EXPERIMENTAL EVALUATION OF TENSILE STRENGTH OF GFRP LAMINATES WITH SILICA AND STUDY ON THEIR DRILLING BEHAVIOUR

Transcription

1 International Journal of Mechanical Engineering and Technology (IJMET) Volume 9, Issue 12, December 2018, pp , Article ID: IJMET_09_12_112 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed EXPERIMENTAL EVALUATION OF TENSILE STRENGTH OF GFRP LAMINATES WITH SILICA AND STUDY ON THEIR DRILLING BEHAVIOUR R.Raja, Sabitha Jannet* and Rajesh Ruban S Assistant Professor, Mechanical Department, Karunya University, Coimbatore, India *Corresponding author ABSTRACT Fiber Reinforced Polymer (FRP) composite materials are finding increased applications in a variety of engineering fields such as automotive, aeronautical, etc. and subsequently, the accurate machining is needed for the composites has increased enormously. The mechanism behind the machining of fiber reinforced polymer composite is entirely different from the metals, and it brings about so many undesirable results, such as sub-surface layer with cracks and delamination. Glass fiber reinforced polymer (GFRP) composites have been steadily replacing metals as a better choice in place of engineering materials for various applications. Drilling holes efficiently are vital to minimize the waste and defects of GFRP. It is most essential to understanding the machining behavior of GFRP. There is a need to turn to analytical and experimental approaches to fully understand the machining process. This work aimed to make a preliminary investigation on drilling behavior of the GFRP with the additional reinforcement of silica and also to optimize process parameters. Keywords: GFRP, Silica. Feed, speed, delamination factor Cite this Article: R.Raja, Sabitha Jannet and Rajesh Ruban S, Experimental Evaluation of Tensile Strength of Gfrp Laminates with Silica and Study on Their Drilling Behaviour, International Journal of Mechanical Engineering and Technology, 9(12), 2018, pp INTRODUCTION Glass Fiber Reinforced Composites (GFRP) has become a viable alternative for engineering and Structural Materials. Tool fabricated from mixed alumina cutting tool (CC650), and a SiC whisker reinforced alumina cutting tool were analyzed for wear during drilling of GFRP composite specimens prepared using a hand lay-up w process. [1] The drilling with supported graphite plate improves the surface integrity of drilled hole compared with that without supported graphite plate. It was found that the fiber orientation and cutting direction influence the surface damages and damage mechanisms of the drilled hole. [2] The machining was studied by using editor@iaeme.com

2 R.Raja, Sabitha Jannet and Rajesh Ruban S two different Alumina tools and changing the process parameters and the wear mechanisms were analyzed [3] Drilling with supported graphite plate improved the surface integrity of drilled holes [4] It was reported that thermal ageing affected the compressive and tensile strength of the epoxy composites [5] The erosion was identified at different impingement angles and the loss was found to be highest at 600 [6] Damage was assessed based on data extracted from radiographic images are compared and correlated with mechanical test results-bearing test and delamination onset testand analytical models. [7] The conclusion revealed that feed rate and cutting speed were the most influential factor on the delamination, respectively. [8] [9]. The results showed the drilling behavior of the outer cutting edges and the outer drill tips for candlestick drill and also indicated that the pushdown delamination depended on exit thrust force instead of maximum thrust force. [10] At high fiber volume, fibers do not show much relaxation, and normal hole shrinkage associated with polymeric composites is not observed during drilling. [11] Various proportions of epoxy resin with silica a) epoxy resin b) epoxy resin+ silica (3%) c) Epoxy resin silica (5%) d) Epoxy resin+ Figure 1 and fourth was prepared with 7 % silica by weight. These are shown In figures 1 a),b),c) and d) respectively silica (7%) 2. MATERIALS AND METHODS Glass Fiber Reinforced Plastic (GFRP) has been used extensively used in the recent past because of its low density. It has become a competitive alternative to conventional materials.in this work Glass Fiber has been used as reinforcement in the epoxy resin matrix. Figure 1 exhibits the 4 laminates prepared for this work. Silica has been used as the additional reinforcement by adding it in the epoxy and laminates were prepared using hand lay-up method. Among the 4 laminates Various proportions of epoxy resin with silica a) epoxy resin b) epoxy resin+ silica (3%) c) Epoxy resin silica (5%) d) Epoxy resin+ Table 1 factors and their levels Notation Factor A Diameter of the drill(mm) B Percentage of silica(%) C Spindle speed(rpm) editor@iaeme.com

