FEA and Experimentation evaluation of Composite Sandwich panel under Static Three Point Bending Load

IPASJ International Journal of Mechanical Engineering (IIJME) Web Site: http://www.ipasj.org/IIJME/IIJME.htm

A Publisher for Research Motivation........ Email: [email protected] Volume 4, Issue 4, April 2016 ISSN 2321-6441

Volume 4, Issue 4, April 2016 Page 20

ABSTRACT The use of sandwich structure continues to increase rapidly due to the wide fields of their application, for instance: satellites, aircraft, ships, automobiles, rail cars, wind energy systems, and bridge construction to mention only a few. The sandwich composites are multi-layered materials made by bonding stiff, high strength skins facings to low density core material. The main benefits of using the sandwich concept in structural components are the high stiffness and low weight ratios. In this paper, composite panel made of 8 layers of Glass fiber sheets arranged with different degree of orientation is taken into consideration. Gradually increasing loads(1KN-7KN) are applied to check the behavior of honeycomb sandwich composites through three-point bending. The objective of this work is to minimize weight of sandwich panel with respect to bending stiffness and strength.FEA results are compared with experimentally tested results. Keywords: Composites, honeycomb panel, three point bending, Glass fiber, UTM

1. INTRODUCTION Static and fatigue behaviors of honeycomb sandwich composites, made of aramide fibers and aluminum cores, are investigated through four-point bending tests[1]. Flexural behavior of composite sandwich beams is determined experimentally and results are compared with theoretical models. Sandwich beams were fabricated by bonding unidirectional carbon/epoxy face sheets (laminates) to aluminum honeycomb cores with an adhesive film. . Sandwich beams were tested under four-point and three-point bending [2]. Light-weight sandwich panel for trailers is designed Strength calculations and selection of different materials was carried out in order to find a new solution for this specific application. The sandwich materials were fabricated using vacuum infusion technology [3]. To restrict de-bonding, carbon fiber reinforced lattice-core sandwich composites with compliant skins were designed and manufactured. Compression behaviors of the lattice composites and sandwich columns with different skin thicknesses were tested [4]. The bending strength, stiffness and energy absorption of corrugated sandwich composite structure were investigated to explore novel designs of lightweight load-bearing structures that are capable of energy absorption in transportation vehicles. The results revealed that the hybridization of glass fibers and carbon fibers (50:50) in face-sheets was able to achieve the equivalent specific bending strength as the facet-sheets made entirely of carbon fiber composites [5].

Fig 1. Composite layer panel

FEA and Experimentation evaluation of Composite Sandwich panel under Static Three

Point Bending Load

Nitin Ratan Gir1, prof.A.Z Patel2 , prof.A.B Ghalke3

1 P.G Student, M.E Design Engineering, COE Osmanabad, Maharashtra, India.

2 Associate Professor, Mechanical Engineering Department, P.G coordinator, COE Osmanabad, Maharashtra, India.

3Associate Professor, Mechanical Engineering Department, H.O.D, COE Osmanabad, Maharashtra, India.




2. DESCRIPTION OF PROBLEM A study of composite sandwich panel, under uniform static three point bend loading with undamaged models is considered for study. The sandwich panel consists of 8 layers of GFC plate at top and bottom face sheet, each layer has 0.15mm thickness and core is present between top and bottom face sheets which has 15mm thickness. A sandwich panel that consists of GFC face sheets and aluminum honeycomb core has been considered for the analysis. Aim is to check the FEA results with experimental results. and to determine Flexural strength of Honeycomb Panel . 3. CAD AND MESHING DETAILS A honeycomb panel of dimensions (300 X 150 X 15) is drawn in CatiaV5. The .iges model of the honeycomb is further taken for analysis.

Fig 2. CAD geometry of honeycomb in CatiaV5 Fig 3. Meshing done in Hypermesh

The CAD model is imported to Hypermesh and the geometry cleanup is done. The appropriate element size is selected according to the geometry features. Then using quad element the aluminum honeycomb is meshed and then the composite plates maintaining the connectivity. The meshed model is checked for element criteria. Quad4 element type is used for the meshing. Number of nodes and elements are 59316 and 50562 respectively. 4. MATERIAL PROPERTIES OF SANDWICH PANEL

Table 1. Material properties for Aluminum core

Property Value Young’s Modulus, E 68.9 GPa Poisson’s Ratio ,ν 0.33 Density, ρ 2700 kg/m3 Yield Stress, σyield 214 MPa Ultimate Tensile Stress, σuts 241 MPa

Table 2: Material properties for glass fiber:

Property Value Longitudinal Modulus, E1 59 GPa Lateral Modulus, E2 20GPa Poisson’s Ratio ,ν 0.35 Longitudinal tension strength Xt 2000 MPa Longitudinal compression strength Xc 1240 MPa Transverse tension strength Yt 82 MPa Transverse compression strength Yc 200 MPa Density, ρ 2.02 g/cm3

In plane shear S 165 MPa




The composite panel is made of 8 layers of Glass fiber sheets arranged with different degree of orientation. The layers of thickness 0.15mm are arranged as, 45o,90o,-45o,-90o,45o,90o,-45o,-90o .The top and bottom layers are arranged as in the order by total 16 layers. The Aluminum core is sandwiched between the layers. 5. BOUNDARY CONDITIONS The Honeycomb is panel is constrained at the bottom side at a distance of 3/4 of its length and the loading is applied at the center at 1/2 of its length. The boundary conditions applied are as shown below.

