Papers by Keyword: Simulation

Abstract: Recently, all inorganic perovskite solar cells have triggered great attention thanks to the rising performance during their development in solid state photovoltaics showing enhanced characteristics, such as: good stability, high photoluminescence quantum yield, tunable size, and morphology. In this work, a high open-circuit voltage solar cell based on all-inorganic perovskite through SCAPS simulator program is presented by analysing electron transport layer (ETL), perovskite layer, hole transport layer (HTL) thickness and doping density from a FTO/TiO₂/CsPbBr₃/Spiro-OMeTAD/Au structure were modified to observe its influence on solar cell performance. Therefore, simulation results show that a thicker ETL hinders carrier transport towards the FTO layer due to larger distance which leads to higher recombination rate, reducing carrier’s lifetime. Albeit high doping density values in ETL enhances the overall solar cell performance. As for the absorber layer, while its thickness increases, carrier collection rate decreases due to recombination impacting Voc, which results from thickness increase. Based on the results, solar cell efficiency improvement is attributed to the built-in electric field as absorber layer doping density increases. While HTL thickness has minimum impact on the solar cell output, doping density enhances device parameters significantly. Summarising the results obtained from thickness and doping density simulations, the optimal solar cell operation was obtained at 10 nm, 600 nm, and 100 nm layer thickness as well as 10²⁰ cm^-3, 10¹⁶ cm^-3, and 10²⁰ cm^-3 doping density (TiO₂, CsPbBr₃ and Spiro-OMeTAD). Results from three different sources, collected from literature, were used to compare, and fitting them along with simulation results.

Abstract: In this paper, a numerical simulation methodology has been applied to optimize the design of extruded aluminium products. The methodology, PRO^{3 TM} , incorporates product properties, production-and material costs as well as CO₂ footprint in an optimisation procedure. This allows for multi-objective optimisation and avoids sub-optimisation of for instance properties on the expense of production costs or CO₂ emissions. The outcome that follows from this multi-objective optimisation procedure, is that the resulting profile cross section will be different when the optimisation is based solely on property considerations, than when costs and CO₂ emissions are introduced in the optimisation procedure. The present methodology requires that the main processes and operations along the aluminium process chain are represented by physics based, predictive models of various types, including material-and mechanical models, in addition to cost-, and sustainability models. A standard multi-objective optimization algorithm is used to combine the models and for automatic running through-process simulations in iterations. In this article, the PRO^{3 TM} methodology has been applied for optimisation of the profile cross section in case-studies with various user requirements. It has been demonstrated that the resulting cross section geometry depends on the specified relative importance of conflicting requirements like the desire for high productivity on the one hand, and the desire for low material costs and low CO₂ emissions on the other.

Abstract: The purpose of the work is to quantify and predict the influence of inhomogeneity of local properties on the overall behavior of the selected casting aluminum wheel and knuckle in different loading cases. Smooth and notched tensile specimens and torsion specimens are extracted from different positions in the wheel and knuckle and tested. The dependences of the flow stress, the fracture strain, and the S-N curve on position for specimen extraction are evaluated. Metallographic investigations are performed to reveal the relations between microstructure/microdefects and the mentioned properties. A damage model based on a triaxiality-dependent fracture strain is calibrated and used to simulate the specimens and component tests. The simulations of static wheel tests and knuckle fatigue tests are performed with position-dependent material parameters. The prediction of the component tests is compared with the experimental results.

Abstract: The paper presents the experience of development and implementation of an integrated approach of extrusion simulation with the automated design of the dies as a new way to speed up the technology development and its optimisation based on the QForm UK Extrusion simulation program and QForm Extrusion Die Designer (QExDD) design system. Bearing and prechamber optimisation types are considered for the porthole design. Welding quality and possible streaking lines in the profile are analysed for the tool construction with optimised prechamber contour.

Abstract: The injection moulding industry is dynamically developing. The growing demand for more customizable products can be served by low or middle volume production using prototype moulds and inserts. The conventional material of prototype moulds is aluminum because of its excellent machinability, acceptable strength and stiffness and outstanding thermal conductivity. Prototype moulds are gaining ground in the injection moulding industry, yet their operational behavior (including exact mechanical and thermal process parameters) is largely unknown. We created a comprehensive state monitoring system that measures the operational strain, cavity pressure and temperature of different prototype injection moulds. This way, all important process parameters can be measured and the relations between the moulding parameters and the operational pressure loads, deformations and temperatures can be quantified and analysed.

