Session: 05-06-01: Lightweight Sandwich Composites and Layered Structures

Paper Number: 120320

120320 - Bending Behavior of Sandwich Panels With Folded Core 

A sandwich panel usually consists of a top face sheet, a bottom face sheet, and a core sheet, and is designed to achieve high bending stiffness with little resultant weight penalty. Foam core and honeycomb core are the most commonly used core materials. Recently, folded-core sandwich panels have gained significant attention due to their potential for weight reduction and structural efficiency advantages. These core structures offer the ability to create complex shapes, making them suitable for various applications such as aircraft power plant nacelles, fairings, and vehicle bulges, which require intricate geometries to minimize drag forces. This work presents a comparative analysis of sandwich panels with different folded-core geometries, exploring the efficiency and effectiveness of different core designs. Three-point bending response is studied to investigate the bending behavior of these sandwich panels. In addition to developing a comprehensive three-dimensional finite element model, the homogenization approach is another way that can efficiently study the mechanical behavior of folded-core sandwich panels. Due to the inherent periodic feature of folded core, one single unite cell can be studied to evaluate the equivalent stiffness properties of the core.

In the current study, the homogenization process is performed numerically by using the finite element method. A set of periodic boundary conditions is applied to the unit cell to determine the [A], [B], and [D] matrices. Furthermore, cantilever beam models with a pressure load on top are employed to ascertain the transverse shear stiffness terms. The obtained elasticity constants are then utilized to construct equivalent sandwich panel models for each core geometry. The process of homogenization plays a critical role in accurately predicting the mechanical behavior of these panels, enabling the creation of simplified equivalent models instead of complex 3D geometries. By varying the dimensions and geometries of different folded-core patterns, the study aims to identify the optimal core design for creating efficient sandwich panels. In this work, three-dimensional comprehensive finite element models that exactly describe the geometry of folded-core sandwich panels are also developed and studied for comparison purposes. The results obtained from the 3D and the equivalent sandwich panel model are thoroughly compared to assess the accuracy and reliability of the homogenization process. The homogenization of folded core sandwich panels offers a significant advantage in simplifying the design process and reducing computational complexity. Numerical results are presented and discussed. The findings from this work will aid in identifying the more efficient core design for optimum sandwich panel performance, while also simplifying the modeling process. Ultimately, the insights gained from this study will facilitate advancements in lightweight structural designs across various industries, leading to enhanced efficiency and reduced costs.

Presenting Author: Zhangxian Yuan Worcester Polytechnic Institute

Presenting Author Biography: Zhangxian Yuan is an Assistant Professor in the Aerospace Engineering Department at the Worcester Polytechnic Institute. His research interests lie primarily in the broad areas of structural mechanics, with a focus on developing theoretical models and computational techniques to understand and simulate the mechanical behavior of advanced structures.

Authors:

Kerim Dovletov Worcester Polytechnic Institute
Zhangxian Yuan Worcester Polytechnic Institute