Mechanical and Energy Engineering Works
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Item Structural and Electrochemical Properties of the High Ni Content Spinel LiNiMnO4(MDPI, 2021) Li, Tianyi; Chang, Kai; Hashem, Ahmed M.; Abdel-Ghany, Ashraf E.; El-Tawil, Rasha S.; Wang, Hua; El-Mounayri, Hazim; Tovar, Andres; Zhu, Likun; Julien, Christian M.; Mechanical and Energy Engineering, School of Engineering and TechnologyThis work presents a contribution to the study of a new Ni-rich spinel cathode material, LiNiMnO4, for Li-ion batteries operating in the 5-V region. The LiNiMnO4 compound was synthesized by a sol-gel method assisted by ethylene diamine tetra-acetic acid (EDTA) as a chelator. Structural analyses carried out by Rietveld refinements and Raman spectroscopy, selected area electron diffraction (SAED) and X-ray photoelectron (XPS) spectroscopy reveal that the product is a composite (LNM@NMO), including non-stoichiometric LiNiMnO4-δ spinel and a secondary Ni6MnO8 cubic phase. Cyclic voltammetry and galvanostatic charge-discharge profiles show similar features to those of LiNi0.5Mn1.5O4 bare. A comparison of the electrochemical performances of 4-V spinel LiMn2O4 and 5-V spinel LiNi0.5Mn1.5O4 with those of LNM@NMO composite demonstrates the long-term cycling stability of this new Ni-rich spinel cathode. Due to the presence of the secondary phase, the LNM@NMO electrode exhibits an initial specific capacity as low as 57 mAh g−1 but shows an excellent electrochemical stability at 1C rate for 1000 cycles with a capacity decay of 2.7 × 10−3 mAh g−1 per cycle.Item Analysis of Composite Structures in Curing Process for Shape Deformations and Shear Stress: Basis for Advanced Optimization(MDPI, 2021) Kumbhare, Niraj; Moheimani, Reza; Dalir, Hamid; Mechanical and Energy Engineering, School of Engineering and TechnologyIdentifying residual stresses and the distortions in composite structures during the curing process plays a vital role in coming up with necessary compensations in the dimensions of mold or prototypes and having precise and optimized parts for the manufacturing and assembly of composite structures. This paper presents an investigation into process-induced shape deformations in composite parts and structures, as well as a comparison of the analysis results to finalize design parameters with a minimum of deformation. A Latin hypercube sampling (LHS) method was used to generate the required random points of the input variables. These variables were then executed with the Ansys Composite Cure Simulation (ACCS) tool, which is an advanced tool used to find stress and distortion values using a three-step analysis, including Ansys Composite PrepPost, transient thermal analysis, and static structural analysis. The deformation results were further utilized to find an optimum design to manufacture a complex composite structure with the compensated dimensions. The simulation results of the ACCS tool are expected to be used by common optimization techniques to finalize a prototype design so that it can reduce common manufacturing errors like warpage, spring-in, and distortion.Item Multilevel Design of Sandwich Composite Armors for Blast Mitigation using Bayesian Optimization and Non-Uniform Rational B-Splines(2021) Valladares, Homero; Tovar, Andres; Mechanical and Energy Engineering, School of Engineering and TechnologyIn regions at war, the increasing use of improvised explosive devices (IEDs) is the main threat against military vehicles. Large cabin”s penetrations and high gross accelerations are primary threats against the occupants” survivability. The occupants” survivability under an IED event largely depends on the design of the vehicle armor. Under a blast load, a vehicle armor should maintain its structural integrity while providing low cabin penetrations and low gross accelerations. This investigation employs Bayesian global optimization (BGO) and non-uniform rational B-splines (NURBS) to design sandwich composite armors that simultaneously mitigate the cabin”s penetrations and the reaction force at the armor”s supports. The armors are made of four layers: steel, carbon fiber reinforced polymer (CFRP), aluminum honeycomb, and CFRP. BGO is a methodology to solve optimization problems that require the evaluation of expensive black-box functions such as the finite element (FE) simulations of the vehicle armor under a blast event. BGO has two main components: the surrogate model of the black-box function and the acquisition function that guides the optimization. In this study, the surrogate models are Gaussian processes and the acquisition