Search results for: tectonic plates

Authors: Sarada Nivedita Bhuyan

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Earthquake is the sudden, rapid movement of the earth’s crust and is the natural means of releasing stress. Tectonic plates play a major role for earthquakes as tectonic plates are the crust of the planet. The boundary lines of tectonic plates are usually known as fault lines. To understand an earthquake before its occurrence, different types of earthquake precursors are studied by different researchers. Surface temperature, strange cloud cover, earth’s electric field, geomagnetic phenomena, ground water level, active faults, ionospheric anomalies, tectonic movements are taken as parameters for earthquake study by different researchers. In this paper we tried to gather complete and helpful information of earthquake precursors which have been studied until now.

Keywords: earthquake precursors, earthquake, tectonic plates, fault

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Authors: Sayed Abdallah Mohamed Dahy

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Northeastern part of Egypt is considered one of the few regions of the world whereas evidence of historical activities has been documented during the last 48 centuries or more. Instrumental, historical and pre-historical seismicity data indicate that large destructive earthquakes have occurred quite frequently in the investigated area. The main aims in the present study were to redraw attention to the fact that the northeastern part of Egypt is seismically active and this result is associated with earthquake risk in the region. The interaction of the African, Arabian and Eurasian plates and Sinai subplate, is the main factor behind the earthquake activities of northeastern part of Egypt. All earthquakes occur at shallow depth and are concentrated at four seismic zones, these zones including the Gulfs of Suez and Aqaba, around the entrance of the Gulf of Suez and the fourth one is located at the south-west of great Cairo (Dahshour area). The seismicity map of the previous zones shows that the activity is coincide with the major tectonic trends of the Suez rift, Aqaba rift with their connection with the great rift system of the Red Sea and Gulf of Suez-Cairo-Alexandria trend.

Keywords: earthquake ectivities, Egypt, northeastern, tectonic setting

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Authors: Mahmoudi Noureddine

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In this study the use of two variable refined plate theories of laminated composite plates to static response of laminated plates. The plate theory accounts for parabolic distribution of the transverse shear strains, and satisfies the zero traction boundary conditions on the surfaces of the plate without using shear correction factor. The validity of the present theory is demonstrated by comparison with solutions available in the literature and finite element method. The result is presented for the static response of simply supported rectangular plates under uniform sinusoidal mechanical loadings.

Keywords: bending, composite, laminate, plates, fem

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Authors: Pratyasha Patnaik, A. V. Asha

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Laminated composite plates are made up of plates consisting of layers bonded together and made up of materials chemically different from each other but combined macroscopically. These have an application in aircrafts, railway coaches, bridges etc. because they are easy to handle, have got improved properties and the cost of their fabrication is low. But their failure can lead to catastrophic disasters. And generally, the failure of these structures is due to the combined effect of excessive stresses on it and buckling. Hence, the buckling behavior of these kinds of plates should be analyzed properly. Holes are provided either at the center or elsewhere in the laminar plates for the purpose of pipes for electric cables or other purposes. Due to the presence of holes in the plates, the stress concentration is near to the holes and the stiffness of the plates is reduced. In this study, the effect of a cut-out, its shape, different boundary conditions, length/thickness ratio, stacking sequence, and ply orientation has been studied. The analysis was carried out with laminated composite plates with circular, square and triangular cut-outs. Results show the effect of different cut-out shapes, boundary conditions, the orientation of layers and length/thickness ratio of the buckling load

Keywords: buckling, composite plates, cut-out, stress

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Authors: Fazl E. Ahad, Shi Dongyan, Anees Ur Rehman

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Plates are one of the most important structural components used in many industries like aerospace, marine and various other engineering fields and thus motivate designers and engineers to study the vibrational characteristics of these structures. This paper is a review of existing literature on vibration analysis of plates. Focus has been kept on prominent studies related to isotropic plates based on Mindlin plate theory; however few citations on orthotropic plates and higher order shear deformation theories have also been included. All citations are in English language. This review is aimed to provide contemporarily relevant survey of papers on vibrational characteristics of thick plates and will be useful for scientists, designers and researchers to locate important and relevant literature/research quickly.

Keywords: mindlin plates, vibrations, arbitrary boundary conditions, mode shapes, natural frequency

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Authors: Si Abdallah Mayouf

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In this work, the effects of the wavy surface on free convection heat transfer boundary layer flow between two parallel wavy plates have been studied numerically. The two plates are considered at a constant temperature. The equations and the boundary conditions are discretized by the finite difference scheme and solved numerically using the Gauss-Seidel algorithm. The important parameters in this problem are the amplitude of the wavy surfaces and the distance between the two wavy plates. Results are presented as velocity profiles, temperature profiles and local Nusselt number according to the important parameters.

