Browsing by Subject "Finite Element Analysis"

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    Design and Experimental Validation of Voice Coil Motor for High Precision Applications
    (IEEE, 2018-04) Shewale, Mahesh S.; Razban, Ali; Deshmukh, Suhas P.; Mulik, Sharad S.; Zambare, Hrishikesh B.; Mechanical Engineering and Energy, School of Engineering and Technology
    Flexural structures are extensively beneficial when differentiated with conventional inflexible body structures where point accuracy positioning is strongly required extending in the range of microns. To fulfill clear and accurate positioning requirements, we come up with the solution of voice coil motors (VCM) with position estimator algorithm. Appropriate magnet and coil assembly is designed by considering the ultimate force for the application. Voice coil motor components are fabricated on milling machine and then assembled. This VCM is incorporated with dSPACE DS1104 R&D controller with the help of linear current amplifier (LCAM) which controls VCM with respect to desired amplitude and frequency. Displacement of coil of VCM is detected with respect to fixed magnet by using linear variable differential transformer (LVDT) which generates analog voltage signal in relation with motion of coil. Static characteristic such as stiffness is determined using force-deflection plot and dynamic characteristic like damping factor and frequency response are estimated with the help of transient response obtained by providing step input to the motor. Further, PID controller is implemented on this VCM and it is error observed is less than ±0.S microns.
  • Thumbnail Image
    Item
    Electromagnetic simulation for diagnosing damage to femoral neck vasculature: A feasibility study
    (Elsevier, 2018-12) Rizkalla, James; Jeffers, Matthew; Salama, Paul; Rizkalla, Maher; Electrical and Computer Engineering, School of Engineering and Technology
    BACKGROUND: Femoral neck fractures are common injuries managed by orthopedic surgeons across the world. From pediatrics to geriatrics, disruption of the blood supply to the femoral neck is a well-recognized source of morbidity and mortality, oftentimes resulting in avascular necrosis of the femoral head. This devastating complication occurs in 10-45% of femoral neck fractures. Therefore, it is vital for orthopedic surgeons provide efficient treatment of this injury, in order to optimize the patient's potential outcome and prevent long-term sequelae. METHODS: In this study, the anatomy of the proximal femur, including femoral metaphysis, femoral neck, vasculature, and femoral head, were simulated in COMSOL Finite Element Analysis (FEA) software. Electric fields were generated in a fashion that exploited disruptions within the vasculature of the femoral neck. This study was aimed at developing an alternative imaging modality for narrowing or disrupting the femoral neck's vasculature. The variables used for investigation included: frequency, penetration depth, and magnitude of the electrical energy. These variables, when combined, allowed for enhanced simulated visualization of the vasculature of the femoral neck and theoretically expedited diagnosis of obvious, or occult, femoral neck injury. RESULTS: Simulated blood vessels were developed in two-dimensions: the phi direction (circular), and z-direction. Two different frequencies, 3 GHz, and 5 GHz were considered, with 100-J energy pulses within blood vessels of 2.54 mm in diameter. The fat surrounding the bone to the outside surface body was simulated at 0.25 inch (0.65 cm). An additional model, with layered fat and skin above the vessels, was simulated at 2000J and successfully able to visualize the femoral neck's blood vessels. Results showed a distinguished E field across the blood boundary of nearly 170 V/M. CONCLUSIONS: The electric field simulation data within the Phi and Z directions promises the feasibility of a subsequent practical model.