function is the multi-objective expected improvement function. NURBS generate the armor”s shape. The numerical examples show three alternatives to optimize the armor at two levels: (1) thicknesses of the sandwich”s layers and (2) the armor”s shape. The three design alternatives differ in the number of optimized levels and the optimization approach (sequential or simultaneous). The results show that the simultaneous optimization of the thicknesses of the sandwich”s layers and the armor”s shape is the most effective approach to design vehicle armors for blast mitigation.Item Modeling of Temperature Swing Effect in Silica Reinforced Porous Anodized Aluminum Based Thermal Barrier Coating(SAE International, 2021) Gulhane, Abhilash; Zhang, Jian; Yang, Xuehui; Lu, Zhe; Park, Hye-Yeong; Jung, Yeon-Gil; Li, Yafeng; Zhang, Jing; Mechanical and Energy Engineering, School of Engineering and TechnologyThis paper presents a finite element (FE) based model to simulate the temperature swing phenomenon of Silica Reinforced Porous Anodized Aluminum (SiRPA) thermal barrier coatings (TBCs). A realistic 3D SiRPA coating microstructure is constructed, based on the morphology of an experimentally grown coating structure, and the known relationship of geometry and anodization parameters. The coatings’ thermophysical properties are first computed using the FE model. The predicted thermal conductivity, thermal diffusivity, and bulk density are compared well with the experimental values. Also, transient thermal analysis is conducted to model the temperature swing effect of the coating by comparing the temperature fluctuation of SiRPA coating with conventional Yttria Stabilized Zirconia (YSZ) based TBCs. With the predicted thermophysical properties, the model is capable to predict the “temperature swing” effect of SiRPA by a transient thermal analysis. Temperature fluctuation of SiRPA is found greater compared to YSZ coating, suggesting its applicability in internal combustion engines. The porosity-dependent thermal conductivity of SiRPA coating is numerically derived. The thermal conductivity decreases linearly with increasing total porosity. The modeling data illustrate that the SiRPA coating shows a higher fluctuation compared to YSZ based TBCs, suggesting its applicability in internal combustion engines.Item Structural and Electrochemical Properties of the High Ni Content Spinel LiNiMnO4(MDPI, 2021) Li, Tianyi; Chang, Kai; Hashem, Ahmed M.; Abdel-Ghany, Ashraf E.; El-Tawil, Rasha S.; Wang, Hua; El-Mounayri, Hazim; Tovar, Andres; Zhu, Likun; Julien, Christian M.; Mechanical and Energy Engineering, School of Engineering and TechnologyThis work presents a contribution to the study of a new Ni-rich spinel cathode material, LiNiMnO4, for Li-ion batteries operating in the 5-V region. The LiNiMnO4 compound was synthesized by a sol-gel method assisted by ethylene diamine tetra-acetic acid (EDTA) as a chelator. Structural analyses carried out by Rietveld refinements and Raman spectroscopy, selected area electron diffraction (SAED) and X-ray photoelectron (XPS) spectroscopy reveal that the product is a composite (LNM@NMO), including non-stoichiometric LiNiMnO4-δ spinel and a secondary Ni6MnO8 cubic phase. Cyclic voltammetry and galvanostatic charge-discharge profiles show similar features to those of LiNi0.5Mn1.5O4 bare. A comparison of the electrochemical performances of 4-V spinel LiMn2O4 and 5-V spinel LiNi0.5Mn1.5O4 with those of LNM@NMO composite demonstrates the long-term cycling stability of this new Ni-rich spinel cathode. Due to the presence of the secondary phase, the LNM@NMO electrode exhibits an initial specific capacity as low as 57 mAh g−1 but shows an excellent electrochemical stability at 1C rate for 1000 cycles with a capacity decay of 2.7 × 10−3 mAh g−1 per cycle.Item Nanostructured Molybdenum-Oxide Anodes for Lithium-Ion Batteries: An Outstanding Increase in Capacity(MDPI, 2021) Wang, Hua; Li, Tianyi; Hashem, Ahmed M.; Abdel-Ghany, Ashraf E.; El-Tawil, Rasha S.; Abuzeid, Hanaa M.; Coughlin, Amanda; Chang, Kai; Zhang, Shixiong; El-Mounayri, Hazim; Tovar, Andres; Zhu, Likun; Julien, Christian M.; Mechanical and Energy Engineering, School of Engineering and TechnologyThis work aimed at synthesizing MoO3 and MoO2 by a facile and cost-effective method using extract of orange peel as a biological chelating and reducing agent for ammonium molybdate. Calcination of the precursor in air at 450 °C yielded the stochiometric MoO3 phase, while calcination in vacuum produced the reduced form MoO2 as evidenced by X-ray powder diffraction, Raman scattering spectroscopy, and