Computer-aided Simulation Model Research Articles

Induction motor with rotor circuit with pulse-and-switch control for mining machines

Regarding the cyclic mechanisms of mining machines, it is proposed to improve induction motors by adding them with pulse-and-switch control using the power switches GTO, IGBT and MOSFET with the update control circuits. The motors of mining machines down to date use the relay–contact resistance control based on the induction motor with phase-wound rotor. This article discusses the advanced and relatively simple variant of modernization of such induction motors. The computer-aided simulation model is designed and described. The simulation results allow drawing a conclusion that the dualcircuit system with the internal relay circuit of rectified rotor current and the external circuit of velocity at proportional control and PI regulators ensures good performance both in statics and dynamics at simple drive circuit. Modeling was undertaken to compare the dynamics and power performance of the proposed induction motor with vector control and direct orientation in the rotor field. The comparison proves similarity of transient processes with respect to smooth components of mechanical coordinates. The economic effect of the proposed system with the pulse-and-switch control at total re-equipment of the obsolete drives and their replacement by the frequency-variable drives, with all required components and at ‘gentle’ modernization, with substitution of the frequency converter by the new variant proposed in this article while the existing motor with the phase rotor is left. The comparison proves the competitiveness of the proposed variant of induction motor with simpler devices. This study may be useful to design or update induction motors with pulse-and-switch control.The study was supported by the government, Project No. FSWF-2020-0019.

Analytical modelling and device design optimisation of epitaxial layer‐based III–V tunnel FET

The line tunnelling and heterojunction are two important techniques to improve the performance of the tunnelling field-effect transistors (TFETs). The TFETs that utilise both of these techniques perform superior to the conventional TFETs. The recently proposed T-shaped TFET (TTFET) is one such heterojunction-based line tunnelling device that is expected to become energy efficient switch. For the first time, a physics-based analytical model for surface potential and drain current of epitaxial layer-based heterojunction line TFET has been developed. The model describes the impact of device design parameters on the electrical performance of the device. The Poisson equation is solved with precise boundary conditions to obtain the surface potential model. Kane's model is used to calculate drain current by utilising surface potential model. A good agreement between Synopsys technology computer-aided design simulation and analytical model is observed with 5.4% error in on current at V GS = V DS = 0.5 V, an average error of 5.80% in surface potential and 7.24% in transconductance. Finally, a device design guideline is presented according to the analytical expressions.

Model-Based Evaluation of the Effects of River Discharge Modulations on Physical Fish Habitat Quality

The increase in minimum flows has rarely been considered to mitigate the ecological impact of hydroelectric power plants because it requires a site-specific design and expensive long-term monitoring procedure to identify the most beneficial scenario. This study presents a model-based method to estimate, within the model constraints, the most sustainable scenario of water resource sharing between nature and human needs. We studied physical habitat suitability of the Isar River in Munich (Germany) for three protected fish species: Thymallus thymallus L., Hucho hucho L., and Chondostroma nasus L. The analysis combined a high-resolution two-dimensional (2D) hydromorphological model with expert-based procedures using Computer Aided Simulation Model for Instream Flow Requirements (CASiMIR). We simulated a range of minimum discharges from 5 to 68.5 m³/s and four scenarios: (A) maximum use of the resource for humans; (B) slight increase in the minimum water flow; (C) medium increase in the minimum water flow; and, (D) without diversion for hydroelectric production. Under the current hydromorphological conditions, model outputs showed that different life stages of the fish species showed preferences for different scenarios, and that none of the four scenarios provided permanently suitable habitat conditions for the three species. We suggest that discharge management should be combined with hydromorphological restoration actions to re-establish parts of the modified channel slope and/or parts of the previously lost floodplain habitat in order to implement a solution that favors all species at the same time. The modeling procedure that is presented may be helpful to identify the discharge scenario that is most efficient for maintaining target fish species under realistic usage conditions.

System Dynamic Modeling of Low Carbon Strategy in Latvia

In this paper we study development patterns of Latvian electricity market based on a newly developed computer-aided simulation model. A system dynamics approach was applied to simulate long-term development of electricity sector in the region under the existing policy design. Results show that despite the relatively large share of renewable energy sources in Latvian electricity generation mix, natural gas will remain its significant role in national electricity supply. Alternative policy strategies should be developed to allow achieving CO2 emission reductions greater than 30% by 2050.

