Browsing by Author "Dalir, Hamid"

Now showing 1 - 10 of 64
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    Advances in Vehicular Aerodynamics
    (2024-05) Dave, Deepam; Dalir, Hamid; El-Mounayri, Hazim A.; Tovar, Andres; Anwar, Sohel
    This article-based research traces the evolution and advancements of vehicular aerodynamic concepts and emphasizes on the significance of vehicle aerodynamics for high-performance vehicles. The thesis further explores the scope of integrating advanced vehicle aerodynamic concepts into consumer vehicles. The thesis aims to point out the significant improvements achieved with the integration of active aerodynamic concepts in terms of both vehicle performance as well as efficiency figures for consumer vehicles. Additionally, exploring the scope for the development of these advanced active aerodynamic systems as third-party modifications is the secondary objective of the presented research. The thesis also highlights the development and integration of unique active aerodynamic systems featured in performance vehicles and analyzes the performance gains achieved using MATLAB program-based simulations supported by a graphical representation of analyzed output data. The study of Active aerodynamic systems for both performance/track-oriented and consumer vehicles remains the primary emphasis for the presented thesis.
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    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 Technology
    Identifying 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.
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    Analysis of Process Induced Shape Deformations and Residual Stresses in Composite Parts during Cure
    (2019-05) Patil, Ameya S.; Dalir, Hamid; El-Mounayri, Hazim; Zhang, Jing
    Process induced dimensional changes in composite parts has been the topic of interest for many researchers. The residual stresses that are induced in composite laminates during curing process while the laminate is in contact with the process tool often lead to dimensional variations such as spring-in of angles and warpage of flat panels. The traditional trial-and-error approach can work for simple geometries, but composite parts with complex shapes require more sophisticated models. When composite laminates are subjected to thermal stresses, such as the heating and cooling processes during curing, they can become distorted as the in-plane and the throughthickness coeffcients of thermal expansion are di erent, as well as chemical shrinkage of the resin, usually cause spring-in. Deformed components can cause problems during assembly, which significantly increases production costs and affects performance. This thesis focuses on predicting these shape deformations using software simulation of composite manufacturing and curing. Various factors such as resin shrinkage, degrees of cure, difference between through thickness coeffcient of thermal expansion of the composite laminate are taken into the consideration. A cure kinetic model is presented which illustrates the matrix behavior during cure. The results obtained using the software then were compared with the experimental values of spring-in from the available literature. The accuracy of ACCS package was validated in this study. Analyzing the effects of various parameters of it was estimated that 3D part simulation is an effective and cost and time saving method to predict nal shape of the composite part.
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    Analysis of Spring-in for Composite Plates Using ANSYS Composite Cure Simulation
    (American Society for Composites, 2019) Patil, Ameya; Moheimani, Reza; Shakhfeh, Talal; Dalir, Hamid; Mechanical and Energy Engineering, School of Engineering and Technology
    Process induced dimensional changes in composite parts has been the topic of interest for many researchers. The residual stresses that develop in fiber-reinforced laminates during curing process while the laminate is confined to the process tool often leads to dimensional changes such as spring-in of angles and warpage of flat sections. Many experimental studies have put emphasis on this issue and various researches show different methods to predict these dimensional changes. The traditional trial-and-error approach can work for simple geometries, but composite parts with complex shapes require more sophisticated models. When composite laminates are subjected to thermal stresses, such as the heating and cooling processes during curing, they can become distorted as the difference between the in-plane and the through-thickness thermal expansion coefficient, as well as chemical shrinkage of the epoxy, causes the enclosed angle of curved sections and angle components to be reduced. Distorted components can cause problems during assembly, significantly increasing production costs and affecting performance. This paper focuses on predicting these shape deformations using software simulation of composite manufacturing and curing. Various factors such as resin shrinkage, degrees of cure, difference between coefficient of thermal expansion of mold and composite are taken into consideration. A cure kinetic model is presented which illustrates the matrix behavior during cure.