Abstract: A challenge in the development of Silicon carbide (SiC) gate turn-off thyristors lie in an uneven transient behaviour, necessitating expensive snubbers. To address these limitations and simplify circuit topology we present an optimized 16 kV n-type SiC integrated gate commutated thyristor (IGCT) design, which utilises a novel highly doped base strip (HDBS). A particular focus is on optimizing the gate commutation of the GCT during switching, and the trade-offs in the HDBS base design were investigated. The findings reveal that compared with conventional GCT design, the HDBS design under high current conditions recorded a 11.8% reduction in turn-off power losses. When simulating the device in a high-voltage scenario, the HDBS IGCT demonstrated a 3.9% reduction in turn-off power losses and an improved turn-on power loss performance. This resulted in a reduction of power losses by 12.1% and 2.3% in high current and high voltage conditions, respectively. In summary, the novel SiC HDBS IGCT design paves the way towards a secure, high current density, and low loss switching SiC thyristor device.

Abstract: Effective control of device geometry is key to mitigating high localized electric fields in next-generation SiC power devices. Advanced trench processing allows for highly tunable trench-gate architectures in trench MOSFETs. By utilizing a two-step inductively coupled plasma reactive ion etch (ICP-RIE) process, a high degree of trench base corner rounding can be achieved, irrespective of trench opening corner geometry prior to post etch treatments. Sentaurus TCAD device modelling highlights the importance of effective electric field dispersion at the gate oxide using rounded trench corners, while I-V characterization of fabricated trench MOS-capacitor devices demonstrate the influence of trench base corner rounding on gate oxide breakdown.

Abstract: Silicon-carbide-on-insulator (SiCOI) is a promising platform for photonic integrated circuits. However, the development of this new photonic platform is hindered by the lack of high-quality commercial SiC-on-insulator substrates. In this study, we present a demonstration of the transfer of a single crystalline semi-insulating 4H-SiC thin film on a SiO₂ insulated substrate at 150 mm wafer scale using the Smart Cut™ technology. We describe the development of SiCOI substrates and their characterization at each key step of the process. In particular, we provide a detailed study of bow compensation related to the implanted SiC donor substrate. The quality of the transferred SiC layer was investigated as a function of the final annealing temperature applied. The optical indices of the bulk SiC were measured using spectroscopic ellipsometry, and an advanced model has been used to take into account the strong birefringence of the silicon carbide film. Finally, simulations were conducted to design a preliminary set of basic and advanced photonic devices.

Abstract: The unkempt state of many ceiling fans in offices, homes and industries due to poor maintenance in term of cleaning and the wastage of energy as a result of carelessness in appliance usage inform the design of a ceiling fan with autonomous capability. The design of the ceiling fan was done using appropriate design equations and Solidworks CAD software. Different concepts were conceived and the best concept was determined using one of the Multi – Criteria decision Tools named Pugh Matrix Method. After which, simulation was done using ANSYS and Proteus 8.1 design suite to test functionality of the design. The outcome shows that at no load in the room, the ceiling fan switches off automatically and also when occupants are in the room with an increase in temperature above ambient temperature (25 °C), the ceiling fan switches on. The simulation results analysis of stress, strain, shear force, deflection, factor of safety and bending moment on the embedded cleaner gave 112.717 MPa, 0.007496, 5 N, 60.28 mm, 1.8346 and 0.8965 Nm respectively. Furthermore, the result revealed that the autonomous capability of the cleaning mechanism gave an efficiency of 85%. The cost to implement this innovation is estimated at twenty five dollar.

Abstract: Deep learning has achieved great progress in image recognition, segmentation, semantic recognition, and game theory. It also shows potential to solve scientific computing such as simulation problems in engineering. On the other hand, the numerical simulation method requires constitutive modelling, involves a huge computation volume and takes a long time. In this paper, two mirror U-Net models were proposed for the simulation of the heat transfer during the casting process. These models include an upper U-Net branch for the treatment of the geometries of casting, mold, and chill, and a lower U-Net branch for the treatment of the initial temperature field. Their difference is whether the bottoms of upper and lower U-Nets are shared. These two branches tackle the problems involving the input of a geometrical model which consists of three types of materials and the input of an initial or current temperature field image. These models were trained and validated with a big database with hundreds of casting shapes. The prediction results show that the average accuracy reaches 98.8%.