Sains Malaysiana 41(7)(2012): 901–906

Molecular Dynamics Modeling and Simulations of Carbon Nanotube-based Gears

(Permodelan Dinamik Molekul dan Simulasi Gear Berasaskan Nanotiub Karbon)

Yeak Su Hoe*,

Institut Kajian Sains Fundamental Ibnu Sina

Universiti Teknologi Malaysia, 81300 UTM Skudai, Johor, Malaysia

Che Lokman Jaafar

Department of Mathematical Science, Faculty of Science Universiti Teknologi Malaysia

81300 UTM Skudai, Johor Malaysia

Ng Teng Yong

School of Mechanical and Aerospace Engineering, Nanyang Technological University

50 Nanyang Avenue, Singapore 639798

Diserahkan: 14 Januari 2011 / Diterima: 2 Februari 2012

ABSTRACT

A molecular dynamics (MD) modeling method was applied to investigate the properties of carbon nanotube-based gears (CNT gears). The Brenner’s reactive hydrocarbon potential was used in order to calculate the short range interatomic forces. The Lennard-Jones 6-12 (LJ) was used to calculate the long range van der Waals potential for intermolecular interactions between gears. One gear was powered by forcing the atoms near the end of the first CNT to rotate, and a second gear was allowed to rotate by keeping the atoms near the end of second CNT constrained to a cylinder. We used the hybrid minimization to simulate the CNT-gears by coupling the unconstraint conjugate gradient minimization with the one-dimensional minimization, Brent’s method. The hybrid minimization was successfully implemented by introducing two regions in CNT gear. The switch function will affect the smoothness of the gear rotation. The switch function also affects the minimization process where simulation time will be reduced.

Keywords: Carbon nanotube-based gears; hybrid minimization; modeling; molecular simulation

ABSTRAK

Permodelan dinamik molekul telah dijalankan ke atas gear nanotiub karbon (CNT). Potensi Brenner jenis hidrokarbon telah digunakan dalam pengiraan julat pendek daya antara atom. Lennard-Jones 6-12 digunakan dalam julat jauh potensi van der Waals untuk interaksi antara molekul dengan roda gigi. Gear tiub pertama diberi kuasa berdekatan dengan pinggir tiub supaya berputar dan gean kedua dibenarkan berputar pada paksi yang ditetapkan. Kami gunakan teknik minimum hibrid untuk simulasi gean CNT dengan bergading dengan minimum tanpa kekangan jenis kecerunan konjugat dan kaedah Brent. Minimum hibrid telah berjaya digunakan dengan bantuan dua bahagian dalam gear CNT. Fungsi suis didapati memberi kesan dalam kelicinan putaran gear. Fungsi suis juga berjaya memendekkan masa simulasi dalam proses minimum.

Kata kunci: Gear nanotiub karbon;peminimuman hibrid; permodelan; simulasi molekul

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*Pengarang untuk surat-menyurat; email: s.h.yeak@utm.my