Life-Cycle Prediction
Yinusa Ahmed; Sobamowo Gbeminiyi
Abstract
Iron micro-particles when eject to the atmosphere from industries, factory and production enterprises pollute the atmosphere and generally affect the respiratory system. This paper presents a solution to such transient problem analytically by employing Variation of Parameter Method (VPM). For proper ...
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Iron micro-particles when eject to the atmosphere from industries, factory and production enterprises pollute the atmosphere and generally affect the respiratory system. This paper presents a solution to such transient problem analytically by employing Variation of Parameter Method (VPM). For proper understanding of the problem chemistry and associated time of burning, the parameters involved are meticulously studied. The radiation property of the iron particle at high temperature as well as the impact of this temperature level on density are considered by incorporating radiation and linear micro particles density variation in the governing model. The obtained exact solution using VPM is verified with Runge-Kutta and also compared with the results of other works. Furthermore, error analysis is performed and discussed. The obtained result shows how the surrounding temperature and the heat realization term continue to influence combustible temperature history until an asymptotic behaviour is attained. It is envisaged that the present study will gain application in trying to annul some of the challenges the industries and firms have to overcome on combustion of solid combustibles like iron particles and also in the optimization of different particles burning time.
Ajibola I. Quadri
Abstract
Nowadays assessment of fatigue and reliability of structures have increased dramatically. This is confirmed by the recommendations of the standards and constitutive model of concrete in which the rules and requirements to ensure safety, serviceability and durability of the structure are stated. This ...
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Nowadays assessment of fatigue and reliability of structures have increased dramatically. This is confirmed by the recommendations of the standards and constitutive model of concrete in which the rules and requirements to ensure safety, serviceability and durability of the structure are stated. This study is directed to the reliability assessment of reinforced concrete column and fatigue comparison of (BS: 8110, 1997) and Eurocode 2 (EN: 2, 2004) ultimate limit state requirements on nominal eccentricity of short column resisting moments and forces. The column was modelled as one end fixed to resist moment reaction and free at the other end. It was then examined on fatigue and probabilistically assessed with the variables relating to the uncertainty loading conditions. The First-Order Reliability Method (FORM 5) encoded in CalREL was employed to estimate the implied probability of failure by varying load ratio and reinforcement ratio. And was verified with numerical simulation on CONCRETE MODEL OF 3 Dimension (COM 3). The results obtained have shown that the column assessed lost its flexural and shear carrying capacity gradually as the percentage load increased especially at the joint. Reinforced concrete column’s performance may be dependent on the applied load and could fail if it carries a lot more than the designed loads. It is therefore necessary to perform fatigue investigation to double check the resistant capacity of the column.
Failure Probability
Bijan SayyafZadeh; Saeedeh Kouhestani; Mahdi Sharifi
Abstract
Today oil, gas and petrochemical plants risk mitigation and management due to various aspects such as energy supply, financial implications, life loss and repairs has become a primary concern. One of the approaches that can be used for risk assessment of such these plants which are composed of different ...
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Today oil, gas and petrochemical plants risk mitigation and management due to various aspects such as energy supply, financial implications, life loss and repairs has become a primary concern. One of the approaches that can be used for risk assessment of such these plants which are composed of different types of equipment and structures that have different responses and consequences is the probabilistic analysis. Flare is a process equipment that is widely used in oil, gas and petrochemical plants and depending on the height and type of lateral stability is categorized into self-supported, guy-supported and derrick-supported. In this article seismic behavior of a derrick-supported flare is investigated using finite element method and incremental dynamic analysis as a case study. For this purpose, various limit states were considered and for each of them a fragility curve is calculated and also presented with statistical parameters. The results showed that in ordinary seismic intensities there is no significant seismic demand on the investigated structure but in the range of rare intensities that can trigger technological disasters, there is probability of failure and consequently escalating the disaster.
System Reliability
Ashraf Elfasakhany
Abstract
Incorrect tire pressure reduces vehicle performance, braking effectiveness, system control, and a ride comfort. Tire pressure checking framework (TPCF) is a system framework applied for checking tire pressure. This study aim at summarizing early work for the tire pressure checking framework including ...
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Incorrect tire pressure reduces vehicle performance, braking effectiveness, system control, and a ride comfort. Tire pressure checking framework (TPCF) is a system framework applied for checking tire pressure. This study aim at summarizing early work for the tire pressure checking framework including early different methods. Direct and indirect tire pressure checking frameworks are discussed and a comparison between both methods is summarized. A development of tire pressure checking framework is presented. Risks of the low/high tire pressures are discussed. Operating the tire at lower and/or higher pressure than the specified one can cause several severe problems. Direct TPCF uses physical sensors, however, the indirect TPCF uses velocity and vibration sensors to monitor the tire pressure. Direct TPCF framework method is more accurate than the indirect one; however, the direct showed some problems related to battery life and framework costs. The indirect needs calibration/adjustment by the drivers, and cannot realize the simultaneous loss of pressure from more than one tire in time.