Keywords: free convection, wavy surface, parallel plates, fluid dynamics

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Authors: Nabil Abaab, Dhaou Akrout, Riadh Ahmadi, Mabrouk Montacer

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The study of fluid pressure and its evolution have a critical importance as they lead to understanding the tectonic history of the region. Therefore, the present work focuses on a microtectonic study of tectonic and hydraulic fracture at the anticline structure of Zemlet El Beidha (North Chott range). The study and the analysis of several stations of tectonic and hydraulic fracture allow revealing the witnesses of a paléosurpression in the deposits of Lower Cretaceous (Bouhedma Formation). In fact, we noticed that the overpressure is directly involved in the creation of various types of fractures as evidenced by the different measures and the stereographic projections. Thus, the orientations of fibers of mineralization that fills the Beefs type fracture have the same direction as the main constraint. Furthermore, we discussed the different overpressure build-up mechanisms. The results showed that tectonics is likely, responsible for this anomaly. This is confirmed by the description of the fibers and the projection of the different measurements of Beefs. The mineralization transformation from gypsum to anhydrite is heavily involved in this stress regime especially in the presence of all necessary conditions of dehydration of gypsum.

Keywords: Zemlet El Beidha, overpressure, tectonic fracture, hydraulic fracture, gypsum beefs

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Authors: Xianghong Lu, Yuejun Wang, Chengshi Gan, Xin Qian

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The North Sulawesi Arc, located on the east of Indonesia and to the south of the Celebes Sea, is the north part of the K-shape of Sulawesi Island and has a complex tectonic history since the Cenozoic due to the convergence of three plates (Eurasia, India-Australia and Pacific plates). Published rock records contain less precise chronology, mostly using K-Ar dating, and rare geochemistry data, which limit the understanding of the regional tectonic setting. This study presents detailed zircon U-Pb geochronological and Hf-O isotope and whole-rock geochemical analyses for the Na-rich granites from the North Sulawesi Arc. Zircon U-Pb geochronological analyses of three representative samples yield weighted mean ages of 30.4 ± 0.4 Ma, 29.5 ± 0.2 Ma, and 27.3 ± 0.4 Ma, respectively, revealing the Oligocene magmatism in the North Sulawesi Arc. The samples have high Na₂O and low K₂O contents with high Na₂O/K₂O ratios, belonging to Low-K tholeiitic Na-rich granites. The Na-rich granites are characterized by high SiO₂ contents (75.05-79.38 wt.%) and low MgO contents (0.07-0.91 wt.%) and show arc-like trace elemental signatures. They have low (⁸⁷Sr/⁸⁶Sr)i ratios (0.7044-0.7046), high εNd(t) values (from +5.1 to +6.6), high zircon εHf(t) values (from +10.1 to +18.8) and low zircon δ18O values (3.65-5.02). They show an Indian-Ocean affinity of Pb isotopic compositions with ²⁰⁶Pb/²⁰⁴Pb ratio of 18.16-18.37, ²⁰⁷Pb/²⁰⁴Pb ratio of 15.56-15.62, and ²⁰⁸Pb/²⁰⁴Pb ratio of 38.20-38.66. These geochemical signatures suggest that the Oligocene Na-rich granites from the North Sulawesi Arc formed by partial melting of the juvenile oceanic crust with sediment-derived fluid-related metasomatism in a subducting setting and support an intra-oceanic arc origin. Combined with the published study, the emergence of extensive calc-alkaline felsic arc magmatism can be traced back to the Early Oligocene period, subsequent to the Eocene back-arc basalts (BAB) that share similarity with the Celebes Sea basement. Since the opening of the Celebes Sea started from the Eocene (42~47 Ma) and stopped by the Early Oligocene (~32 Ma), the geodynamical mechanism of the formation of the Na-rich granites from the North Sulawesi Arc during the Oligocene might relate to the subduction of the Indian Ocean.

Keywords: North Sulawesi Arc, oligocene, Na-rich granites, in-situ zircon Hf–O analysis, intra-oceanic origin

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Authors: Karan Modi, Rajesh Kumar, Jyoti Katiyar, Shreya Thusoo

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This paper presents Finite Element Method (FEM) for analyzing the internal responses generated in thin rectangular plates with various edge conditions and rigidity conditions. Comparison has been made between the FEM (ANSYS software) results for displacement, stresses and moments generated with and without the consideration of hole in plate and different aspect ratios. In the end comparison for responses in plain and composite square plates has been studied.

