,18Thinner369,3924 grams x 2Rp. 112.295,29Coconut Fiber4 layers x 2Rp. 8748,00Armor vest (without panel)1Rp. 90.000,00Total PriceRp. 857.126,65The Fourth Panel SpecimenThe Fourth Panel Specimen SpecificationThe specification of the fourth panel specimen layer design can be seen below :Table 4.7.The specification of the fourth panel specimenNumberObserved aspectInformation1.Width15 cm x 15 cm2.Mass550 gram3.Thickness1,86 cmThe photo of the fourth panel specimen can be seen below :Photo 4.6. : The fourth panel specimenThe illustration layers of the fourth panel specimen can be seen below :Illustration 4.4. : Fourth panel layer specimenDescription :1.posite material consist of 8 layers of s-glass fiber cloth, 5 layers of e-glass fiber cloth, and 5 layers of jeans sheet with the proportion reinforcement with matrix is 5 : 3 with the thickness 5,70 mm.1.posite material consist of 8 layers of s-glass fiber cloth, 5 layers of e-glass fiber cloth, and 5 layers of jeans sheet with the proportion reinforcement with matrix is 5 : 3 with the thickness 5,95 mm.2.2 layers of composite untreated chopped strand mat coconut fiber with the thickness 3,45 mmThe fourth panel layer photo can be seen below :Photo 4.7. : The fourth panel layer photoThe Fourth Panel Specimen Production CostThe fourth panel specimen production cost is given in form of table that can be seen below :Table 4.8.The production cost of fourth panel specimenMaterialQuantityCostS-Glass Fiber Cloth16 layers x 2Rp. 297.432,00E-Glass Fiber Cloth10 layers x 2Rp. 64.881,00Jeans Sheet10 layers x 2Rp. 7898,00Polyester Resin & Catalyst-Epoxy Resin599,4 grams x 2 Rp. 89.910,00Hardener413,1 grams x 2Rp. 61.965,00Thinner271,35 grams x 2Rp. 82490,40Coconut Fiber4 layers x 2Rp. 8748,00Armor vest (without panel)1Rp. 90.000,00Total PriceRp. 703.324,40 Price Comparison between Stab-Ballistic Vest made from Coconut Fiber and Ballistic Vest made from Para-AramidThe table of price comparison between stab-ballistic panels made from coconut fiber and ballistic panels made from para-aramid can be seen below :Table 4.9Price Comparison between Stab-Ballistic Vest made from Coconut Fiber and Ballistic Vest made from Para-AramidLevel ProtectionPanel SpecimenCost (Rp)IIASecond Panel DesignRp. 809.062,92IIAThird Panel DesignRp. 857.126,65IIAFourth Panel DesignRp. 703.324,40IIAPara-Aramid PanelRp. 2.420.700,00Ballistic Test ResultBallistic tests are done with M1911 pistol chambered for 0.45 inch ACP for level IIA impact and Revolver Colt Police Positive Special chambered for 0.38 S&W Special for level I impact. The photos of the firearm that used to test the specimen can be seen below : Photo 4.8. : M1911 Pistol (left) and Revolver Colt Police Positive Special (right)The ballistic tests result are given in table that can be seen below :Table 4.10Ballistic Test Result with 0.38 S&W Special in 5 m and 1,5 m distancePanel SpecimenPenetration Depth (mm)Backing Material Deformation (mm)First Panel DesignComplete penetrationComplete penetrationSecond Panel DesignNo penetrationNo deformationTable 4.11Ballistic Test Result with 0.45 ACP in 5 m distancePanel SpecimenPenetration Depth (mm)Backing Material Deformation (mm)Second Panel DesignNo penetrationNo deformationThird Panel DesignNo penetrationNo deformationFourth Panel Design3 mmNo deformationStab Test ResultStab tests is done with Edged Blade bayonette by human power. The tests result show that second panel design resist sharp point impact until it penetrate 2 mm. The same behavior is also shown by the third panel design which resist sharp point impact until it penetrate 1 mm and the fourth panel design which resist sharp point impact until it penetrate 3 mm.DiscussionsBased on the ballistic tests and stab tests. There are some differences between stab-resistance and ballistic vest made from kevlar