Structural Simulation
Sobhan Mosayebidorcheh; M. Mahmoodi; Taha Mosayebidorcheh; D. D. Ganji
Abstract
This article is aimed to introduce a new hybrid analytical-digital technique for solving a wide range of problems in fluid mechanics. This method is according to the Different Transform Method (DTM) and Newton’s Iterative Method (NIM). In the Boundary Value Problems (BVP), the system and the boundary ...
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This article is aimed to introduce a new hybrid analytical-digital technique for solving a wide range of problems in fluid mechanics. This method is according to the Different Transform Method (DTM) and Newton’s Iterative Method (NIM). In the Boundary Value Problems (BVP), the system and the boundary conditions converted to an algebraic equation set, and the Taylor series of the solution are subsequently calculated. By finding Jacobian matrix, the unknown parameters of the solution may be calculated using the multi-variable iterative Newton's method. The techniques are employed to determine a proximate solution for the problem. To expound upon the application of the new hybrid method illustratively, two nonlinear problems in fluid mechanics are considered: condensation film on the inclined rotating disk and the rotating MHD flow on a porous shrinking sheet. Using comparing the present results obtained with the numerical solutions and results presented in the literature, an excellent accuracy is observed. Quick convergence of the solution is another important merit of the proposed method.
Structural and Infrastructural Safety
Sachin Popat Patil; Jagadish G Kori
Abstract
According to current practices in earthquake engineering, and as per guidelines of codes the multistoried structures are analyzed and designed only for a single, rare design earthquake. In reality, most of the locations are affected by multiple earthquakes within short time intervals, also the repeated ...
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According to current practices in earthquake engineering, and as per guidelines of codes the multistoried structures are analyzed and designed only for a single, rare design earthquake. In reality, most of the locations are affected by multiple earthquakes within short time intervals, also the repeated earthquake effect is ignored. The repeated earthquake affects the strength and stiffness degradation of the structure. In this paper4-, 8-, 12-, 16-storey structures are investigated under repeated earthquakes. The Time history analysis is performed with single, double, and triple earthquake events for calculating drift, displacement, and ductility. The result shows that the drift, displacement, and ductility demand increase with compared to a single earthquake. This research focuses on the study of the effect of a single and repeated earthquake on the multistoried structure and damage identification can be found using deformation in building frame or in frame element with the formation of plastic hinges. The default hinge properties are assigned to elements of structure and the study is carried out to find the location, formation of plastic hinges, and plastic hinge rotation due to repeated earthquake and this study is used to strengthening the element strength. This paper studies the interstory drift ratio and displacement under aftershocks of an earthquake and remedial measures are suggested to strengthen the structure capacity.
Probabilistic Design Approaches
A. Mustapha; Olugbenga Abejide
Abstract
The profound changes in engineering over the last few decades were reflected by ideas of uncertainty recognized in engineering today. Civil engineering structures like steel transmission poles are to be designed for loads created by environmental actions such as wind, snow and earthquake, but these actions ...
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The profound changes in engineering over the last few decades were reflected by ideas of uncertainty recognized in engineering today. Civil engineering structures like steel transmission poles are to be designed for loads created by environmental actions such as wind, snow and earthquake, but these actions are exceptionally uncertain in their manifestations as one is required to quantify the risks and benefits involved. The subject of structural reliability offers a rational framework to quantify uncertainties mathematically. This study presents a probabilistic assessment of the strength of steel poles in service, the resistance of the steel poles, ultimate strength of steel, section modulus, cross sectional dimensions of the poles, distance at which the load acts on the pole and the magnitude of the load acting on the pole are treated as random variables, which can be significantly influenced by time and location. The study has been carried out to determine the structural safety levels of electric distribution steel poles under uncertain loadings using First Order Reliability Method (FORM) in MATLAB with FERUM Version 4.0. The reliability analyses in MATLAB gave lower values of reliability index, (1.4802E+00) and probability of failure (6.9407E-02) for moment failure mode, while higher values of (2.339E+01 and 5.1245E+01) were obtained respectively for deflection and shear failures, with negligible values of 0.100E-10. The effect of variation of parameters like thickness, diameters and length of steel poles were also studied, which indicates that the thickness, diameters and length significantly affects the strength of steel poles.