Keywords: ANSYS, finite element method, plates, static analysis

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Authors: Ufuk Aydın

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The Coda attenuation and frequency dependency of seismic wave are strongly dependent on the effective stresses structures within the upper crust. In this study, the data of three different stations were used to examine the lateral variation of stress. The tectonic structures of these three areas have been examined comparatively using lateral coda tomography. In the study using the single scatter method, the window length selected to be 20 second. Coda values 80 with 94 and frequency dependency values obtained between 0.69 and 1.21. The 1/QC values for the three regions ranged from 0.0012 to 0.017, highlighting the regional differences in the seismotectonic activity of the crust. The lowest absorption values obtained from Erzurum station when the highest absorption values obtained at the Kemaliye station. The low Qc and high frequency dependency values obtained Kemaliye, which indicates that it has highest tectonic activity than other two regions. The seismo-dynamics data obtained from the study found to be in agreement with the tectonic structure of the region.

Keywords: regional coda attenuation, tectonic stress, crustal deformation

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Authors: Bae Doobyong, Yoo Jaejun, Park Ilgyu, Choi Seowon, Oh Chang Kook

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Variation of slip coefficient in slip-critical connections of curved plates. This paper presents the results of analytical investigations of slip coefficients in slip-critical bolted connections of curved plates. It may depend on the contact stress distribution at interface and the flexibility of spliced plate. Non-linear FEM analyses have been made to simulate the behavior of bolted connections of curved plates with various radiuses of curvature and thicknesses.

Keywords: slip coefficient, curved plates, slip-critical bolted connection, radius of curvature

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Authors: Yang Zhong, Heng Liu

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The decoupling method and the modified Naiver method are combined for accurate bending analysis of rectangular thick plates with all edges clamped supported. The basic governing equations for Mindlin plates are first decoupled into independent partial differential equations which can be solved separately. Using modified Navier method, the analytic solution of rectangular thick plate with all edges clamped supported is then derived. The solution method used in this paper leave out the complicated derivation for calculating coefficients and obtain the solution to problems directly. Numerical comparisons show the correctness and accuracy of the results at last.

Keywords: Mindlin plates, decoupling method, modified Navier method, bending rectangular plates

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Authors: David Boyajian, Tadeh Zirakian

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Stability and performance of steel plates are characterized by geometrical buckling and material yielding. In this paper, the geometrical buckling and material yielding behaviors of low yield point (LYP) steel plates are studied from the point of view of their application in steel plate shear wall (SPSW) systems. Use of LYP steel facilitates the design and application of web plates with improved buckling and energy absorption capacities in SPSW systems. LYP steel infill plates may yield first and then undergo inelastic buckling. Hence, accurate determination of the limiting plate thickness corresponding to simultaneous buckling and yielding can be effective in seismic design of such lateral force-resisting and energy dissipating systems. The limiting thicknesses of plates with different loading and support conditions are determined theoretically and verified through detailed numerical simulations. Effects of use of LYP steel and plate aspect ratio parameter on the limiting plate thickness are investigated as well. In addition, detailed studies are performed on determination of the limiting web-plate thickness in code-designed SPSWs. Some practical recommendations are accordingly provided for efficient seismic design of SPSW systems with LYP steel infill plates.

Keywords: buckling, low yield point steel, plates, steel plate shear walls, yielding

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Authors: Irakli Gamkrelidze, David Shengelia, Giorgi Chichinadze, Tamara Tsutsunava, Giorgi Beridze, Tamara Tsamalashvili, Ketevan Tedliashvili, Irakli Javakhishvili

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The Caucasus is situated between the Eurasian and Africa-Arabian plates and represents a component of the Mediterranean (Alpine-Himalayan) collision belt. The Loki crystalline massif crops out within one of the terranes of the Caucasus – Baiburt-Sevanian terrane. By the end of 2018, a digital geological map (1:50 000) of the Loki massif was compiled. The presented map is of great importance for the region since there is no large-scale geological map which reflects the present standards of the geological study of the massif up to the last time. The existing State Geological Map of the Loki massif is very outdated. A new map drown by using GIS (Geographic Information System) technology is loaded with multi-informative details that include: specified contours of geological units and separate tectonic scales, key mineral assemblages and facies of metamorphism, temperature conditions of metamorphism, ages of metamorphism events and the massif rocks, genetic-geodynamic types of magmatic rocks. Explanatory note, attached to the map includes the large specter of scientific information. It contains characterization of the geological setting, composition and petrogenetic and geodynamic models of the massif formation. To create a geological map of the Loki crystalline massif, appropriate methodologies were applied: a sampling of rocks, GIS technology-based mapping of geological units, microscopic description of the material, composition analysis of rocks, microprobe analysis of minerals and a new interpretation of obtained data. To prepare a digital version of the map the appropriated activities were held including the creation of a common database. Finally, the design was created that includes the elaboration of legend and the final visualization of the map. The results of the study presented in the explanatory note are given below. The autochthonous gneissose quartz diorites of normal alkalinity and sub-alkaline gabbro-diorites included in them belong to different phases of magmatism. They represent “igneous” granites corresponding to mixed mantle-crustal type granites. Four tectonic plates of the allochthonous metamorphic complex–Lower Gorastskali, Sapharlo–Lok-Jandari, Moshevani, and Lower Gorastskali differ from each other by structure and degree of metamorphism. The initial rocks of these plates are formed in different geodynamic conditions and during the Early Bretonian orogeny while overthrusting due to tectonic compression they form a thick tectonic sheet. The Lower Gorastskali overthrust sheet is a fragment of ophiolitic association corresponding to the Paleotethys oceanic crust. The protolith of the ophiolitic complex basites corresponds to the tholeiitic series of basalts. The Sapharlo–Lok-Jandari overthrust sheet is metapelites, metamorphosed in conditions of greenschist facies of regional metamorphism. The regional metamorphism of Moshevani overthrust sheet crystalline schists quartzites corresponds to a range from greenschist to hornfels facies. The “mélange” is built of rock fragments and blocks of above-mentioned overthrust sheets. Sub-alkaline and normal alkaline post-metamorphic granites of the Loki crystalline massif belong to “igneous” and rarely to “sialic” and “anorogenic” types of granites.