X-ray photoelectron spectroscopy results. Scanning and transmission electron microscopy images showed different morphologies and sizes of MoOx particles. MoO3 formed platelet particles that were larger than those observed for MoO2. MoO3 showed stable thermal behavior until approximately 800 °C, whereas MoO2 showed weight gain at approximately 400 °C due to the fact of re-oxidation and oxygen uptake and, hence, conversion to stoichiometric MoO3. Electrochemically, traditional performance was observed for MoO3, which exhibited a high initial capacity with steady and continuous capacity fading upon cycling. On the contrary, MoO2 showed completely different electrochemical behavior with less initial capacity but an outstanding increase in capacity upon cycling, which reached 1600 mAh g−1 after 800 cycles. This outstanding electrochemical performance of MoO2 may be attributed to its higher surface area and better electrical conductivity as observed in surface area and impedance investigations.Item Mechanical environment for lower canine T-loop retraction compared to en-masse space closure with a power-arm attached to either the canine bracket or the archwire(EH Angle Education and Research Foundation, 2020-11-01) Jiang, Feifei; Roberts, W. Eugene; Liu, Yanzhi; Shafiee, Abbas; Chen, Jie; Mechanical and Energy Engineering, School of Engineering and TechnologyObjectives: To assess the mechanical environment for three fixed appliances designed to retract the lower anterior segment. Materials and methods: A cone-beam computed tomography scan provided three-dimensional morphology to construct finite element models for three common methods of lower anterior retraction into first premolar extraction spaces: (1) canine retraction with a T-loop, (2) en-masse space closure with the power-arm on the canine bracket (PAB), and (3) power-arm directly attached to the archwire mesial to the canine (PAW). Half of the symmetric mandibular arch was modeled as a linear, isotropic composite material containing five teeth: central incisors (L1), lateral incisor (L2), canine (L3), second premolar (L4), and first molar (L5). Bonded brackets had 0.022-in slots. Archwire and power-arm components were 0.016 × 0.022 in. An initial retraction force of 125 cN was used for all three appliances. Displacements were calculated. Periodontal ligament (PDL) stresses and distributions were calculated for four invariants: maximum principal, minimum principal, von Mises, and dilatational stresses. Results: The PDL stress distributions for the four invariants corresponded to the displacement patterns for each appliance. T-loop tipped the canine(s) and incisors distally. PAB rotated L3 distal in, intruded L2, and extruded L1. PAW distorted the archwire resulting in L3 extrusion as well as lingual tipping of L1 and L2. Maximum stress levels in the PDL were up to 5× greater for the PAW than the T-loop and PAB methods. Conclusions: T-loop of this type is more predictable because power-arms can have rotational and archwire distortion effects that result in undesirable paths of tooth movement.Item Development and Use of Open Educational Resources in an Undergraduate Heat and Mass Transfer Course(American Society of Engineering Education, 2021-07-26) Mendez, Julie; Mechanical and Energy Engineering, School of Engineering and Technology, IUPUCHigher education costs have been increasing more rapidly than inflation over the last few decades. One way to decrease textbook costs is to use open educational resources (OER), which are materials licensed in a way that allows everyone to engage in the “5R activities”: retain, reuse, revise, remix and redistribute. The most significant benefits of using OER or other no-cost digital materials instead of traditional textbooks is cost savings to students and the ability of all students to have access to the course materials on the first day of class. Studies have investigated faculty and student perceptions of open course materials, and most have had positive experiences with them. Several studies have indicated that students in courses using OER either achieved the same learning outcomes or show improved learning outcomes compared to courses that required traditional textbooks. This paper describes the use of OER and other no-cost digital materials in an undergraduate heat and mass transfer course, as well as the development of instructor-created videos. The main resources include an electronic textbook available at no charge and openly licensed videos. Compared to a previous offering of the course, there was a statistically significant improvement in course