Search results for: vertical and lateral loads

Authors: Aaron Aboshio

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Numerical study of the static response of homogeneous clay stratum considering a wide range of cohesion and subject to foundation loads is presented. The linear elastic–perfectly plastic constitutive relation with the von Mises yield criterion were utilised to develop a numerically cost effective finite element model for the soil while imposing a rigid body constrain to the foundation footing. From the analyses carried out, estimate of the bearing capacity factor, Nc as well as the ultimate load-carrying capacities of these soils, effect of cohesion on foundation settlements, stress fields and failure propagation were obtained. These are consistent with other findings in the literature and hence can be a useful guide in design of safe foundations in clay soils for buildings and other structure.

Keywords: bearing capacity factors, finite element method, safe bearing pressure, structure-soil interaction

Procedia PDF Downloads 303

Authors: Arunkumar Balamurugan, G. Soundharya Lakshmi, V. Thenmozhi, M. Jegannath, V. R. Sanal Kumar

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Aerodynamics of insects is of topical interest in aeronautical industries due to its wide applications on various types of Micro Air Vehicles (MAVs). Note that the MAVs are having smaller geometric dimensions operate at significantly lower speeds on the order of 10 m/s and their Reynolds numbers range is approximately 1,50,000 or lower. In this paper, numerical study has been carried out to capture the flow physics of a biological inspired Swallowtail Butterfly with fixed wing having twin tail at a flight speed of 10 m/s. Comprehensive numerical simulations have been carried out on swallow butterfly with twin tail flying at a speed of 10 m/s with uniform upper and lower angles of attack in both lateral and longitudinal position for identifying the best wing orientation with better aerodynamic efficiency. Grid system in the computational domain is selected after a detailed grid refinement exercises. Parametric analytical studies have been carried out with different lateral and longitudinal angles of attack for finding the better aerodynamic efficiency at the same flight speed. The results reveal that lift coefficient significantly increases with marginal changes in the longitudinal angle and vice versa. But in the case of drag coefficient the conventional changes have been noticed, viz., drag increases at high longitudinal angles. We observed that the change of twin tail section has a significant impact on the formation of vortices and aerodynamic efficiency of the MAV’s. We concluded that for every lateral angle there is an exact longitudinal orientation for the existence of an aerodynamically efficient flying condition of any MAV. This numerical study is a pointer towards for the design optimization of Twin tail MAVs with flapping wings.

Keywords: aerodynamics of insects, MAV, swallowtail butterfly, twin tail MAV design

Procedia PDF Downloads 395

Authors: M. Najafi

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In the present paper, a large turbo-generator shaft train including a heavy-duty gas turbine engine, a coupling, and a generator is established. The method of analysis is based on finite element simplified model for lateral and torsional vibration calculation. The basic elements of rotor are the shafts and the disks which are represented as circular cross section flexible beams and rigid body elements, respectively. For more accurate results, the gyroscopic effect and bearing dynamics coefficients and function of rotation are taken into account, and for the influence of shear effect, rotor has been modeled in the form of Timoshenko beam. Lateral critical speeds, critical speed map, damped mode shapes, Campbell diagram, zones of instability, amplitudes, phase angles response due to synchronous forces of excitation and amplification factor are calculated. Also, in the present paper, the effect of imbalanced rotor and effects of changing in internal force and temperature are studied.

Keywords: rotor dynamic analysis, finite element method, shaft train, Campbell diagram

Procedia PDF Downloads 136

Authors: Sofia Figueroa, Efrain Bernal, Silvia Del Pilar Forero, Humberto Ramirez

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This work shows a detailed review of the scope of global research on the road infrastructure using materials from Construction and Demolition Waste (C&DW), also called RCD. In the first phase of this research, a segment of road was designed using recycled materials such as Reclaimed Asphalt Pavement (RAP) on the top, the natural coarse base including 30% of RAP and recycled concrete blocks. The second part of this segment was designed using regular materials for each layer of the pavement. Both structures were built next to each other in order to analyze and measure the material properties as well as performance and environmental factors in the pavement under real traffic and weather conditions. Different monitoring devices were installed among the structure, based on the literature revision, such as soil cells, linear potentiometer, moisture sensors, and strain gauges that help us to know the C&DW as a part of the pavement structure. This research includes not only the physical characterization but also the measured parameters in a field such as an asphalt mixture (RAP) strain (ετ), vertical strain (εᵥ) and moisture control in coarse layers (%w), and the applied loads and strain in the subgrade (εᵥ). The results will show us what is happening with these materials in order to obtain not only a sustainable solution but also to know its behavior and lifecycle.