Keywords: digital geological map, 1:50 000 scale, crystalline massif, the caucasus

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Authors: Muhammad Arif Rahman, Gamma Abdul Jabbar, Enggar Handra Pangestu, Alfi Syahrin Qadri, Iryan Anugrah Putra, Rizqi Ramadhandi.

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Indonesia lies above three major tectonic plates, Indo-Australia plate, Eurasia plate, and Pacific plate. Interactions between those plates resulted in high tectonic and volcanic activities that corelates into high risk of geological hazards in adjacent areas, one of the areas is in North of Sulawesi’s Islands. This case raises a problem in terms of infrastructure in order to mitigate existing infrastructure and various future infrastructures plan. One of the infrastructures that is essentials to enhance telecommunication aspect is submarine fiber optic cable, that has risk to geological hazard. This cable is essential that act as backbone in telecommunication. Damaged fiber optic cables can pose serious problem that make existing signal to be loss and have negative impact to people’s social and economic factor with also decreasing various governmental services performance. Submarine cables are facing challenges in terms of geological hazards, for instance are seamounts activity. Previous studies show that until 2023, five seamounts are identified in North of Sulawesi. Seamounts itself can damage and trigger many activities that can risks submarine cables, one of the examples is submarine landslide. Main focuses of this study are to identify new possible seamounts and submarine landslide path in area North of Sulawesi Islands to help minimize risks pose by those hazards, either to existing or future plan submarine cables. Using bathymetry data, this study conduct slope analysis and use distinctive morphological features to interpret possible seamounts. Then we mapped out valleys in between seamounts and determine where sediments might flow in case of landslide, and to finally, know how it affect submarine cables in the area.

Keywords: bathymetry, geological hazard, mitigation, seamount, submarine cable, submarine landslide, volcanic activity

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Authors: Arpit Bhardwaj, Koushik Roy

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The work includes derivation of the exact-closed form solution for simply supported quasicrystal and crystal plates by using propagator matrix method under surface loading and free vibration. As a numerical example a quasicrystal and a crystal plate are considered, and after investigation, the variation of displacement and stress fields along the thickness of these two plates are presented. Further, it includes analyzing the displacement and stress fields for two plates having two different stacking arrangement, i.e., QuasiCrystal/Crystal/QuasiCrystal and Crystal/QuasiCrystal/Crystal and comparing their results. This will not only tell us the change in the behavior of displacement and stress fields in two different materials but also how these get changed after trying their different combinations. For the free vibration case, Crystal and Quasicrystal plates along with their different stacking arrangements are considered, and displacements are plotted in all directions for different Mode Shapes.

Keywords: free vibration, multilayered plates, surface loading, quasicrystals

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Authors: Aymen Arfaoui, Abdelkader Soumaya, Ali Kadri, Noureddine Ben Ayed

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The Tunisian dorsal backland is located on the Eastern Atlas side of the Maghrebides (North Africa). The analysis of collected field data in the Rouas and Ruissate mountains area allowed us to develop new interpretations for its structural framework. Our kinematic analysis of fault-slip data reveals the presence of an extensional tectonic regime with NE-SW Shmin, characterizing the Mesozoic times. In addition, geophysical data shows that the synsedimentary normal faulting is accompanied by thickness variations of sedimentary sequences and Triassic salt movements. Then, after the Eurasia-Africa plate’s convergence during the Eocene, compressive tectonic deformations affected and reactivated the inherited NW-SE and N-S trending normal faults as dextral strike-slip and reverse faults, respectively. This tectonic inversion, with compression to the transpressional tectonic regime and NW-SE SHmax, continued during the successive shortening phases of the upper Miocene and Quaternary. The geometry of the Rouas and Ruissate belt is expressed as a fault propagation fold, affecting Jurassic and Cretaceous deposits. The Triassic evaporates constitute the decollement levels, facilitating the detachment and deformation of the sedimentary cover. The backland of this thrust belt is defined by NNE-SSW trending imbrication features that are controlled by a basement N-S fault.

