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Reasons of adding carbon nanotubes into composite systems - review paper

Randjbaran E., Zahari R., Majid D. L., Sultan M. T. H., Mazlan N.

Mechanics and Mechanical Engineering

2017

Vol. 21, nr 3

549--568

The inclusion of CNT in the laminated composite system was found to increase the energy absorption of the whole composite after impact. The main important criteria is happened CNTs, which have good interfacial adhesion strong bonding with the matrix. Thus, it will be improve the properties/performance of the composite. Therefore, in current review paper the concentration/amount of the CNT, in term of loading, affect the performance of the composite and the mechanism on how the presence of CNT tends to absorb high amount of energy after impact have been discussed.

Enhancing capabilities of Atomic Force Microscopy by tip motion harmonics analysis

Babicz S., Smulko J., Zieliński A.

Bulletin of the Polish Academy of Sciences. Technical Sciences

2013

Vol. 61, nr 2

535--539

Motion of a tip used in an atomic force microscope can be described by the Lennard-Jones potential, approximated by the van der Waals force in a long-range interaction. Here we present a general framework of approximation of the tip motion by adding three terms of Taylor series what results in non-zero harmonics in an output signal. We have worked out a measurement system which allows recording of an excitation tip signal and its non-linear response. The first studies of spectrum showed that presence of the second and the third harmonics in cantilever vibrations may be observed and used as a new method of the investigated samples characterization.

Using stability analysis of discrete elastic systems to study the buckling of nanostructures

Korobeynikov S. N., Alyokhin V. V., Annin B. D., Babichev A. V.

Archives of Mechanics

2012

Vol. 64, nr 4

367-404

Stability/instability criteria of discrete elastic systems are used to study the buckling of nanostructures. The deformation of nanostructures is simulated by solving the nonlinear equations of molecular mechanics. The external forces applied to the nanostructure are assumed to be dead (that is the directions of their action remain constant throughout nanostructure deformation). We note that the positive-definiteness property of the tangential stiffness matrix of a nanostructure is a universal sufficient stability criterion for both equilibrium states and quasi-static/dynamic motions of the nanostructure. The equilibrium configurations are stable in Lyapunov's sense, and quasi-static/dynamic motions are stable in a finite time interval t "isin" (0, Tcr) in which the positive-definiteness property of this matrix is preserved. For dynamic motions of nanostructures, the stability property in this time interval follows from Lee’s criterion of quasi-bifurcation of solutions of second order ODEs. The non-positive definiteness of the tangential stiffness matrix of nanostructures at a time t > Tcr corresponds to both unstable equilibrium configurations and unstable dynamic motions. Computer procedures for determining the critical time and buckling mode(s) are developed using this criterion and are implemented in the PIONER FE code. This code is used to obtain new solutions for the deformation and buckling of twisted (10, 10) armchair and (10, 0) zigzag single-walled carbon nanotubes