Keywords: sustainable pavements, construction & demolition waste-C&DW, recycled rigid concrete, reclaimed asphalt pavement-rap

Procedia PDF Downloads 165

Authors: Shu Hwang Ang, Choo Yee Yu, Geik Yong Ang, Yean Yean Chan, Yatimah Binti Alias, And Sook Mei Khor

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With the high prevalence of Type 2 diabetes mellitus across the world, the morbidities and mortalities associated with Type 2 diabetes have significant impact on the production line for a nation. With routine scheduled clinical visits to manage Type 2 diabetes, diabetic patients with hectic lifestyles can have low clinical compliance. Hence, it often decreases the effectiveness of diabetic management personalized for each diabetic patient. Here, we report a useful developed point-of-care (POC) device that detect glycated hemoglobin (HbA1c, biomarker for long-term Type 2 diabetic management). In fact, the established POC devices certified to be used in clinical setting are not only expensive ($ 8 to $10 per test), they also require skillful practitioners to perform sampling and interpretation. As a paper-based biosensor, the developed HbA1c biosensor utilized lateral flow principle to offer an alternative for cost-effective (approximately $2 per test) and end-user friendly device for household testing. Requiring as little as 2 L of finger-picked blood, the test can be performed at the household with just simple dilution and washings. With visual interpretation of numbers of test lines shown on the developed biosensor, it can be interpreted as easy as a urine pregnancy test, aided with scale of intensity provided. In summary, the developed HbA1c immunosensor has been tested to have high selectivity towards HbA1c, and is stable with reasonably good performance in clinical testing. Therefore, our developed HbA1c immunosensor has high potential to be an effective diabetic management tool to increase patient compliance and thus contain the progression of the diabetes.

Keywords: blood, glycated hemoglobin (HbA1c), lateral flow, type 2 diabetes mellitus

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Authors: Rachid Dehini, Brahim Berbaoui

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The main objectives of shunt active power filter (SAPF) is to preserve the power system from unwanted harmonic currents produced by nonlinear loads, as well as to compensate the reactive power. The aim of this paper is to present a (PAPF) supplied by the Photovoltaic cells ,in such a way that the (PAPF) feeds the linear and nonlinear loads by harmonics currents and the excess of the energy is injected into the power system. In order to improve the performances of conventional (PAPF) This paper also proposes artificial neural networks (ANN) for harmonics identification and DC link voltage control. The simulation study results of the new (SAPF) identification technique are found quite satisfactory by assuring good filtering characteristics and high system stability.

Keywords: SAPF, harmonics current, photovoltaic cells, MPPT, artificial neural networks (ANN)

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Authors: M. Saiful Islam, M. Mohandes, S. Rehman, S. Badran

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Increasing necessity of wind power is directing us to have precise knowledge on wind resources. Methodical investigation of potential locations is required for wind power deployment. High penetration of wind energy to the grid is leading multi megawatt installations with huge investment cost. This fact appeals to determine appropriate places for wind farm operation. For accurate assessment, detailed examination of wind speed profile, relative humidity, temperature and other geological or atmospheric parameters are required. Among all of these uncertainty factors influencing wind power estimation, vertical extrapolation of wind speed is perhaps the most difficult and critical one. Different approaches have been used for the extrapolation of wind speed to hub height which are mainly based on Log law, Power law and various modifications of the two. This paper proposes a Artificial Neural Network (ANN) and Genetic Algorithm (GA) based hybrid model, namely GA-NN for vertical extrapolation of wind speed. This model is very simple in a sense that it does not require any parametric estimations like wind shear coefficient, roughness length or atmospheric stability and also reliable compared to other methods. This model uses available measured wind speeds at 10m, 20m and 30m heights to estimate wind speeds up to 100m. A good comparison is found between measured and estimated wind speeds at 30m and 40m with approximately 3% mean absolute percentage error. Comparisons with ANN and power law, further prove the feasibility of the proposed method.

Keywords: wind profile, vertical extrapolation of wind, genetic algorithm, artificial neural network, hybrid machine learning

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Authors: K. Al Ammari, B. G. Clarke

