ARID ZONE JOURNAL OF ENGINEERING, TECHNOLOGY & ENVIRONMENT AZOJETE December 2022. Vol. 18(4):683-692 Published by the Faculty of Engineering, University of Maiduguri, Maiduguri, Nigeria. Print ISSN: 1596-2644, Electronic ISSN: 2545-5818 www.azojete.com.ng Corresponding author’s e-mail address: okpanachi.george@cstd.nasrda.gov.ng 683 ORIGINAL RESEARCH ARTICLE SIMULATION AND EXPERIMENTAL STUDY OF TENSILE STRENGTH OF UKAM FIBRE REINFORCED POLYESTER COMPOSITES USING ANSYS G. E. Okpanachi*, A. S. Hassan, El – M. A. Ahmed, S. U. Hussein and F. Alapa Centre for Satellite Technology Development, National Space Research and Development Agency, Abuja, Nigeria. *Corresponding author’s email address: okpanachi.george@cstd.nasrda.gov.ng 1.0 Introduction Over the past few decades, there has been a growing interest in the use of natural fibres in composite applications and the needs for Green environment has motivated researchers to seek for an eco-friendly alternative (Jeyasekaran, 2016; Nishieo et al., 2003; Aondona, 2017). These types of composites present many advantages compared to synthetic fibres, such as low tool wear, low density, cheaper cost, availability, and biodegradability (Zampaloni, 2007). Fibre reinforced composite materials have been increasingly used as structural members in many structures such as airplane, which in flight condition undergoes temperature as low as - 60°C or in acryogenic tank which may be exposed to temperature below -150°C (Ogakwu and Okpanachi, 2016). Composite materials have the potential of reducing costs in construction, operation and development while improving structural reliability and enhancing safety. Because of these unique specifications, they are widely used in high technology structural applications, such as aeronautic and aerospace (Nishiro et al., 2003). Cochlospermum planchonii known locally as Ukam fibres grow in savannah and forest savannah in West Africa. They are cellulose based natural fibres with good mechanical properties, low density, abundant and renewable (Aondona, 2017 and Olusegun et al., 2012). The people of the area where these plants are found use their fibres as sponge and also to ARTICLE INFORMATION ABSTRACT Polymers are commonly used in different applications even though it causes environmental problems. Natural fibre reinforced composites can be used as substitute for the synthetic fibre composites because of their biodegradable properties which will be a key to solving environmental problems although, the strength of natural fibres is not as high as glass fibres, their specific properties are comparable. The hand lay–up method of fabrication was employed in preparing the composite. This study investigates the tensile strength of the composite using experimental and numerical method. The test specimen of natural composite was fabricated using ASTM standard and the tensile strength of the composite determined using Hounsfield Tensometer. A 3D Finite Element (FE) model was created to simulate tensile strength in ANSYS 18. Alkali treated samples exhibited the highest increase in tensile strength at all fibre loadings. Modulus of elasticity (MOE) and percentage elongation also increased with increase in fibre loading for all treatments. The experimental values of tensile strength at 25 % were in agreement with the FEM tensile strength using ANSYS. © 2022 Faculty of Engineering, University of Maiduguri, Nigeria. All rights reserved. Submitted 21 April, 2022 Revised 14 June, 2022 Accepted 20 June, 2022 Keywords: ANSYS Composites Ukam Tensile strength Reinforcement finite element http://www.azojete.com.ng/ mailto:okpanachi.george@cstd.nasrda.gov.ng mailto:okpanachi.george@cstd.nasrda.gov.ng Arid Zone Journal of Engineering, Technology and Environment, December, 2022; Vol. 18(4):683-692 ISSN 1596-2644; e-ISSN 2545-5818; www.azojete.com.ng Corresponding author’s e-mail address: okpanachi.george@cstd.nasrda.gov.ng 684 reinforce clay with which they produced intricate earthen pots and silos (Ihom and Onah, 2016). Olusegun et al. (2012) evaluated the mechanical properties of ukam, banana, sisal, coconut, hemp and e-glass fibre reinforced laminates to assess the possibility of using them as new material in engineering applications. Samples were fabricated by the hand lay-up process (30:70 fibre and matrix ratio by weight) and the properties evaluated using the INSTRON material testing system. The mechanical properties were tested and showed that glass laminate has the maximum tensile strength of 63 MPa, bending strength of 0.5 MPa, compressive strength of 37.75 MPa and the impact strength of 17.82 J/m2. The ukam plant fibre laminate has the maximum tensile strength of 16.25 MPa and the impact strength of 9.8 J/m among the natural fibres.The mechanical properties such as tensile strength, flexural strength, impact strength and