Keywords: Tunisian dorsal backland, fault slip data; synsedimentary faults, tectonic inversion, decollement level, fault propagation fold

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Authors: Mokhtar Bouazza

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In this paper, the simplified theory will be used to predict the thermoelastic buckling behavior of rectangular functionally graded plates. The material properties of the functionally graded plates are assumed to vary continuously through the thickness, according to a simple power law distribution of the volume fraction of the constituents. The simplified theory is used to obtain the buckling of the plate under different types of thermal loads. The thermal loads are assumed to be uniform, linear, and non-linear distribution through the thickness. Additional numerical results are presented for FGM plates that show the effects of various parameters on thermal buckling response.

Keywords: buckling, functionally graded, plate, simplified higher-order deformation theory, thermal loading

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Authors: Chih-Chia Lin, Ching-Ying Huang, Cheng-Hong Liu, Wen-Lin Wang

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A complete fuel cell stack comprises several single cells with end plates, bipolar plates, gaskets and membrane electrode assembly (MEA) components. Electrons generated from cells are conducted through bipolar plates. The amount of cells' components increases as the stack voltage increases, complicating the fuel cell assembly process and mass production. Stack assembly error influence cell performance. PEM fuel cell stack importing laser welding technique could eliminate transverse deformation between bipolar plates to promote stress uniformity of cell components as bipolar plates and MEA. Simultaneously, bipolar plates were melted together using laser welding to decrease interface resistance. A series of experiments as through-plan and in-plan resistance measurement test was conducted to observe the laser welding effect. The result showed that the through-plane resistance with laser welding was a drop of 97.5-97.6% when the contact pressure was about 1MPa to 3 MPa, and the in-plane resistance was not significantly different for laser welding.

Keywords: PEM fuel cell, laser welding, through-plan, in-plan, resistance

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Authors: Shahriyar Keshtgar, Mahmoud Reza Heyhat, Sasan Bagheri, Ebrahim Gholami, Seyed Naser Raiisosadat

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Various tectonic interpretations have been presented by different researchers to explain the geological evolution of eastern Iran, but there are still many ambiguities and many disagreements about the geodynamic nature of the Paleogene mountain range of eastern Iran. The purpose of this research is to clarify and discuss the tectonic position of the foreland and hinterland regions of eastern Iran from the tectonic perspective of sedimentary basins. In the tectonic model of oceanic subduction crust under the Afghan block, the hinterland is located to the east and on the Afghan block, and the foreland is located on the passive margin of the Sistan open ocean in the west. After the collision of the two microcontinents, the foreland basin must be located somewhere on the passive margin of the Lut block. This basin can deposit thick Paleocene to Oligocene sediments on the Cretaceous and older sediments. Thrust faults here will move towards the west. If we accept the subduction model of the Sistan Ocean under the Lut Block, the hinterland is located to the west towards the Lut Block, and the foreland basin is located towards the Sistan Ocean in the east. After the collision of the two microcontinents, the foreland basin with Paleogene sediments should expand on the Sefidaba basin. Thrust faults here will move towards the east. If we consider the two-sided subduction model of the ocean crust under both Lut and Afghan continental blocks, the tectonic position of the foreland and hinterland basins will not change and will be similar to the one-sided subduction models. After the collision of two microcontinents, the foreland basin should develop in the central part of the eastern Iranian orogen. In the oroclinic buckling model, the foreland basin will continue not only in the east and west but continuously in the north as well. In this model, since there is practically no collision, the foreland basin is not developed, and the remnants of the Sistan Ocean ophiolites and their deep turbidite sediments appear in the axial part of the mountain range, where the Neh and Khash complexes are located. The structural data from this research in the northern border of the Sistan belt and the Lut block indicate the convergence of the tectonic vergence directions towards the interior of the Sistan belt (in the Ahangaran area towards the southwest, in the north of Birjand towards the south-southeast, in the Sechengi area to the southeast). According to this research, not only the general movement of thrust sheets do not follow the linear orogeny models, but the expected active foreland basins have not been formed in the mentioned places in eastern Iran. Therefore, these results do not follow previous tectonic models for eastern Iran (i.e., rifting of eastern Iran continental crust and subsequent linear collision of the Lut and Afghan blocks), but it seems that was caused by buckling model in the Late Eocene-Oligocene.