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Soil improvement using vibro stone column techniques consists of two main parts: (1) the installed load bearing columns of well-compacted, coarse-grained material and (2) the improvements to the surrounding soil due to vibro compaction. Extensive research work has been carried out over the last 20 years to understand the improvement in the composite foundation performance due to the second part mentioned above. Nevertheless, few of these studies have tried to quantify some of the key design parameters, namely the changes in the stiffness and stress state of the treated soil, or have consider these parameters in the design and calculation process. Consequently, empirical and conservative design methods are still being used by ground improvement companies with a significant variety of results in engineering practice. Two-dimensional finite element study to develop an axisymmetric model of a single stone column reinforced foundation was performed using PLAXIS 2D AE to quantify the effect of the vibro installation of this column in soft saturated clay. Settlement and bearing performance were studied as an essential part of the design and calculation of the stone column foundation. Particular attention was paid to the large deformation in the soft clay around the installed column caused by the lateral expansion. So updated mesh advanced option was taken in the analysis. In this analysis, different degrees of stone column lateral expansions were simulated and numerically analyzed, and then the changes in the stress state, stiffness, settlement performance and bearing capacity were quantified. It was found that application of radial expansion will produce a horizontal stress in the soft clay mass that gradually decrease as the distance from the stone column axis increases. The excess pore pressure due to the undrained conditions starts to dissipate immediately after finishing the column installation, allowing the horizontal stress to relax. Changes in the coefficient of the lateral earth pressure K ٭, which is very important in representing the stress state, and the new stiffness distribution in the reinforced clay mass, were estimated. More encouraging results showed that increasing the expansion during column installation has a noticeable effect on improving the bearing capacity and reducing the settlement of reinforced ground, So, a design method should include this significant effect of the applied lateral displacement during the stone column instillation in simulation and numerical analysis design.

Keywords: bearing capacity, design, installation, numerical analysis, settlement, stone column

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Authors: Gee-Cheol Kim, Joo-Won Kang

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Structural characteristics of spatial structure are different from that of rahmen structures and it has many factors that are unpredictable experientially. Both horizontal and vertical earthquake should be considered because of seismic behaviour characteristics of spatial structures. This experimental study is conducted about seismic response characteristics of roof structure according to the effect of columns or walls, through scale model of arch structure that has the basic dynamic characteristics of spatial structure. Though remarkable response is not occurred for horizontal direction in the region of higher frequency than the region of frequency that seismic energy is concentrated, relatively large response is occurred in vertical direction. It is proved that seismic response of arch structure with column is varied according to property of column.

Keywords: arch structure, seismic response, shaking table, spatial structure

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Authors: Xuewen Chen, Aizhen Liang, Xiaoping Zhang

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To better understand the spatial variability of soil penetration resistance (SPR) and soil water content (SWC) induced by different tillage and crop rotation in a Mollisol of Northeast China, the soil was sampled from the tillage experiment which was established in Dehui County, Jilin Province, Northeast China, in 2001. Effect of no-tillage (NT), moldboard plow (MP) and ridge tillage (RT) under corn-soybean rotation (C-S) and continuous corn (C-C) system on SPR and SWC were compared with horizontal and vertical variations. The results showed that SPR and SWC spatially varied across the ridge. SPR in the rows was higher than inter-rows, especially in topsoil (2.5-15 cm) of NT and RT plots. SPR of MP changed in the trend with the curve-shaped ridge. In contrast to MP, NT, and RT resulted in average increment of 166.3% and 152.3% at a depth of 2.5-17.5 cm in the row positions, respectively. The mean SPR in topsoil in the rows means soil compaction is not the main factor limiting plant growth and crop yield. SPR in the row of RT soil was lower than NT at a depth of 2.5-12.5 cm. The SWC in NT and RT soil was highest in the inter-rows and least in the rows or shoulders, respectively. However, the lateral variation trend of MP was opposite to NT. From the profile view of SWC, MP was greater than NT and RT in 0-20 cm of the rows. SWC in RT soil was higher than NT in the row of 0-20 cm. Crop rotation did not have a marked impact on SPR and SWC. In addition to the tillage practices, the factor which affects SPR greatly was depth but not position. These two factors have significant effects on SWC. These results indicated that the adoption of RT was a more suitable conservation tillage practices than NT in the black soil of Northeast China.

Keywords: row, soil penetration resistance, spatial variability, tillage practice

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Authors: Aqoul H. H. Alanezy, Ali M. Abdelsalam, Nouby M. Ghazaly

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In recent years, progress has been made in increasing the renewable energy share in the power sector particularly in the wind. The experimental study conducted in this paper aims to investigate the effects of number of blades and inflow wind speed on vibration signals of a vertical axis Savonius type wind turbine. The operation of the model of Savonius type wind turbine is conducted to compare two, three and four blades wind turbines to show vibration amplitudes related with wind speed. It is found that the increase of the number of blades leads to decrease of the vibration magnitude. Furthermore, inflow wind speed has reduced effect on the vibration level for higher number of blades.