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    Application of Laminated Composite Grids as a Reinforcing Element of Automotive Components
    (ASC, 2018-09) Ehsani, Amir; Dalir, Hamid; Mechanical Engineering and Energy, School of Engineering and Technology
    This paper intends to present the application of laminated grid structures as a new class of stiffeners for reinforcing body and chassis of transportation vehicles. A laminated grid plate is constituted from several grid plies with different orientations. Therefore, the grid layers with various fibers, patterns, and orientations can be used, resulting in laminates with enhanced stiffness and coupling effects. In this study, a hypothetical trunk floor is assumed as a sandwich panel with two skins and a composite laminated grid core, which is clamped along all edges. Three different grid structures are considered as the core to strengthen the trunk floor subjected to arbitrary lateral loads. Moreover, the first natural frequency of the plates are achieved. The Ritz method is employed to obtain the maximum deflection and free vibration frequencies of the trunk’s floor panel. The results indicate that employing the laminated grids considerably enhances the response of the panel in comparison with conventional grids.
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    Bree's diagram of a functionally graded thick-walled cylinder under thermo-mechanical loading considering nonlinear kinematic hardening
    (Elsevier, 2018-09-01) Damadam, Mohsen; Moheimani, Reza; Dalir, Hamid; Mechanical and Energy Engineering, School of Engineering and Technology
    In this paper, elasto-plastic analysis of a thick-walled cylinder made of functionally graded materials (FGMs) subjected to constant internal pressure and cyclic temperature gradient loading is carried out using MATLAB. The material is assumed to be isotropic and independent of temperature with constant Poisson's ratio and the material properties vary radially based on a power law volume function relation. The Von Mises’ yield criterion and the Armstrong-Frederick nonlinear kinematic hardening model were implemented in this investigation. To obtain the incremental plastic strain, return mapping algorithm (RMA) was used. At the end, the Bree's interaction diagram is plotted in terms of non-dimensional pressure and temperature which represents an engineering index for optimum design under thermo-mechanical loading.
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    Carbon and cellulose based nanofillers reinforcement to strengthen carbon fiber-epoxy composites: Processing, characterizations, and applications
    (Frontiers, 2023-01-10) Biswas, Pias Kumar; Omole, Oluwaseun; Peterson, Garrett; Cumbo, Eric; Agarwal, Mangilal; Dalir, Hamid; Mechanical Engineering, School of Engineering and Technology
    Since the inception of carbon fiber reinforced polymer (CFRP) composites, different nanofillers have been investigated to strengthen their mechanical and physical properties. To date, the majority of research has focused on enhancing fiber/matrix interface characteristics and/or optimizing nanofiller dispersion within the matrix, both of which improve the performance of carbon fiber-epoxy composite structures. Nanofillers can be dispersed into the polymer matrix by different techniques or nanofillers are chemically bonded to fiber, polymer, or both via multiple reaction steps. However, a few studies were conducted showing the effects of different nanofillers on the performance of carbon fiber-epoxy composites. Here a critical study has been done to explore different carbon and cellulose-based nanofillers which are used to enhance the mechanical and physical properties of carbon fiber-epoxy composites. After giving a short history of carbon fiber production, the synthesis of carbon nanotubes (CNTs), graphene, cellulose-based nanofillers (cellulose nanocrystals and nanofibers), their dispersion in the polymer matrix, and chemical/physical bonding with the fiber or polymer have been extensively described here along with their processing techniques, characterizations, and applications in various fields.