Keywords: foreland, hinterland, tectonic vergence, orocline buckling, eastern Iran

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Authors: Fernando G. Torres, Donna M. Ebenstein, Monica Merino

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Most fish are covered by a protective external armour. The characteristics of these armours depend on the individual elements that form them, such as scales, scutes or dermal plates. In this work, we assess the properties of two different types of protective elements: scales from A. gigas and dermal plates from P. pardalis. A. Gigas and P. Pardalis are two Amazonian fish with a rather prehistoric aspect. They have large scales and dermal plates that form two different types of protective body armours. Although both scales and dermal plates are formed by collagen and hydroxyapatite, their structures display remarkable differences. The structure and composition of the samples were assessed by means of X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). Morphology studies were carried out using a Scanning Electron Microscopy (SEM). Nanoindentation tests were performed to measure the reduced moduli in A. gigas scales and P. pardalis plates. The similarities and differences between scales and dermal plates are discussed based on the experimental results. Both protective armours are designed to be lightweight, flexible and tough. A. Gigas scales are are light laminated composites, while P. pardalis dermal plates show a sandwich like structure with dense outer layers and a porous inner matrix. It seems that the armour of P. pardalis is more suited for a bottom-dwelling fish and allows for protection against predators. The scales from A. Gigas are more adapted to give protection to a swimming fish. The information obtained from these studies is also important for the development of bioinspired nanocomposites, with potential applications in the biomedical field.

Keywords: pterygoplichthys pardalis, dermal plates arapaima gigas, fish scales

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Authors: Zainab D. Abd Ali, Thamir H. Khalaf

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In this paper, the characteristics of electric discharge in gap between two (parallel-plate) dielectric plates are studies, the gap filled with Argon gas in atm pressure at ambient temperature, the thickness of gap typically less than 1 mm and dielectric may be up 10 cm in diameter. One of dielectric plates a sinusoidal voltage is applied with Rf frequency, the other plates is electrically grounded. The simulation in this work depending on Boltzmann equation solver in first few moments, fluid model and plasma chemistry, in one dimensional modeling. This modeling have insight into characteristics of Dielectric Barrier Discharge through studying properties of breakdown of gas, electric field, electric potential, and calculating electron density, mean electron energy, electron current density ,ion current density, total plasma current density. The investigation also include: 1. The influence of change in thickness of gap between two plates if we doubled or reduced gap to half. 2. The effect of thickness of dielectric plates. 3. The influence of change in type and properties of dielectric material (gass, silicon, Teflon).

Keywords: computational diagnostics, Boltzmann equation, electric discharge, electron density

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Authors: Mizan Ahmed, Srikanth Venkatesan

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Geological and tectonic framework indicates that Bangladesh is one of the most seismically active regions in the world. The Bengal Basin is at the junction of three major interacting plates: the Indian, Eurasian, and Burma Plates. Besides there are many active faults within the region, e.g. the large Dauki fault in the north. The country has experienced a number of destructive earthquakes due to the movement of these active faults. Current seismic provisions of Bangladesh are mostly based on earthquake data prior to the 1990. Given the record of earthquakes post 1990, there is a need to revisit the design provisions of the code. This paper compares the base shear demand of three major cities in Bangladesh: Dhaka (the capital city), Sylhet, and Chittagong for earthquake scenarios of magnitudes 7.0MW, 7.5MW, 8.0MW and 8.5MW using a stochastic model. In particular, the stochastic model allows the flexibility to input region specific parameters such as shear wave velocity profile (that were developed from Global Crustal Model CRUST2.0) and include the effects of attenuation as individual components. Effects of soil amplification were analysed using the Extended Component Attenuation Model (ECAM). Results show that the estimated base shear demand is higher in comparison with code provisions leading to the suggestion of additional seismic design consideration in the study regions.

Keywords: attenuation, earthquake, ground motion, Stochastic, seismic hazard

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Authors: Kyle Saltmarsh

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Acoustic testing possesses many benefits due to its non-destructive nature and practicality. There hence exists many scenarios in which using acoustic testing for condition testing shows powerful feasibility. A wealth of information is contained within the acoustic and vibration characteristics of structures, allowing the development meaningful features for the classification of their respective condition. In this paper, methods, results, and discussions are presented on the use of non-destructive acoustic testing coupled with acoustic feature extraction and machine learning techniques for the condition testing of manufactured circular steel plates subjected to varied levels of damage.