water absorption properties of ukam, sisal and banana fibres reinforced composites have been observed and found that there is the significant improvement in mechanical strength and reduction in water absorption rate while hybridizing the banana fibre with sisal fibre reinforced composites (Ihom and Onah, 2015). The ukam/glass fibre reinforced composites have good tensile property with minimum deflection when compared to the flax/glass composites (Aondona, 2017). Also the ukam fibres reinforced composites hold more flexural and impact strengths when compared to the flax/glass fibres reinforced polymer composites. Banana, hemp and glass fibre reinforced hybrid composites have been developed and the mechanical properties of these composites were evaluated (Olusegun et al., 2006). Velmurugan et al. (2015) carried out the analysis of tensile properties of palmyra fibre reinforced epoxy composite. The simulation according to Jeyasekaran et al. (2016) was carried out using FEA under different fibre volume fraction and fibre length and validated with the experimental result and found to have less error percentage. Ramakrishnan et al. (2010) investigated the mechanical properties of vinyl ester resin reinforced with different weight fractions of 17 selected natural fibres by mathematical modelling and ANSYS simulation. From the observations, it is evident that increase in fibre content significantly improves the mechanical properties. The theoretical and ANSYS results indicate that vinyl ester reinforced with the fibres abaca, hemp and banana shows better tensile strength properties. The highest tensile modulus values are obtained for the fibres ramie, abaca, and sisal incorporated in vinyl ester. Similarly, for toughness and impact strength applications, the fibres banana, sisal and cotton are found to be suitable reinforcement for vinyl ester resin. Venkateshwaran et al. (2010) suggested in construction, automobile and manufacturing industries, composites with natural fibres are highly expected because of its high tensile strength and modulus, as well as for its low density and low elongation. From the available literature, it has been found that, the quantitative analysis on the mechanical properties of these composites is still a valid problem, and hence, there is a need for carrying out such studies on composite materials. To take the advantage of ukam fibres, they have been reinforced with a polyester resin, so that an optimal and economical composite is obtained. Hence the objective of the present study is to investigate the tensile strength of the composite. The experimental results are compared with results obtained from finite element analysis (FEA) using ANSYS software. file:///C:/user/Downloads/azojete143/www.azojete.com.ng mailto:okpanachi.george@cstd.nasrda.gov.ng Okpanachi et al: Simulation and Experimental Study of Tensile Strength of Ukam Fibre Reinforced Polyester Composites using ANSYS. AZOJETE, 18(4):683-692. ISSN 1596-2644; e-ISSN 2545-5818, www.azojete.com.ng Corresponding author’s e-mail address: okpanachi.george@cstd.nasrda.gov.ng 685 2. Materials and Methods 2.1 Materials Some of the materials used in this study include; Cobalt Methyl Ethyl Ketone Peroxide (MEKP) Ukam Fibre Polyester resin Polyvinyl Alcohol (PVA) Potassium Permanganate (KMnO4) Acetic Acid Silane Solution Sodium Hydroxide The ukam fiber utilized is presented in Figure 1. Figure 1: Produced Ukam Fibres 2.2 Methods 2.2.1 Alkali treatment This treatment is carried out in order to produce the modified fibres for the composites and the treatment process involves the use of Sodium hydroxide solution in accordance with Liu et al., (2009). The Ukam fibres were then soaked in NaOH of 5 % concentration at room temperature for 24 hours. To remove any alkali solution sticking to the fibre surface the fibres were washed severally with water neutralized with dilute acetic acid and then washed again with water. 2.2.2 Silane treatment The treatment is carried out in order to produce modified fibres for the composites and the treatment process involves the use of Silane solution dissolved in water (Valadez – Gonzalex et al., 2008). The Ukam fibres were immersed in silane dissolved in a water-ethanol mixture for 3 hours. The Potential of Hydrogen of the solution was 9.0. This contains 60 % ethanol and 40 % water mixed well and allowed to stand for an hou 2.2.3 Potassium permanganate (KMnO4) treatment The treatment is carried out in order to produce modified fibres for the composites and the treatment process involves the use of 0.5 % of potassium permanganate dissolved in acetone was used in soaking the alkali treated fibres for half an hour after been thoroughly washed with water. Distilled water was used in soaking the permanganate fibre for ten minutes in order to catalyse the reaction. Furthermore, the