3 Experimental Evaluation of Tensile Strength of Gfrp Laminates with Silica and Study on Their Drilling Behaviour D Feed (mm/rev) Run A B C D Thrust Temperature1 Temperature2 Delamination force(n) ( c) ( c) factor Design matrix and respond data: 27 runs First laminate was prepared without any silica content, second laminate was prepared with 3 % silica by weight third laminate was prepared with 5% silica by weight 2.1. Process parameters Drilling of composites is different from the drilling of metals. Because of the anisotropy nature of the composites and abrasive properties of fibers the drilled hole diameter is larger than the predetermined diameter. Thrust force developed at the drill bit during its contact with the workpiece is a measure of the effectiveness of the drilling process. From the literature, it has been found that spindle speed, feed, and diameter of the drill bit are the three process parameters influence the drilling process. In this work, an attempt is made to know the effect of silica in the GFRP laminate on its mechanical behavior. Hence silica content in the laminate is also as process parameters in this work 2.2. DESIGN OF EXPERIMENT editor@iaeme.com

4 R.Raja, Sabitha Jannet and Rajesh Ruban S 4 factor 3 level factorial design of experiment was selected for Experimentation. Thrust force experienced by the drill bit, temperatures at the drill bit workpiece interface on the top surface and bottom surface as temperature 1 and temperature 2 and the delamination factor at the entry were considered as output responses for this work. 3. RESULTS & DISCUSSION 3.1. Effect of silica content in GFRP on its tensile strength Tensile strength of the laminates were tested as per ASTM 3039 standard as per the specimen sizes shown in figure 2.Figure 3 shows tensile strength behavior of GFRP laminates, when silica is added to the extent of 3 % and 5% there has been an increase in tensile strength but beyond 5% (that is 7 %) when it is added its strength decreased. This phenomenon could be attributed to the fact that beyond 5% agglomeration of the silica particles in the laminate. It has been observed that up to the 5% silica addition particles spread all through the laminate it eventually adds strength to the laminate. Figure 2. ASTM D3039 used for tensile testing Figure 3 The weight percentage of SiC Vs Tensile Strength editor@iaeme.com

5 Experimental Evaluation of Tensile Strength of Gfrp Laminates with Silica and Study on Their Drilling Behaviour 3.2. Effect of speed on the thrust force for a various percentage of silica Figure 4. Spindle speed Vs Thrust force Figure 4 shows the effect of speed on the thrust force for different feeds. Higher feeds result in higher thrust forces for the otherwise same set of operating conditions. At the higher feeds, the uncut fibers get entangled with cut fibers Figure 5 The weight percentage of SiC Vs Thrust force Figure 5 shows the effect of silica content in GFRP on thrust force during drilling for the same set of operating conditions. The GFRP laminate with higher silica content experiences higher thrust force. It is because higher silica content results in higher stiffness of the laminate. GFRP with higher stiffness resists more the movement of the drill bit on the GFRP laminate editor@iaeme.com

6 R.Raja, Sabitha Jannet and Rajesh Ruban S Figure 6. drill bit diameter Vs delamination factor Figure 6 shows the effect of drill bit diameter on the delamination factor for the same set of operating conditions apart from a different feed. When the drill bit diameter increases delamination factor also increases. It is due to the fact that when more fibers cut at a time in also entangles large amount of uncut fibers and takes away them from the laminate. This phenomenon causes more delamination when larger diameter holes are produced. Figure 7 The weight percentage of SiC Vs Delamination factor Figure 7 shows the influence of weight percentage of SiC in the GFRP on the delamination factor of the drills produced. This is plotted for the three laminates for the same set of operating conditions apart from different feeds. Higher silica content makes the laminate stiffer hence eventually laminates with high silica content gives higher resistance for the laminates. This phenomenon makes high silica content laminates to have relatively more delamination. 3.2 SEM Analysis Figure 8 Scanning electron microscope images of the surfaces of GFRP laminate with different percentages of silica content. Laminates with 3% and 5% show the uniform distribution of silica content but laminate with 7% silica shows the agglomeration of silica particles in the laminate. Hence we could conclude the additional filler/reinforcement material beyond a point will become counterproductive by giving undesirable responses such as lesser tensile strength more thrust force during drilling of the laminate editor@iaeme.com