Keywords: Savonius type wind turbine, number of blades, renewable energy, vibration signals

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Authors: Chamnan Kumsap, Somsarit Sinnung, Suriyawate Boonthalarath, Teeranai Srithamarong

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This research paper addresses the GIS analysis approach to the investigation of suitable sites for a vertical takeoff and landing drone. The study manipulated GIS and terrain layers into a proper input before the spatial analysis that included slope, reclassify, classify, and buffer was applied to the individual layers. The output layers were weighted, and multi-criteria analyzed before those patches failing to comply with filtering out criteria were discarded. Field survey for each suitable candidate site was conducted to cross-check the proposed approach with the real world. Conclusion was extracted for the VTOL takeoff and landing sites, and discussion was provided with further study being suggested on the mission simulation of selected takeoff and landing sites.

Keywords: GIS approach, site selection, VTOL, takeoff and landing

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Authors: Qian You, Ibrahim Hassan, Lyes Kadem

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An experiment is conducted to fundamentally investigate flow oscillation characteristics in different sizes of single microtubes in vertical upward flow direction. Three microtubes have 0.889 mm, 0.533 mm, and 0.305 mm hydraulic diameters with 100 mm identical heated length. The mass flux of the working fluid FC-72 varies from 700 kg/m2•s to 1400 kg/m2•s, and the heat flux is uniformly applied on the tube surface up to 9.4 W/cm2. The subcooled inlet temperature is maintained around 24°C during the experiment. The effect of hydraulic diameter and mass flux are studied. The results showed that they have interactions on the flow oscillations occurrence and behaviors. The onset of flow instability (OFI), which is a threshold of unstable flow, usually appears in large microtube with diversified and sustained flow oscillations, while the transient point, which is the point when the flow turns from one stable state to another suddenly, is more observed in small microtube without characterized flow oscillations due to the bubble confinement. The OFI/transient point occurs early as hydraulic diameter reduces at a given mass flux. The increased mass flux can delay the OFI/transient point occurrence in large hydraulic diameter, but no significant effect in small size. Although the only transient point is observed in the smallest tube, it appears at small heat flux and is not sensitive to mass flux; hence, the smallest microtube is not recommended since increasing heat flux may cause local dryout.

Keywords: flow boiling instability, hydraulic diameter effect, a single microtube, vertical upward flow

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Authors: L. Magerramova, M. Volkov, A. Stadnikov, A. Khakimov, D. Slugina, V. Isakov, I. Kabanov

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The manufacture of parts of aviation gas turbine engines by additive methods is currently widespread due to the possibility of improving designs. However, the characteristics of the powder materials used in these technologies have not yet been sufficiently studied to our best knowledge. The issue of the resistance of such structures to vibration loads is particularly acute. This paper is devoted to the study of the characteristics of high cycle fatigue of objects (samples and parts) made using additive technologies from modern powder materials of titanium, nickel, and cobalt alloys under high cyclic loading, as well as typical blades of aviation gas turbine engines that experience vibration loads during operation.

Keywords: additive manufacture, gas turbine engines, high cycle fatigue, experimental studies

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Authors: Güneş Aydın, Razi Kalantari Osgouei, Murat Emre Öztürk, Ahmad Partovi Meran, Ekrem Tüfekçi

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Advanced lightweight laminated composite shells are increasingly being used in all types of modern structures, for enhancing their structural efficiency and performance. Such thin-walled structures are susceptible to buckling when subjected to various loading. This paper focuses on the buckling of cylindrical shells under axial compression and torsional loads. Effects of fiber orientation on the maximum buckling load of carbon fiber reinforced polymer (CFRP) shells are optimized. Optimum fiber angles have been calculated analytically by using MATLAB program. Numerical models have been carried out by using Finite Element Method program ABAQUS. Results from analytical and numerical analyses are also compared.

Keywords: buckling, composite, cylindrical shell, finite element, compression, torsion, MATLAB, optimization

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Authors: Gautam, Arjun, V. R. Sharma

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In the civil construction steel and concrete plays a different role but the same purposes dealing with the design of structures that support or resist loads. Concrete has been used in construction since long time from now. Being brittle and weak in tension, concrete is always reinforced with steel bars for the purposes in beams and columns etc. The paper deals with idea of special designed 3D materials which we named as “BUM629” to be placed/anchored in the structural member and mixed with concrete later on, so as to resist the developments of cracks due to shear failure , buckling,tension and compressive load in concrete. It had cutting edge technology through Draft, Analysis and Design the “BUM629”. The results show that “BUM629” has the great results in Mechanical application. Its material properties are design according to the need of structure; we apply the material such as Mild Steel and Magnesium Alloy. “BUM629” are divided into two parts one is applied at the middle section of concrete member where bending movements are maximum and the second part is laying parallel to vertical bars near clear cover, so we design this material and apply in Reinforcement of Civil Structures. “BUM629” is analysis and design for use in the mega structures like skyscrapers, dams and bridges.