fibres were sun dried after it was decanted http://www.azojete.com.ng/ mailto:okpanachi.george@cstd.nasrda.gov.ng Arid Zone Journal of Engineering, Technology and Environment, December, 2022; Vol. 18(4):683-692 ISSN 1596-2644; e-ISSN 2545-5818; www.azojete.com.ng Corresponding author’s e-mail address: okpanachi.george@cstd.nasrda.gov.ng 686 2.2.4 Acetylation The treatment is carried out in order to produce modified fibres for the composites and the treatment process involves the use of Ukam fibres been soaked in demineralized water for an hour, filtered and placed in a flask, containing acetylating solution (Bledzki et al., 2008). Acetylating solution is made of 250 ml toluene, 125 ml acetic anhydride and a small amount of catalyst per chloric acid (60 %). The process temperature of acetylation was 60oC and duration of 1 to 3 hour. After modification, the fibre was washed thoroughly with distilled water until acid free. The treated fibres were sun dried before the manufacturing of the composites. 2.2.5 Determination of Tensile strength Tensile strength test was conducted using Hounsfield (Monsanto) Tensometer (model No. S/N 8889) according to ASTM D 638 – 03 (Croccolo et al., 2013). The width and the thickness of the specimens were measured and recorded (360mm by 20mm by 5mm) From the test, elastic modulus, ultimate tensile strength and percentage elongation were determined. 2.3 Finite Element Modeling and Analysis Finite Element Analysis provide safe simulation of destructive load conditions and failure modes. A 3D FE model was created to simulate tensile in ANSYS 18. Solving the numerical simulation was conducted based on laboratory conditions used in a practical test for the tensile test where the shape and geometry of the sample process and the boundary conditions were taken into consideration. For performing this analysis the material property, Young’s modulus, Poisson’s ratio, density, boundary conditions and load conditions were applied similar to the experimental condition and these were obtained from the experimental results. Shell elements are typically used for structure where the thickness is negligible compared to its length and width. Nevertheless, a plate modeled with solid element would provide similar results. The disadvantage lies in the computation time. ANSYS provides large choices of elements (Desal and Abeljf, 1977). Two main aspects of the procedure are modeling the specimen, and calculating the stresses to failure. 2.3.1 Preprocessor steps The 3D model was created using the dimension of the specimens used in the experiment as shown in Figure 2 (D638 – 03, 2005). The model created is made up of the polyester resin and the fibres. The model of the composite is to discretize the model into small elements. The mesh of the model (SHELL 181) is created with 8-nodes and each node has (6 degrees of freedom) with element size of and using the free meshing type to mesh all the models as shown in Figure 3. 2.3.2 Solution processor The Analysis of the composite is conducted using ANSYS. The tensile load is applied as distributed load on the nodes at one end of the model the same as the load values in experimental test and with the model at the other end fixed. These steps are repeated for each model of tensile composition with fibre surface treatment (Hassan et al., 2013). file:///C:/user/Downloads/azojete143/www.azojete.com.ng mailto:okpanachi.george@cstd.nasrda.gov.ng Okpanachi et al: Simulation and Experimental Study of Tensile Strength of Ukam Fibre Reinforced Polyester Composites using ANSYS. AZOJETE, 18(4):683-692. ISSN 1596-2644; e-ISSN 2545-5818, www.azojete.com.ng Corresponding author’s e-mail address: okpanachi.george@cstd.nasrda.gov.ng 687 Figure 2: Geometry of tensile simulation specimen on ANSYS workbench Figure 3: Boundary condition and load applied for ANSYS work bench model 3. Results and Discussion The experimental tensile strength as presented in Figure 4 and Table 1 was observed to increase with increase in fibre loading for all the treatments. Fibres are normally stronger and stiffer than the matrix, therefore strength of composites are generally seen to increase with increased fibre loading (Olusegun et al., 2012). An exceptional increase in tensile strength was noticed in alkali treated samples at all fibre loading. This means that alkali treated samples exhibited the highest increase in tensile strength at all fibre loadings. This is because during alkaline treatment, hemicellulose and lignin are removed, the interfibrillar regions are likely to be less dense and less rigid, and that makes the fibrils moreable to rearrange themselves along the direction of tensile loading. Olusegun et al. (2012) was of the opinion that physical and chemical treatments improved the wettability of fibre and thus improve the interfacial strength leading to