Keywords: plates, deformation, acoustic features, machine learning

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Authors: Abdelkader Soumaya, Noureddine Ben Ayed, Mojtaba Rajabi, Mustapha Meghraoui, Damien Delvaux, Ali Kadri, Moritz Ziegler, Said Maouche, Ahmed Braham, Aymen Arfaoui

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The northern Maghreb region (Western Mediterranean) is a key area to study the seismotectonic deformations across the Africa-Eurasia convergent plate boundary. On the basis of young geologic fault slip data and stress inversion of focal mechanisms, we defined a first-order transpression-compatible stress field and a second-order spatial variation of tectonic regime across the Maghreb region, with a relatively stable SHmax orientation from east to west. Therefore, the present-day active contraction of the western Africa-Eurasia plate boundary is accommodated by (1) E-W strike-slip faulting with a reverse component along the Eastern Tell and Saharan-Tunisian Atlas, (2) a predominantly NE trending thrust faulting with strike-slip component in the Western Tell part, and (3) a conjugate strike-slip faulting regime with a normal component in the Alboran/Rif domain. This spatial variation of the active stress field and the tectonic regime is relatively in agreement with the inferred stress information from neotectonic features. According to newly suggested structural models, we highlight the role of main geometrically complex shear zones in the present-day stress pattern of the Maghreb region. Then, different geometries of these major preexisting strike-slip faults and related fractures (V-shaped conjugate fractures, horsetail splays faults, and Riedel fractures) impose their component on the second- and third-order stress regimes. Smoothed present-day and Neotectonic stress maps (mean SHmax orientation) reveal that plate boundary forces acting on the Africa-Eurasia collisional plates control the long wavelength of the stress field pattern in the Maghreb. The seismotectonic deformations and the upper crustal stress field in the study area are governed by the interplay of the oblique plate convergence (i.e., Africa-Eurasia), lithosphere-mantle interaction, and preexisting tectonic weakness zones.

Keywords: Maghreb, strike-slip fault, seismotectonic, focal mechanism, inversion

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Authors: Merbouha Barka, K. H. Benrahou, A. Fakrar, A. Tounsi, E. A. Adda Bedia

Abstract:

This paper presents an analytical investigation on the buckling and postbuckling behaviors of thick functionally graded plates subjected to thermal load .Material properties are assumed to be temperature dependent, and graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of constituents. The formulations are based on first order shear deformation plate theory taking into account Von Karman nonlinearity and initial geometrical imperfection. By applying Galerkin method, closed-form relations of postbuckling equilibrium paths for simply supported plates are determined. Analysis is carried out to show the effects of material and geometrical properties, in-plane boundary restraint, and imperfection on the buckling and postbuckling loading capacity of the plates.

Keywords: functionally graded materials, postbuckling, first order shear deformation theory, imperfection

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Authors: Mazin Mohammed S. Sarhan

Abstract:

This study presents the performance of concrete beams reinforced with steel plates as a technique of reinforcement. Three reinforced concrete beams with the dimensions of 200 mm x 300 mm x 4000 mm (width x height x length, respectively) were experimentally investigated under flexural loading. The deformed steel bars were used as the main reinforcement for the first beam. A steel plate placed horizontally was used as the main reinforcement for the second beam. The bond between the steel plate and the surrounding concrete was enhanced by using steel bolts (with a diameter of 20 mm and length of 100 mm) welded to the steel plate at a regular distance of 200 mm. A pair of steel plates placed vertically was used as the main reinforcement for the third beam. The bond between the pair steel plates and the surrounding concrete was enhanced by using 4 equal steel angles (with the dimensions of 75 mm x 75 mm and the thickness of 8 mm) for each vertical steel plate. Two steel angles were welded at each end of the steel plate. The outcomes revealed that the bending stiffness of the beams reinforced with steel plates was higher than that reinforced with deformed steel bars. Also, the flexural ductile behavior of the second beam was much higher than the rest beams.

Keywords: concrete beam, deflection, ductility, plate

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Authors: Alden Boby, Dane Brown, James Connan

Abstract:

Character recognition is a well-researched topic across disciplines. Regardless, creating a solution that can cater to multiple situations is still challenging. Vehicle licence plates lack an international standard, meaning that different countries and regions have their own licence plate format. A problem that arises from this is that the typefaces and designs from different regions make it difficult to create a solution that can cater to a wide range of licence plates. The main issue concerning detection is the character recognition stage. This paper aims to create an object detection-based character recognition model trained on a custom dataset that consists of typefaces of licence plates from various regions. Given that characters have featured consistently maintained across an array of fonts, YOLO can be trained to recognise characters based on these features, which may provide better performance than OCR methods such as Tesseract OCR.

