Description:Field of Invention
The present invention pertains to the development of 2D plain-woven pattern kevlar composite reinforced with polyester resin with better tensile strength and flexural strength.
Background of the Invention
Composites are primarily used in structural engineering for the construction of bridges, aircraft structures, and automotive structures, among other things. The strength-to-weight ratio is higher when compared to reinforced concrete and steel, KFRP (Kevlar Fibre Reinforced Polymer) is better suited to handle peak loads than other composites. Kevlar fibre is a type of synthetic fibre that belongs to the Aramid family. It is widely used as a replacement for alloys and composites in all material manufacturing processes. Researchers all over the world are working on advanced materials for improving the mechanical properties of high-performance fibers.
CN114163775A the invention provides a composite material with a composite reinforcement structure that uses epoxy resin as a matrix and Kevlar fibre as a composite reinforcement raw material. The composite reinforcement also uses multilayer and plain weave units as proportioning units. The plain weave is a fundamental weave unit of a corner interlocking weave in the woven weave structure, and the multilayer weave is a plain weave structure in a two-dimensional woven weave. The laminated composite material has excellent tensile resistance and higher integrity than the multilayer fabric reinforced composite material, but because of the interlayer strength of the laminated composite material's lower interlayer strength, the delamination phenomenon is more likely to occur. The multilayer fabric composite material not only has the benefits of high specific stiffness, high specific strength, fatigue resistance, and similar properties of the laminated composite material, but also can overcome the flaw of low interlayer strength of the laminated composite material and can improve the interlayer performance and damage tolerance of the composite material. The fabric can be woven or modified on a common loom, has a high rate of production, and is also sustainable.
US5168006A, A woven fabric for a fiber-reinforced thermoplastic resin laminate that has warps and wefts, each of which has at least one separate thermoplastic resin yarn and at least one separate high-modulus reinforcing yarn, both of which are arranged alternately, and the reinforcing yarns of the warps and wefts, which by themselves make up a weave. Any yarn with a melting point higher than that of the thermoplastic resin fibre yarns, such as, for instance, glass fibres, carbon fibres, aramid fibres, alumina fibres, and metallic fibres, may be utilized as the reinforcing yarns for the woven fabrics of the present invention.
JP4506189B2, In recent years, a prepreg suitable for lightweight design has been demanded in particular due to further weight reduction requirements of fiber reinforced composite materials. High-modulus carbon fibers are used as the reinforcing fibers and the fiber content in the prepreg tends to be increased. is there. However, when a high elastic modulus carbon fiber is used as the reinforcing fiber, the drapeability of the prepreg tends to be lowered. When the reinforcing fiber content is increased, the tackiness is lowered and the handling property is sacrificed. Therefore, in order to improve handling, a method of combining a liquid epoxy resin having a specific viscosity range, an epoxy resin having a softening point in a specific range, and a thermoplastic resin having a specific weight average molecular weight has been proposed.
US4536438A invention relates to fibre reinforced composites suitable for aerospace applications. Fibre reinforced composites are being used in aerospace applications because of the high strength to weight ratio of such materials compared to materials conventionally used. Use of such composites in aircraft allows more efficient use of fuel and improved radius of operation or increased payload capability. In addition such composites allow cost reductions to be made due to the ability to mould complex structures in one operation and the need for fewer labour intensive joining processes. According to the invention a fibre reinforced composite includes one or more layers of unidirectional non-woven fibres alternated with one or more layers of woven fibres, embedded in a plastics matrix.The fibres of the woven and non-woven layers may be any known fibres used in fibre reinforced composites, including carbon fibres and Kevlar and the fibres of the woven fabric may be the same as those of the non-woven layers or they may be different.
US7825045B1, the invention is directed to a material such as fabric materials comprising high strength, high modulus polymeric fibers or yarns impregnated with a fluid, composed of particles suspended in a solvent, which undergoes a shear-thickening transition such that the coefficient of friction between the fibers or yarns is increased during an impact event. If the article has a plurality of layers, then each layer containing a material, preferably a ballistic material can be comprised of the same or different materials. In other words it is possible to have a plurality of layers, such as a twenty-eight layer article that contains different layers of different materials that dissipate the kinetic energy or are stab resistant or puncture resistant. For example, some of the layers can use a Kevlar® impregnated with STF, while other layers can use a different ballistic or puncture resistant material such as nylon fibers impregnated with STF and other layers can be non-impregnated Kevlar®. The outer layers closest to the body or the object being protected, do not have to be impregnated with STF. The layers impregnated with STF are preferably integrated into the article and are not just the exterior layer closest to the object or body being protected.