or para-aramid and stab-resistance and ballistic vest made from coconut fiber. Although stab-resistance and ballistic vest made from coconut fiber is less flexible and heavier than kevlar. It can be seen that this vest is cheaper and easier to be made. The ballistic tests show that second, third, and fourth panel specimen can resist level IIA bullet impact. Even, the second, third, and fourth panel specimen can bounce back the bullet impact. This result shows that this vest give no blunt trauma effect to the user which different from the kevlar that still give blunt trauma effect to the user.The hypotheses that researcher state as follows : (1) fiberglass cloth function is to absorb kinetic energy of the impact, either bullet or sharp point impact and change bullet shape to be wider area surface. So, the friction between stab-resistant and ballistic panel can be increased, (2) coconut fiber function is to distribute the kinetic energy of the impact, either bullet or sharp point impact, slowly decreases its velocity, and to reduce blunt trauma to the user, (3) stab-resistant and ballistic vest made from coconut fiber can resist level IIA bullet impact and level II sharp point impact. (4) stab-resistant and ballistic vest made from coconut fiber can be alternative protection vest that cheaper, semi-organic, and easier to be made than ballistic vest made from para-aramid synthetic are proven true based from the previous research as R&D cycle and this ballistic test. It can be seen that fiberglass composite material main function is to absorb kinetic energy and widen bullet surface area to increase the friction between bullet and panel specimen. The first research as R&D cycle with pump air gun tests also show that fiberglass composite material isn’t strong enough to resist air gun bullet impact without reinforced by coconut fiber. Therefore, coconut fiber main function is to distribute the kinetic energy to the user.CHAPTER VCONCLUSION AND SUGGESTIONS5.1. ConclusionsBased on the result above. It can be drawn some conclusions as follows :The second, third, and fourth panel specimen can resist level IIA bullet impact and level II sharp point impact with minimum thickness 1,35 cm and minimum mass 2,916 kg as expected research purposes.Although stab-resistant and ballistic vest made from coconut fiber is less flexible and heavier than stab-resistant and ballistic vest made from kevlar, it is cheaper, easier to be made, more organic, and give no blunt trauma effect to the user.The most effective performance of panel specimen reviewed from its weight, thickness, and protection is the second panel specimen which uses 32 layers of s-glass fiber cloth and 4 layers of chopped strand mat coconut fiber.The most efficient panel specimen reviewed from its production cost is the fourth panel specimen which uses 16 layers of s-glass fiber cloth, 10 layers of e-glass fiber cloth, 10 layers of jean sheets, and 4 layers of chopped strand mat coconut fiber. 5.2. SuggestionsIn the closing, researcher would like to give suggestions to the public and all parties so that the performance of stab-resistant and ballistic vest made from coconut fiber can be developed more. The suggestions are given as follow :Further research should be done to make the stab-resistant and ballistic panel made from coconut fiber be flexible and more comfortable.Further research should be done to reduce the proportion of reinforcement with matrix to increase the stab-resistant and ballistic vest made from coconut fiber toughness and to reduce its weight, cost, and thickness.Further research should be done to increase the protection of stab-resistant and ballistic panel made from coconut fiber for more powerful firearms bullet. Especially, assault rifle bullet with controlled weight not more than 8 kg.Further test