Keywords: BUM629, magnesium alloy, cutting edge technology, mechanical application, draft, analysis and design, mega structures

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Authors: Yen-Fen Shen, Meng-Fan Li

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The study aims to investigate the effect of full-body vertical rhythmic training on fatigue, physical activity, and quality of life among middle-aged and elderly hemodialysis patients. The study adopted a quasi-experimental research method and recruited 43 long-term hemodialysis patients from a medical center in northern Taiwan, with 23 and 20 participants in the experimental and control groups, respectively. The experimental group received full-body vertical rhythmic training as an intervention, while the control group received standard hemodialysis care without any intervention. Both groups completed the measurements by using "Fatigue Scale", "Physical Activity Scale" and "Chinese version of the Kidney Disease Quality of Life Questionnaire" before and after the study. The experimental group underwent a 10-minute full-body vertical rhythmic training three times per week, which lasted for eight weeks before receiving regular hemodialysis treatment. The data were analyzed by SPSS 25 software, including descriptive statistics such as frequency distribution, percentages, means, and standard deviations, as well as inferential statistics, including chi-square, independent samples t-test, and paired samples t-test. The study results are summarized as follows: 1. There were no significant differences in demographic variables, fatigue, physical activity, and quality of life between the experimental and control groups in the pre-test. 2. After the intervention of the “full-body vertical rhythmic training,” the experimental group showed significantly better results in the category of "feeling tired and fatigued in the lower back", "physical functioning role limitation", "bodily pain", "social functioning", "mental health", and "impact of kidney disease on life quality." 3. The paired samples t-test results revealed that the control group experienced significant differences between the pre-test and post-test in the categories of feeling tired and fatigued in the lower back, bodily pain, social functioning mental health, and impact of kidney disease on life quality, with scores indicating a decline in life quality. Conversely, the experimental group only showed a significant worsening in bodily pain" and the impact of kidney disease on life quality, with lower change values compared to the control group. Additionally, there was an improvement in the condition of "feeling tired and fatigued in the lower back" for the experimental group. Conclusion: The intervention of the “full-body vertical rhythmic training” had a certain positive effect on the quality of life of the experimental group. While it may not entirely enhance patients' quality of life, it can mitigate the negative impact of kidney disease on certain aspects of the body. The study provides clinical practice, nursing education, and research recommendations based on the results and discusses the limitations of the research.

Keywords: hemodialysis, full-body vertical rhythmic training, fatigue, physical activity, quality of life

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Authors: T. H. Young, Y. J. Tsai

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A method for determining the stress distribution of a rectangular plate subjected to two pairs of arbitrarily distributed in-plane edge shear loads is proposed, and the free vibration and buckling of such a rectangular plate are investigated in this work.  The method utilizes two stress functions to synthesize the stress-resultant field of the plate with each of the stress functions satisfying the biharmonic compatibility equation. The sum of stress-resultant fields due to these two stress functions satisfies the boundary conditions at the edges of the plate, from which these two stress functions are determined. Then, the free vibration and buckling of the rectangular plate are investigated by the Galerkin method. Numerical results obtained by this work are compared with those appeared in the literature, and good agreements are observed.

Keywords: stress analysis, free vibration, plate buckling, nonuniform in-plane edge shear

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Authors: H. R. Vosoughifar, Seyedeh Zeinab. Hosseininejad, Nahid Shabazi, Seyed Mohialdin Hosseininejad

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In recent years, structure designers advocate further application of energy absorption devices for lateral loads damping. The Un-bonded Braced Frame (UBF) system is one of the efficient damping systems, which is made of a smart combination of steel and concrete or mortar. In this system, steel bears the earthquake-induced axial force as compressive or tension forces without loss of strength. Concrete or mortar around the steel core acts as a constraint for brace and prevents brace buckling during seismic axial load. In this study, the optimal bracing system in the high-rise structures has been evaluated considering the seismic stress distribution in the connections. An actual 18-story structure was modeled using the proper Finite Element (FE) software where braced with UBF, Eccentrically Braced Frames (EBF) and Concentrically Braced Frame (CBF) systems. Nonlinear static pushover and time-history analyses are then performed so that the acquired results demonstrate that the UBF system reduces drift values in the high-rise buildings. Further statistical analyses show that there is a significant difference between the drift values of UBF system compared with those resulted from the EBF and CBF systems. Hence, the seismic stress distribution in the connections of the proposed structure which braced with UBF system was investigated.

