Finite Element Analysis of Sandwich Plates with Different Percentages of Delamination

Abstract

The present study pinpoints the effect of delamination in multilayer glass fiber-reinforced composite slabs. The unit cell method of homogenization has been used to find the effect of air inclusion in the glass fiber-reinforced polymer composite. The natural frequency has been obtained up to different modes on every condition. The modal analysis module of ANSYS has been used to obtain the natural frequency for different boundary conditions The present study considered 0% to 10 % of total volume as delamination in four steps (0.5, 1.0, 5.0, and 10%). Two types of boundary were considered in the present study, in the first condition the plate is fixed from all four sides, the second two sides are assumed to be free, and the remaining two sides are fixed.

Introduction

I. INTRODUCTION

The traditional materials used in the past have several important properties such as strength, stiffness, etc. The present modern era requires several distinct properties to be incorporated in one single material for application in areas such as aerospace, defence, submarine, and nuclear fields. For this functionally graded material (FGM) is one choice, FGM is a material whose properties will vary in the transversal direction and thus behaves differently compared to that of conventional material. In this regard, several reports are available in the open domain published by various researchers [1-4].  The layered structures such as laminates or sandwich structures also have varying properties in the transversal direction and thus come in the category of FGM.  Nguyen et al. utilized the first-order deformation theory for vibration analysis of the FGM sandwich plate [5-6].  The third-order shear deformation theory, together with the sinusoidal shear deformation theory was used by Zenkour in their study to determine the deflection, stresses, and free vibration of functionally graded sandwiched plated (FGSP) [7-8]. Vinh et al. investigated the effect of nanoparticle inclusion on the free vibration of the FGM plate. In this study, the author presented a comparative report on static bending and free vibration of FGM plate without Nano infusion and FGM plate with nanoparticles infusion [9-10]. A rigorous study on the effect of thermo-mechanical bending on the behavior of FGM sandwiched plated was presented by Li. et al. using the four-variable refined plate theory [11]. Wang et al. in their study presented free vibration analysis of through width isotopic delaminated beam with coupling effect. [12]. In the latest publication, Vinh and Hay presented a compressive study on the effect of porosity on the free vibration and buckling effect of FGM sandwich plates. They reported that the level of porosity will increase the bending and critical deflection of the FGM sandwich plates [13].   

It is clear from the literature presented that there is a lack of literature in the open domain about the free vibration analysis on the phenolic core with a GFRP multiple-layer sandwich plate. The analysis presented in this paper considers the effect of delamination on the free vibration of the FGM sandwich plate together with the effect of air inclusion on the free vibration of the sandwich FGM plate. Two end conditions were considered in the study. All four sides are fixed in one condition. Two sides are fixed and the other two are free in the second condition.

II. GEOMETRICAL MODELLING

A square sandwich plate of size 1000 mm x 1000 mm is considered for the analysis. GFRP skin and modified phenolic core are used to construct the sandwich plate as shown in figure 1.

Four different sizes of deboning are considered to examine the dynamic behavior as shown in Table 1 and Figure 2 shows the geometry of the plate with four different delamination areas

Conclusion

The change in natural frequency due to delamination has been successfully found using ANSYS software. The following conclusions are obtained from the analysis: 1) For a fully bonded plate, the natural frequency and deflection are found to be higher for the plate fixed from all sides than fixed from two opposite sides. 2) In both boundary conditions, the natural frequency decreases in all delaminated plate cases. 3) The maximum decrease in natural frequency is occurring for 10% delamination for both boundary conditions. 4) On comparing the case of fixed from two sides and all sides we find that the decrease in frequency is more in the case of fixed on all sides.

References

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Copyright

Copyright © 2024 Kali Pandey, Ganesh Pal Singh Jadon, Manoj Narwariya. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.