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    Carbon Fiber Reinforced Lithium-Ion Battery Composites with Higher Mechanical Strength: Multifunctional Power Integration for Structural Applications
    (2021-08) Jadhav, Mayur Shrikant; Agarwal, Mangilal; Dalir, Hamid; Zhang, Jing
    This study proposes and evaluates a multi-functional carbon fiber reinforced composite with embedded Lithium-ion battery for its structural integrity concept. The comparison of versatile composite structures manufactured conventionally, air-sprayed and electrospun multi walled carbon nano tubes in order to discover a better packaging method for incorporating lithium-ion batteries at its core is determined. In the electrospinning process recognized globally as a flexible and cost-effective method for generating continuous Nano filaments. It was incorporated exactly on the prepreg surface to obtain effective inter-facial bonding and adhesion between the layers. The mechanical and physical properties of carbon fiber reinforced polymers (CFRP) with electrospun multi walled carbon nano tubes (CNTs) have evidenced to possess higher mechanical strength incorporated between the layers of the composite prepreg than the traditional CFRP prepreg composite, At the same time the air sprayed CFRP with CNTs offers mechanical strength more than the traditional CFRP prepreg but lesser than the electrospun. This can be a design consideration from the economic feasibility viewpoint. They also contribute to efficient load transfer and structural load bearing implementation without compromising the chemistry of battery. The design validation, manufacture methods, and experimental characterization (mechano-electrical) of Multi-functional energy storage composites (MESCs) are examined. Experimental results on the electrochemical characterization reveal that the MESCs show comparable performance to the standard lithium-ion pouch cells without any external packaging and not under any loading requirements. The mechanical performance of the MESC cells especially electrospun CFRP is evaluated from three-point bending tests with the results demonstrating significant mechanical strength and stiffness compared to traditional pouch cells and conventional, air-sprayed CFRP and at lowered packaging weight and thickness. This mechanical robustness of the MESCs enable them to be manufactured as energy-storage devices for electric vehicles.
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    A Case Study of Safe and Cost-Effective Hospital HVAC Strategies
    (2022-08-02) Caesar, Jeffrey; Ray, Matthew Veto; Koo, Dan; Dalir, Hamid
    The pressures of healthcare facilities to keep patients safe while also maintaining financial viability have been felt in recent years amongst industry leaders. The impacts COVID has had on patient safety and planning has in any way fast-tracked patient safety progress, but certainly at a financial cost. As hospital leaders and facility leaders attempt to grapple with these realities, a facility's operating strategy that addresses both safety and cost should be employed. The below study aims to solve two issues facing hospital facility leadership in regards to the facilities’ HVAC system. The first issue is how to decrease energy consumption and operating expenses in light of industry pressures to improve the financial outlook and secondly, how to increase patient safety as a direct result of COVID-19 realities. Increasing safety and ultimately flexibility can many times increase costs, so utilizing the most appropriate and tested techniques that follow patient safety protocols will be necessary. The importance of this study cannot be understated. As with any healthcare system, improving patient outcomes are at the heart of the industry and especially in light of our recent pandemic. The fundamental question as to how facilities can keep patients safer while simultaneously reducing energy consumption is a tough question to answer, but manageable due to both recent industry experience and up-to-date research on the topic. The methodology will be to conduct a straightforward cost benefit analysis that takes into account both patient safety and energy consumption. The first step will be to gather baseline data for Lutheran Hospital’s HVAC system to gauge current system performance vs. benchmarked performance. Next, the data will inform us as to what strategies to implement to both curb costs and increase patient safety. The third step will be to implement those strategies where possible and measure their benefits. Lastly, a conclusion will be made as to what long-term solutions will be most useful to both this hospital and the other hospitals within Lutheran Health Network.
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    Case Study – Solar Panel Installation in Mitsubishi Turbocharger and Engine America Plant – Feasibility Study
    (2022-08-02) Bajgoric, Kenan; Ray, Veto; Koo, Dan; Dalir, Hamid
    Data collected from the MTEA site as well as contractor-provided information was analyzed and reviewed to show how solar power can contribute to MTEA's overarching strategic plan of reducing CO2 emissions and lowering operating costs. This study is significant because the results will demonstrate that harnessing solar energy is financially and technologically feasible for MTEA.