Israel E. Herrera, Franklin M. Torres, Jatziri Y. Moreno, J. M. Gutierrez, Noé Saldaña
The development and construction of highway infrastructure are essential in developing countries, whereas its layout and construction sometimes interact with the coastal environment. One problem to attend to is that the outline and geometry designs impact as little as possible on the hydrodynamic circulation of coastal bodies in order to alter the associated ecosystem as little as possible. The study area is located in the north of Colombia, and is made up of a continental coastal zone (Mallorquín Lagoon) and a marine zone (Caribbean Sea), in which a highway is projected that provides communication between two locations. This study presents the application of a numerical model previously developed and modified by the Berkhoff equation, which is developed in a finite difference scheme and has been validated and applied in different works in coastal and fluvial shallow water areas. The application of the model was carried out in a hydrodynamic circulation research project for a one-way highway through a coastal lagoon, where the knowledge of the magnitude of the incident wave height in the structure of the road body is necessary for the design, protection elements, and road geometry. Two numerical simulation scenarios were carried out, specifying normal conditions and extraordinary wave conditions in the month of November with a simulation time of 15 days, obtaining the velocity field associated with coastal currents, waves, and wave modification phenomena, such as refraction, diffraction, and reflection, which provide the height of the incident wave on the highway and the recirculation patterns in the coastal lagoon to identify alterations in the ecosystem. The results of the wave height in each scenario and the velocity field provide values to be used in the design, type of armor, and dimensions of the protection works required for the proper functioning of the road structure.
{"title":"Numerical Modelling of Free Surface Agitation in a Coastal Lagoon by Roadway Path Influence","authors":"Israel E. Herrera, Franklin M. Torres, Jatziri Y. Moreno, J. M. Gutierrez, Noé Saldaña","doi":"10.1155/2023/9580327","DOIUrl":"https://doi.org/10.1155/2023/9580327","url":null,"abstract":"The development and construction of highway infrastructure are essential in developing countries, whereas its layout and construction sometimes interact with the coastal environment. One problem to attend to is that the outline and geometry designs impact as little as possible on the hydrodynamic circulation of coastal bodies in order to alter the associated ecosystem as little as possible. The study area is located in the north of Colombia, and is made up of a continental coastal zone (Mallorquín Lagoon) and a marine zone (Caribbean Sea), in which a highway is projected that provides communication between two locations. This study presents the application of a numerical model previously developed and modified by the Berkhoff equation, which is developed in a finite difference scheme and has been validated and applied in different works in coastal and fluvial shallow water areas. The application of the model was carried out in a hydrodynamic circulation research project for a one-way highway through a coastal lagoon, where the knowledge of the magnitude of the incident wave height in the structure of the road body is necessary for the design, protection elements, and road geometry. Two numerical simulation scenarios were carried out, specifying normal conditions and extraordinary wave conditions in the month of November with a simulation time of 15 days, obtaining the velocity field associated with coastal currents, waves, and wave modification phenomena, such as refraction, diffraction, and reflection, which provide the height of the incident wave on the highway and the recirculation patterns in the coastal lagoon to identify alterations in the ecosystem. The results of the wave height in each scenario and the velocity field provide values to be used in the design, type of armor, and dimensions of the protection works required for the proper functioning of the road structure.","PeriodicalId":45541,"journal":{"name":"Modelling and Simulation in Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89141838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hewan Getachew Yenealem, D. T. Redda, Awel Mohammedseid
This study investigated the influence of axle load on the wear rate of railway wheel material. Excessive wear of wheel/rail materials and reduced service life of the wheel/rail system might be caused by the increase in axle load and traffic volume. Two kinds of rail and wheel steels have been studied against different axle load steps, simulating them for wear performance analysis using multibody simulation software (SIMPACK) and MATLAB programming. The simulation model results are validated against the vehicle’s specifications and wear depth measured on Ethiopia—Addis Ababa Light Rail Transit (LRT), and experimental results from the literature. The result shows that the wear rate increases proportionally with the increasing of applied load and that the proportionality coefficient is 0.1393, which has a very good agreement with the experimental results from the works of literature. Likewise, the estimated total tread wear amount after a mileage of 52,000 km is 2% larger than the measured one in LRT, which is indeed an excellent result taking into account the inaccuracy of the wheel diameter gauge used to measure the wheel transversal profile. In normalized UIC 50 kg/m rail and S1002 wheel profile, the wear rate increases linearly from 5110.02, 9997.87, and 18990.17 mm3/km on 11, 21, and 30 tones applied load, respectively. Apparently, on the hardened UIC 60 kg/m and S1002 wheel profiles, the wear rate has been improved by 14.5%, 10.8%, and 7.5% on 11, 21, and 30 tones applied load, respectively, in comparison to normalized rail/wheel match. Briefly, the wheel wear rate is highly influenced by the increasing applied load, referring proportionality coefficient of 0.1393.
