Joo Shin Park¹, Jung Kwan Seo^2,3

CMES-Computer Modeling in Engineering & Sciences, Vol.106, No.4, pp. 291-308, 2015, DOI:10.3970/cmes.2015.106.291

Abstract Ships, ship-shaped offshore structures, land-based structures and aerospace structures typically consist of various curved plate components. It is difficult to simulate the buckling and post-buckling of curved thin and/or thick plates that have characteristics of nonlinear structural mechanics, such as nonlinear behaviour when loading is applied. The elastic post-buckling behaviour of a curved plate is very complex, and accompanied by mode changes due to the occurrence of secondary buckling behaviour. Therefore, it is very important to clarify the elastic post-buckling behaviour when subjected to axial loading. The aim of this study was to derive an analytical calculation based on the… More >

Yongfeng Zhang¹, Hanchen Huang^1,2, Satya N. Atluri³

CMES-Computer Modeling in Engineering & Sciences, Vol.35, No.3, pp. 215-226, 2008, DOI:10.3970/cmes.2008.035.215

Abstract Molecular dynamics simulations reveal the asymmetrical yield strength of twinned copper nanowires under tension and compression. The simulation results show that the strength of nanowires depends on loading conditions, morphologies, and twin spacing. Under tensile loading condition the Schmidt factor of the leading partial is larger than that under compression. Effectively, the yield strength under tension is smaller than that under compression. When the cross-section is circular in morphology, dislocation nucleation requires larger stress, and the asymmetry of yield strength depends on the nucleation stress. When the cross section is square in morphology, dislocation nucleation requires smaller stress, and the… More >

Jin Ma¹, Jay C. Hanan¹, Ranga Komanduri¹, Hongbing Lu²

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.4, pp. 349-384, 2012, DOI:10.3970/cmes.2012.086.349

Abstract Amorphous metallic foams are an exciting class of materials for an array of high impact absorption applications, the mechanical behavior of which is only beginning to be characterized. To determine mechanical properties, guide processing, and engineer the microstructure for impact absorption, simulation of the mechanical properties is necessary as experimental determination alone can be expensive and time consuming. In this investigation, the material point method (MPM) with C1 continuous shape function is used to simulate the response of a bulk metallic glass (BMG) closed-cell foam (Pd42.5Cu30Ni7.5P20) under compression. The BMG foam was also tested experimentally under compression for validation of… More >

Weiwei Gong¹, Xiong Zhang^1,2, Xinming Qiu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.82, No.3&4, pp. 195-214, 2011, DOI:10.32604/cmes.2011.082.195

Abstract Due to its high strength, low weight and strong anti impact capability, aluminum foam has great potential in the fields of transportation, aerospace and building structures as energy absorbing materials. Due to its complicated microstructures, it is desirable to develop an efficient numerical method to study the dynamic response of the aluminum foam under impact loading. In this paper, the material point method (MPM) is extended to the numerical simulation of the dynamic response of the aluminum foam under impact loading by incorporating the Deshpande Fleck's model and a volumetric strain failure model into our three-dimensional explicit material point method… More >

Jun Zhang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.22, No.2, pp. 91-96, 2007, DOI:10.3970/cmes.2007.022.091

Abstract The most commonly used wavelets for image processing are the tensor-product of univariate wavelets, which have a disadvantage of giving a particular importance to the horizontal and vertical directions. In this paper, a new class of wavelet, non-separable wavelet, is investigated for image compression applications. The comparative results of image compression preprocessed with two different kinds of wavelet transform are presented: (1) non-separable wavelet transform; (2) tensor-product wavelet transform. The results of our experiments show that in the same vanishing moment, the non-separable wavelets perform better than the tensor-product wavelets in dealing with still images. More >

Chengyu Wei^{1, 2}, Deepak Srivastava ², Kyeongjae Cho¹

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.2, pp. 255-262, 2002, DOI:10.3970/cmes.2002.003.255

Abstract The temperature dependence of the plastic collapse of single-wall carbon nanotubes under axial compression has been studied with classical molecular dynamics simulations using Tersoff-Brenner potential for C-C interactions. At zero temperature, an (8,0) single-wall carbon nanotube under axial compression collapses by forming fins-like structure which remains within the elastic limit of the system, in agreement of previous molecular dynamics study. At finite temperatures, however, we find that temperature dependent fluctuations can activate the formation of sp3 bonds, in agreement with a recently proposed plastic collapse mechanism of the same nanotube with a generalized tight-binding molecular dynamics description. Furthermore, Stone-Wales defects… More >

E. Ferretti¹, A. Di Leo¹

CMC-Computers, Materials & Continua, Vol.7, No.2, pp. 59-80, 2008, DOI:10.3970/cmc.2008.007.059

Abstract The main assumption on the basis of the identifying model of the effective law, developed by the Author, is the impossibility of considering the specimen as a continuum, when an identifying procedure from load-displacement to stress-strain in uniaxial compression is attempted. Actually, a failure mechanism with propagation of a macro-crack was found to activate from the very beginning of the uniaxial compression test forth. This leads to considering the acquired displacements as composed by two quotes: one constitutive, due to the material strain, and one of crack opening. Since the ratio between these two quotes is not constant during the… More >

Xuwei Tang¹, Juan Xu^1,2,3,*, Bojia Duan¹

CMC-Computers, Materials & Continua, Vol.57, No.2, pp. 307-319, 2018, DOI:10.32604/cmc.2018.03693

Abstract Grover's search algorithm is one of the most significant quantum algorithms, which can obtain quadratic speedup of the extensive search problems. Since Grover's search algorithm cannot be implemented on a real quantum computer at present, its quantum simulation is regarded as an effective method to study the search performance. When simulating the Grover's algorithm, the storage space required is exponential, which makes it difficult to simulate the high-qubit Grover's algorithm. To this end, we deeply study the storage problem of probability amplitude, which is the core of the Grover simulation algorithm. We propose a novel memory-efficient method via amplitudes compression,… More >

Lingyun Xiang^1,2, Yan Li², Wei Hao^3,*, Peng Yang⁴, Xiaobo Shen⁵

CMC-Computers, Materials & Continua, Vol.55, No.3, pp. 541-559, 2018, DOI: 10.3970/cmc.2018.03510

Abstract For protecting the copyright of a text and recovering its original content harmlessly, this paper proposes a novel reversible natural language watermarking method that combines arithmetic coding and synonym substitution operations. By analyzing relative frequencies of synonymous words, synonyms employed for carrying payload are quantized into an unbalanced and redundant binary sequence. The quantized binary sequence is compressed by adaptive binary arithmetic coding losslessly to provide a spare for accommodating additional data. Then, the compressed data appended with the watermark are embedded into the cover text via synonym substitutions in an invertible manner. On the receiver side, the watermark and… More >

J. Joseph¹, Y. C. Lu ¹,

CMC-Computers, Materials & Continua, Vol.42, No.1, pp. 63-74, 2014, DOI:10.3970/cmc.2014.042.063

Abstract The super-long, vertically aligned carbon nanotubes (SL-VACNTs) are novel carbon nanomaterial produced from template-free synthesis. The mechanical responses of such material have been investigated by continuum finite element modeling and compared with experimental observations. The crushable foam model has been adequate in modeling the stress-strain curve and deformation of the SL-VACNTs under compression. SL-VACNTs are seen to exhibit transient elastic deformation at small displacement and then plastic deformation at large displacement. The deformation mostly occur at the position immediately beneath the compression platen (indenter face) due to the high stress/strain concentrations. More >