Browsing by Subject "MATLAB"
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Item Application of an innovative MBSE (SysML-1D) co-simulation in healthcare(2018-05) Kalvit, Kalpak; El-Mounayri, HazimItem Design optimization of heterogeneous microstructured materials(2014) Emami, Anahita; Tovar, Andrés; Zhu, Likun; Wasfy, Tamer; Chen, JieOur ability to engineer materials is limited by our capacity to tailor the material’s microstructure morphology and predict resulting properties. The insufficient knowledge on microstructure-property relationship is due to complexity and randomness in all materials at different scales. The objective of this research is to establish a design optimization methodology for microstructured materials. The material design problem is stated as finding the optimum microstructure to maximize the desired performance satisfying material processing constrains. This problem has been solved in this thesis by means of numerical techniques through four main steps: microstructure characterization, model reconstruction, property evaluation, and optimization. Two methods of microstructure characterizations have been investigated along with the advantages and disadvantages of each method. The first microstructure characterization method is a statistical method which utilizes correlation functions to extract the microstructural information. Algorithms for calculating these correlations functions have been developed and optimized based on their computational cost using MATLAB software. The second microstructure characterization method is physical characterization which works based on evaluation of physical features in microstructured domain. These features have been measured by means of MATLAB codes. Three model reconstruction techniques are proposed based on these characterization methods and employed to generate material models for further evaluation. The first reconstructing algorithm uses statistical functions to reconstruct the statistical equivalent model through simulating annealing optimization method. The second algorithm uses cellular automaton concepts to simulate the grain growth utilizing physical descriptors, and the third one generates elliptical inclusions in a material matrix using physical characteristic of microstructure. The finite element method is used to analysis the mechanical behavior of material models. Several material samples with different microstructural characteristics have been generated to model the micro-scale design domain of AZ31 magnesium alloy and magnesium matrix composite with silicon carbide fibers. Then, surrogate models have been created based on these samples to approximate the entire design domain and demonstrate the sensitivity of the desired mechanical property to two independent microstructural features. Finally, the optimum microstructure characteristics of material samples for fracture strength maximization have been obtained.Item Design Requirements of Human-Driven, Hybrid, and Autonomous Trucks for Collision-Avoidance in Platooning(2024-05) Shanker, Shreyas; Nalim, M. Razi; Anwar, Sohel; Tovar, AndresThe trucking industry faces many challenges, the most pressing of them being the rising costs to run the fleets. This is mainly caused by driver shortage, low driver retention and high wages for the drivers as well as rising fuel costs. Autonomous trucks promise to solve these issues by eliminating this bottleneck in the industry and bringing some relief to logistics companies and fleet owners. A prelude to fully autonomous trucks is expected to be seen as part of a hybrid platoon where a human driver would lead one or more autonomous trucks close behind them thus enabling higher tonnage to be transported by one driver. This enables early autonomous software to be tested and phased onto highways in a more controlled manner since present software can maintain set distances behind vehicles and respect lane markers already. Platooning also enables significant fuel savings from reduced aerodynamic drag on all vehicles at close distances. Since vehicle functionality is largely built around the driver, the removal of this piece affords the opportunity to rethink parts of the design to suit the needs of the future more favorably. Based on the prevalent literature as well as simulation of platooning scenarios under various vehicle and environmental conditions, the thesis will analyze the development of autonomous vehicles with a focus on the opportunities to rethink conventional design constraints of a truck and to design one that is better suited to the functions it will be carrying out autonomously and in the context of technologies that are in development and would be available in the future with a special emphasis on platooning scenarios. In this thesis, a MATLAB model was used to simulate a 2-vehicle platoon where the lead truck is a conventional class 8 vehicle while the key parameters of the following truck was tested in various road conditions to minimize Inter Vehicular Distance (IVD) and maximize fuel savings while ensuring safety. The study was able to conclude that an alternative design to autonomous trucks would result in maximum benefits from synergistic technologies like platooning and battery powered trucks. The results showed the most benefits from a reduction in perception-reaction time and communication technology followed by strategic configuration of vehicles in a platoon by Gross vehicle weight (GVW). Also, the need to account for coefficient of friction due to non-ideal environmental conditions with an adjustment in IVD is observed.Item An efficient 3D topology optimization code written in Matlab(Springer, 2015-06) Liu, Kai; Tovar, Andres; Department of Mechanical Engineering, School of EngineeringThis paper presents an efficient and compact Matlab code to solve three-dimensional topology optimization problems. The 169 lines comprising this code include finite element analysis, sensitivity analysis, density filter, optimality criterion optimizer, and display of results. The basic code solves minimum compliance problems. A systematic approach is presented to easily modify the definition of supports and external loads. The paper also includes instructions to define multiple load cases, active and passive elements, continuation strategy, synthesis of compliant mechanisms, and heat conduction problems, as well as the theoretical and numerical elements to implement general non-linear programming strategies