{"title":"Influence of Axle Load on the Wear of Railway Wheel Material","authors":"Hewan Getachew Yenealem, D. T. Redda, Awel Mohammedseid","doi":"10.1155/2023/6730640","DOIUrl":"https://doi.org/10.1155/2023/6730640","url":null,"abstract":"This study investigated the influence of axle load on the wear rate of railway wheel material. Excessive wear of wheel/rail materials and reduced service life of the wheel/rail system might be caused by the increase in axle load and traffic volume. Two kinds of rail and wheel steels have been studied against different axle load steps, simulating them for wear performance analysis using multibody simulation software (SIMPACK) and MATLAB programming. The simulation model results are validated against the vehicle’s specifications and wear depth measured on Ethiopia—Addis Ababa Light Rail Transit (LRT), and experimental results from the literature. The result shows that the wear rate increases proportionally with the increasing of applied load and that the proportionality coefficient is 0.1393, which has a very good agreement with the experimental results from the works of literature. Likewise, the estimated total tread wear amount after a mileage of 52,000 km is 2% larger than the measured one in LRT, which is indeed an excellent result taking into account the inaccuracy of the wheel diameter gauge used to measure the wheel transversal profile. In normalized UIC 50 kg/m rail and S1002 wheel profile, the wear rate increases linearly from 5110.02, 9997.87, and 18990.17 mm3/km on 11, 21, and 30 tones applied load, respectively. Apparently, on the hardened UIC 60 kg/m and S1002 wheel profiles, the wear rate has been improved by 14.5%, 10.8%, and 7.5% on 11, 21, and 30 tones applied load, respectively, in comparison to normalized rail/wheel match. Briefly, the wheel wear rate is highly influenced by the increasing applied load, referring proportionality coefficient of 0.1393.","PeriodicalId":45541,"journal":{"name":"Modelling and Simulation in Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87519368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the teaching of plastic mechanics and applications of slip-line theory using conventional methods, multivalued results are usually caused by the uncertain direction of the slip line and dip angles. Determination rules for the α and β directions and φ values are proposed to improve slip-line theory according to the particle flow law under the effect of principal stress, and slip lines and dip angles suitable for a typical stress boundary problem are described. The α and β slip lines should simultaneously point to or away from the intersection, and the synthetic direction of the slip lines should point to the first principal stress σ1 or away from the direction of the third principal stress σ3. When the Hencky stress equation of the α line is applied, two points on the α line should maintain the same direction, and the absolute value of the φ difference should be less than or equal to π. Moreover, the α line of two points should simultaneously point to the inner and outer normal direction of the β line when the Hencky stress equation of the β line is used. The average stress and critical load of plastic deformation in the plane lath V-notch tension are solved using slip-line theory. Both the calculated critical stress and the load maintain uniformity using different slip lines and dip angles, and the proposed determination rule reliably avoids multivalued solutions. This is important for students and researchers in correctly understanding and applying slip-line theory.
