L. Susmel^1,2, D. Taylor², R. Tovo¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.1, No.2, pp. 81-86, 2007, DOI:10.3970/icces.2007.001.081

Abstract This paper investigates some practical aspects related to the use of the Theory of Critical Distances (TCD) when employed to estimate notch fatigue limits. The accuracy of different formalisations of the theory was checked by using experimental data taken from the literature. This exercise allowed us to confirm that the simplest formalisation of the TCD, in which both critical distance and critical stress are material constants [1], is also the most accurate one, giving predictions falling within an error interval of about ±20%. The TCD is also accurate when applied to notches having large opening angles. More >

Surkay D. Akbarov^1,2, Nazmiye Yahnioglu³, Ayfer Tekin⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.64, No.2, pp. 147-186, 2010, DOI:10.3970/cmes.2010.064.147

Abstract A three-dimensional buckling delamination problem for the sandwich rectangular plate made from elastic and viscoelastic material is studied. It is supposed that the plate contains interface rectangular cracks (Case 1) and interface rectangular edge-cracks (Case 2) and edge-surfaces of these cracks have initial infinitesimal imperfections. The evolution of these initial imperfections with an external compressive loading acting along the cracks (for a case where the materials of layers of the plate are elastic) or with duration of time (for a case where the materials of layers of the plate are viscoelastic) is investigated within the framework of the piecewise homogeneous… More >

Lin Chen^1,*, Atsuki Komiya², Shigenao Maruyama^2,3

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.3, pp. 169-169, 2019, DOI:10.32604/icces.2019.05885

Abstract The heat transfer of near-critical fluids has become a key topic as the transcritical/supercritical energy systems are more and more proposed in recent years. When fluids go across the critical point or the equilibrium curve in the phase boundaries in the critical region, dramatic changes happen in fluid properties. For example, the thermal diffusivity goes to zero and the compressibility diverges. Such effects introduce additional complexibility in thermal systems with supercritical fluids (heat exchanger, turbines, reactors, etc.). For the efficiency analysis in heat transfer and stability in small-scale, the current numerical study is proposed. In this study, non-equilibrium cooling process… More >

Zhenchuan Wang^1,2, Ruina Xu², Peixue Jiang^2,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.3, pp. 154-154, 2019, DOI:10.32604/icces.2019.05023

Abstract Deeply analysis and prediction of turbulent convection heat transfer of supercritical pressure fluid in one-side non-uniform heating vertical tube plays a major role in system design and security. The Over-prediction of convection heat transfer of supercritical pressure fluid in vertical tube is attributed, at least partly, to the invalid of turbulent model on simulating the buoyancy effect. The present paper adopt an improved turbulent model, which is validated suitable to three dimensional model, to simulate flow and heat transfer of supercritical pressure water in vertical non-uniform heating tube. Heat transfer deterioration phenomenon occurs in non-uniform heating condition, while the degree… More >

N. A. Sri Aprilia¹, M. S. Nurul Atiqah², Zhari Ismail³, C. Y. Loo², Chaturbhuj K. Saurabh², Rudi Dungani⁴, Abdul Khalil H.P.S^2*

Journal of Renewable Materials, Vol.5, No.5, pp. 380-387, 2017, DOI:10.7569/JRM.2017.634130

Abstract Due to environmental concerns, green composites have become a highly researched material. In the present study, kenaf fiber was used as reinforcement in epoxy-based composite with weight fraction ranges from 0, 5, 10, and 15% (w/w of resin). The ratio of epoxy to hardener was 65:32.5. Prior to incorporation, kenaf bast fiber underwent Soda-AQ pulping followed by total chlorine-free bleaching (OAZP sequence). The obtained pulp was then subjected to supercritical carbon dioxide extraction (SCE) treatment. It was observed that epoxy composite with 10% of fiber loading demonstrated the highest mechanical properties with a tensile strength of 64 MPa, tensile modulus… More >