Computer based FEM stabilization of oxygen transport model for material and energy simulation in corroding reinforced concrete

This paper unveils a new computer based stabilization methodology for automated modeling analysis and its experimental verification for corrosion in reinforced concrete structures under the effect of varying oxygen concentration. Various corrosion cells with different concrete compositions under four different environmental conditions (air dry, submerged, 95% R.H and alternate wetting-drying) have been investigated under controlled laboratory conditions. The results of these laboratory tests were utilized with an automated computer-aided simulation model. This model based on mass and energy stabilization through the porous media for the corrosion process was coupled with modified stabilization methodology. By this coupling, it was possible to predict, maintain and transfer the influence of oxygen concentration on the corrosion rate of the reinforcement in concrete under various defined conditions satisfactorily. The variation in oxygen concentration available for corrosion reaction has been taken into account simulating the actual field conditions such as by varying concrete cover depth, relative humidity, water-cement ratio etc. The modeling task has been incorporated by the use of a computer based durability model as a finite element computational approach for stabilizing the effect of oxygen on corrosion of reinforced concrete structures.

Comprehensive MMF–MFL inspection for corrosion detection and estimation in embedded prestressing strands

This paper describes the development of a magnetic sensor system for the evaluation of the condition of prestressed strands inside the bottom layer of concrete box beams. The sensor consists of an electromagnet which magnetizes embedded prestressing strand and measures the magnetic field response of the strands using Hall sensors embedded at different positions on the electromagnet. The novel aspect of this comprehensive system is the integration of measuring magnetic flux leakage (MFL) and main magnetic flux (MMF) signals. A computer-aided simulation model has also been developed to use these signals in estimating corrosion. The MFL signal gives indications of the presence of corrosion and cracks or fractures in the strands. The MMF signal quantifies the amount of steel loss in the strands due to corrosion or rusting. Both these techniques have been independently evaluated using magnetic inspection systems which made them suitable to be used in a single sensor system. This comprehensive system was evaluated in a laboratory setting to identify corrosion and strand breaks in prestressing strands. It was observed that the MFL signal could identify the presence of corrosion and strand breaks, while the MMF signal could be used to estimate the loss of steel due to corrosion. This system was also evaluated using it in an inspection of decommissioned prestressed box beams removed from Ohio’s oldest prestressed box-beam bridge. The findings from this inspection revealed a good match with the dissected areas of the box beams. Steps to move the system to implementation are also discussed. With further development improving the accuracy of this inspection system, it can become a valuable tool to bridge engineers for box-beam inspection.

A Computer-Aided Process Simulation Model to Navigate Value Chain Reconfiguration Using a Three-Layered Methodology

This paper develops a computer-aided process simulation model (CPSM) to navigate value chain reconfiguration. The model uses a three-layered methodology incorporating the principle of knowledge-integrated traceability (KIT) to create more efficient performance measures and provides a rigorous and stepwise clustered module structure that will act as a guideline for all entities decision makers are involved. The model is based on three kinds of mature toolsets variable. First, an in-depth interview of a group of experts makes the BSC (Balanced Scorecard) KIT model along with AHP (Analytic Hierarchy Process) technique into an integrated AHP-BSC structure. Second, internal validation of core propositions during CPSM development is then used to construct an account both qualitative and quantitative decision factors in the best delivery causality diagram of theory-building mode. Defining the KIT of toolset variables into two specific themes allows a practical hierarchy for AHP-BSC structure to be evaluated without excessive computation barriers, and the systems thinking archetype of strategic activities in the ARIS-EPCs (Architecture of Integrated Information System/extending Event-driven Process Chains) architecture delivers the validity and reliability of research methodology as validation model of CPSM development. Third, the hybrid ST-ARIS (System Thinking) simulation model is constructed based on the feasibility test of relevant decision factors whether or not KPI (Key Performance Indicator) could be measured. The reconfiguration provides new insights for contributing to the foundations to link the process capability of the value chain with the three-layered methodology, and emphasises the CPSM development by highlighting a specific approach associated with KIT.

Computer-aided oxygen transport model of mass and energy simulation for corrosion of reinforced steel

The paper includes automated modeling and experimental verification of corrosion in reinforced concrete construction under the effect of varying oxygen concentration. Various construction corrosion cells with different concrete compositions under four different environmental conditions (air dry, submerged, 95% R.H and alternate wetting–drying) have been investigated under controlled laboratory conditions. Using the results (half-cell potential and gravimetric corrosion mass loss) of these laboratory tests and an automated computer-aided simulation model based on mass and energy transfer through the porous construction media for the corrosion process, it was possible to predict, maintain and manage the influence of oxygen concentration on the corrosion rate of the reinforcement in concrete construction under various defined conditions satisfactorily. The variation in oxygen concentration available for corrosion reaction has been taken into account simulating the actual construction field conditions such as by varying concrete cover depth, relative humidity, water–cement ratio, etc. The modeling task has been incorporated by the use of an automated computer based construction durability model ‘DuCOM’ developed by our construction research group at The University of Tokyo as a finite element computational approach for the effect of oxygen on corrosion in relation to W/C, concrete cover, chloride concentration and various environmental humidity construction conditions. This paper is of interest to a broad readership for those interested in automation in reinforced concrete construction involving durability design & engineering related to corrosion of steel in concrete, corrosion resistant construction technology, corrosion maintenance & management. The scope of this paper encompasses various stages of the corrosion in construction life cycle from initial planning and design, through construction of steel reinforced concrete facility, its operation and maintenance, to the estimation of demolishing due to limiting oxygen controlled corrosion damage. This paper contains novel investigations involving computer-aided durability design, corrosion modeling under varying oxygen, classification and standardization of corrosion product data. The paper incorporates mass and energy process simulation models and graphics for the effect of oxygen on corrosion and its automated inspection as well as management. This comprehensive automated modeling and experimental investigation involving variety of materials and environmental variables will help in profound understanding, maintenance and management of oxygen controlled corrosion reaction in RC construction and will provide significant future research prospects in the field of oxygen limiting automated corrosion modeling of RC construction.