{"title":"Determination Rule for α, β Directions and φ in Teaching of Slip-Line Theory","authors":"R. Mei, L. Bao, Han Gao, Xin Zhang","doi":"10.1155/2023/8863386","DOIUrl":"https://doi.org/10.1155/2023/8863386","url":null,"abstract":"In the teaching of plastic mechanics and applications of slip-line theory using conventional methods, multivalued results are usually caused by the uncertain direction of the slip line and dip angles. Determination rules for the α and β directions and φ values are proposed to improve slip-line theory according to the particle flow law under the effect of principal stress, and slip lines and dip angles suitable for a typical stress boundary problem are described. The α and β slip lines should simultaneously point to or away from the intersection, and the synthetic direction of the slip lines should point to the first principal stress σ1 or away from the direction of the third principal stress σ3. When the Hencky stress equation of the α line is applied, two points on the α line should maintain the same direction, and the absolute value of the φ difference should be less than or equal to π. Moreover, the α line of two points should simultaneously point to the inner and outer normal direction of the β line when the Hencky stress equation of the β line is used. The average stress and critical load of plastic deformation in the plane lath V-notch tension are solved using slip-line theory. Both the calculated critical stress and the load maintain uniformity using different slip lines and dip angles, and the proposed determination rule reliably avoids multivalued solutions. This is important for students and researchers in correctly understanding and applying slip-line theory.","PeriodicalId":45541,"journal":{"name":"Modelling and Simulation in Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79129991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rollover is a dangerous phenomenon. It is closely related to the vehicle roll angle. The greater the roll angle, the greater the risk of rollover. The vehicle roll angle when steering depends on many factors, such as the size of the vehicle, speed of movement, steering angle, etc. In this paper, the author has simulated the oscillation of a car when steering using MATLAB® software with three specific cases. The purpose of the study is to evaluate the dependence of the roll angle on other factors. Each case handles two scenarios: vehicle speed change (fixed height) and vehicle height change (fixed speed). The model of a complex dynamic, a combination of many nonlinear components, is used to simulate vehicle oscillations. According to the study’s results, the roll angle will increase if the speed or the distance from the center of gravity (CG) to roll axis (RA) increases, respectively. Once the roll angle’s value rises, the roll index also increases, which causes the dynamic force at the wheel to decrease. If the vertical force at the wheel approaches zero, a rollover may occur. The rollover phenomenon occurred in the second case, corresponding to speeds v = 80 (km/h) and v = 85 (km/h). The peak values of the roll angle are 7.77° and 7.63°, respectively. This result helps to identify the factors affecting the rollover phenomenon more clearly.
{"title":"Investigate the Relationship between the Vehicle Roll Angle and Other Factors When Steering","authors":"Duc Ngoc Nguyen, T. Nguyen","doi":"10.1155/2023/6069078","DOIUrl":"https://doi.org/10.1155/2023/6069078","url":null,"abstract":"Rollover is a dangerous phenomenon. It is closely related to the vehicle roll angle. The greater the roll angle, the greater the risk of rollover. The vehicle roll angle when steering depends on many factors, such as the size of the vehicle, speed of movement, steering angle, etc. In this paper, the author has simulated the oscillation of a car when steering using MATLAB® software with three specific cases. The purpose of the study is to evaluate the dependence of the roll angle on other factors. Each case handles two scenarios: vehicle speed change (fixed height) and vehicle height change (fixed speed). The model of a complex dynamic, a combination of many nonlinear components, is used to simulate vehicle oscillations. According to the study’s results, the roll angle will increase if the speed or the distance from the center of gravity (CG) to roll axis (RA) increases, respectively. Once the roll