Experimental Investigation of Jute & E-Glass Fiber Reinforced Hybrid Composites for Free vibration
Ashwini P1, SureshBabu S U2 and Manjunath G B3
1 PG Student, Department of Mechanical Engineering, G M Institute of Technology, Davanagere, Karnataka, India.
2, 3 Assistant professor, Department of Mechanical Engineering, G M Institute of Technology, Davanagere, Karnataka, India.
Abstract—The recent interest in new light weight natural fibers can be used due to their low density, low cost and bio-degradability. During the motion of aircraft, wing and control surfaces undergo through severe vibration. This vibration can be controlled by selecting proper material, thickness, fiber orientation etc. This work focuses on vibration characteristics such as natural frequency and damping ratio Jute & E-Glass Fiber Reinforced Hybrid Composites For Free vibration composites at various fiber orientations and end conditions. The specimens of jute/E-glass fiber fiber and epoxy matrix composites are fabricated by the hand-lay-up technique with different composition and orientation. An experimental investigation is carried out using modal analysis technique with Fast Fourier Transform Analyzer (FFT), impact hammer and contact accelerometer to obtain the Frequency Response Functions. Vibration tests of simply supported beam for different composites are performed. The response curves of amplitude; phase vs. natural frequency was recorded. Damping factor was determined by taking the highest peak of amplitude vs. frequency. Depending on the obtained results, best suited composite was chosen by comparing all the combinations.
Keywords—Polymer composites, Natural fiber, FFT, Amplitude, Phase, Natural frequency.
I. INTRODUCTION
Natural fibers are a possible replacement for synthetic fibers in automotive and aerospace engineering applications due to less weight, high strength, low density, eco-friendly and easily available. Decreasing the resonant frequency of the vibration is an important issue for designing of machine components [1]. The damping associated with the structure of polymer composite is mainly influencing the resonant amplitude of vibration [2]. Now a day the dynamic design with lightweight structures has increased demand. This development is noticed for the design of modern aircraft applications where dynamic loads can produce a high amplitude of vibrations [3]. Several researchers have been developed different solutions to analyze the dynamic behavior of laminated composites.
Though experimental investigations on woven fabric composite laminated Structures are still limited [4]. Damping of a structure can be achieved by passive or active methods. A passive method uses the inherent capacity of certain materials to absorb the vibration energy, thus providing passive energy dissipation. An active method uses sensor and actuators to attain vibration sensing and activation to control the vibration in a real time. Polymers have mainly used the material for vibrational damping because of its viscoelastic property [5]. The properties polymer composite materials depend on numerous parameters such as the material of fiber and matrix, composition, fiber orientation, stacking sequence in laminates. However, fibers are the main factors controlling the properties of polymer composites [6]. M Rajesh et al [1] studied the Free Vibration Characteristics of Banana/Sisal Natural Fibers Reinforced Hybrid Polymer Composite. It is found that chemical treatment improves the free vibration properties of polymer composites due to the enhancement of interfacial bond between fiber and matrix. J. Alexander et al [2]
investigate the Free Vibration and Damping Characteristics of GFRP and BFRP Laminated Composites at Various Boundary Conditions. The natural frequency changes with fiber orientations. Due to its high stiffness, the natural frequency of Owen fabric composites is higher than that of unidirectional composites. P.S.Senthil Kumar et al [5]
study the damping characteristics of the Hybrid polymer composite. The result indicates that the characteristics damping improved with an increase in weight percentage reinforcement content. Omer Yavuz Bozkurt et al [6]
effect of fiber orientations. The increase in angle of fiber orientation resulted in a decrease in natural frequencies and an increase in damping ratios.
Based on the available literature it was observed that studies on the vibration characteristics of hybrid laminates with fiber orientations are very less. To the authors’ knowledge, there is only one open literature available on vibration characteristics of polymer composites. The aim of current study is to determine the vibration characteristics of the Jute/ E-glass epoxy composite laminates, and the evaluation of the effect of fiber orientations on the vibration characteristics.
II. MATERIALS AND METHODOLOGY
The following materials such as Jute/ E-Glass fiber, epoxy resin are used. Fibers which are used in the present work are purchased from local dealers and L12 epoxy resin and K6 harder with a ratio of 10:1 used as matrix material. The composite laminates for different volume fractions are prepared with dimensions of 200mm x 30mm x 7 mm using compression molding method in a hydraulic hot press machine. Three laminates having different fiber orientation with stacking sequence were prepared. The details are shown in the Table 1. Designation and stacking sequence of different composite materials are shown in Table 2.