Computer-aided Simulation Model of Stator Groundwall Insulation of Induction Motor based on Current Park’s Vector Approach

Modeling and simulation studies published in the literature have shown that the stator winding faults are one of the major causes of induction motor failure. The spectrum analysis and AI-based fault diagnosis techniques were introduced to detect such faults at the early stage. However, there is not much mention about the deterioration of stator winding on account of degradation of stator groundwall insulation. This paper investigates the methodology to simulate the percentage of degradation related with deterioration of stator groundwall insulation of induction motor. A design of computer based simulation model to generate the stator current data pattern for the simulation of degree of degradation of stator groundwall insulation based on Current Park‟s vector approach [1] is presented. The generated stator current data pattern can be further applied to any suitable artificial neural network classifier for the artificial intelligence based fault diagnosis process. The need for the evaluation, based on computer simulation is also indicated.

SIMULATION OF RAIL DIRECTIONS WORK

The computer-aided simulation model is offered that can be used for the research of the railway traffic organization and also for the estimation of influence of the train parameters on the operation indices of railway lines and directions.

Computer-Aided Simulation Model for Natural Gas Pipeline Network System Operations

This paper presents the development of a computer-aided simulation model for natural gas pipeline network system operations. The simulation model is a useful tool for simulating and analyzing the behavior of natural gas pipeline systems under different operating conditions. Historical data and knowledge of natural gas pipeline system operations are crucial information used in formulating the simulation model. This model incorporates the natural gas properties, energy balance, and mass balance that lay the foundation of knowledge for natural gas pipeline network systems. The user can employ the simulation model to create a natural gas pipeline network system, selecting the components of natural gas, pipe diameters, and compressor capacities for different seasons. Because the natural gas consumption rate continuously varies with time, the dynamic simulation model was built to display state variables of the natural gas pipeline system and to provide guidance to the users on how to operate the system properly...

Modelling of the Microstructure and the Mechanical Property Variation across the Transverse Direction of Hot Rolled Steels and the Effect of Edge Shielding.

A computer-aided simulation model which can predict the temperature variation and the microstructural evolution in the process of hot rolling was developed by combining a metallurgical model and a thermal model. The developed model was utilized to analyze the variation of temperature and microstructure during hot rolling process and the mechanical properties of the final products across the transverse direction of a strip. The results of the simulation along with those of the mill trial tests indicated that the mechanical properties across the transverse direction were significantly influenced by the metallurgical inhomogeneities developed in the stage of recrystallization and grain growth during rolling as well as the stage of transformation during cooling. In addition, the effect of the edge shielding during water cooling was quantitatively estimated by the present simulation model and the edge shielding was found to be effective in achieving uniform microstructure and mechanical properties in the hot rolled steels, especially, steels with high hardenability.

Simulation model of cold pilgering

Cold pilger rolling is an established technique used for the production of precision tubes that are closely related to energy production (nuclear power, off-shore engineering), the fabrication of ball bearings, etc. This process is attractive despite the difficulties in controlling the complicated strain path, which latter influences the process parameters and the behaviour of the material being pilgered. There are only a few models available that can be used in practice for the proper choice of suitable dimensions of the pierced billet for the pilger rolling of a particular tube and of optimal process parameters. A special computer-aided simulation model has been developed for the analysis of the influence of different process- and material-parameters on the rolling forces, the deformation, the distribution of accumulated strain, the temperatures and the materials properties of the pilgered tubes. Strain increments and the distribution of the accumulated strain in the material being pilgered are computed with regard to the strain path and combined with characterization of the material behaviour in terms of plastic anisotropy and cyclic deformation mode. The simulation model developed, PILGER, is used for investigation of the influence of the tube geometry, the rolling geometry, the plastic properties, friction, lubrication and cooling on the roll-separating forces, temperatures, deformation and properties of the pilgered tubes. The simulation model is a powerful tool for optimization of the process and control of the final properties of the product.