angle’s value rises, the roll index also increases, which causes the dynamic force at the wheel to decrease. If the vertical force at the wheel approaches zero, a rollover may occur. The rollover phenomenon occurred in the second case, corresponding to speeds \u0000 \u0000 v\u0000 =\u0000 80\u0000 \u0000 (km/h) and \u0000 \u0000 v\u0000 =\u0000 85\u0000 \u0000 (km/h). The peak values of the roll angle are 7.77° and 7.63°, respectively. This result helps to identify the factors affecting the rollover phenomenon more clearly.","PeriodicalId":45541,"journal":{"name":"Modelling and Simulation in Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82365261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ayush Narang, Siddhartha Roy, Tarun Kataray, Vishal Bonde, S. Rajesh, C. Chiranjeevi, Utkarsh Chadha, Bulcha Bekele Hirpha
Freshwater scarcity is increasing across many parts of the globe; to meet this demand, seawater desalination is the best choice, and the electrical energy consumption is escalating due to urbanization and industrialization. Sustainable production of electricity and freshwater can be met by an integrating photovoltaic-thermal (PVT) module with stepped solar still (SSS). The present study focuses on the theoretical modeling of the PVT-SSS desalination system for evaluating thermal efficiency, energy efficiency, freshwater productivity, and electrical power generation. The solar still productivity will be influenced by the depth of water, insulation thickness, glass cover material, thickness and inclination, and operational factors like preheating the input water supply and water salinity. A comparative analysis has been made of summer, winter, and rainy climatic conditions of Vellore town (12.9165° N, 79.1325° E), Tamil Nadu. In the present work, a thermodynamic model based on mass and energy balance is developed for the PVT-SSS system, and it is solved by a numerical method. A Runge-Kutta technique of 4th order is employed using a Python program for solving the thermodynamic simulation model. The results from the model depict that for summer, winter, and rainy climatic seasons, the freshwater productivity of PV/T-SSS was determined to be 12.18 kg/m2day, 6.67 kg/m2day, and 2.77 kg/m2day. Also, it is found that electrical efficiency for summer, winter, and rainy seasons is 8.91%, 9.135%, and 9.53%, respectively. A maximum and minimum freshwater production of 1668 kg/m2 and 1218 kg/m2 are observed for a depth of 2 cm and 5 cm, respectively.
{"title":"Performance Evaluation of a Photovoltaic-Thermal Collector Coupled Stepped Solar Still for Indian Climatic Conditions","authors":"Ayush Narang, Siddhartha Roy, Tarun Kataray, Vishal Bonde, S. Rajesh, C. Chiranjeevi, Utkarsh Chadha, Bulcha Bekele Hirpha","doi":"10.1155/2022/4179612","DOIUrl":"https://doi.org/10.1155/2022/4179612","url":null,"abstract":"Freshwater scarcity is increasing across many parts of the globe; to meet this demand, seawater desalination is the best choice, and the electrical energy consumption is escalating due to urbanization and industrialization. Sustainable production of electricity and freshwater can be met by an integrating photovoltaic-thermal (PVT) module with stepped solar still (SSS). The present study focuses on the theoretical modeling of the PVT-SSS desalination system for evaluating thermal efficiency, energy efficiency, freshwater productivity, and electrical power generation. The solar still productivity will be influenced by the depth of water, insulation thickness, glass cover material, thickness and inclination, and operational factors like preheating the input water supply and water salinity. A comparative analysis has been made of summer, winter, and rainy climatic conditions of Vellore town (12.9165° N, 79.1325° E), Tamil Nadu. In the present work, a thermodynamic model based on mass and energy balance is developed for the PVT-SSS system, and it is solved by a numerical method. A Runge-Kutta technique of 4th order is employed using a Python program for solving the thermodynamic simulation model. The results from the model depict that for summer, winter, and rainy climatic seasons, the freshwater productivity of PV/T-SSS was determined to be 12.18 kg/m2day, 6.67 kg/m2day, and 2.77 kg/m2day. Also, it is found that electrical efficiency for summer, winter, and rainy seasons is 8.91%, 9.135%, and 9.53%, respectively. A maximum and minimum freshwater production of 1668 kg/m2 and 1218 kg/m2 are observed for a depth of 2 cm and 5 cm, respectively.","PeriodicalId":45541,"journal":{"name":"Modelling and Simulation in Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2022-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76390947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fangjin Sun, Haoxuan Tang, Mingjin Lu, Daming Zhang, Chen Lu
