Dynamic crushing behavior of open-cell aluminum foam with negative Poisson’s ratio

2017 ◽  
Vol 123 (5) ◽  
Author(s):  
Peiwen Zhang ◽  
Zhihua Wang ◽  
Longmao Zhao
Keyword(s):  
Poisson’S Ratio ◽  
Aluminum Foam ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Open Cell ◽  
Negative Poisson's Ratio ◽  
Crushing Behavior ◽  
Dynamic Crushing

Modeling the Transition From Conventional to Auxetic Behavior in Compressed Foams

2011 ◽  
Author(s):  
J. C. Matheny ◽  
L. M. Berhan
Keyword(s):  
Trabecular Bone ◽  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Central Research ◽  
Negative Poisson’S Ratio ◽  
Open Cell ◽  
Human Trabecular Bone ◽  
Auxetic Materials ◽  
Human Cancellous Bone ◽  
Negative Poisson's Ratio

In theory, a negative Poisson’s ratio (i.e. auxetic) material has improved hardness, impact resistance, fracture toughness, and shear modulus over one with a positive Poisson’s ratio and comparable stiffness. These enhanced properties make them attractive candidates for a wide range of applications, including ones in the biomedical industry. Over the past two decades there has been increasing interest in auxetic materials leading to the discovery and development of new auxetic materials at the micro- and macro-scales. It has been reported in the literature that some human trabecular bone is auxetic; however verification of this claim and measurement of the Poisson’s ratio of biological materials remains a challenge. This research need is the motivation for the current work. The central research objective of this project is to develop an approach to gain fundamental insight into the geometric characteristics of auxetic open cell materials by studying the underpinning mechanics behind the transition from positive to negative Poisson’s ratio that takes place when open-cell foam is compressed and heat treated. The approach involves detailed image analysis and finite element modeling of the microstructure of polyurethane foam, which is commonly used as a test material to model the structure of human cancellous bone. By studying both conventional and auxetic foam, and the process by which conventional foams are transformed to auxetic, we seek to identify the critical features of auxetic open-cell structures. The results will lead to a better understanding of auxetic cellular materials in general, and will be used to develop a framework for use in determining the mechanical properties and potential auxeticity of human trabecular bone and to aid in the design of synthetic auxetic biomaterials. In this paper we report on preliminary results of our modeling efforts.

Free vibration and sound insulation of functionally graded honeycomb sandwich plates

2021 ◽  
pp. 109963622110204
Author(s):  
Fenglian Li ◽  
Wenhao Yuan ◽  
Chuanzeng Zhang
Keyword(s):  
Free Vibration ◽  
Poisson’S Ratio ◽  
Functionally Graded ◽  
Poisson's Ratio ◽  
Dynamic Equations ◽  
Sound Insulation ◽  
Sandwich Plates ◽  
Negative Poisson’S Ratio ◽  
Honeycomb Sandwich ◽  
Negative Poisson's Ratio

Based on the hyperbolic tangent shear deformation theory, free vibration and sound insulation of two different types of functionally graded (FG) honeycomb sandwich plates with negative Poisson’s ratio are studied in this paper. Using Hamilton’s principle, the vibration and vibro-acoustic coupling dynamic equations for FG honeycomb sandwich plates with simply supported edges are established. By applying the Navier’s method and fluid–solid interface conditions, the derived governing dynamic equations are solved. The natural frequencies and the sound insulation of FG honeycomb sandwich plates obtained in this work are compared with the numerical results by the finite element simulation. It is proven that the theoretical models for the free vibration and the sound insulation are accurate and efficient. Moreover, FG sandwich plates with different honeycomb cores are investigated and compared. The corresponding results show that the FG honeycomb core with negative Poisson’s ratio can yield much lower frequencies. Then, the influences of various geometrical and material parameters on the vibration and sound insulation performance are systematically analyzed.

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