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American Society for Testing and Materials

https://repository.kulib.kyoto-u.ac.jp/dspace/bitstream/2433/85808/1/KJ00004746786.pdf

Time-Dependent Statistics of the Ising Model

In human-made malleable materials, microdamage such as cracking usually limits material lifetime. Some biological composites, such as bone, have hierarchical microstructures that tolerate cracks but cannot withstand high elongation. We demonstrate a directionally solidified eutectic high-entropy alloy (EHEA) that successfully reconciles crack tolerance and high elongation. The solidified alloy has a hierarchically organized herringbone structure that enables bionic-inspired hierarchical crack buffering. This effect guides stable, persistent crystallographic nucleation and growth of multiple microcracks in abundant poor-deformability microstructures. Hierarchical buffering by adjacent dynamic strain-hardened features helps the cracks to avoid catastrophic growth and percolation. Our self-buffering herringbone material yields an ultrahigh uniform tensile elongation (~50%), three times that of conventional nonbuffering EHEAs, without sacrificing strength.

Hierarchical crack buffering triples ductility in eutectic herringbone high-entropy alloys

Abstract Highly ordered 2-D mesostructured MoS 2 was prepared by a nanocasting approach using mesoporous silica SBA-15 as a hard template and phosphomolybdic acid (H 3 PMo 12 O 40 ) as a precursor. The resulting material constructed by interconnected aligned and regularly packed nanowires shows a rod-shaped morphology (0.4–0.7 μm in diameter and 0.8–1.2 μm in length). This mesoporous MoS 2 exhibits reversible lithium storage capacity as high as 630 mAh g −1 with excellent cycling performance when used as an electrode material for lithium ion batteries.

Lithium storage performance in ordered mesoporous MoS2 electrode material (vol 151, pg 418, 2012)

A review of ultrasonic peening treatment

In this paper, a hybrid method which combines reverberation-ray matrix method and wave propagation method is developed to investigate the stability of multi-span viscoelastic functionally graded material (FGM) pipes conveying fluid. The material properties of FGM pipes are considered as graded distribution along thickness direction according to a power-law. A parametric study is conducted to verify the effectiveness of present method and investigate effects of volume fraction exponent, fluid velocity, internal pressure and internal damping on stability of the FGM pipes conveying fluid. The numerical results demonstrate that the present method provides accurate results by using only a small number of elements and the viscoelastic FGM pipes exhibit some special dynamic behaviors. Moreover, the results also reveal that the natural frequencies of FGM piping system could be adjusted by devising the volume fraction exponent. This particular feature of FGM pipes can be tailored to fulfill the special applications in engineering.

Stability analysis of multi-span viscoelastic functionally graded material pipes conveying fluid using a hybrid method

The evolutions of ratcheting strains of polymethyl methacrylate (PMMA) at different temperatures and stress levels were experimentally investigated. A steady ratcheting strain growth region with a constant rate was observed in all specimens, which occupied significant part of total fatigue failure life. Experimental results also showed that the steady ratcheting growth rate varied with applied temperatures and loading. In this paper, theory of thermally activated process for glassy polymers was used to describe the plastic deformations during the cycle. Based on the correlations between ratcheting strains per cycle and hysteresis loop energy, a new ratcheting strains accumulative model for polymer materials was developed, which quantificationally elucidated the effects of temperature, loading frequency, mean stress and stress amplitude on the accumulative rate of ratcheting strains. Comparing the predications from the proposed model with experimental ratcheting strain data of PMMA, it was found that the model could describe the steady ratcheting strain accumulative behaviors under arbitrary temperatures and loading conditions exactly.

Steady ratcheting strains accumulation in varying temperature fatigue tests of PMMA

Size-dependent vibration and stability of multi-span viscoelastic functionally graded material nanopipes conveying fluid using a hybrid method

A type of nickel/manganese oxide (Ni/MnO)/carbon nanocomposite fibers were prepared via a facile and scalable electrospinning and carbonization approach. In comparison to the pure carbon showing a severe agglomeration, the uniformly embedded MnO and Ni nanoparticles promoted the formation of the fibrous carbon-based nanocomposites with an average diameter of 250 nm and a rough surface. The synergistic coactions of the MnO nanoparticles acting as impedance modulating mediator, the magnetic Ni nanoparticles, and the conductive, fibrous carbon with large aspect ratio and rough surface contributed to the excellent electromagnetic wave (EMW) absorbing performance of the nanocomposites. The nanocomposites with a MnO/Ni ratio of 1:1 exhibited an effective absorption bandwidth of 6.5 GHz at a thickness of 2.9 mm and a minimum reflection loss of −53.23 dB at a thickness of 2.3 mm. The EMW absorption mechanisms of the nanocomposite fibers were discussed at length, which showed the importance of the multi-component building units and microstructure for achieving high EMW absorbing performance. This work thus suggested a convenient, facile, and scalable manufacturing approach for constructing high-performance multi-component nanocomposite fiber based EMW absorbing materials. 

Facile manufacturing of Ni/MnO nanoparticle embedded carbon nanocomposite fibers for electromagnetic wave absorption

In this paper, the dynamic behaviors of a multi-span viscoelastic functionally graded material pipe conveying fluid are investigated by dynamic stiffness method. The material properties of the functionally graded material pipe are considered as graded distribution along the thickness direction according to a power-law. Several numerical examples are performed to study the effects of volume fraction exponent, fluid velocity, internal pressure, and internal damping on the stability and frequency response of the fluid-conveying functionally graded material pipe. It’s found that the viscoelastic functionally graded material pipe exhibits some special dynamic behaviors and it could increase the stability significantly when compared with the aluminum and steel pipes. The numerical results also demonstrate that by the introduction of the functionally graded material, the stiffness of the piping system could be modulated easily by designing the volume fraction function. Therefore, if the dominant frequency conten...

Wei Liu

Papers

Stability analysis of multi-span viscoelastic functionally graded material pipes conveying fluid using a hybrid method

Steady ratcheting strains accumulation in varying temperature fatigue tests of PMMA

Size-dependent vibration and stability of multi-span viscoelastic functionally graded material nanopipes conveying fluid using a hybrid method

Facile manufacturing of Ni/MnO nanoparticle embedded carbon nanocomposite fibers for electromagnetic wave absorption

Dynamic behaviors of multi-span viscoelastic functionally graded material pipe conveying fluid