This paper reports the wind pressure characteristics on long-span roofs under fluctuating wind in a vertical direction based on a large eddy simulation (LES). Three types of roofs, i.e., saddle, wavy, and continuous arch roofs, are tested. First, the membrane structure canopy is measured, and the model is established for numerical simulation. The computational models and methods are verified by comparing the obtained wind pressure distributions on the roof with the measured results and numerical simulation results under other methods. Next, a numerical simulation is performed to understand not only the wind pressure and the wind speed time series but also the wind vibration responses and fluid-solid coupling. The effects of lateral fluctuating wind at different wind speeds on the wind-induced vibration response and wind pressure distribution of different membrane structures are studied. Based on the results, the wind pressure zones of the roofs are discussed. Furthermore, the original structures are optimized and numerically simulated considering the streamlined design concept to study the influence mechanism of fluctuating wind on the roof in more detail.
{"title":"A Study on Wind Pressure Characteristics of a Large-Span Membrane Structure under the Fluctuating Wind in a Vertical Direction Based on a Large Eddy Simulation","authors":"Fangjin Sun, Haoxuan Tang, Mingjin Lu, Daming Zhang, Chen Lu","doi":"10.1155/2022/8209487","DOIUrl":"https://doi.org/10.1155/2022/8209487","url":null,"abstract":"This paper reports the wind pressure characteristics on long-span roofs under fluctuating wind in a vertical direction based on a large eddy simulation (LES). Three types of roofs, i.e., saddle, wavy, and continuous arch roofs, are tested. First, the membrane structure canopy is measured, and the model is established for numerical simulation. The computational models and methods are verified by comparing the obtained wind pressure distributions on the roof with the measured results and numerical simulation results under other methods. Next, a numerical simulation is performed to understand not only the wind pressure and the wind speed time series but also the wind vibration responses and fluid-solid coupling. The effects of lateral fluctuating wind at different wind speeds on the wind-induced vibration response and wind pressure distribution of different membrane structures are studied. Based on the results, the wind pressure zones of the roofs are discussed. Furthermore, the original structures are optimized and numerically simulated considering the streamlined design concept to study the influence mechanism of fluctuating wind on the roof in more detail.","PeriodicalId":45541,"journal":{"name":"Modelling and Simulation in Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2022-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80321446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The influence of masonry infill walls on the progressive collapse performance of reinforced concrete (RC) frame structures was investigated in this paper, using a nonlinear dynamic analysis approach. Based on ANSYS/LS-DYNA finite element software, two finite element models of RC frame structures with and without masonry infilled walls were established. Then, the collapse modes of the two RC frame structure models were analyzed for different scaled distance blast loads, different locations of column damage, and different span numbers. The results show that with the increase of explosive amount, the collapse degree of the structure is more serious in the same time. Under the condition of destroying the outermost central column, the degree of progressive collapse of the RC frame model with infilled walls in the same time is lower than that of the RC frame model without infilled walls. The RC frame model with infilled walls is more resistant to collapse when the outermost side columns are damaged. With the increase of span number, the structure is more likely to be damaged and collapsed.
