A Review on Structural Investigation and Experimental Behavior of Kevlar Fiber

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A Review on Structural Investigation and Experimental Behavior of Kevlar Fiber

Dr. H. V. Vankudre


Vidyavardhinis College of Engineering and Technology, Vasai (West), Mumbai, India

Ms. Pooja B. Patil

Assistant Professor,

Annasaheb Dange College of Engineering & Technology, Ashta, Sangli, India

Mr. Suyash A. Jangam


Annasaheb Dange College of Engineering & Technology, Ashta, Sangli, India

Abstract – We all are well familiar with the different types of fiber reinforced composites and its applications. As a Kevlar fiber has its own unique properties that have significant application in various fields. To increase the fiber utilization for tremendous emerging application needs the detail study of structural and behavioral pattern. This paper gives a detail review of structural and experimental behavior of Kevlar fiber.

Keywords Kevlar fiber, structural study, experimental view


    The compounds are used in a variety of applications where structural integrity and mechanical properties should be maintained in the face of adverse conditions such as pipes and tanks.[1]

    Composites powered by carbon, glass and annular fibers are often used in aircraft structures, building structures, wind turbines and sports equipment. Hardness. However, due to its breakage and generally an easy-to-break matrix, it is more susceptible to impact damage and is a glass fiber- reinforced composite (GFC) and Kevlar reinforced composite (KRC) has less impact resistance. The combination of two closely integrated fibers, such as Kevlar and CFRP, continuously improves capacity and impact resistance. Weight loss, impact resistance. Fatigue contributes to about 55% of aircraft structure failures. [2]

    Fiber-reinforced polymer alloys have received great attention due to their high specific strength and toughness and are used as a kind of high performance material in the aerospace, marine and automotive industries. In order to improve the delineation hardness of composite laminates, attempts have been made to break down matrix resin from rubber particles, metal fibers and various powders.[3]

    The results showed that Kevlar has good tensile strength and therefore it can be a good alternative to conventional materials for many applications in the mechanical engineering industry. Kevlar is a Paris Armide synthetic fiber that has good tensile modules, a high strength to weight ratio and a high energy absorption capacity. It also has good ballistic impact resistance, especially designed for defense applications. Kevlar composites were experimentally subjected to ballistic impact tests and improved sequences were shown on multi-structured multi-layer fabrics. Kevlar

    fiber as reinforcement and polycarbonate (PC) and acrylonitrile-butadiene-styrene (ABS) as a matrix [5].

    Kevlar is the most used material for physical protection because it has more effect than synthetic fibers such as carbon, glass, etc. Shock waves caused by ballistic effect can cause severe wear and tear to the wearer. Different researchers have demonstrated the ballistic performance of natural fibers based polymer compounds. (Crova, Malwa, Mallow, Kenaf, Bagsy, Rami and Bamboo). Research has focused on the effect of editing epoxy matrix with different weights. Ballistic performance of composites was enhanced by graphene nanoplates (GnPs) with Kevlar / cocas nucifera shells [7].

    A matrix of fiber-linked composites (FRCs) glues the fibers together and, in turn, transmits the force to the fibers, which provide greater strength and flexibility. Due to its high strength, low viscosity and low volatility, epoxy is the most popular thermosetting polymer available and shrinking rates compared to other thermosetting polymers. [9] Vacuum auxiliary resin transfer molding process is a preferable process for less insecure and flawless fiber pieces. Fiber volume and stacking order are important parameters that should be considered for obtaining better composite materials with superior mechanical properties. The proposed work focuses on the manufacture of covalent and EGlass-reinforced epoxy matrix composites to maximize the hybrid structure of different volume ratios and impact and bending behavior through vacuum assisted resin transfer molding. The author's inclusion of Kevlar fibers in the phenolic resin reduced the friction ability. The reason is that glass fiber composites have weaker compression than other fiber-reinforced resins, but can also be

    attributed to the resin matrix.

  2. MATERIAL AND MANUFACTURING PROCESS Two four-layer laminates were fabricated using hybrid

    fabric with e-glass and Kevlar 49 fibers and orthophilic unsaturated thermosetting polyester resin, which is Novapole- 120 (Fig. 1 (a)). The two pieces use different methods of hybridization of more reinforced fabrics, as shown in Figure 1

    (b) and (c). The hybrid fabric in Fig. 1 (b) is a hybrid-stranded two-dimensional textile, that is, each of the standalone E- fibers comprising of fibers and Kevlar 49 fibers, in both

    directions (weft and warp), obtained from the Tax Lugs Company. And is commercially known as the KV-650.

