Vol. 7 No. 2 Pages 93-162 (2019) | |||
Open Access Article | |||
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Orthotropic mode II shear test fixture: Iosipesque modification
, Pages: 93-108 Nabi Mehri Khansari, Ahmadreza Farrokhi and Amir Mosavi ![]() |
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Abstract: In-plane strength and constitutive properties of composite materials is known as crucial problems. Although, several studies have been made for obtaining the in-plane mode II properties, the common test fixtures are blind in confrontation of shear zone. Furthermore, toughening mechanisms and consequently mode II fracture toughness cannot be evaluated, precisely. Also, proposing the convenient configuration of shear test fixture increase the accuracy of evaluation for the shear-zone energy dissipation, especially in orthotropic materials. Hence in the present research, a novel shear fixture configuration is proposed based on Iosipesque structural modification. Hereof, some arbitrary composite materials (e.g. graphite/epoxy and wood) were studies on the basis of DOE and E-691 ASTM. Furthermore, as the numerical method for indicating the comparison of the uniform and non-uniform shear stress distribution in the modified and common shear test fixture, a statistical procedure is used based on ASTM standard in addition to FEM analysis. The obtained results reveal that applying major amendments through the new scheme of the shear test fixture, would provide a remarkable precision and a reasonable estimation of the shear strength in comparison with the previous Iosipesque experiments. DOI: 10.5267/j.esm.2019.4.003 Keywords: Orthotropic Mode II, Shear test fixture, Composite materials, Isotropic materials, In-Plane, EFM
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Analysis of the attenuative behaviour of accelerated cement based materials through a series of ultrasound Pulse Echo measurements
, Pages: 109-120 Nabil Khatib, El Houssaine Ouacha, Bouazza Faiz, Mohamed Ezzaidi and Hicham Banouni ![]() |
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Abstract: In this study, the effects of alkaline accelerating admixture and its dosage on cementitious material’s behavior at early ages were evaluated through a series of ultrasound Pulse echo measurements. Thus, those measurements consist on following the evolution of frequency dependent attenuation coefficient during cementitious material age. Four stages can be identified on the attenuation coefficient vs. mortar age graphs, indicating that the development of the attenuation parameter is closely related to the setting and the hardening phenomena. Also, the ultrasound histograms, representing the evolution of the different echoes backscattered by the media of the container, filled with cementitious material’s samples, were characterized in order to assess the attenuative effect of alkaline accelerator and its dosage during the setting and the hardening period. Thus, the combined use of ultrasound P-wave measured density and young modulus parameters results in a comprehensive ultrasound method that gives a more effective picture of the void volume and resistivity of the accelerated cementitious materials. Ultrasound P-waves were generated using a 1 MHz central frequency immersion transducer and mortar samples were prepared with Portland composite cement CPJ 45. DOI: 10.5267/j.esm.2019.4.002 Keywords: Non-destructive testing, Ultrasound, Pulse echo method, Mortar, Alkaline Accelerator
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Experimental investigation and numerical prediction for the fatigue life durability of austenitic stainless steel at room temperature
, Pages: 121-130 M. A. Khairul, S. M. Sapuan Faris M. AL-Oqla and E. S. Zainudin ![]() |
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Abstract: This work investigated and predicted the fatigue life durability of Austenitic Stainless Steel 316L due to its importance in plant industries worldwide. Modelling and simulations were performed to clarify the fracture as well as stress distribution using integrated mechanism. Experimental fatigue validations were also carried out to demonstrate the effect of various fatigue life parameters. Various loading conditions with variable load amplitudes were validated utilizing a frequency of 5 Hz and a stress ratio of 0.1. The accuracy of the simulation results were also verified based on the experimental data. High consistencies between the predicted fatigue life and the experimental results were achieved which increases the validity of the built model. DOI: 10.5267/j.esm.2019.4.001 Keywords: Fatigue life, Composites, Stainless steel, Modelling, Prediction
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Electrolytic plasma polishing technique for improved surface finish of ED machined components
, Pages: 131-136 T. R. Ablyaz, K. R. Muratov, L. A. Ushomirskaya, D. A. Zarubin and S. S. Sidhu ![]() |
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Abstract: The development of techniques that allow producing high-finish surfaces of geometrically-complex parts of difficult-to-machine materials by electrical discharge machining (EDM) is an emerging research area. The aim of this work is to study the application of electrolytic-plasma polishing technique for the high-quality surface finish of the parts obtained by EDM process. The structural alloy steel 38KH2N2MA (GOST 4543 – 71) was selected as the processing material. The morphology of the machined surface was examined using optical micrographs. It was observed that applying the electrolytic plasma polishing for the duration of 5 minutes results in reducing the surface roughness of the ED machined surface by a factor of 5. It is also concluded that the combined action of EDM with electrolytic plasma polishing method is suitable for attaining the desired surface finish. DOI: 10.5267/j.esm.2019.3.003 Keywords: Electrical discharge machining (EDM), Electrolytic plasma polishing, Roughness, Quality
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Thermo-physico-chemical and statistical mechanical properties of Washingtonian filifera new lignocellulosic fiber
, Pages: 137-150 Djamel Edinne Gaagaia, Mustapha Bouakba and Abdelheq Layachi ![]() |
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Abstract: In this work, novel cellulosic fibers are extracted from Washingtonia Filifera (WF) plant using an environment friendly technique. Morphological, physico-chemical, thermal and mechanical properties are reported in this paper. Micro graphical SEM shows the presence of cells in the fiber. FTIR and XRD experimental analyzes show a cristinality index of 48.88%, and the WF fibers are found to be thermally stable until 201°C by using TGA and DTG thermo graphic analyzes with an appropriate activation energy of 72.46 kJ/mol, where Young modulus and tensile strength of strain were determined using tensile tests of single fiber at 2.17 GPa, 134 MPa and 26.55%, respectively. Mechanical properties are analyzed using a statistical method. DOI: 10.5267/j.esm.2019.3.002 Keywords: WF fibers, Mechanical properties, FTIR, XRD, TGA, Statistical methods
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Finite element analysis of fibre-reinforced constitutive formulation of Cadisc-L
, Pages: 151-162 Ali Ansari, Hamidreza Ghasemi Bahraseman, Morteza Mohssenzadeh, Mohammad Haghpanahi, Kamran Hassani and Hossein Derakhshandeh ![]() |
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Abstract: The current study measures the mechanical behavior of both natural and the monobloc elastomeric disc prosthesis (CadiscTM-L) by employing a finite element method (FEM) to study the fiber-reinforced constitutive formulation provided in the literature. The three-dimensional geometry was created by computed tomography (CT) scan imaging technique. Frontal pure rotational, sagittal, and axial momentum of 7.5 N·m were applied on the top of L3 while the lower half of the L5 was fixed in all directions. This investigation was performed considering two stages: (1) intact L3–L5 lumbar spine (INT model), and (2) Cadisc implemented between L4 and L5 (IMP model). The numerical results for the INT model were validated by experimental data from the literature. Several parameters including the inter-segmental rotation, range of motion in flexion-extension, axial rotation and lateral bending were analyzed. Our numerical results show that the IMP model has a 50% reduction in the ‘range of motion’ and a 33% reduction in flexion in lateral bending compared to the INT model. These outcomes of this paper reveal the feasibility of applying a fibre-reinforced constitutive formulation to generate an accurate three-dimensional FEM model. DOI: 10.5267/j.esm.2018.12.004 Keywords: Cadisc-L, Finite element method, Fibre-reinforced constitutive formulation
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