{"title":"Numerical Simulation Study of Progressive Collapse of Reinforced Concrete Frames with Masonry Infill Walls under Blast Loading","authors":"Qinghua Xu, Xuezhi Zhen, Yu Zhang, Mengjun Han, Wenkang Zhang","doi":"10.1155/2022/1781415","DOIUrl":"https://doi.org/10.1155/2022/1781415","url":null,"abstract":"The influence of masonry infill walls on the progressive collapse performance of reinforced concrete (RC) frame structures was investigated in this paper, using a nonlinear dynamic analysis approach. Based on ANSYS/LS-DYNA finite element software, two finite element models of RC frame structures with and without masonry infilled walls were established. Then, the collapse modes of the two RC frame structure models were analyzed for different scaled distance blast loads, different locations of column damage, and different span numbers. The results show that with the increase of explosive amount, the collapse degree of the structure is more serious in the same time. Under the condition of destroying the outermost central column, the degree of progressive collapse of the RC frame model with infilled walls in the same time is lower than that of the RC frame model without infilled walls. The RC frame model with infilled walls is more resistant to collapse when the outermost side columns are damaged. With the increase of span number, the structure is more likely to be damaged and collapsed.","PeriodicalId":45541,"journal":{"name":"Modelling and Simulation in Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90992297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A superconducting magnet for particle accelerators is often modeled as an ideal inductor, as it indeed exhibits a completely negligible resistance; this is fully satisfactory, as an example, for control purposes, as the time constant formed by the magnet inductance and the resistance of normal conducting cables connecting it to the power converter accurately describe the essentially dominant dynamics of the circuit. Such a model would however fail to correctly represent the noise attenuation mechanism at play in practical superconducting magnets, which also include a vacuum pipe or a beam screen in the inner part of the aperture, an iron yoke on the outer part, and, potentially, a stainless steel or aluminum collar in between. Even at relatively low frequencies, a more accurate model is therefore needed. A sufficiently general one is proposed and illustrated.
{"title":"Low-Frequency Analytical Model of Superconducting Magnet Impedance","authors":"M. Martino","doi":"10.1155/2022/2105847","DOIUrl":"https://doi.org/10.1155/2022/2105847","url":null,"abstract":"A superconducting magnet for particle accelerators is often modeled as an ideal inductor, as it indeed exhibits a completely negligible resistance; this is fully satisfactory, as an example, for control purposes, as the time constant formed by the magnet inductance and the resistance of normal conducting cables connecting it to the power converter accurately describe the essentially dominant dynamics of the circuit. Such a model would however fail to correctly represent the noise attenuation mechanism at play in practical superconducting magnets, which also include a vacuum pipe or a beam screen in the inner part of the aperture, an iron yoke on the outer part, and, potentially, a stainless steel or aluminum collar in between. Even at relatively low frequencies, a more accurate model is therefore needed. A sufficiently general one is proposed and illustrated.","PeriodicalId":45541,"journal":{"name":"Modelling and Simulation in Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2022-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79227654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper examines the application of the Wiener process as a degradation model. Its appropriateness as a degradation model is discussed and demonstrated with the aid of Monte Carlo simulations. In particular and for monotonically degrading systems, this paper demonstrates that the irreversible accumulation of damage can be modelled by the Wiener maximum process. First passage times of the Wiener and its maximum process are also revealed to coincide. Practical advantages of assessing system reliability from degradation data are highlighted by applying the Wiener process model to a real gallium arsenide (GaAs) laser data for telecommunication systems. The real data application results demonstrate that degradation analysis allows for conclusions about system reliability to be reached earlier without compromising estimation accuracy—a major practical advantage.