Fig 4. Showing constraints on two sides Fig 5. Showing loads acting at center

The Loads of 1 to 7KN is applied as different load steps and the Linear static analysis is carried out in Radioss. The results are plotted as shown below. 6. FEA RESULTS Deformation Plots

Graph plot for Load vs deformation for FEA results




Von-mises stress:

7. Results and discussion FEA results The braking load of the component is expected to between 4 to 5KN as the ultimate strength of aluminum is 241Mpa. Experimentation and Results

Fig 6. Honeycomb placed on UTM bed Fig 7. Application of force by UTM on honeycomb




Procedure for testing

1. The Honeycomb panel is mounted on the bed of the UTM for flexural test. 2. The prototype is placed in the machine between the grips. The machine itself records the displacement between its

cross heads on which the specimen is held. 3. Adjust the load cell to read zero on the computer up to peak load. Once the machine is started it begins to apply an

increasing load on specimen. 4. Throughout the tests the control system and its associated software record the load and displacement of the

specimen. 5. Plot the variation of displacement with load.

8. Validation Experimental Results: For the load applied on the Honeycomb the deformation is noted down and the graph is plotted on Load vs Deformation

It is observed that the deformation at load 4.5KN is 21.6 mm FEA results: Graph plot for Load vs deformation for FEA results

It is observed that the deformation at load 4.5KN is 20 mm The Maximum deformation through experimental test is found to be 21.6mm at 4.5KN load which is a Flexural

Load. 9. Comparison of FEA and Experimental Results

Force(KN) Deformation results in (mm)

Deformation results in (mm)

% error

FEA Experimental

1 4.3 4.6 6.5

2 8.6 9.2 6.5 3 12.8 13.8 7.2

4 17.1 18.4 7.0 4.5 20 21.6 7.4

10. Conclusion The glass fiber layups are applied on the Honeycomb panel and simulation is carried out in FEA.




The different orientations of the layups result in good results for different loading conditions The fabricated model is tested for flexural strength and then validated against FEA results. Critical Ultimate strength of the material is 241MPa, from the result table we conclude that the Honeycomb panel's

Flexural strength is at 4.5KN loading. Hence the objective is achieved.

References [1]. 1.Belouettar, S., Abbadi, A., Azari, Z., Belouettar, R., &Freres, P. (2009). Experimental investigation of static and

fatigue behaviour of composites honeycomb materials using four point bending tests. Composite Structures, 87(3), 265-273

[2]. 2.Isaac M. Daniel, Jandro L. Abot, J. L. (2000). Fabrication, testing and analysis of composite sandwich beams. [3]. 3.Herranen, H., Pabut, O., Eerme, M., Majak, J., Pohlak, M., Kers, J., ...&Aruniit, A. (2012). Design and testing of

sandwich structures with different core materials. Materials Science, 18(1), 45-50. [4]. 4.Hualin Fan, Lin Yang, Fangfang Sun, Daining FangFan, H., Yang, L., Sun, F., & Fang, D. (2013). Compression

and bending performances of carbon fiber reinforced lattice-core sandwich composites. Composites Part A: Applied Science and Manufacturing, 52, 118-125.

[5]. 5.Jin Zhang, Peter Supernak, Simon Mueller-Alander, Chun H. Wang “Improving the bending strength and energy absorption of corrugated sandwich composite structure” Elsevier, Materials and Design 52 (2013) 767–773

[6]. 6.KavehKabir, Tania Vodenitcharova, Mark Hoffman, “ Response of aluminium foam-cored sandwich panels to bending load”Elsevier,Composites: Part B 64 (2014) 24–32

[7]. 7.Craig A. Steeves, Norman A. Fleck, “Collapse mechanisms of sandwich beams with composite faces and a foam core, loaded in three-point bending”, International Journal of Mechanical Sciences 46 (2004) 561–583

[8]. 8.V. Crupi, G. Epasto, E. Guglielmino, “Comparison of aluminium sandwiches for lightweight ship structures: Honeycomb vs. foam”, Elsevier, Marine Structures 30 (2013) 74–96

[9]. 9.K.KanthaRao, K. JayathirthaRaoA.G.Sarwade, M.Sarath Chandra, “Strength Analysis on Honeycomb Sandwich Panels of different Materials”, International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622

[10]. 10.M.M. Venugopal, S K Maharana, K S Badarinarayan, “Finite Element Evaluation of Composite Sandwich Panel Under Static Four Point Bending Load”, JEST-M, Vol. 2, Issue 1, 2013

Documents

FEA and Experimentation evaluation of Composite Sandwich panel under Static Three Point Bending Load