such as SQP and MMA. The code is intended for students and newcomers in the topology optimization. The complete code is provided in Appendix C and it can be downloaded from http://top3dapp.com.Item Evaluation of performance of an air handling unit using wireless monitoring system and modeling(2014) Khatib, Akram Ghassan; Chen, Jie; Goodman, David; Razban, AliHeating, ventilation, and air conditioning (HVAC) is the technology responsible to maintain temperature levels and air quality in buildings to certain standards. In a commercial setting, HVAC systems accounted for more than 50% of the total energy cost of the building in 2013 [13]. New control methods are always being worked on to improve the effectiveness and efficiency of the system. These control systems include model predictive control (MPC), evolutionary algorithm (EA), evolutionary programming (EP), and proportional-integral-derivative (PID) controllers. Such control tools are used on new HVAC system to ensure the ultimate efficiency and ensure the comfort of occupants. However, there is a need for a system that can monitor the energy performance of the HVAC system and ensure that it is operating in its optimal operation and controlled as expected. In this thesis, an air handling unit (AHU) of an HVAC system was modeled to analyze its performance using real data collected from an operating AHU using a wireless monitoring system. The purpose was to monitor the AHU's performance, analyze its key parameters to identify flaws, and evaluate the energy waste. This system will provide the maintenance personnel to key information to them to act for increasing energy efficiency. The mechanical model was experimentally validated first. Them a baseline operating condition was established. Finally, the system under extreme weather conditions was evaluated. The AHU's subsystem performance, the energy consumption and the potential wastes were monitored and quantified. The developed system was able to constantly monitor the system and report to the maintenance personnel the information they need. I can be used to identify energy savings opportunities due to controls malfunction. Implementation of this system will provide the system's key performance indicators, offer feedback for adjustment of control strategies, and identify the potential savings. To further verify the capabilities of the model, a case study was performed on an air handling unit on campus for a three month monitoring period. According to the mechanical model, a total of 63,455 kWh can be potentially saved on the unit by adjusting controls. In addition the mechanical model was able to identify other energy savings opportunities due to set point changes that may result in a total of 77,141 kWh.Item THE MEMRISTOR: FREQUENCY RESPONSE OF A HYSTERETIC DEVICE(Office of the Vice Chancellor for Research, 2012-04-13) Meijome, Natalia C.; Joglekar, Yogesh N.The memristor, postulated in the 1970’s, was recently realized in a tita-nium dioxide thin-film device and is now being commercially developed. Memristor, short for memory resistor, is the fourth fundamental circuit ele-ment whose instantaneous resistance depends not only on the voltage, but also on the history of the voltage applied to it. We investigate the frequency response of the current through a memristor due to an externally applied periodic voltage with the application of an algorithmic code using MATLAB. With these results, we are able to understand the characteristic response that this device displays for each corresponding input voltage frequency. Due to the range of response exhibited, there is the possibility of using this device in circuits to produce entirely new functions. We expect that this analysis will have implications for scientific advancement in both circuitry development as well as neuroscience due to a memristor’s ability to perform logic operations and store information. This work is supported by the Ronald E. McNair Post-Baccalaureate Achievement Program and a UROP grant (N.M.) and the NSF (Y.J.).Item Model-based Development for Event-driven Applications using MATLAB: Audio Playback Case Study(2007) Schubert, Peter J.; Vitkin, Lev; Braun, DavidAudio playbacks are mechanisms which read data from a storage medium and produce commands and signals which an audio system turns into music. Playbacks are constantly changed to meet market demands, requiring that the control software be updated quickly and efficiently.Item Solar Micro Inverter(2014) Hegde, Shweta; Izadian, Afshin; Rizkalla, Maher E.; Li, Lingxi; King, BrianThe existing topologies of solar micro inverter use a number of stages before the DC input voltage can be converted to AC output voltage. These stages may contain one or more power converters. It may also contain a diode rectifier, transformer and filter. The number of active and passive components is very high. In this thesis, the design of a new solar micro inverter is proposed. This new micro inverter consists of a new single switch inverter which is obtained by modifying the already existing single ended primary inductor (SEPIC) DC-DC converter. This new inverter is capable of generating pure sinusoidal waveform from DC input voltage. The design and operation of the new inverter are studied in detail. This new inverter works with a controller to produce any kind of output waveform. The inverter is found to have four different modes of operation. The new inverter is modeled using state space averaging. The system is a fourth order system which is non-linear due to the inherent switching involved in the circuit. The system is linearized around an operating point to study the system as a linear system. The control to output transfer function of the inverter is found to be non-minimum phase. The transfer functions are studied using root locus. From the control perspective, the presence of right half zero makes the design of the controller structure complicated. The PV cell is modeled using the cell equations in MATLAB. A maximum power point tracking (MPPT) technique is implemented to make sure the output power of the PV cell is always maximum which allows full utilization of the power from the PV cell. The perturb and observe (P&O) algorithm is the simplest and is used here. The use of this new inverter eliminates the various stages involved in the conventional solar micro inverter. Simulation and experimental results carried out on the setup validate the proposed structure of inverter.