Two State M-Integral Analysis for a Nano-Inclusion in Plane Elastic Materials Under Uni-Axial or Bi-Axial Loadings

2009 ◽  
Vol 77 (2) ◽  
Author(s):  
Tong Hui ◽  
Yi-Heng Chen

In this paper, the two state M-integral is extended from macrofacture to nanodefect mechanics. The question as to why the M-integral for a nanovoid or a soft nano-inclusion might be negative is clarified. It is concluded that the surface tension plays a dominant role in evaluating the M-integral, whereas the surface Lamè constants yield much less influence than the surface tension. Their influence on the M-integral for a nanovoid or a soft nano-inclusion could be neglected.

2009 ◽  
Vol 77 (2) ◽  
Author(s):  
Tong Hui ◽  
Yi-Heng Chen

This paper deals with the M-integral analysis for a nano-inclusion in plane elastic materials under uni-axial or bi-axial loadings. Based on previous works (Gurtin and Murdoch, 1975, “A Continuum Theory of Elastic Material Surfaces,” Arch. Ration. Mech. Anal., 57, pp. 291–323; Mogilevskaya, et al., 2008, “Multiple Interacting Circular Nano-Inhomogeneities With Surface/Interface Effects,” J. Mech. Phys. Solids, 56, pp. 2298–2327), the surface effect induced from the surface tension and the surface Lamé constants is taken into account, and an analytical solution is obtained. Four kinds of inclusions including soft inclusion, hard inclusion, void, and rigid inclusions are considered. The variable tendencies of the M-integral for each of four nano-inclusions against the loading or against the inclusion radius are plotted and discussed in detail. It is found that in nanoscale the surface parameters for the hard inclusion or rigid inclusion have a little or little influence on the M-integral, and the values of the M-integral are always negative as they would be in macroscale, whereas the surface parameters for the soft inclusion or void yield significant influence on the M-integral and the values of the M-integral could be either positive or negative depending on the loading levels and the surface parameters. Of great interest is that there is a neutral loading point for the soft inclusion or void, at which the M-integral transforms from a negative value to a positive value, and that the bi-axial loading yields similar variable tendencies of the M-integral as those under the uni-axial tension loading. Moreover, the bi-axial tension loading increases the neutral loading point, whereas the bi-axial tension-compression loading decreases it. Particularly, the magnitude of the negative M-integral representing the energy absorbing of the soft inclusion or void increases very sharply as the radius of the soft inclusion or void decreases from 5 nm to 1 nm.


2008 ◽  
Vol 75 (6) ◽  
Author(s):  
Q. Li ◽  
Y. H. Chen

This paper deals with the surface effect and size dependence on the M-integral representing the energy release due to a nanodefect expansion in plane elasticity. Due to the high surface-to-volume ratio for reinforcing particles in the nanometer scale, the surface effect along the nanosized hole may be induced from the residual surface stress and the surface Lamé constants. The invariant integrals such as the Jk-integral vector and the M-integral customarily used in macrofracture mechanics are extended to treat plane elastic materials containing a nanosized hole. It is concluded that both components of the Jk-integral vanish when the contour selected to calculate the integral encloses the whole nanosized hole. This leads to the independence of the M-integral from the global coordinate shift. It is concluded that the surface effect and the size dependence on the energy release due to the nanohole expansion are significant especially when the hole size is less than 40 nm. This present study reveals that the discrepancies of the M-integral value with the surface effect from the referenced value M0 without the surface effect are mainly induced from the residual surface stress τ0 rather than from the surface Lamé constants μs and λs.


2011 ◽  
Vol 418-420 ◽  
pp. 772-776
Author(s):  
Xi Chang Wang ◽  
Shui Li Gong ◽  
En Ming Guo ◽  
Haiyan Zhao ◽  
Heng Dong Xu

Electron beam surfi-sculpt is a new metal surface processing technology, which is potentially used in many areas. In this paper, forming mechaniam of electron beam surfi-sculpt has been investigated by experiments and numerical simulation. Electron beam surfi-sculpt of Ti-6Al-4V was realized by a new control system and a innovative hexagon scanning waveform. At the same time, microstructure of protrusions was analysed. All the results of experiments and simulation show that forming mechanism is the interaction of vapour pressure and surface tension, but surface tension plays a dominant role during electron beam surfi-sculpt process.


Soft Matter ◽  
2014 ◽  
Vol 10 (39) ◽  
pp. 7723-7729 ◽  
Author(s):  
Tianshu Liu ◽  
Rong Long ◽  
Chung-Yuen Hui

In this paper we present a theoretical study on how surface tension affects fracture of soft solids.


2018 ◽  
Vol 846 ◽  
pp. 1-4
Author(s):  
M. M. Bandi

Surface tension plays a dominant role in the formation and stability of soap films. It renders them both a quasi-two-dimensional fluid and an elastic membrane at the same time. The techniques for measuring the surface tension of the soap solution may very well apply to the static soap film, but how can the surface tension of a soap film be unintrusively measured, and what value would it assume? The answer, being at the intersection of physical chemistry, non-equilibrium physics and interfacial fluid dynamics, is not amenable to deduction via established methods. In a joint theoretical and experimental study, Sane et al. (J. Fluid Mech., vol. 841, 2018, R2) exploit elasticity theory to glean the answer through a simple, yet elegant framework.


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