    Figure.1 : Hybrid of Kevlar 49 and E-glass Fiber

    The hand-up process was used to obtain the fragments and 1% methyl ethyl Ketone peroxide (MEKP) as the catalyst of the matrix while the composite fragments were fixed at ambient temperature[1].The interlaced fabrics were provided in a roll in which the carbon fibers are attached in the direction of the dislocation and the annular fibers act as weights (fig. 1). The unit cell represents the smallest recombination pattern of a fiber cloth, the average area of the unit cell used in hybrid fiber cloth, which is 15.75 mm.

    Figure. 2 : Woven carbon-Kevlar cloth

    The annular fibers were first cut into approximately 3 mm long sections and the amount of cut fibers was measured by weight at a surface density of 10 g / mA. Within a tolerance of 0.001 grams. The final fiber / composite volume ratio for the laminate was 63%. Finally, the sliced annular fibers were stained with mixed resin and coated uniformly in the center plane of the fragment, as shown in Fig. 2.

    Figure. 3 : Sandwich Structure of kevlar and carbon fiber

    Fig. The sandwich structure is adopted, with carbon fiber prepreg sheet at the top and bottom, and Kevlar-fiber layer in the middle. [3]

    1. fiber architecture has a very tight set of cannon and weight fibers, one of the possible ways Z-fibers can perform in the process of making. This path is shown in yellow and connects all layers through thickness. However, there are several different pathways that can be created that create different types of architecture, such as two binding fibers or, depending on the desired volume fraction of each second layer, is tied through the binding yarn.

      Figure. 4 : Z fiber path

      Figure shows the yellow color path represents the course that the Z-fiber follows during the weaving process. Here are some details about the Z Fiber Path. After that it was performed they were infected with SC15 polymer matrix materials using a VRTM method. The material properties of each component are given in Table 1 for reference. Each component is given in Table 1 for reference.

      Fiber Structu re

      Material Properties































      Table1 : Material Properties of each component

      1. (b)

    Figure. 4.1 : Orientation of Z-fiber

    Figure. 4.2 : Orientation of Z-fiber

    The Z-fiber for these samples is glass just shown as Kevlar to differentiate it from the rest of the glass fiber tow bundles , thin unsymmetrical [4].

    The figure 5 (a) shows the fiber in unprocessed manner and figure 5 (b) shows the fiber in woven roving mat chopped in either direction.

    (a) (b)

    Figure. 5: (a) Unprocessed Kevlar fiber, (b) Woven Kevlar fiber, Epoxy LY 556 and Resin HY951 are used

    There are different types of Kevlar with its own unique set of properties and performance characteristics such as Kevlar 29, 49, 100, 119, 129, 149 etc.Table.2 depicts the properties of different types of Kevlar fibers.

    Yarn properti es

    Kevl ar 29

    Kevl ar 49

    Kevl ar 100

    Kevl ar 119

    Kevl ar 129

    Kevl ar 149

    Twar on

    Tensile strengt h (GPa)









    Elastic modulu s (GPa)








    Elongat ion (%)








    Density (g/cc)








    Table 2: Properties of different types of Kevlar.

    Kevlar is a polymer; this means that it is made up of a large number of the same basic unit, called a monomer, which are attached to each other to form a long chain. Kevlar fiber showing in below diagram.

    Figure. 6 : Structure of Kevlar polymer

    The aramid fabric used in this study is Kevlar 29. The density and the thickness of Kevlar 29 fabric are 1.44 g/cm3 and 0.33 mm, respectively . A thermoset liquid epoxy resin (D.E.R.331) with joint amine type (905-3S) curing agent was used as the matrix.

    Figure.7: Plain two-dimensional Kevlar fabric.

    Kevlar has a unique combination of high strength, high modulus, toughness and thermal stability. It was developed to meet the demands of industrial and modern technology applications. Many types of annular caviar are currently manufactured to meet widespread end-use. Kevlar is a chemical fiber, an organic fiber from a family of fragrant polyamides. Molecular formula: C14H14N2O4. Density 1.44, breaking power -328, braking-2920 MPa. Tensile Modules 70500 MPa Interval length 3.6% .

    (a) (b)

    Figure.8: (a) Kevlar fiber 29 (woven), (b) Kevlar fiber 29 (Foam)

    Egg shells are bio-waste and readily available from the food industry as waste, which have high compressive strength and good binding properties that we use. So we chose this material to make the patterns. Here are two samples in which eggs are not treated and treated.

