Experimental and Numerical Evaluation of Tensile Strength of Horse Hair-Glass Fiber/Epoxy Hybrid Composites

Abstract

Natural fibers are environmentally friendly with less weight and energy conservation than the synthetic fibers. The present study assessed on mechanical properties of the hybrid composite which is composed of horsehair and glass fiber materials using experimental methods and Digimat simulation. The impact of weight percentage and orientation of fiber on mechanical properties such as tensile strength is investigated. The total weight of the fiber was 70% and the matrix was 30%. The specimen was prepared using the method of hand layup process. The weight percentage increment was 20% and the orientation of the fiber was 0–900 and 0–900. By doing Digimat simulation and testing the composite; it was rich that there is a basic effect of weight percentage and orientation in mechanical property of composite. With a different weight percentage of fiber, the maximum tensile strength was 282.97Mpa in the experiment result and 290 Mpa Digimat simulation result which is 56% of glass fiber plus 14% of horse hair fiber plus 30% of epoxy resin. Whereas the orientation of fiber 00 has the maximum tensile strength which is 127.2 Mpa in the experiment result and 150.12Mpa in the Digimat simulation result. The test outcomes are drawn and the conclusions were made to compare the result of horsehair/epoxy, glass fiber/epoxy and hybrid composite with software simulation. Further investigation is recommended to test with other animal hairs.

1. Introduction

The availability and distribution of horses and its hair in Ethiopia within the region have been written clearly. Ethiopia is endowed with abundant agricultural resources. The statistics show there are more than 2 million horse’s lives and it is about 33.5% of the African and 3.45% of the world horse population. The population of the horse in Ethiopia ranked the first in Africa and 8th in the world. According to the livestock census of Ethiopia, the distribution of horses in the Oromia region ranked the first and highest population of the horse is found. Around 1,176,301 horses which is 58% of the country has to live in this regime. The second-ranked region in horse population is the south nation and nationality which is 451,799 horses around 22.27% of the population of the country horse. The third one is the Amhara region, which is 396,231 around 19% of the horse population of the country. The other regions and the Tigray region contain 0.73% [1]. The horsehair is not sold in some regions, but in the Amhara region, the horsehair is sold. Commonly, the horse hair is bought from the market from the Amhara region particularly Engibara town in Awi zone.

Due to increasing the need for composite material, the development of natural fiber composite is a new topic in recent research and technology. For increasing environmental awareness, many researchers shift their research in natural fiber composite material. Natural fibers are a capability that replaces synthetic materials and their related products. Natural fibers are less weight and energy conservation applications compared with synthetic fibers. This is mainly due to their advantages compared to synthetic fibers, because of Low cost, low weight, abundant and renewable resources [2, 3, 4]. Due to this reason, this paper came up with a natural resource that is available in our environment.

As the horse hair is naturally gifted fiber and there is no extraction process, the present study focused on horsehair and glass fiber with epoxy resin hybrid composite materials mechanical properties to replace conventional material. Moreover, in this study, the mechanical properties such as the tensile strength of glass fiber and horsehair reinforced polymer hybrid composite material with different orientation and weight percentage of fiber was assessed.

2. Materials and methods

Materials used in this study include commercially available epoxy resin used as a matrix and the reinforcement materials used are commercially available horsehair/glass fiber Raw material suppliers from the market.

2.1 Description of the materials

2.1.1 Horsehair

The availability of horse hair in Ethiopia is written in the introduction part but the horse hair is bought from the market from the Amhara region Engibara town in the Awl zone. The horsehair fiber found in the animal horse. The specific strength and stiffness of horsehair have compared to those of copper wire with the same diameter [5].

2.1.2 E: Glass fiber

E–Glass fiber is one of the most important artificial classes of reinforcement material specially used in polymer composites. Glass fiber has a low thermal coefficient, low dielectric coefficient, and high electrical resistance. This property depends on additives and curing agents [6]. It is obtained from Dejen Aviation Industry which is located at the city Bishfotu in Oromia region.

2.1.3 Hardener

The hardener is used as a binder during the production. Araldite HY951 hardener is used in this study. It has low viscosity, cure at room temperature, good mechanical strength, and Good resistance to atmospheric and chemical degradation. The epoxy resin is obtained from Kadisco Paint Factory.

2.1.4 Remover

Wax is used to safely remove the prepared spacemen from the mold. The remover is available in the market. It is bought from the market.

2.1.5 Epoxy resin

One of the properties of epoxy resin has good additive properties. The additive property is along with its high mechanical strength, low shrinkage, chemically resistant high diffusion density, low viscous and better electric insulation capacity. It is easily reinforced with natural (horsehair) and E glass fibers. LY-501 type of epoxy is used in this study [7]. The epoxy resin is obtained from Kadisco Paint Factory which is found in Addis Ababa lafto sub city around wuha limit.

3. Procedures for preparation of laminate experimental spacemen

Each composite laminate was prepared from the mixture of Epoxy, horse hair fiber, and E-glass fibers. The horsehair used in this procedure is untreated and free from chemicals. Then an open mold of aluminum plate with a dimension of 300 × 300 mm was prepared and the prepared composite was cut for each test. Using the rule of mixtures, the various fiber weight proportions are calculated to achieve laminates with 0:100, 100:0, 80:20, 20:80, 60:40 and 40:60 ratios with former being the ratio of Fiber and the latter is horse hair. The horse hair and E- Glass fibers with the total weight of the composite fiber contained 70%. The composite material had six layers and the orientation of fiber was [0], [90], [0/90]. Laminates were composed of plates of different layer materials or layers of fiber-reinforced lamina prepared with the same matrix material.