Stochastic and Statistical Analysis of Structural Resistance and Material
Kolawole Abejide; Jubril Kaurra Mohammed; A. Lawan; Olugbenga Samuel Abejide
Abstract
This study presents the structural reliability of rolled steel beams on offshore platforms exposed to corrosion during their design period and beyond. The rate of corrosion of the rolled steel beam was determined using a standard expression for extreme marine environment. Limit equations were used to ...
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This study presents the structural reliability of rolled steel beams on offshore platforms exposed to corrosion during their design period and beyond. The rate of corrosion of the rolled steel beam was determined using a standard expression for extreme marine environment. Limit equations were used to evaluate the shear performance, deflection, and resistance moment of the rolled steel beams during their design period. The exposure to corrosion was evaluated using the First Order Reliability Method (FORM) in MATLAB with FERUM Version 4.0 (Finite Element Reliability Using Matlab). An increasing decline in the shear, resistance moment, and deflection was observed as the cross sectional area decreased due to corrosion, which is consistent with experimental data. However, it was also noted that the design formulation is robust enough to exceed the design life prediction in the code.
Uncertainties Evaluation of Loads and Loading Conditions
Farshad Dorri; Hooman Ghasemi; Andrzej Nowak
Abstract
Finding an appropriate system to absorb the intended energy of the earthquake is of great importance in seismic region. The eccentric bracing frame (EBF) is one of the structural systems that reveal proper behavior during earthquakes phenomenon. In doing so, design codes attempt to optimize EBF seismic ...
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Finding an appropriate system to absorb the intended energy of the earthquake is of great importance in seismic region. The eccentric bracing frame (EBF) is one of the structural systems that reveal proper behavior during earthquakes phenomenon. In doing so, design codes attempt to optimize EBF seismic behave to avoid failure of the earthquake regarding a set of the criteria. Indeed, the dynamic nonlinear approaches are the most powerful methods which solve the motion equations based on the time history of the ground motion. However, the dynamic nonlinear methods require a rigorous effort to nail the structural responses. Therefore, there is a need to develop a simplified approach such a pushover method which is based on the non-linear static analysis. The main attempt of this research is to present a simplified push overload pattern for EBF system to sufficiently divulge the structural performance subjected to the seismic loadings. In this investigation, three models of the middle rise and tall rise, 10, 20, 30 stories of buildings are considered, which are designed according to the available codes. Accordingly, several different load patterns are developed. The idea behind of each proposed load patterns inspired by the deflection of a rod subjected to the flame. Herein, the meaning of the flame refers to the region of the structures which is subjected to the plastic hinges.
Failure Probability
Saran Srikanth Bodda; Abhinav Gupta; BuSeog Ju; Minho Kwon
Abstract
Safety of critical industrial facilities such as Nuclear power plants has gained significant attention against external events in the last decade. Fukushima Daiichi nuclear power station disaster occurred due to flooding of the plant which was caused by the Great East Japan earthquake and the subsequent ...
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Safety of critical industrial facilities such as Nuclear power plants has gained significant attention against external events in the last decade. Fukushima Daiichi nuclear power station disaster occurred due to flooding of the plant which was caused by the Great East Japan earthquake and the subsequent tsunami. In the US, failure of floodwall system during hurricane Katrina caused widespread damage. Floodwalls are essential to mitigate the effects of rising sea-levels due to climate change. Critical industrial facilities are being increasingly protected from the effects of floods through the use of flood protection systems such as floodwalls, dams, and weirs. This paper evaluates the fragilities for failure of a concrete floodwall due to various failure modes under a multi-hazard scenario (flooding and seismic events). Structural failure of the concrete floodwall is characterized by excessive deformation failure mode for seismic loads. The failure modes considered for flooding loads are rigid body failure and foundation failure.
Structural Simulation
K.K. Kiran; Jagadish Kori
Abstract
Designer of military and high-security facilities, planner, architects and engineers throughout the world are much concerned against a blast load on structures. Blast load is a human hazard occurring in the world, due to terrorist, chemical explosives, mining area, an accident, and so on. Blast load ...
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Designer of military and high-security facilities, planner, architects and engineers throughout the world are much concerned against a blast load on structures. Blast load is a human hazard occurring in the world, due to terrorist, chemical explosives, mining area, an accident, and so on. Blast load is an unpredictable load occurring. The blast load occurs in a few seconds. The blast load does not only lead to structural but also take the life of occupations. In this study five – storey unsymmetrical structures exposed to blast load are considered. The three different control devices are considered such as cladding material, base isolation with lead rubber bearing (LRB) and MR Damper. Cladding material will absorb energy after the severe pressure release from the blast and then transfer less amount of energy to the structures. Base isolations with lead rubber bearing not only absorb energy but also increase the stiffness of the structure. Among the different devices’ MR Damper plays a vital role reduce the considerable amount of responses.