Keywords: optimal bracing system, high-rise structure, finite element analysis (FEA), seismic stress

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Authors: B. X. Tchomeni, A. A. Alugongo, L. M. Masu

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This paper presents a 4-DOF nonlinear model of a cracked of Laval rotor established based on Energy Principles. The model has been used to simulate coupled torsional-lateral response of the cracked rotor stator-system with multiple parametric excitations, namely, rotor-stator-rub, a breathing transverse crack, unbalanced mass, and an axial force. Nonlinearity due to a “breathing” crack is incorporated by considering a simple hinge model which is suitable for small breathing crack. The vibration response of a cracked rotor passing through its critical speed with rotor-stator interaction is analyzed, and an attempt for crack detection and monitoring explored. Effects of unbalanced eccentricity with phase and acceleration are investigated. By solving the motion equations, steady-state vibration response is obtained in presence of several rotor faults. The presence of a crack is observable in the power spectrum despite the excitation by the axial force and rotor-stator rub impact. Presented results are consistent with existing literature and could be adopted into rotor condition monitoring strategies

Keywords: rotor, crack, rubbing, axial force, non linear

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Authors: Mannal Tariq

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Construction industry is making progress at a high pace. The trend of the world is getting more biased towards the high rise buildings. Deep beams are one of the most common elements in modern construction having small span to depth ratio. Deep beams are mostly used as transfer girders. This experimental study consists of 16 reinforced concrete (RC) deep beams. These beams were divided into two groups; A and B. Groups A and B consist of eight beams each, having 381 mm (15 in) and 457 mm (18 in) depth respectively. Each group was further subdivided into four sub groups each consisting of two identical beams. Each subgroup was comprised of solid/control beam (without opening), opening above neutral axis (NA), at NA and below NA. Except for control beams, all beams with openings were strengthened with carbon fibre reinforced polymer (CFRP) vertical strips. These eight groups differ from each other based on depth and location of openings. For testing sake, all beams have been loaded with two symmetrical point loads. All beams have been designed based on strut and tie model concept. The outcome of experimental investigation elaborates the difference in the shear behaviour of deep beams based on depth and location of circular openings variation. 457 mm (18 in) deep beam with openings above NA show the highest strength and 381 mm (15 in) deep beam with openings below NA show the least strength. CFRP sheets played a vital role in increasing the shear capacity of beams.

Keywords: CFRP, deep beams, openings in deep beams, strut and tie modal, shear behaviour

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Authors: Pouya Kaafi, Gholamreza Ghodrati Amiri

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Abnormal loads due to natural events, implementation errors and some other issues can lead to occurrence of progressive collapse in structures. Most of the past researches consist of 2- Dimensional (2D) models of steel frames without consideration of the floor system effects, which reduces the accuracy of the modeling. While employing a 3-Dimensional (3D) model and modeling the concrete slab system for the floors have a crucial role in the progressive collapse evaluation. In this research, a 3D finite element model of a 5-story steel building is modeled by the ABAQUS software once with modeling the slabs, and the next time without considering them. Then, the progressive collapse potential is evaluated. The results of the analyses indicate that the lack of the consideration of the slabs during the analyses, can lead to inaccuracy in assessing the progressive failure potential of the structure.

Keywords: abnormal loads, composite floor system, intermediate steel moment resisting frame system, progressive collapse

Procedia PDF Downloads 456

Authors: Moustafa Elwan, Sohier Shehata, Fatma Sedek, Manar Hussine

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One of the most risky factors that lead to a foot injury during physical activities are both high and low arched feet. Normally the medial longitudinal arch of the foot develops in the first 10 years of life, so flexible flat foot has an inversely relationship with age in the first decade, all over the world, the prevalence of flat foot is increasing. In approximately 15% of foot deformities cases, the deformity does not disappear and remains throughout adulthood, 90% of the clinical cases are complaining from foot problems are due to flatfoot. Flatfoot creates subtalar over pronation, which creates tibial and femoral medial rotation, and that is accompanied with increases of pelvic tilting anteriorly, which may influence the lumbar vertebrae alignment by increasing muscle tension and rotation. Objective: To study the impact of the flexible flatfoot on lumbosacral angle (angle of Ferguson). Methods: This experiment included 40 volunteers (14 females &26 males) gathered from the Faculty of Physical Therapy, Modern University of Technology and Information, Cairo, Egypt, for each participant, four angles were measured in the foot( talar first metatarsal angle, lateral talocalcaneal angle, , Calcaneal first metatarsal angle, calcaneal inclination angle) and one angle in the lumbar region (lumbosacral angle). Measurement of these angles was conducted by using Surgimap Spine software (version 2.2.9.6). Results: The results demonstrated that there was no significant correlation betweenFerguson angle and lateral talocalcaneal (r=0.164, p=0.313). Also, there was no significant correlation between Ferguson angle and talo first metatarsal “Meary’s angle" (r=0.007, p=0.968). Moreover, there was no significant correlation between Ferguson angle and calcaneal-first metatarsal angle (r=0.083, p=0.612). Also, there was no significant correlation between Ferguson angle and calcaneal inclination angle (r= 0.032, p= 0.846). Conclusion: It can be concluded that there is no significant correlation between the flexible flat foot and lumbosacral angle So, more study should be conducted in large sample and different ages and conditions of foot problems.