GB2276933A, have been proposed in the past for use in ballistic protection. A commonly used composite comprises a laminated structure consisting of woven or knitted glass fibre structures embedded in various types of polymer matrices such as, for example, epoxy resin, polyester resin and phenolic resin. In the main, prior known composites have comprised a single type of glass fibre as the reinforcement embedded in one or more polymer matrices. According to one aspect of the invention there is provided a rigid ballistic armor composite which comprises fibre reinforcement in a polymer matrix, the composite including (a) adjacent the strike face, a layer containing aromatic polyamide fibres in a matrix of a first polymer and, laminated thereto, (b) adjacent the back face, a layer containing magnesium aluminosilicate glass fibres in a matrix of a second polymer. The composites of the invention are asymmetric composites. The invention further provides a method of making a rigid ballistic armor composite including the steps of: (1) providing a first prepreg which consists of a ply of aromatic polyamide fibres impregnated with a first polymer; (2) stacking a plurality of the first prepregs to form a stacked facing layer; (3) subjecting the stacked facing layer to heat and pressure thereby forming a facing laminate; (4) providing a second prepreg which consists of a ply of magnesium aluminosilicate glass fibres impregnated with a second polymer; (5) stacking a plurality of the second prepregs to form a stacked backing layer; (6) subjecting the stacked backing layer to heat and pressure thereby forming a backing laminate; and (7) adhering the facing laminate to the backing laminate by means of an adhesive thereby forming the rigid ballistic armor composite.
US20080044659A1 the present invention resides in one aspect in a method for making a composite laminate. The method comprises providing at least a first composite ply and a second composite ply, each of said first and second composite plies comprising longitudinally oriented fibers in a thermoplastic matrix. The second composite ply is disposed on, and in transverse relation to the first composite ply, and the plies are bonded together. According to yet another aspect, the present invention provides a composite laminate. The composite laminate comprises a plurality of composite plies including at least a first composite ply and a second composite ply, each comprising a plurality of longitudinally oriented fibers in a thermoplastic matrix. The plurality of composite plies are bonded together and wherein the first composite ply is disposed with the fibers therein oriented in transverse relation to the fibers in the second composite ply. In a particular embodiment, the fibers in the first composite ply are different from the fibers in the second composite ply. Preferably, the fibers in the first composite ply are disposed at about 90° relative to the fibers in the second composite ply.
Summary of the Invention
An attempt is made to investigate the mechanical properties of Kevlar composite by performing various mechanical test on UTM (tensile test and flexural test) and the evaluation of maximum tensile strength and flexural bending strength, deflection and other parameters etc. and comparative study on failure behavior of sample laminates on the post tensile test and flexural test.
The sample composite laminates were designed and fabricated using compression molding process at room temperature and material cutting process was performed by using waterjet machining to achieve the accurate shape and size of the composite and also it reduces the manufacturing defects and provides the better bonding properties. The results, in which it improves structural stability of composite with increase the mechanical properties of tensile strength and flexural strength of the Kevlar composite.
Brief Description of Drawings
The invention will be described in detail with reference to the exemplary embodiments shown in the figures wherein:
Figure 1 Fabrication of kevlar composite structure.
Figure 2 Kevlar composite laminates.
Detailed Description of the Invention
The suspended type waterjet machine is preferred because of its better finishing then the entrained type as water and abrasive are added at same interval the material removing was perfectly done and water it’s used as coolant. In this abrasive waterjet machining the injection technology is used which you can see in below figure.
According to ASTM D3039, the tensile testing standard used for polymer composites in which the force required to break the polymer under the action of tensile load applied by UTM is evaluated. A strain gauge can be used to measure the elongation, and this will assist in plotting the stress–strain diagram to find the tensile modulus. The test specimen should have a cross section of 25 mm width and 250 mm length of dimensions was prepared. ASTM D7264 standard features a bending test to determine the flexural properties of polymer matrix composites with a rectangular cross section. Under this standard, the test can be conducted on a three-point or four-point loading system. A three-point loading system is simply a supported beam acted upon by a central load.