Failure Probability
George Uwadiegwu Alaneme; Gregory C. Ezeokpube; Elvis M. Mbadike
Abstract
Building-failure usually results to collapse if not discovered and properly addressed. Building-collapse/failure most times cause loss of properties and lives. A case study of a partially-collapsed one-story building is presented for emphasis with technical-assessment of the actual collapse cause so ...
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Building-failure usually results to collapse if not discovered and properly addressed. Building-collapse/failure most times cause loss of properties and lives. A case study of a partially-collapsed one-story building is presented for emphasis with technical-assessment of the actual collapse cause so as to proffer remedy of the structure. This is achieved through detailed engineering-analysis of the building’s structural-elements and identification of remedial-options. Field-inspection through excavation of the soil to assess the foundation condition, taking soil-samples from the collapsed-building for laboratory study and non-destructive test. From inspection, it was observed that the building construction was not properly supervised and as a result were under-reinforced, which led to excessive cracks and deflection. The soil is classified by AASHTO as A-2-4; maximum-dry-density of 2.15mg/m3 and optimum-moisture-content of 9%. The compressive-strength of the structural elements were measured using the rebound-hammer and a mean compressive-strength of 13N/mm2 was obtained which indicates a low-compressive-strength concrete. Analytical-hierarchical-process is utilized as the multi-criteria decision making method to derive the actual cause of the collapse and from the priority vector 6%, 56%, 26% and 12% was obtained for soil/foundation, under-reinforcement, low-compressive-strength and overloading alternatives respectively. The consistency-ratio was obtained to be 0.065 this showed that the decision-maker’s subjective assessment is consistent. The summary of the failure investigation underscored the importance of ensuring proper supervision and quality control in the construction of framed structures. The remediation measures outlined are engagement of experts to re-design the structure using relevant-codes; then cracking, chiseling, and excavation to re-build the structure with thorough supervision.
Aerospace and Electrical System Reliability
Jalal Talebolhagh; Mehdi Mokhtari
Abstract
Lightning is a natural phenomenon when hits on a body causes multiple damages such as melting and burning at the point of contact, mechanical damage due to sound wave propagation and destruction due to magnetic flux. Lightning drains the electrical current up to 200 kA and the electro-thermodynamic reaction ...
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Lightning is a natural phenomenon when hits on a body causes multiple damages such as melting and burning at the point of contact, mechanical damage due to sound wave propagation and destruction due to magnetic flux. Lightning drains the electrical current up to 200 kA and the electro-thermodynamic reaction of the material may cause degradation, stratification, and surface breakdown. Most of the field observations of TV and FM towers’ collisions due to lightning strikes show that the main tubular columns have been severely ruptured in the vicinity of the foundation. The high temperature generated during the flow of electricity produces heat through the conductive structure of the main body of the tower, as well as the expansion of gas inside the pipe which ultimately results in the explosion of the pipe and rupturing the towers. In this paper, a part of a tubular column of the tower is chosen and analyzed in ABAQUS software under the effect of lightning induced heat flux. The results show that the very high heat flux generated at the tubular column of the tower could be the main reason for the fracture.
Structural and Infrastructural Safety
Sachin Popat Patil; Jagadish G Kori
Abstract
This study evaluates the performance of an RC frame structure using nonlinear static and nonlinear dynamic analysis procedures. To achieve this objective, five-moment resisting frames with 4,8,12,16,20 storied buildings were analyzed and designed following the guidelines of the seismic codes was subjected ...
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This study evaluates the performance of an RC frame structure using nonlinear static and nonlinear dynamic analysis procedures. To achieve this objective, five-moment resisting frames with 4,8,12,16,20 storied buildings were analyzed and designed following the guidelines of the seismic codes was subjected to single, double, and triple earthquake events, that is, repeated earthquakes. The assessment of the structure in terms of the failure of members and the performance of the structure in terms of displacement and ductility was measured for different earthquake events, which was then converted into a multiplying factor. These seismic performance factors were used to increase the strength and stiffness of the structures at various locations. These factors were used for the design of an earthquake force-resisting system in a new building. In this study, the performance of a building subjected to a maximum considered earthquake (MCE) and for a repeated earthquake is checked and applied to the revised design procedure of the structure. By considering different performance points of the structure when subjected to repeated earthquakes, a new design philosophy was introduced. The building was designed using this new philosophy, and the structural stability of the structure was verified by applying repeated earthquakes.
