Session: 16-01-01: Government Agency Student Poster Competition

Paper Number: 149870

149870 - Investigation of 3d-Printed Origami Kresling Cores in Sandwich Structures 

Hypersonic flight requires ultralight and multifunctional materials that can respond to rapidly changing flight conditions. Sandwich composites have been the mainstay of aerospace structures but weight reduction and multifunctionality can be significantly improved using origami sandwich concepts due to their natural wide open architecture and highly nonlinear response envelopes. Origami is the art of taking a 2D model and turning it into a 3D model using only a series of folds. Flexible and adaptable characteristics of origami pattern designs are directly applicable to the design and development of reconfigurable structures, leveraging their bistable and deployable nature. Due to the unique mechanical characteristics of origami, origami methods can be applied to the construction of metamaterials. Metamaterials, known for their unique mechanical properties not found in naturally occurring materials, have grown in popularity for their potential applications in engineering disciplines. 
 
This research project explored mechanical properties of sandwich plate structures that employ fabricated units of the Kresling origami pattern, created through a 3D printing process. By performing three-point bending and compression tests, along with simulations developed using Abaqus software and analytical modeling, this study investigated the mechanical properties of the origami structures under mechanical loading. Structures that utilize a Kresling core metamaterial may improve efficiency and performance in supersonic ehicles. 
 
A Kresling unit was constructed through a series of mountain and valley folds, where multiple folds convert a flat sheet into a 3-D collapsible, cylindrical structure. Two internal angles - alpha and beta - dictated the height and torsion angle, among other characteristics. Beta remained constant, while alpha had an experimental value of 35.5, 39.5, or 50.5 degrees. 
 
Kresling units for each alpha value were fabricated out of Thermoplastic polyurethane (TPU), then sandwiched between two layers of Polyethylene terephthalate (PET) plastic to form a sandwich structure. Each structure underwent a three-point bending test and a compression test in a MTS machine. Findings showed for three-point bending tests, the stiffness increased as the value of the alpha angle increased, meaning Kresling units with lower alpha values had mainly linear and non-linear spring (NLS) characteristics. Kresling units with a higher alpha value started to exhibit quasi-zero stiffness (QZS) factors. For compression tests, the alpha angle greatly affected the mechanical behavior of the sandwich structure. Smaller alpha values led to the structure transitioning from an initially compliant behavior to a higher stiffness state, while higher alpha angles started with initial stiffness then transitioned to compliant behavior. Experimental results validated the initial simulation results, providing confirmation that the simulated model works. 
 
These three-point bending and compression tests highlighted the mechanical properties of the sandwich structures, supporting the use of the Kresling pattern to significantly reduce weight while maintaining structural integrity. Results showed sandwich structures with a Kresling-patterned core have mechanical behaviors such as non-linear spring and quasi-zero stiffness. These properties make ideal structures for aerospace applications that require lightweight, yet strong materials. 

Presenting Author: Kira Seshaiah Smith College

Presenting Author Biography: Kira Seshaiah is a senior at Smith College, where she is double majoring and earning her B.S. in Engineering Science and her B.A. in Mathematics. This past summer she participated in the NSF REU for Advanced Technologies for Hypersonic Propulsive, Energetic and Reusable Platforms (HYPER) at the University of Central Florida. At Smith, she actively researches in both the Engineering and Mathematics departments, focusing on rocketry and applied mathematics.

Authors:

Kira Seshaiah Smith College
Md Shahjahan Hossain University of Central Florida
Omid Bateniparvar University of Central Florida
Ranajay Ghosh University of Central Florida