Keywords: computer vision, character recognition, licence plate recognition, object detection

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Authors: Zhao Cai-qi, Ma Jun

Abstract:

Twin steel plates-concrete composite shear walls are composed of a pair of steel plate layers and a concrete layer sandwiched between them, which have the characteristics of both reinforced concrete shear walls and steel plate shear walls. Twin steel plates-composite shear walls contain very high ultimate bearing capacity and ductility, which have great potential to be applied in the super high-rise buildings and special structures. In this paper, we analyzed the basic characteristics and stress mechanism of the twin steel plates-composite shear walls. Specifically, we analyzed the effects of the steel plate thickness, wall thickness and concrete strength on the bearing capacity of the twin steel plates-composite shear walls. The analysis results indicate that：（1）the initial shear stiffness and ultimate shear-carrying capacity is not significantly affected by the thickness of concrete wall but by the class of concrete,（2）both factors significantly impact the shear distribution of the shear walls in ultimate shear-carrying capacity. The technique of twin steel plates-composite shear walls has been successfully applied in the construction of a 88-meter Huge Statue of Buddha located in Hunan Province, China. The analysis results and engineering experiences showed that the twin steel plates-composite shear walls have great potential for future research and applications.

Keywords: twin steel plates-concrete composite shear wall, huge statue of Buddha, shear capacity, initial lateral stiffness, overturning moment bearing

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Authors: David Shengelia, Giorgi Chichinadze, Tamara Tsutsunava, Giorgi Beridze, Irakli Javakhishvili

Abstract:

The Loki pre-Alpine crystalline massif crops out within the Caucasus region. The massif basement is represented by the Upper Devonian gneissose quartz-diorites, the Lower-Middle Paleozoic metamorphic allochthonous complex, and different magmatites. Earlier, the metamorphic complex was considered as indivisible set represented by the series of different temperature metamorphits. The degree of metamorphism of separate parts of the complex is due to different formation conditions. This fact according to authors of the abstract was explained by the allochthonous-flaky structure of the complex. It was stated that the complex thrust over the gneissose quartz diorites before the intrusion of Sudetic granites. During the detailed mapping, the authors turned out that the metamorphism issues need to be reviewed and additional researches to be carried out. Investigations were accomplished by using the following methodologies: finding of key sections, a sampling of rocks, microscopic description of the material, analytical determination of elements in the rocks, microprobe analysis of minerals and new interpretation of obtained data. According to the author’s recent data within the massif four tectonic plates: Lower Gorastskali, Sapharlo-Lok-Jandari, Moshevani and “mélange” overthrust sheets have been mapped. They differ from each other by composition, the degree of metamorphism and internal structure. It is confirmed that the initial rocks of the tectonic plates formed in different geodynamic conditions during overthrusting due to tectonic compression form a thick tectonic sheet. Based on the detailed laboratory investigations additional mineral assemblages were established, temperature limits were specified, and a renewed trend of metamorphism facies and subfacies was elaborated. The results are the following: 1. The Lower Gorastskali overthrust sheet is a fragment of ophiolitic association corresponding to the Paleotethys oceanic crust. The main rock-forming minerals are carbonate, chlorite, spinel, epidote, clinoptilolite, plagioclase, hornblende, actinolite, hornblende, albite, serpentine, tremolite, talc, garnet, and prehnite. Regional metamorphism of rocks corresponds to the greenschist facies lowest stage. 2. The Sapharlo-Lok-Jandari overthrust sheet metapelites are represented by chloritoid, chlorite, phengite, muscovite, biotite, garnet, ankerite, carbonate, and quartz. Metabasites containing actinolite, chlorite, plagioclase, calcite, epidote, albite, actinolitic hornblende and hornblende are also present. The degree of metamorphism corresponds to the greenschist high-temperature chlorite, biotite, and low-temperature garnet subfacies. Later the rocks underwent the contact influence of Late Variscan granites. 3. The Moshevani overthrust sheet is represented mainly by metapelites and rarely by metabasites. Main rock-forming minerals of metapelites are muscovite, biotite, chlorite, quartz, andalusite, plagioclase, garnet and cordierite and of metabasites - plagioclase, green and blue-green hornblende, chlorite, epidote, actinolite, albite, and carbonate. Metamorphism level corresponds to staurolite-andalusite subfacies of staurolite facies and partially to facies of biotite muscovite gneisses and hornfelse facies as well. 4. The “mélange” overthrust sheet is built of different size rock fragments and blocks of Moshevani and Lower Gorastskali overthrust sheets. The degree of regional metamorphism of first and second overthrust sheets of the Loki massif corresponds to chlorite, biotite, and low-temperature garnet subfacies, but of the third overthrust sheet – to staurolite-andalusite subfacies of staurolite facies and partially to facies of biotite muscovite gneisses and hornfelse facies.

Keywords: regional metamorphism, crystalline massif, mineral assemblages, the Caucasus

Procedia PDF Downloads 135