A new computer-aided simulation model for polycrystalline silicon film resistors : Ching-Yuan Wu and Weng-Dah Ken. Solid-St. Electron.26 (7), 675 (1983)

A new computer-aided simulation model for polycrystalline silicon film resistors : Ching-Yuan Wu and Weng-Dah Ken. Solid-St. Electron.26 (7), 675 (1983)

A computer-aided simulation model for the I–V characteristic of [formula omitted] silicon Schottky-barrier diodes produced by use of low-energy arsenic-ion implantation : Ching-Yuan Wu, Ming-Chein Chang and An-Jui Shey. Solid-St. Electron.26 (9), 893 (1983)

A computer-aided simulation model for the I–V characteristic of [formula omitted] silicon Schottky-barrier diodes produced by use of low-energy arsenic-ion implantation : Ching-Yuan Wu, Ming-Chein Chang and An-Jui Shey. Solid-St. Electron.26 (9), 893 (1983)

A computer-aided simulation model for the I–V characteristic of M- n- p silicon Schottky-barrier diodes produced by use of low-energy arsenic-ion implantation

Current-transport properties of Al-n-p silicon Schottky-barrier diodes have been studied both experimentally and theoretically. An analytical model for the I-V characteristic of a metal- n- p Schottky barrier diode has been developed by using an interfacial layer-thermionic-diffusion model. Assuming a Gaussian distribution for the implanted profile, the barrier-height enhancement and ideality factor have been derived analytically. Using low energy (25 KeV) arsenic implantation with the dose ranged form 8 × 10 10/cm 2 to 10 12/cm 2, Al- n- p silicon Schottky barrier diodes have been fabricated and characterized. Comparisons between the experimental measurements and the results of computer simulations have been performed and satisfactory agreements between these comparisons have been obtained. The reverse I–V characteristics of the fabricated Al- n- p silicon Schottky barrier diodes can also be well simulated by the developed model.

A new computer-aided simulation model for polycrystalline silicon film resistors

A general transport theory for the I–V characteristics of a polycrystalline film resistor has been derived by including the effects of carrier degeneracy, majority-carrier thermionic-diffusion across the space charge regions produced by carrier trapping in the grain boundaries, and quantum mechanical tunneling through the grain boundaries. Based on the derived transport theory, a new conduction model for the electrical resistivity of polycrystalline film resitors has been developed by incorporating the effects of carrier trapping and dopant segregation in the grain boundaries. Moreover, an empirical formula for the coefficient of the dopant-segregation effects has been proposed, which enables us to predict the dependence of the electrical resistivity of phosphorus-and arsenic-doped polycrystalline silicon films on thermal annealing temperature. Phosphorus-doped polycrystalline silicon resistors have been fabricated by using ion-implantation with doses ranged from 1.6 × 10 11 to 5 × 10 15/cm 2. The dependence of the electrical resistivity on doping concentration and temperature have been measured and shown to be in good agreement with the results of computer simulations. In addition, computer simulations for boron-and arsenic-doped polycrystalline silicon resistors have also been performed and shown to be consistent with the experimental results published by previous authors.

The development of a computer-aided building environment and services simulation model: Architectural Sci. Rev., Vol 15 (1972) No 4, pp 77–85

SUMMARY This paper describes the development of an interactive. computer-aided simulation model for the design and analysis of the service systems creating and maintaining the internal environment of a high-rise office building. The model is part of an overall programme of computer-aided architectural design being developed by the Department of Architectural Science at the University of Sydney, Australia. The model is seen as a practical design-analysis tool as well as a powerful research tool enabling a more thorough investigation of building services and. in particular, their interactions with other components of the building situation. The work described is concerned with the high-rise office building situation although the arguments and principles proposed could be extended to other building types. The first part of the paper presents relevant background matcrial to establish a context for the study. Current design methods for building services are reviewed and the application of computers to services...

THE DEVELOPMENT OF A COMPUTER-AIDED BUILDING ENVIRONMENT AND SERVICES SIMULATION MODEL

SUMMARY This paper describes the development of an interactive. computer-aided simulation model for the design and analysis of the service systems creating and maintaining the internal environment of a high-rise office building. The model is part of an overall programme of computer-aided architectural design being developed by the Department of Architectural Science at the University of Sydney, Australia. The model is seen as a practical design-analysis tool as well as a powerful research tool enabling a more thorough investigation of building services and. in particular, their interactions with other components of the building situation. The work described is concerned with the high-rise office building situation although the arguments and principles proposed could be extended to other building types. The first part of the paper presents relevant background matcrial to establish a context for the study. Current design methods for building services are reviewed and the application of computers to services...