RESUMEN
A crashworthiness design of foam-filled local nanocrystallized thin-walled tubes (FLNTs) is proposed by using foam-filled structures and ultrasonic impact surface treatment. The crashworthiness and deformation modes of FLNTs are studied using an experiment and numerical analysis. A finite element numerical model of FLNTs is established, and the processing and test platform of FLNTs is set up to verify the numerical predication and analytical design. The results show that local nanocrystallization is an effective method to enhance crashworthiness for hexagonal FLNTs. The FLNTs with four circumferential continuous stripes of surface nanocrystallization exhibit a level of 47.12% higher specific energy absorption than the untreated tubes in numerical simulations for tubes with a 50% ratio of nanocrystallized area. Inspired by the strength mechanism, a novel nested foam-filled local surface nanocrystallization tube is further designed and studied in detail.
RESUMEN
In this paper, a kind of single-walled carbon nanotube nonlinear model is developed and the strongly nonlinear dynamic characteristics of such carbon nanotubes subjected to random magnetic field are studied. The nonlocal effect of the microstructure is considered based on Eringen’s differential constitutive model. The natural frequency of the strongly nonlinear dynamic system is obtained by the energy function method, the drift coefficient and the diffusion coefficient are verified. The stationary probability density function of the system dynamic response is given and the fractal boundary of the safe basin is provided. Theoretical analysis and numerical simulation show that stochastic resonance occurs when varying the random magnetic field intensity. The boundary of safe basin has fractal characteristics and the area of safe basin decreases when the intensity of the magnetic field permeability increases.
RESUMEN
Inspired by strong mechanical stability of "Y"-shaped beams for building construction, we design a new class of quasi-one-dimensional graphene nanostructures, namely, tri-wing graphene (TWG) nanoribbons. TWG possesses significantly augmented mechanical stability against torsional and compression forces, and also each wing of the TWG can retain independent electronic properties of the constituent graphene nanoribbons. As such, by tailoring the wing structures, the TWGs can provide broader property tunability for nanoelectronic application. In addition, zigzag-edged TWG is a metallic ferromagnet with a large magnetic moment. When its edges are decorated with suitable chemical functional groups, a TWG can be converted to a half metal for potential spintronic applications.