After this the above process, horse hair and glass fiber were cut based on the length of the mold. Based on the calculation of weight proportion appropriate amount of horse hair fibers, glass fiber and epoxy resin are considered. Then the first layer was placed in the mold based on the calculated amount of fiber. Next epoxy resin LY501 and the hardener HY-951 were mixed with a ratio of 2:1 before preparing the first layered fibers and apply a mixture of epoxy resin and hardener on the first layer fiber. Unidirectional E-glass fiber had prepared into required mold size and positioned over other fibers. Again, the calculated amount of epoxy resin and hardener mixture was applied over E-glass fiber. The second layer is prepared with horse hair fibers placed over a prepared E glass fiber and again a mixture of epoxy resin and hardener was applied. The resin mixture was spread by hand layup method uniformly around the corners. After spreading resin mixture Deadweight was applied over the open mold to remove air. Then after some time, the laminate was removed from the open mold and put in suitable temperature for curing. Finally, the composite was dried for seven days and the specimen was prepared by cutting the plat with the required dimension of each test with a grinder [8].

3.1 Tensile test

According to American society of teeth manufacturing (ASTM–D 3039) standard tensile test on composite specimens where the young modulus of elasticity of glass fiber and horsehair hybrid reinforced polymer was done to observe the behavior of hybrid material under load. The test specimen in tensile testing or tension testing was a fundamental material science test in which a test specimen is subjected to uniaxial tension until specimen failure. The results of the test were commonly used to select a material for quality control and application.

They also used to predict how a material will react under other types of forces. The material properties such as ultimate tensile strength, maximum elongation and reduction in the area are measured in a tensile test. The properties like Young’s modulus and yield strength are also determined from these measurements. The aim of this photo is to show what type of testing machine i used (Figure 1).

Figure 1.

A universal testing machine for tensile test (photo taken by Mamaru Wutabachew, 2019).

3.2 Specimen size

The most commonly used specimens for American society of teeth manufacturing (ASTM 3039) were constant rectangular cross-Section 25 mm (1 in) wide, 250 mm (10 in) long and 4 mm thickness [9]. Optionally tabs were used to bonded the ends of the specimen to prevent gripping damage. For each test, a composite of three specimens were tested and the average value of each test was taken for analysis (Figure 2).

Figure 2.

Hybrid spacemen sample for tensile test (photo taken by Mamaru Wutabachew, 2019).

4. Result and dissection

4.1 Validation of software and experimental result

The Figures 3 and 4 shows the stress–strain diagram of hybrid composite with different weight percentage and hybrid composite with different orientation of fiber respectively. Both experimental and software results of the composite materials were plotted. As shown in each figure there was a deviation of result in experiment and software, but the variation of strain is nearly the same. In the graph of the software, the tensile strength is linearly increased throughout the strain. This is because the material property fill-in the software is a liner, elastic and isotropic property.

Figure 3.

The experimental and software result of hybrid composite with a weight percentage.

Figure 4.

Experimental and software result of composite with orientation.

But in the experiment, the graph was not linear, because the material property was a lot of losses like specimen preparation accuracy, temperature variation, testing machine adjustment; due to this reason the graph was sometimes liner other time, non-liner. The tensile strength of experimental and software results approaches each other when the load approaches maximum. Therefore, the maximum average tensile strength was taken for each composite material and the deviation of experimental and a software result was calculated. The result of each deviation (error) indicated in Table 1. The table is also showing the experimental and software result of the maximum tensile strength of 7 different composite materials.

No.	Tensile strength (Mpa)	Experimental	Software	Error
1	0-degree hybrid	127.2	150.12	0.1527
2	90-degree hybrid	4.833	9.565	0.2020
3	0–90-degree hybrid	89.5	111.33	0.1960
4	14% glass hybrids	48.87	49.758	0.0178
5	28% glass hybrids	93.7	102.95	0.0898
6	42% glass hybrids	151.733	181.41	0.1636
7	56% glass hybrids	282.97	290	0.0173

Table 1.

Seven different composite tensile strengths with experimental and software results.

The table shows that the deviation or error of the software and experimental result is calculated by the software result minus experimental result divided by software result.

4.2 Hybrid composite with a different weight percentage

Figure 3 shows the stress–strain diagram of glass fiber and horsehair fiber with epoxy resin hybrid composite. The result shows four different weight percentages of each fiber but it has the same orientation of fiber. Starting from the initial point to some amount of strain the stress–strain graph is far apart but, the load reaches to maximum the maximum tensile stress of the materials both experimental and software results approach each other. The graph shows that experimental and software deviation of the above Table 1.

4.3 Hybrid composite with orientation

The Figure 4 shows the stress–strain diagram of glass fiber and horsehair with epoxy resin hybrid composite with different orientation of fiber. The weight percentage of the fibers was equal. The result also shows the maximum tensile strength of experimental result approaches to the software result when the increase.

5. Conclusion

The investigation of glass fiber and horsehair fiber hybrid composite leads to the following conclusions. For tensile test; 70% glass fiber/epoxy composite has the average tensile strength is 220.8Mpa but, the hybridization of 56% glass fiber and 14%horse hair the tensile strength is 282.97Mpa which is enhancing the tensile strength approximately 21.97%. In the direction of fiber orientation 0⁰ has maximum tensile strength but for other direction the tensile strength is reduced. In hybridization of horse hair and glass fiber, incasing weight proportion of glass fiber and decreasing weight proportion of horse hair fiber enhancing the tensile strength of the composite.

Acknowledgments

The authors acknowledge the valuable suggestion ministry of education. The financial support is from Fedral Democratic Republic of Ethiopia, minister of education. The authors also thank our university Debre Darkos University who provided guides and advice for the research.