performance on two module-level outcomes. A survey at the end of the course indicated that students found the no-cost digital textbook to be about the same quality as or better than the quality of the textbooks in their other courses. Overall, students reported using the textbook in this course more frequently than textbooks in a typical course.Item Corrosion resistance and thermal stability of sputtered Fe44Al34Ti7N15 and Al61Ti11N28 thin films for prospective application in oil and gas industry(Elsevier, 2021-10-01) Maruf, Mahbub Alam; Rizvi, Syed Muhammad Mujtaba; Noor-A-Alam, Mohammed; Shin, Donghyun; Haider, Waseem; Shabib, Ishraq; Mechanical and Energy Engineering, School of Engineering and Technology, IUPUCFe-and Al-based thin-film metallic glass coatings (Fe44Al34Ti7N15 and Al61Ti11N28) were fabricated using magnetron co-sputtering technique, and their corrosion performances compared against wrought 316L stainless steel. The results of GI-XRD and XPS analyses demonstrated amorphous structure and oxide layer formation on the surface of the fabricated thin films, respectively. The potentiodynamic (PD) polarization test in chloride-thiosulfate (NH4Cl + Na2S2O3) solution revealed lower corrosion current (Icorr) (0.42 ± 0.02 μA/cm2 and 0.086 ± 0.001 μA/cm2 Vs. 0.76 ± 0.05 μA/cm2), lower passivation current (Ipass) (1.45 ± 0.03 μA/cm2 and 1.83 ± 0.07 μA/cm2 Vs. 1.98 ± 0.04 μA/cm2), and approximately six-fold higher breakdown potential (Ebd) for Fe- and Al-based coatings than those of wrought 316L stainless steel. Electrochemical Impedance Spectroscopy (EIS) of both films showed 4- and 2-fold higher charge transfer resistance (Rct), 7- and 2.5-times higher film resistance (Rf), lower film capacitance values (Qf) (10 ± 2.4 μS-sacm-2, and 5.41 ± 0.8 μS-sacm-2 Vs. 18 ± 2.21 μS-sacm-2), and lower double-layer capacitance values (Qdl) (31.33 ± 4.74 μS-sacm-2, and 15.3 ± 0.48 μS-sacm-2 Vs. 43 ± 4.23 μS-sacm-2), indicating higher corrosion resistance of the thin films. Cyclic Voltammetry (CV) scan exhibited that the passive films formed on the Fe- and Al-based coatings were more stable and less prone to pitting corrosion than the wrought 316L stainless steel. The surface morphology of both films via SEM endorsed the CV scan results, showing better resistance to pitting corrosion. Furthermore, the thermal analysis via TGA and DSC revealed the excellent thermal stability of the thin films over a wide temperature range typically observed in oil-gas industries.Item Improving the Robustness of Object Detection Through a Multi-Camera–Based Fusion Algorithm Using Fuzzy Logic(Frontiers, 2021) Khan, Md Nazmuzzaman; Al Hasan, Mohammad; Anwar, Sohel; Mechanical and Energy Engineering, School of Engineering and TechnologyA single camera creates a bounding box (BB) for the detected object with certain accuracy through a convolutional neural network (CNN). However, a single RGB camera may not be able to capture the actual object within the BB even if the CNN detector accuracy is high for the object. In this research, we present a solution to this limitation through the usage of multiple cameras, projective transformation, and a fuzzy logic–based fusion. The proposed algorithm generates a “confidence score” for each frame to check the trustworthiness of the BB generated by the CNN detector. As a first step toward this solution, we created a two-camera setup to detect objects. Agricultural weed is used as objects to be detected. A CNN detector generates BB for each camera when weed is present. Then a projective transformation is used to project one camera’s image plane to another camera’s image plane. The intersect over union (IOU) overlap of the BB is computed when objects are detected correctly. Four different scenarios are generated based on how far the object is from the multi-camera setup, and IOU overlap is calculated for each scenario (ground truth). When objects are detected correctly and bounding boxes are at correct distance, the IOU overlap value should be close to the ground truth IOU overlap value. On the other hand, the IOU overlap value should differ if BBs are at incorrect positions. Mamdani fuzzy rules are generated using this reasoning, and three different confidence scores (“high,” “ok,” and “low”) are given to each frame based on accuracy and position of BBs. The proposed algorithm was then tested under different conditions to check its validity. The confidence score of the proposed fuzzy system for three different scenarios supports the hypothesis that the multi-camera–based fusion algorithm improved the overall robustness of the detection system.