    (a) (b)


    Figure.9: (a) Before Chemical process Egg shell, (b) After Chemical process Egg Shell, (c) Fabrication of Kevlar fiber

    (a) (b)

    (c) (d)

    (e) (f)

    Figure.10: (a) Sample 1, (b) Layer arrangement Sample 1,

    (c) Sample 2, (d) Layer arrangement Sample 2,

    1. Sample 3, (b) Layer arrangement Sample 3

      Epoxy resins are the most commonly used resins. Epoxy LY 556 resin, chemically belonging to the epoxide family is used as the matrix material. The low temperature curing epoxy resin (Araldite LY 556) and the corresponding hardener (HY 951) are mixed in a ratio of 3:1 by weight as recommended.

      Figure.11: Reinforced fibers chopped carbon and short Kevlar fiber used for epoxy composite system

      Figure.12: CKS-220 Carbon/Kevlar Hybrid Fabric

      The specimens identifications, associated with this hybrid composite laminate, are described below and used to better understand the comparative analyses between their mechanical properties:

      • CLCO – CL specimens with carbon fibers in the direction of the applied load and in the original condition (without hole);

      • CLKO – CL specimens with Kevlar fibers in the direction of the applied load and in the original condition (without hole);

      • CLCH – CL specimens with carbon fibers in the direction of the applied load and with a circular hole;

      • CLKH – CL specimens with Kevlar fibers in the direction of the applied load and with a circular hole.


The Author taking at three different fiber directions, They are 0 , 45 and 90 below Figure [1].

Figure 13: Carbon-Kevlar hybrid composite cut at three different fiber directions

Fiber direction s[ °]

Tensile strength[M Pa]

Tensile Modulus[G Pa]

Elongati on at break (mm)

Poisson s Ratio


554 ± 26.9

54.95 ± 1.67

6.31 ± 0.1



110.5 ± 3.81

6.35 ± 0.13

61.42 ± 1.4



23.67 ± 1.2

11.05 ± 0.9


Table. 3: Result of Tensile test

  1. (b)

    Figure 14: (a) Stress-strain curves of the hybrid Composite at different fiber directions (b) Load Displacement curve of hybrid composite cut at 0°and 90°fiber

    Figure 15: Loaddisplacement curves of Hybrid composite cut 45 ° grain direction

    The effective modules of different architectures can be seen in Table 3. It should be noted here that the proportions of proportional samples are due to different levels of strain insulation (carbon side vs. glass side) hybridization and error inequality, which leads to bending.

    The average curves obtained in the unconnected tensile tests, which are the original condition for the test samples, are the disciplinary tests. (0/90) and GLO (± 45) of Fig.16. The stresses are shown in the diagram. For the GLO (0/90) test samples, the behavior between the tension and the length of the pieces was linear, but for the GLO (±. 45).

    Figure. 16: Stress-strain diagram (average curves) GL laminate (original condition)

    With respect to the average curve profiles obtained in the uniaxial tensile tests for test specimens with a central hole,

    GLH (0/90) and GLH (±45) exhibited similar behavior to that of test specimens in the original condition.

    Figure. 17: Stress-strain diagram (average curves) GL laminate (central hole condition)

    The tensile test of composites was conducted by universal testing machine at specified load and cross head speed, range. Image showing tensile test conducted Kevlar hybrid composite specimen on Universal Testing Machine Before and after tension on specimen.

    1. (b)

Figure. 18: (a) Tensile test setup specimen on UTM before testing (b) Tensile test setup specimen on UTM after testing

Sr. No

Specim en Name

Sequence s of Layer Arrange ment

Tensil e modul us (GPa)

Tensi le streng th (GPa)

Force (KN)

Thick ness (mm)


T1(SK C)

(K + C1

+ C2 + K)






T2 (SKE)

(K + E1

+ E2 + K)







(K + E1

+ C2 + E2 + k)





Table. 4: Tensile behaviors of Kevlar hybrid composite

  1. (b)

    (c) (d)

    Figure. 19: (a) Tensile strength of Kevlar hybrid composite

  2. Tensile strength of Sample 1 (c) Tensile strength of Sample 2

(d) Tensile strength of Sample 3


A detailed review on orientation pattern, mechanical properties, experimental behavior, have been carried out by the different researcher is reported in this paper. Kevlar has a good strength, toughness and better thermal behavior compared with other fiber. The different orientation of the Kevlar fiber leads to give the considerable changes in the behavior. Tensile testing of Kevlar for different orientation gives the significant change in the tensile strength.


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