This test can provide data such as maximum flexural stress, flexural strength and maximum strain. The maximum span-to-thickness ratio is specified for this test as 32:1. A specimen with a 130.56X13 mm cross section was tested on a three-point system to identify the damage propagation of a Tin-Kevlar/polyester specimen.
By performing tensile and flexural tests on the composite material, we were able to determine that specimen-2 of woven Kevlar fibre had the highest tensile strength, which was found to be 200.706 MPa for the Ultimate Load of 17.060 kN. When compared to specimen 4, the displacement of 11.340 mm is the smallest possible, and the elastic modulus E is 4.4247 GPa. the maximum load When the test was completed, we saw that the laminate was substantially stronger since the matrix (polyester) had increased the fiber's must-effective property, and that just one layer had really broken. For the ultimate load of 0.122 kN, specimen-3 of braided Kevlar fibre was determined to have a maximum flexural strength of 132.488 MPa. The specimen of woven Kevlar fibre has a maximum deflection of 20.0 mm, a minimum flexural strength of 85.248 MPa, an ultimate load of 0.0785 kN, and a minimum deflection of 11 mm in comparison to specimen 3. For an ultimate load of 0.11 kN, specimen 2's flexural strength is 119.457 MPa, and its deflection is nearly identical to that of specimen 3's. Flexural test findings suggest that specimen 3 is the strongest of all the specimens, which helps us understand how well the matrix (polyester) and Kevlar fibre combination was done as demonstrated. Although the laminate was partially fractured, it was being bent; the maximum bending was at the centre. We already know that because composite is stronger in the longitudinal direction rather than parallel to the axis, the ultimate load will be lower for composite in flexural tests. According to the results of both studies, Kevlar and polyester work well together for aircraft structural applications. The woven Kevlar fibre specimen-4 minimum tensile strength was found to be 59.176 MPa for an ultimate load of 5.030 kN, whereas specimen-2,the maximum displacement was 18.270 mm and its minimum elasticity modulus was 1.3045 GPa. Tensile test findings that were obtained.
Kevlar is an example of aramid fibre. It is woven into textile materials and is extremely strong and lightweight, with corrosion and heat resistance. It is used in a wide range of applications, including aerospace engineering (such as aircraft bodies), body armor, bulletproof vests, car brakes, and boats. Kevlar® fibre is more than a collection of threads. DuPont TM Kevlar® fibres are used to make clothing, accessories, and equipment safer and more durable. It's the go-to fibre for protective apparel and accessories, with five times the strength of steel based on equal weight. Kevlar® fibre and filament are available in a variety of forms, each with its own set of properties and performance characteristics tailored to specific protection requirements.

Kevlar is available in three grades: Kevlar 29, Kevlar 49, and Kevlar 149. The table below depicts the differences in material properties between the various grades. It is most likely the Kevlar 49 version, which is widely available. The three versions are compared Tensile Modulus of Kevlar 29 = 83 G Pa, Tensile Strength = 3.6 GPA, Elongation = 4.0 percent Tensile Modulus of Kevlar 49 = 131 G Pa, Tensile Strength = 4.0 G Pa, Elongation = 2.8 percent Kevlar 149 has a tensile modulus of 186 G Pa, a tensile strength of 3.4 G Pa, and an elongation of 2.0 percent

3 Claims & 2 Figures , Claims:The scope of the invention is defined by the following claims:

Claim:
1. A 2d plain-woven pattern kevlar composite reinforced with polyester resin fabrication process comprising:
a) The compression molding is used for molding material, generally preheated with room temperature, is first placed in an open, heated mold cavity the mold is closed with top force or plug member, the pressure applied to force the material into contact with all mold areas, while heat and pressure are maintained until the molding material has cured.
b) The polyester resin is applied between the Kevlar fibre layers for better bonding. After adding the polyester resin material is placed in the compression molding at 25°C.
2. As mentioned in claim 1, tensile test is carried out to determine the force required to break the composite specimen and extension at the breaking force. This data helps to determine the yield strength and the modulus of elasticity of the test specimen.
3. According to claim 1, Flexural test is carried out to determine the maximum deflection of the specimen at the breaking force.