7 Experimental Evaluation of Tensile Strength of Gfrp Laminates with Silica and Study on Their Drilling Behaviour. Figure 8. Various SEM images of GFRP with silica a) epoxy resin b) epoxy resin+ silica (3%) c) Epoxy resin silica (5%) d) Epoxy resin+ silica (7%) 4. CONCLUSION Glass fiber reinforced polymer (GFRP) laminates were prepared with different percentage of silica content through a hand lay-up method. The tensile strength of this laminates was arrived by the Universal Testing Machine (UTM) machine. It is found that when silica is added to the extent of 3 % and 5%, there has been an increase in tensile strength but beyond 5% (that is 7 %) when it is added its power decreased. It is because beyond 5% presence of agglomeration of the silica particles in the laminate.4 factor 3 level 27 run factorial design has been used for experimentation of drilling the laminates with different diameter drill bits, different spindle speeds, and different feeds. The laminate with lesser silica content (3%) gave better holes than the laminates with higher silica contents. In the case of machining parameters higher spindle speed (1260 rpm), Low feed (0.05 mm/rev), smaller drill bit diameter (3mm) gave better holes with geometrical and dimensional integrity. The optimum parameter variables in this work are High spindle speed (1260 rpm) Low feed (0.05 mm/rev) Drill bit diameter (3mm) Laminate with 3% silica REFERENCES [1] [2] [3] [4] [5] S. Kumar, M. Gupta, P.S. Satsangi, Engineering Science and Technology, an International Journal Multiple-response optimization of cutting forces in turning of UD-GFRP composite using Distance-Based Pareto Genetic Algorithm approach, Eng. Sci. Technol. an Int. J. 18 (2015) doi: /j.jestch Y. Xing, J. Deng, G. Zhang, Z. Wu, F. Wu, Assessment in drilling of C / C-SiC composites using brazed diamond drills, 26 (2017) doi: /j.jmapro M.A. Khan, A.S. Kumar, Machinability of glass fibre reinforced plastic (GFRP) composite using alumina-based ceramic cutting tools, J. Manuf. Process. 13 (2011) doi: /j.jmapro D. Kwon, P. Shin, J. Kim, Y. Baek, H. Park, K.L. Devries, J. Park, Interfacial properties and thermal aging of glass fi ber / epoxy composites reinforced with SiC and SiO 2 nanoparticles, Compos. Part B. 130 (2017) doi: /j.compositesb Y. Fouad, Erosion behaviour of epoxy based unidirectionl (GFRP) composite materials, Alexandria Eng. J. 50 (2011) doi: /j.aej editor@iaeme.com

8 R.Raja, Sabitha Jannet and Rajesh Ruban S [6] T.J. Adam, P. Horst, Fatigue damage and fatigue limits of a GFRP angle-ply laminate tested under very high cycle fatigue loading, Int. J. Fatigue. 99 (2017) doi: /j.ijfatigue [7] L. Durão, J. Tavares, V. de Albuquerque, J. Marques, O. Andrade, Drilling Damage in Composite Material, Materials (Basel). 7 (2014) Doi: /ma [8] E. Kilickap, Optimization of cutting parameters on delamination based on Taguchi method during drilling of GFRP composite, Expert Syst. Appl. 37 (2010) doi: [9] H. Hocheng, C.C. Tsao, The path towards delamination-free drilling of composite materials, J. Mater. Process. Technol. 167 (2005) doi: /j.jmatprotec [10] Y. Liu, J. Xiao, D. Shu, Free Vibration of Exponential Functionally Graded Beams with Single Delamination, Procedia Eng. 75 (2014) doi: /j.proeng [11] Velayudham, R. Krishnamurthy, T. Soundarapandian, Evaluation of drilling characteristics of high volume fraction fibre glass reinforced polymeric composite, Int. J. Mach. Tools Manuf. 45 (2005) doi: editor@iaeme.com