TABLEI:DESIGNATIONFORDIFFERENTORIENTATIONS Designations Orientations
JG0 00
JG1 300
JG2 450
TABLEII:DESIGNATIONANDSEQUENCEFORDIFFERENTVOLUMEFRACTIONOFTHECOMPOSITE Designations Orientations Compositions
(Jute + E-glass + Epoxy)
Sequences
JG01
00
30% J + 30% G + 40% E J1G2
JG02 25% J + 25% G + 50% E J1G2
JG03 20% J + 20% G + 60% E J1G2
JG11
300
30% J + 30% G + 40% E J1G2
JG12 25% J + 25% G + 50% E J1G2
JG13 20% J + 20% G + 60% E J1G2
JG21
450
30% J + 30% G + 40% E J1G2
JG22 25% J + 25% G + 50% E J1G2
JG23 20% J + 20% G + 60% E J1G2
III. EXPERIMENTAL SET UP FOR VIBRATION ANALYSIS
The experimental setup for of simply supported beam conducting modal analysis is shown in Fig 1. The beam is supported by hinges at both ends. Middle of the beam mounting accelerometers to measure acceleration of vibration for the free vibration. Beam can be excited for free vibration at point and response is observed using OROS software for coherence. Once coherence is observed, the results are stored and the point of excitation is charged.
Fig. 1 Experimental setup of simply supported beam using FFT Analyzer
IV. RESULT AND DISCUSSION
A. Damping Factor of Jute and E-Glass Epoxy Hybrid Composites materials in Simply Supported Beam test The Table 3 shows the calculated values of damping factor for jute and E-glass hybrid composite specimens with different compositions and different orientations. The values of ω1,ω2 and ωn are identified in the exploded view of highest peak in the response curve. By taking these values damping factors are to be determined for all the materials.
The material JG11 shows highest damping factor about 0.512 and material JG03 shows the lowest damping factor is about 0.146.
TABLEIII:DAMPINGFACTORVALUESOFJUTE ANDE-GLASSEPOXYHYBRIDCOMPOSITES
Specimen
Damping Factor
JG01 0.0026 0.0054 0.004 0.350
JG02 0.0031 0.0047 0.004 0.212
JG03 0.0036 0.0048 0.0041 0.146
JG11 0.0021 0.0062 0.004 0.512
JG12 0.0036 0.0057 0.0041 0.268
JG13 0.0035 0.0062 0.0041 0.329
JG21 0.0031 0.0062 0.004 0.387
JG22 0.0029 0.0059 0.0045 0.333
JG23 0.28 0.0049 0.0039 0.269
B. Damping Factor v/s Fiber composition for JG0 Material
Fig. 2 shows the damping factor v/s fiber composition for JG0 specimen. It shows the minimum damping factor
= 0.146 value and maximum damping factor =0.35 value is obtained for 60% fiber content and 40% epoxy content
Fig. 2 Damping factor v/s fiber composition of JG0 Material C. Damping Factor v/s Fiber composition for JG1 Material
Fig. 3 Damping factor v/s fibre composition of JG1 Material
Fig.3 shows the damping factor v/s fiber composition for JG0 specimen. It shows the minimum damping factor
= 0.268 value and maximum damping factor =0.512 value is obtained for 60% fiber content and 40% epoxy content composite specimen. Hence this ratio exhibits epoxy content decreases the damping value increases for 30 degree orientation specimen.
D. Damping Factor v/s Fiber composition for JG2 Material
Fig.4 shows the damping factor v/s fiber composition for JG2 specimen. It shows the minimum damping factor
= 0.269 value and maximum damping factor =0.387 value is obtained for 60% fiber content and 40% epoxy content composite specimen. Hence this ratio exhibits epoxy content decreases the damping value increases for 45degree orientation specimen.
Fig. 4 Damping factor v/s fibre composition of JG2 Material E. Average damping factor v/s. fibre Orientation (JG0, JG1, JG2)
Fig. 5 Damping factor v/s. fiber Orientation
Fig. 5 shows the damping factor v/s fiber orientation of jute and E-glass epoxy hybrid composite for the simply supported beam. It shows higher the damping factor value for 30° orientation and lowers the damping factor value for 0° orientation. The value of damping factor of 45° orientation of material is intermediate between 0° & 30° fiber orientation of the composite.
V. CONCLUSION
The investigated of damping characteristics of jute and E-glass epoxy hybrid composites was studied. The specimens are obtained for 00, 300, 450 (JG0, JG1, JG2) angle orientation with a different composition. Vibration tests were conducted by using an FFT analyzer for simply supported beam.
The damping factor decreases from 0.35 to 0.146 when increasing the percentage of in JG0 composite material.
The damping factor decreases from 0.387 to 0.269 when increasing the percentage of epoxy JG2 composite material.
Finally JG1 shows higher the damping factor value about 0.369 and JG0 shows lower the damping factor value about 0.236.
It can be concluded that the damping factor is decreases with increasing epoxy percentage for all different fiber orientation of the composite material.
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