The elastic properties and high strain compressive behaviour of micro- and nano-sized irregular honeycombs and open-cell foams

Zhang, Hongchao 2014. The elastic properties and high strain compressive behaviour of micro- and nano-sized irregular honeycombs and open-cell foams. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Cellular solids widely exist in nature. Many researchers have analyzed the mechanical properties of macro-sized cellular solids. Following the rapid development of nano science and manufacturing technology, micro- and nano-sized cellular solids (i.e. honeycombs and open-cell foams) are now widely used in many areas. The purpose of this study is to investigate the elastic properties and the high strain compressive behaviour of micro- and nano-sized periodic random irregular honeycombs and opencell foams. In general, at the micro-meter scale, the strain gradient effect plays an important role in deformation. Meanwhile, at the nano-meter scale, the surface elasticity and the initial stress or strain are the dominant deformation mechanisms. According to the equivalence of the bending, transverse shear, torsion, and axial stretching or compression rigidities, these effects can be incorporated into the simulations by using the obtained equivalent Young’s modulus, Poisson’s ratio, and cross-sectional size. The results of this study indicate that the elastic properties and high strain compressive behaviour of micro- and nano-sized irregular honeycombs and open-cell foams are size-dependent and tunable. The smaller cross-sectional size of the cell walls/struts, the larger the dimensionless Young’s modulus, bulk modulus, shear modulus, the tangent modulus and the dimensionless compressive stress, and the smaller the Poisson’s ratio. Both the dimensionless Young’s modulus and compressive stress of nano-sized irregular honeycombs can be controlled to vary over a range of around 100% by adjusting the amplitude of the initial strain in the cell wall direction between -0.06 and 0.06. For nano-sized irregular open-cell foams, both the dimensionless Young’s modulus and compressive stress can be controlled to vary over a range of about 50% by adjusting the amplitude of the initial strain between -0.1 and 0.1. The cell regularity also significantly influences the elastic properties and the high strain compressive behaviour of micro- and nano-sized irregular honeycombs and open-cell foams.

Item Type:	Thesis (PhD)
Status:	Unpublished
Schools:	Engineering
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Uncontrolled Keywords:	micro-and nan-sized; irregular honeycombs; irregular open-cell foams; the size-dependent effect; elastic properties; high strain compressive behaviour.
Date of First Compliant Deposit:	30 March 2016
Last Modified:	19 Mar 2016 23:53
URI:	https://orca.cardiff.ac.uk/id/eprint/70324

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