improvement in mechanical properties as the cellulose structure is totally modified. http://www.azojete.com.ng/ mailto:okpanachi.george@cstd.nasrda.gov.ng Arid Zone Journal of Engineering, Technology and Environment, December, 2022; Vol. 18(4):683-692 ISSN 1596-2644; e-ISSN 2545-5818; www.azojete.com.ng Corresponding author’s e-mail address: okpanachi.george@cstd.nasrda.gov.ng 688 Figure 4: Influence of Surface Treatment and Fibre Composition on Tensile Strength of Composites Table 1: Summary of tensile strength test results Summary Composition (%) UTS(δ) (MPa) % Elongation Modulus of Elasticity Alkali 5 181.95 12 1.5276 10 210.60 15 1.5531 15 326.35 20 1.7504 20 333.2 21 1.9578 25 326.9 23 2.7521 Silane 5 157.54 13 1.5046 10 171.24 15 1.9319 15 207.04 17 2.0808 20 213.83 17.9 1.4196 25 224.59 19 2.3668 Kmno4 5 135.23 7 1.4120 10 140.22 9.3 1.7703 15 135.13 7 1.5922 20 149.45 10 1.3238 25 223.22 18 1.906 Acetylation 5 143.17 8 1.2640 10 151.07 10 1.0543 15 158.97 11 1.2640 20 159.67 11 1.6852 25 172.81 15 1.7677 Untreated 5 126.86 5 1.0218 10 129.31 6 1.0364 15 133.83 6 1.1582 20 146.86 9 1.2061 25 163.22 14 1.7837 0 50 100 150 200 250 300 350 5 10 15 20 25 U lt im at e t e n si le s tr e n gt h M P a Fibre loading (wt%) ALKALI SILANE KMNO4 ACETYLATION UNTREATED file:///C:/user/Downloads/azojete143/www.azojete.com.ng mailto:okpanachi.george@cstd.nasrda.gov.ng Okpanachi et al: Simulation and Experimental Study of Tensile Strength of Ukam Fibre Reinforced Polyester Composites using ANSYS. AZOJETE, 18(4):683-692. ISSN 1596-2644; e-ISSN 2545-5818, www.azojete.com.ng Corresponding author’s e-mail address: okpanachi.george@cstd.nasrda.gov.ng 689 Figures 5 – 9 present the FE (ANSYS) simulation results for the composite to study the effect of fibre surface treatment and fibre loading on the tensile properties of composites at 25 % fibre loading for all the treatments. Colours were used to differentiate regions of stress concentration with red showing regions with the highest value of stress concentration. The highest levels of stress concentrations were observed to be at the sharp corners of the Von Mises sample. The predicted tensile strength values by FE model matched with the experimental values. This was also confirmed by the regression of the predicted and experimental tensile strength presented in Figure 10. However, there was high correlation between the predicted and experimental tensile strength with R2 value of 0.9994. Hence, the visual checking of predicted and experimental values confirms that the FE model was successful in predicting tensile strength. Moderate percentage error was observed between experimental and FEA. The slight difference in results between FEA and experimental analysis is due to true loading condition and method of composite fabrication compared with the experimental tensile test (Prasad et al., 2014). Figure. 5: Contour Plots Showing Regions of Stress Concentration for Untreated Fibres Figure. 6: Contour Plots Showing Regions of Stress Concentration for Acetylation Treated Fibres http://www.azojete.com.ng/ mailto:okpanachi.george@cstd.nasrda.gov.ng Arid Zone Journal of Engineering, Technology and Environment, December, 2022; Vol. 18(4):683-692 ISSN 1596-2644; e-ISSN 2545-5818; www.azojete.com.ng Corresponding author’s e-mail address: okpanachi.george@cstd.nasrda.gov.ng 690 Figure.7: Contour Plots Showing Regions of Stress Concentration for Alkali Treated Fibres Figure. 8: Contour Plots Showing Regions of Stress Concentration for KMnO4 Treated Fibres Figure. 9: Contour Plots Showing Regions of Stress Concentration for Silane Treated Fibres file:///C:/user/Downloads/azojete143/www.azojete.com.ng mailto:okpanachi.george@cstd.nasrda.gov.ng Okpanachi et al: Simulation and Experimental Study of Tensile Strength of Ukam Fibre Reinforced Polyester Composites using ANSYS. AZOJETE, 18(4):683-692. ISSN 1596-2644; e-ISSN 2545-5818, www.azojete.com.ng Corresponding author’s e-mail address: okpanachi.george@cstd.nasrda.gov.ng 691 Figure. 10: Correlation of Predicted with Experimental Tensile Strength using Finite Element Modelling 4. Conclusion Ukam fibre reinforced composites was prepared to experimentally investigate the tensile strength of the composites. A 3D FE model was created using the experimental data and ANSYS software to numerically investigate the tensile strength of the composites. Additionally, the experimental result was compared with numerical result which shows that Alkali treated samples exhibited the highest increase in tensile strength at all fibre loadings. Modulus of elasticity (MOE) and percentage elongation also increased with increase in fibre loading for all treatments. The experimental values of tensile strength at 25 % were in agreement with the FEM tensile strength using ANSYS. 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