Keywords: calcaneal first metatarsal, calcaneal inclination, flatfoot, ferguson’s angle, lateral talocalcaneal angle, lumbosacral angle, and talar first metatarsal angle

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Authors: B. V. Murlimanju, R. Abisshek Balaji, Apoorva Aggarwal, Mangala M. Pai

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Background: Since the literature is scarce from the South Indian population about the sesamoid bones of the thumb, the present study was undertaken. The objective of the present study was to figure out the muscle of the thumb which contain these sesamoid bones. Methods: The present study included 25 cadaveric thumbs, which were obtained from the anatomy laboratory of our institution. Thumbs were studied for the prevalence of sesamoid bones at the metacarpophalangeal and interphalangeal joints. The muscle which contain these sesamoid bones were identified. Results: The present study observed that, there were 2 sesamoid bones (92%) at the metacarpophalangeal joint of the thumb each at its medial and lateral aspect. The medial sesamoid bone was found inside the adductor pollicis muscle and lateral one was found either in the flexor pollicis brevis muscle or abductor pollicis brevis muscle. However, among the 25 thumbs being studied, 2 thumbs (8%) had solitary sesamoid bone. The interphalangeal joint of the thumb exhibited only one sesamoid bone at the median plane. Conclusion: The morphological data of the present study from the South Indians can be used as a database, which is enlightening to the operating hand surgeon and radiologist.

Keywords: morphology, muscles, sesamoid bones, thumb

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Authors: A. Mohamed, A. El-Hamalawi, M. Frost, A. Connell

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Often design standards do not provide guidance or formulae for the calculation of stresses on buried pipelines caused by external loads. Frequently engineers rely on other methods and published sources of information to calculate such imposed stresses and a variety of methods can be used. This paper reviews three current approaches to soil pipeline interaction modelling to predict stresses on buried pipelines subjected to soil overburden and traffic loading. The traditional approach to use empirical stress formulas to calculate circumferential bending stresses on pipelines. The alternative approaches considered are the use of a finite element package to compute an estimate of circumferential bending stress and a proprietary stress analysis system (SURFLOAD) to estimate the circumferential bending stress. The results from analysis using the methods are presented and compared to experimental results in terms of predicted and measured circumferential stresses. This study shows that the approach used to assess externally generated stress is important and can lead to an over-conservative analysis. Using FE analysis either through SURFLOAD or a general FE package to predict circumferential stress is the most accurate way to undertake stress analysis due to traffic and soil loads. Although conservative, classical empirical methods will continue to be applied to the analysis of buried pipelines, an opportunity exists, therefore, in many circumstances, to use applied numerical techniques, made possible by advances in finite element analysis.

Keywords: buried pipelines, circumferential bending stress, finite element analysis, soil overburden, soil pipeline interaction analysis (SPIA), traffic loadings

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Authors: Shruti Motiwale, Xianlin Zhou, Reuben H. Kraft

Abstract:

Military and sports personnel are often required to wear heavy helmets for extended periods of time. This leads to excessive cyclic loads on the neck and an increased chance of injury. Computational models offer one approach to understand and predict the time progression of disc degeneration under severe cyclic loading. In this paper, we have applied an analytic non-linear damage evolution model to estimate damage evolution in an intervertebral disc due to cyclic loads over decade-long time periods. We have also proposed a novel strategy for inclusion of recovery in the damage model. Our results show that damage only grows 20% in the initial 75% of the life, growing exponentially in the remaining 25% life. The analysis also shows that it is crucial to include recovery in a damage model.