Roshan Kumar^1,*, Wei Zhao¹, Vikash Singh²

Structural Durability & Health Monitoring, Vol.12, No.2, pp. 65-83, 2018, DOI: 10.3970/sdhm.2018.02329

Abstract This paper presents an evaluation of time-frequency methods for the analysis of seismic signals. Background of the present work is to describe, how the frequency content of the signal is changing in time. The theoretical basis of short time Fourier transform, Gabor transform, wavelet transform, S-transform, Wigner distribution, Wigner-Ville distribution, Pseudo Wigner-Ville distribution, Smoothed Pseudo Wigner-Ville distribution, Choi-William distribution, Born-Jordan Distribution and cone shape distribution are presented. The strengths and weaknesses of each technique are verified by applying them to a particular synthetic seismic signal and recorded real time earthquake data. More >

Ricky Martinez^†, Hai-Chao Han^‡

Molecular & Cellular Biomechanics, Vol.9, No.1, pp. 55-76, 2012, DOI:10.3970/mcb.2012.009.055

Abstract The stability of arteries is essential to normal arterial functions and loss of stability can lead to arterial tortuosity and kinking. Collagen is a main extracellular matrix component that modulates the mechanical properties of arteries and collagen degradation at pathological conditions weakens the mechanical strength of arteries. However, the effects of collagen degradation on the mechanical stability of arteries are unclear. The objective of this study was to investigate the effects of collagen degradation on the critical buckling pressure of arteries. Arterial specimens were subjected to pressurized inflation testing and fitted with nonlinear thick-walled cylindrical model equations to determine their… More >

D. Chrupalla¹, J. Kreikemeier¹, S. Berg², L. Kärger³, M. Doreille⁴, T. Ludwig⁴, E. Jansen², R. Rolfes², A.Kling¹

CMC-Computers, Materials & Continua, Vol.32, No.3, pp. 159-176, 2012, DOI:10.3970/cmc.2012.032.159

Abstract In this paper, a loose coupling multiscale modeling technique for the detailed numerical analysis of critical areas in composite structures is presented. It is used to describe the global (macroscopic) behaviour of composite structures taking into account the effects of local phenomena. This is done by indirectly connecting the global and local FE-models. Prescribed displacements are assigned to the local boundaries in the transition from the global to local modeling level. The local-to-global transition is realized by assigning averaged local stresses to the respective global Gauss points and by updating the global tangent stiffness operator. To illustrate the feasibility of… More >

S. D. Akbarov¹, N. Yahnioglu², E. E. Karatas²

CMC-Computers, Materials & Continua, Vol.30, No.1, pp. 1-18, 2012, DOI:10.3970/cmc.2012.030.001

Abstract In Akbarov, Yahnioglu and Karatas (2010) a buckling delamination problem for a rectangular viscoelastic composite plate with a band and edge cracks was investigated under uniaxial compression of the plate. In the present study this investigation is developed for the case where the mentioned rectangular plate contains an embedded rectangular crack and in addition it is assumed that the plate is subjected to two-axial compression.
It is supposed that all end surfaces of the considered plate are simply supported and that these ends are subjected to uniformly distributed normal compressive forces with intensity p₁ and p₃ which act along… More >

S.D. Akbarov^1,2, N. Yahnioglu¹, A. Tekin¹

CMC-Computers, Materials & Continua, Vol.29, No.1, pp. 41-74, 2012, DOI:10.3970/cmc.2012.029.041

Abstract A three-dimensional buckling delamination problem for a rectangular sandwich plate made from elastic and viscoelastic materials is studied. It is supposed that the plate contains interface embedded rectangular cracks and that the edge-surfaces of these cracks have initial infinitesimal imperfections. The evolution of these initial imperfections with an external bi-axial compressed force (for the case where the materials of the layers of the plate are elastic) or with duration of time (for the case where the materials of the layers of the plate are viscoelastic) is investigated. The corresponding boundary value problem is formulated within the framework of the piecewise… More >