Structural and Infrastructural Safety
Vahed Ghiasi; Mehran Azami
Abstract
In this review article, we examine the behavior of earthen dams under earthquake movements. Earthen dams perform satisfactorily when exposed to strong earthquakes. Their performance is usually related to the nature of the soil used for the structure. Most well-constructed earthen dams can significantly ...
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In this review article, we examine the behavior of earthen dams under earthquake movements. Earthen dams perform satisfactorily when exposed to strong earthquakes. Their performance is usually related to the nature of the soil used for the structure. Most well-constructed earthen dams can significantly vibrate the earthquake without damaging effects. Dams made of compacted clay materials on clay foundations or bedrock withstood strong ground movement. Compared to older embankments built on sandy materials or of sand or silt with inefficient density and tailings dams, all of them showed almost some instances of failure, which was initially due to the liquefaction capability of these materials. They are considered a type of hydraulic structure in this period, and tailings dams are the most dangerous types of earth dams. The more accurate and durable equipment and tools are used during the construction and operation of the dam, the minor deformation is created in the dam, and the more controllable it becomes. Utilizing up-to-date knowledge and benefiting from the construction and maintenance experiences of the dam can help the optimal management of the dam during construction and operation. The main finding from this study is earth dams have better flexibility to accept the dynamic load due to earthquake force than concrete dams.
Structural and Infrastructural Safety
Vahed Ghiasi; Fahime Sohrabi
Abstract
Excess soil stress may lead to an additional settlement or shear failure of the soil, which in both cases, causes damage to the structure. Therefore, geotechnical and structural engineers who design the foundation must evaluate the bearing capacity of the soil. Most of the foundations are implemented ...
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Excess soil stress may lead to an additional settlement or shear failure of the soil, which in both cases, causes damage to the structure. Therefore, geotechnical and structural engineers who design the foundation must evaluate the bearing capacity of the soil. Most of the foundations are implemented on unsaturated soils, and using the relations, due to considering the soil as saturated and with lower shear strength, leads to conservative results and is cost-intensive. This study discusses the optimization of the bearing capacity of shallow foundations and a comparison between deterministic and probabilistic methods. In this study, the bearing capacity of shallow foundations using the Monte Carlo method and constructive solutions to improve shallow foundations’ performance.
Risk Assessment
K.K. Kiran; Jagadish G Kori
Abstract
Blast load is an impulse, unpredictable load occurs on the structure. It causes not only damage to the structure but also takes the life of the people. Here an attempt is studied is carried out for a high-rise structure exposed to blast load. The response is calculated by using Adaptative based modal ...
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Blast load is an impulse, unpredictable load occurs on the structure. It causes not only damage to the structure but also takes the life of the people. Here an attempt is studied is carried out for a high-rise structure exposed to blast load. The response is calculated by using Adaptative based modal push over analysis. The responses are storey drift, displacement, velocity, accelerations, pressure, impulse, base shear, interstorey displacement, storey drift ratio and normalized pressure impulse. The three-dimensional analysis is carried out. The response is controlled by using M R damper and cladding material. The different algorithm is used for the analysis of MR damper are Bang Bang, Clipped Optimal, Lyapunov and LQR control algorithm.
Uncertainties Evaluation of Loads and Loading Conditions
Franziska Schmidt; Marcel Nowak; Mariia Nesterova; Oliver Fischer
Abstract
When dealing with the construction of a bridge or the assessment of an existing bridge to traffic loads, one important point is the prediction of reliability levels for critical details to the expected traffic loads in its remaining lifetime: this is done here for details of a steel-orthotropic bridge ...
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When dealing with the construction of a bridge or the assessment of an existing bridge to traffic loads, one important point is the prediction of reliability levels for critical details to the expected traffic loads in its remaining lifetime: this is done here for details of a steel-orthotropic bridge deck based on limited traffic monitoring data. A comparison of results from different statistical approaches is made by analyzing the recorded data for the traffic actions: to do that, the work begins with the writing of limit state functions for the ultimate limit state using various probability distributions, to evaluate the corresponding reliability indexes. Indeed, three methods to assess extreme values, Generalized Extreme Value, Peaks-over-Threshold and Level Crossing Counting, are applied. Therefore, one of the extrapolation methods that have been used in the background works for the European Norms (Eurocode 1) is treated here. Moreover, the comparison with the European design load model and the corresponding ultimate limit state is made.