should be done to know the endurance of stab-resistant and ballistic vest made from coconut fiber to resist level II and level IIIA bullet impact and level III sharp point impact in Spike class.REFERENCESAlaudin, M., (2007). Misteri di balik rompi anti-peluru. . Accessed on 20 April 2014Al-Hasani, Emad S., (2007). Study of Tensile Strength and Hardness Property of Epoxy Reinforced With Glass Fiber Layers 25 : 8Aziz, Mariad Emam. (2010). A Study on The Effect of Hardener on The Mechanical Properties of Epoxy Resin. M.Sc. Program. University of Technology. BaghdadBorneocom, Eko. (2013). Cara kerja Rompi Anti Peluru. . Accessed on 20 April 2014Cripps, David. (2014). Resin Types. . Accesed on 21 April 2014Cripps, David. (2014). Polyester Resins. guide/polyester-resins/8. Accessed on 22 April 2014Cripps, David. (2014). Vinylester Resins. . Accessed on 22 April 2014Davallo, M., H. Pasdar, M. Mohseni. (2010). Mechanical Properties of Unsaturated Polyester Resin. Chemistry Technology Journal 2 : 4 DuPont. (1971). Kevlar Techical Guide. DuPont. RichmondFauzi, Muhammad Iqbal, Aristo Kevin A. P. (2014). Rompi Balistik dari Sabut Kelapa. SMAN 3 Semarang. SemarangHalliday, David, Robert Resnick, Jearl Walker. (2005). Physics 7th extended edition. USA : John Wiley & SonsHarish, S., D. Peter Michael, A. Bensely, D. Mohan Lal, A. Rajadurai. (2009). Mechanical property evaluation of natural fiber coir composite. Volume 60 Page 44-49.Hartman, David, Mark E. Greenwood, David M. Miller. (2006). High Strength Glass Fibers. AGY. South CarolinaHindratmo, Astria. (2013). Inovasi Rompi Anti Peluru Untuk Militer dengan bahan Cair. Rompi Anti Peluru Untuk Militer dengan bahan Cair. Accesed on January 10th 2014Li, Xue, Lope G. Tabil, Satyanarayan Panigrahi. (2007). Chemical Treatments of Natural Fiber for Use in Natural Fiber-Reinforced Composites : A Review. Polymer Environment Journal 15 : 25 – 33Molenda, Michael. (2003). In Search of the Elusive ADDIE Model. Performance improvement. Number 42 Volume 5 Page 2. ., Yuhazri, Dan, M.M.P. (2008). High Impact Hybrid Composite Material For Ballistic Armor. Manufacturing Engineering Journal 2 : 1-9National Institute of Justice. (2000). Ballistic Resistance of Personal Body Armor – NIJ Standard – 0101.04. Office of Science and Technology. Washington D.C.National Institute of Justice. (2000). Stab Resistance of Personal Body Armor – NIJ Standard – 0115.00. Office of Science and Technology. Washington D.C.Wikipedia. (2014). Composite Material. . Accessed on 23 April 2014Wikipedia. (2014). Thermoplastic. . Accessed on 21 April 2014W.S.T, Arh Basuki. (2014). Jenis, Bahan, dan Cara Kerja Rompi Anti Peluru. . Accessed on 20 April 2014ATTACHMENT Materials that are usedPhoto 1 : E-glass fiber cloth (left) and S-glass fiber cloth (right)Photo 2 : Coconut FiberPhoto 3 : Polyester Resin & Catalyst (left) and Epoxy Resin & Hardener (right)Photo 4 : Epoxy Thinner Research ActivitiesPhoto 5 : Cutting Fiber Cloth (left) and measuring epoxy resin and hardener ratio (right)Photo 6 : Measuring thinner ratio (left) and preparing coconut fiber (right)Photo 7 : Pressing the panel with workshop pressure toolPhoto 8 : Testing the panel with Steyr LG-110 FT gas air gun ; bullet caliber 0.67 and 0.69 inch (left) and testing the panel with Revolver Colt Police Positive Special firearm ; bullet caliber 0.38 inch (right) Photo 9 : Testing the panel with Open Sport Gun ; bullet caliber 9 mm Full Metal Jacketed (FMJ)Stab-Resistant and Ballistic Specimen after TestPhoto 10 : Stab-resistant and ballistic vest made from coconut fiber second specimen.Photo 11 : Stab-resistant and ballistic vest made from coconut fiber third specimen.Photo 12 : Stab-resistant and ballistic vest made from coconut fiber fourth specimen. ................
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