{"title":"On Wiener Process Degradation Model for Product Reliability Assessment: A Simulation Study","authors":"Herbert Hove, Farai Mlambo","doi":"10.1155/2022/7079532","DOIUrl":"https://doi.org/10.1155/2022/7079532","url":null,"abstract":"This paper examines the application of the Wiener process as a degradation model. Its appropriateness as a degradation model is discussed and demonstrated with the aid of Monte Carlo simulations. In particular and for monotonically degrading systems, this paper demonstrates that the irreversible accumulation of damage can be modelled by the Wiener maximum process. First passage times of the Wiener and its maximum process are also revealed to coincide. Practical advantages of assessing system reliability from degradation data are highlighted by applying the Wiener process model to a real gallium arsenide (GaAs) laser data for telecommunication systems. The real data application results demonstrate that degradation analysis allows for conclusions about system reliability to be reached earlier without compromising estimation accuracy—a major practical advantage.","PeriodicalId":45541,"journal":{"name":"Modelling and Simulation in Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2022-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74952128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A slope riverbank failure is a natural event that occurs globally on each riverbank, and a drawdown event usually causes slope riverbank failure. This case study is aimed at analysing slope riverbank failures by evaluating the seepage and slope stability of the riverbank under slow and rapid drawdown. The riverbank in this case study is located at KM 3.49, Jalan Pantai Luagan in the Sipitang district (N 4° 59 ′ 12.9 ″ E 115° 31 ′ 13.3 ″ ). A literature review was conducted to view the current study pattern and retrieve a methodology based on the current study pattern. GeoStudio is a commercial finite element software. The data obtained from the borehole log report and online resources were utilised to create the riverbank model in software. The phreatic line shows a slow change over time, indicating that the riverbank takes a long time to stabilise after the drawdown. The FOS value decreases during the drawdown occurrence and slowly increases after the drawdown has ended. In conclusion, the drawdown event can cause slope riverbank failure, and the seepage and stability analysis using GeoStudio can show the condition of the riverbank during the drawdown event.
坡面河堤破坏是发生在各个河堤上的全局自然事件，而滑坡事件通常会导致坡面河堤破坏。本案例研究的目的是通过评估缓慢和快速下降下的河岸渗流和边坡稳定性来分析斜坡河岸破坏。本案例研究中的河岸位于西皮塘地区Jalan Pantai Luagan的KM 3.49(北纬4°59′12.9″东经115°31′13.3″)。通过文献综述来查看当前的研究模式，并检索基于当前研究模式的方法。GeoStudio是一款商业有限元软件。利用钻孔测井报告和在线资源获得的数据在软件中创建河岸模型。潜水线随时间的变化缓慢，表明河岸在下降后需要很长时间才能稳定下来。FOS值在降载发生时减小，在降载结束后缓慢增大。综上所述，滑坡事件会导致坡面河堤破坏，利用GeoStudio进行的渗流与稳定性分析可以反映滑坡事件发生时河堤的状况。
{"title":"Case Study on Analyses of Slope Riverbank Failure","authors":"N. Taha, M. Shariff, M. A. Ladin","doi":"10.1155/2022/1965224","DOIUrl":"https://doi.org/10.1155/2022/1965224","url":null,"abstract":"A slope riverbank failure is a natural event that occurs globally on each riverbank, and a drawdown event usually causes slope riverbank failure. This case study is aimed at analysing slope riverbank failures by evaluating the seepage and slope stability of the riverbank under slow and rapid drawdown. The riverbank in this case study is located at KM 3.49, Jalan Pantai Luagan in the Sipitang district (N 4° 59\u0000 \u0000 ′\u0000 \u0000 12.9\u0000 \u0000 \u0000 \u0000 \u0000 ″\u0000 \u0000 \u0000 \u0000 E 115° 31\u0000 \u0000 ′\u0000 \u0000 13.3\u0000 \u0000 \u0000 \u0000 \u0000 ″\u0000 \u0000 \u0000 \u0000 ). A literature review was conducted to view the current study pattern and retrieve a methodology based on the current study pattern. GeoStudio is a commercial finite element software. The data obtained from the borehole log report and online resources were utilised to create the riverbank model in software. The phreatic line shows a slow change over time, indicating that the riverbank takes a long time to stabilise after the drawdown. The FOS value decreases during the drawdown occurrence and slowly increases after the drawdown has ended. In conclusion, the drawdown event can cause slope riverbank failure, and the seepage and stability analysis using GeoStudio can show the condition of the riverbank during the drawdown event.","PeriodicalId":45541,"journal":{"name":"Modelling and Simulation in Engineering","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2022-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84493195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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