Browsing by Subject "FDM"

Now showing 1 - 3 of 3
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    Charge optimization of lithium-ion batteries for electric-vehicle application
    (2015-03-02) Pramanik, Sourav; Anwar, Sohel; Wasfy, Tamar; Li, Lingxi
    In recent years Lithium-Ion battery as an alternate energy source has gathered lot of importance in all forms of energy requiring applications. Due to its overwhelming benefits over a few disadvantages Lithium Ion is more sought of than any other Battery types. Any battery pack alone cannot perform or achieve its maximum capacity unless there is some robust, efficient and advanced controls developed around it. This control strategy is called Battery Management System or BMS. Most BMS performs the following activity if not all Battery Health Monitoring, Temperature Monitoring, Regeneration Tactics, Discharge Profiles, History logging, etc. One of the major key contributor in a better BMS design and subsequently maintaining a better battery performance and EUL is Regeneration Tactics. In this work, emphasis is laid on understanding the prevalent methods of regeneration and designing a new strategy that better suits the battery performance. A performance index is chosen which aims at minimizing the effort of regeneration along with a minimum deviation from the rated maximum thresholds for cell temperature and regeneration current. Tuning capability is provided for both temperature deviation and current deviation so that it can be tuned based on requirement and battery chemistry and parameters. To solve the optimization problem, Pontryagin's principle is used which is very effective for constraint optimization with both state and input constraints. Simulation results with different sets of tuning shows that the proposed method has a lot of potential and is capable of introducing a new dynamic regeneration tactic for Lithium Ion cells. With the current optimistic results from this work, it is strongly recommended to bring in more battery constraints into the optimization boundary to better understand and incorporate battery chemistry into the regeneration process.
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    Design of Self-supported 3D Printed Parts for Fused Deposition Modeling
    (2016) Lischke, Fabian; Tovar, Andres; Anwar, Sohel; Jones, Alan S.
    One of the primary challenges faced in Additive Manufacturing (AM) is reducing the overall cost and printing time. A critical factor in cost and time reduction is post-processing of 3D printed (3DP) parts, which includes removing support structures. Support is needed to prevent the collapse of the part or certain areas under its own weight during the 3D printing process. Currently, the design of self-supported 3DP parts follows experimental trials. A trial and error process is needed to produce high quality parts by Fused Depositing Modeling (FDM). An example for a chamfer angle, is the common use of 45 degree angle in the AM process. Surfaces that are more flat show defects than inclined surfaces, and therefore a numerical model is needed. The model can predict the problematic areas at a print, reducing the experimental prints and providing a higher number of usable parts. Physical-based models have not been established due to the generally unknown properties of the material during the AM process. With simulations it is possible to simulate the part at different temperatures with a variety of other parameters that have influence on the behavior of the model. In this research, analytic calculations and physical tests are carried out to determine the material properties of the thermoplastic polymer Acrylonitrile - Butadiene - Styrene (ABS) for FDM at the time of extrusion. This means that the ABS is going to be extruded at 200C to 245C and is a viscus material during part construction. Using the results from the physical and analytical models, i.e., Timoshenko’s modified beam theory for micro structures, a numerical material model is established to simulate the filament deformation once it is deposited onto the part. Experiments were also used to find the threshold for different geometric specifications, which could then be applied to the numerical model to improve the accuracy of the simulation. The result of the nonlinear finite element analysis is compared to experiments to show the correlation between the prediction of deflection in simulation and the actual deflection measured in physical experiments. A case study was conducted using an application that optimizes topology of complex geometries. After modeling and simulating the optimized part, areas of defect and errors were determined in the simulation, then verified and and measured with actual 3D prints.
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    Sintering and Characterizations of 3D Printed Bronze Metal Filament
    (2018-12) Ayeni, Oyedotun Isaac; Zhang, Jing; Hazim, El-Mounayri; Xiaoliang, Wei
    Metal 3D printing typically requires high energy laser or electron sources. Recently, 3D printing using metal filled filaments becomes available which uses PLA filaments filled with metal powders (such as copper, bronze, brass, and stainless steel). Although there are some studies on their printability, the detailed study of their sintering and characterizations is still missing. In this study, the research is focused on 3D printing of bronze filaments. Bronze is a popular metal for many important uses. The objectives of this research project are to study the optimal processing conditions (like printer settings, nozzle, and bed temperatures) to print bronze metal filament, develop the sintering conditions (temperature and duration), and characterization of the microstructure and mechanical properties of 3D printed specimens to produce strong specimens. The thesis includes three components: (1) 3D printing and sintering at selected conditions, following a design of experiment (DOE) principle; (2) microstructure and compositional characterizations; and (3) mechanical property characterization. The results show that it is feasible to print using bronze filaments using a typical FDM machine with optimized printing settings. XRD spectrums show that there is no effect of sintering temperature on the composition of the printed parts. SEM images illustrate the porous structure of the printed and sintered parts, suggesting the need to optimize the process to improve the density. The micro hardness and three-point bending tests show that the mechanical strengths are highly related to the sintering conditions. This study provides important information of applying the bronze filament in future engineering applications.