Keywords: cervical spine, computational biomechanics, damage evolution, intervertebral disc, continuum damage mechanics

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Authors: Mehmet Alpaslan Köroğlu, Musa Hakan Arslan, Muslu Kazım Körez

Abstract:

Basic objective of this study is to create a regression analysis method that can estimate the length of a plastic hinge which is an important design parameter, by making use of the outcomes of (lateral load-lateral displacement hysteretic curves) the experimental studies conducted for the reinforced square concrete columns. For this aim, 170 different square reinforced concrete column tests results have been collected from the existing literature. The parameters which are thought affecting the plastic hinge length such as cross-section properties, features of material used, axial loading level, confinement of the column, longitudinal reinforcement bars in the columns etc. have been obtained from these 170 different square reinforced concrete column tests. In the study, when determining the length of plastic hinge, using the experimental test results, a regression analysis have been separately tested and compared with each other. In addition, the outcome of mentioned methods on determination of plastic hinge length of the reinforced concrete columns has been compared to other methods available in the literature.

Keywords: columns, plastic hinge length, regression analysis, reinforced concrete

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Authors: M. Shokry Rashwan

Abstract:

This study follows a number of experiments conducted at Red River College (RRC) to investigate the short term properties of tire derived aggregate (TDA) produced from shredding off-the-road (OTR) wasted tires in a proposed new application. The application targets replacing natural material used under concrete slabs and as backfills for residential homes’ basement slabs and walls, respectively, with TDA. The experimental work included determining: compressibility, gradation distribution, unit weight, hydraulic conductivity and lateral pressure. Based on the results of those short term properties; it was decided to move forward to study the long-term performance of this otherwise waste material through on-site demonstration. A full-scale basement replicating a typical Manitoba home was therefore built at RRC where both TDA and Natural Materials (NM) were used side-by-side. A large number of sensing and measuring systems are used to compare between the performances of each material when exposed to the typical ground and weather conditions. Parameters monitored and measured include heat losses, moisture migration, drainage ability, lateral pressure, relative movements of slabs and walls, an integrity of ground water and radon emissions. Up-to-date results have confirmed part of the conclusions reached from the earlier laboratory experiments. However, other results have shown that construction practices; such as placing and compaction, may need some adjustments to achieve more desirable outcomes. This presentation provides a review of both short-term tests as well as up-to-date analysis of the on-site demonstration.

Keywords: tire derived aggregate (TDA), basement construction, TDA material properties, lateral pressure of TDA, hydraulic conductivity of TDA

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Authors: Omar Eldenali, Ahmed M. Bufares

Abstract:

There are primarily two types of Unmanned Aerial Vehicle (UAVs), namely, multirotor and fixed wing. Each type has its own advantages. This study introduces a design of a fixed wing vertical take-off and landing (VTOL) UAV. The design is classified as ready-to-fly (RTF) fixed wing UAV. This means that the UAV is capable of not only taking off, landing, or hovering like a multirotor aircraft but also cruising like a fixed wing UAV. In this study, the conceptual design of 15 kg takeoff weight twin-tail boom configuration FW-VTOL plane is carried out, the initial sizing of the plane is conducted, and both the horizontal and vertical tail configurations are estimated. Moreover, the power required for each stage of flight is determined. Finally, the stability analysis of the plane based on this design is performed, the results shows that this design based on the suggested flight mission is stable and can be utilized.

Keywords: FW-VTOL, initial sizing, constrain analysis, stability

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Authors: Zekun Lin, Xun Li

Abstract:

Silicon photonics has gained much interest and extensive research for a promising aspect for fabricating compact, high-speed and low-cost photonic devices compatible with complementary metal-oxide-semiconductor (CMOS) process. Despite the remarkable progress made on the development of silicon photonics, high-performance, cost-effective, and reliable silicon laser sources are still missing. In this work, we present a 1550 nm III-V/silicon laser design with stable single-mode lasing property and robust and high-efficiency vertical coupling. The InP cavity consists of two uniform Bragg grating sections at sides for mode selection and feedback, as well as a central second-order grating for surface emission. A grating coupler is etched on the SOI waveguide by which the light coupling between the parallel III-V and SOI is reached vertically rather than by evanescent wave coupling. Laser characteristic is simulated and optimized by the traveling-wave model (TWM) and a Green’s function analysis as well as a 2D finite difference time domain (FDTD) method for the coupling process. The simulation results show that single-mode lasing with SMSR better than 48dB is achievable, and the threshold current is less than 15mA with a slope efficiency of around 0.13W/A. The coupling efficiency is larger than 42% and possesses a high tolerance with less than 10% reduction for 10 um horizontal or 15 um vertical dislocation. The design can be realized by standard flip-chip bonding techniques without co-fabrication of III-V and silicon or precise alignment.

Keywords: III-V/silicon integration, silicon photonics, single mode laser, vertical coupling

Procedia PDF Downloads 156