  • Thumbnail Image
    Item
    Fabrication and Characterization of Lithium-ion Battery Electrode Filaments Used for Fused Deposition Modeling 3D Printing
    (2022-08) Kindomba, Eli; Zhang, Jing; Zhu, Likun; Schubert, Peter
    Lithium-Ion Batteries (Li-ion batteries or LIBs) have been extensively used in a wide variety of industrial applications and consumer electronics. Additive Manufacturing (AM) or 3D printing (3DP) techniques have evolved to allow the fabrication of complex structures of various compositions in a wide range of applications. The objective of the thesis is to investigate the application of 3DP to fabricate a LIB, using a modified process from the literature [1]. The ultimate goal is to improve the electrochemical performances of LIBs while maintaining design flexibility with a 3D printed 3D architecture. In this research, both the cathode and anode in the form of specifically formulated slurry were extruded into filaments using a high-temperature pellet-based extruder. Specifically, filament composites made of graphite and Polylactic Acid (PLA) were fabricated and tested to produce anodes. Investigations on two other types of PLA-based filament composites respectively made of Lithium Manganese Oxide (LMO) and Lithium Nickel Manganese Cobalt Oxide (NMC) were also conducted to produce cathodes. Several filaments with various materials ratios were formulated in order to optimize printability and battery capacities. Finally, flat battery electrode disks similar to conventional electrodes were fabricated using the fused deposition modeling (FDM) process and assembled in half-cells and full cells. Finally, the electrochemical properties of half cells and full cells were characterized. Additionally, in parallel to the experiment, a 1-D finite element (FE) model was developed to understand the electrochemical performance of the anode half-cells made of graphite. Moreover, a simplified machine learning (ML) model through the Gaussian Process Regression was used to predict the voltage of a certain half-cell based on input parameters such as charge and discharge capacity. The results of this research showed that 3D printing technology is capable to fabricate LIBs. For the 3D printed LIB, cells have improved electrochemical properties by increasing the material content of active materials (i.e., graphite, LMO, and NMC) within the PLA matrix, along with incorporating a plasticizer material. The FE model of graphite anode showed a similar trend of discharge curve as the experiment. Finally, the ML model demonstrated a reasonably good prediction of charge and discharge voltages.
  • Thumbnail Image
    Item
    Finite Element Analysis of and Multiscale Skeletal Tissue Mechanics Concerning a Single Dental Implant Site
    (2016) Sego, Timothy James; Tovar, Andres; Chu, Tien-Min Gabriel; Anwar, Sohel
    Finite element analysis (FEA) in implantology is performed in design applications concerning the complex topology of an implant, according to theoretical assumptions about and clinical data concerning the biomechanical nature of skeletal tissue. Implants are placed in topologically and physiologically complex sites, and major disagreement exists in literature about various aspects concerning their modeling and analysis. Current research seeks to improve the implementation of an implant by the use of short implants, which negate the necessity of additional surgical procedures in regions of limited bone height. However, short implants with large crown heights introduce biomechanical complications associated with increased stress and strain distributions in skeletal tissue, which may cause bone loss and implant failure. The short implant is characterized by the geometric ratio of the crown height to the implant length, called the crown-to-implant (C/I) ratio. In this work nonlinear FEA was performed to investigate the effects and significance of the C/I ratio on long-term implant stability. A finite element model was developed according to literature, and emulation of previous research and comparison of reported results were performed. Comparison of results demonstrated significant sources of error in previous research, which are argued to be caused by mesh-dependency from common model idealizations in literature. A convergence test was then performed, which verified the mesh-dependency of results and challenged the reliability of some common model assumptions and methods of analysis in literature. A 16-point design of experiments was then performed to evaluate the significance and influence of the C/I ratio, considering a proposed novel method for evaluating results and predicting long-term stability. Analysis of results demonstrated that the C/I ratio augments the inherent biomechanical effects of an implant design, particularly overloading strain concentrations at implant interface features. The use of short implants with high C/I ratios is determined to be inadvisable, considering the physiological response of tissue to strain distributions and biological context. A novel, multiscale material model is then proposed to describe the short-term accumulation of damage and biomechanical remodeling response in orthotropic skeletal tissue, as a potential solution to the mesh-dependency of results.
  • Thumbnail Image
    Item
    Research and Development of Electric Micro-Bus Vehicle Chassis
    (2022-12) Coovert, Benjamin; Tovar, Andres; Nematollahi, Khosrow; El-Mounayri, Hazim
    In this project, a chassis concept has been developed for a small electric vehicle ’minibus’. The vehicle is intended to be used as a transport between agricultural locations in Ethiopia to cities where the products can be sold. The objective is to develop a chassis that can house several different modular structures for the purposes of transporting refrigerated goods, a mobile power grid, or people. Literature studies have been conducted on current electric vehicle markets, battery markets, chassis materials, and optimal cross-sections. The battery housings have also been analyzed from an environmental perspective to account for conditions in Ethiopia. Based on this, it was found that a four-wheeled ’minibus’ design including space for approximately fourteen custom batteries is optimal. It is essential to keep in mind that this project has been carried out both on a conceptual level within the framework of a degree project as well as a production project for use in Ethiopian rural areas. This master thesis project aims to provide a solid benchmark for further development and research within the subject.