Hamid Dalir

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https://hdl.handle.net/1805/26673

Lighter Composite Parts for Automotive and Aerospace Structures

While conventional carbon fiber composites are being widely used in aerospace and defense sectors, their layered nature causes interlaminar strength disadvantages leading to their premature failure under operational loading. After working for almost eight years in composites R&D for aerospace and defense and understanding the key challenges, Professor Dalir, along with Professor Mangilal Agarwal and Professor Amanda Siegel, started investigating the use of fine filaments ("'100 nm) of Carbon Nanotube/Epoxy nanocomposites developed as part of this project at INDI enabling the industry a potential 30% additional weight saving.

Manufacturing lighter but tougher structures motivated the researchers to inaugurate a university startup named "Multiscale Integrated Technology Solutions LLC" in June of 2019 where the focus has been on working with companies such as Dallara, SRAM, and Bauer to reduce the weight and cost of their parts which means less use of non-eco-friendly carbon fibers leading to lower CO2 emissions improving the quality of life of our nation. In 2021, they secured several grants and investments on their technology. They also won a statewide competition held by Indiana Elevate Nexus, which resulted in investments from the state in their technology.

They also received over $400,000.00 grants from various agencies including National Science Foundation (NSF), Indiana Economic Development Corporation (IEDC), and Elevate, among others. In addition, they have been featured in several interviews such as "Inside Indiana Business", "Tech Talk with Steve Sweitzer'', "FOX 59", and "WTHR".

They anticipate additional investments in 2022. MITS has secured the key IP from IUPUI including full rights to develop, exercise, license, sublicense, market, and sell technologies related to the material system proposed in this research.

Professor Dalir's translation of research into advanced, eco-friendly automotive and aerospace structures is another excellent example of how IUPUI's faculty members are TRANSLATING their RESEARCH INTO PRACTICE.

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Now showing 1 - 10 of 24

Flexural modes coupling in cantilever-type piezoelectric energy harvesters
(Elsevier, 2021-11) Pasharavesh, Abdolreza; Dalir, Hamid; Mechanical and Energy Engineering, School of Engineering and Technology
The ability to harness the waste mechanical energy and convert it into useful electrical power has made kinetic energy harvesters a promising candidate to provide an everlasting energy source for wireless autonomous devices. Nonlinearities, whether introduced deliberately for the sake of bandwidth broadening or present intrinsically, can highly influence the dynamic response and output power behavior of these type of energy scavengers. This paper aims to investigate the effect of nonlinearity on multi-mode vibrational response of a harvester composed of a cantilevered piezoelectric composite beam with an attached mass of finite dimensions. To that end, first of all a 3-DoF lumped parameter coupled electromechanical model of the device is developed through a comprehensive mathematical approach and its mode shapes and natural frequencies are calculated. The perturbation method of multiple scales is then applied to obtain the steady state solutions to the extracted order-reduced governing equations of the system. Results indicate that a harvester with a cubic attached mass exhibits a simple Duffing-type resonance as the excitation frequency falls in the vicinity of each natural frequency. That occurs while for a U-shaped mass the vibration modes would be coupled through occurrence of an internal resonance. In this latter case, both flexural modes of the piezoelectric beam are stimulated by a single frequency excitation and contribute to the power generation leading to an enhancement of the total output power which is the major advantage of the proposed design in this paper compared to the other existing energy harvesters. The frequency response curves of the output power are found to be composed of four branches and include Hopf bifurcations and instability regions. To verify the results obtained from the analytical approach, they are compared to a numerical solution where a good agreement is observed between them.
Synthesis of V2O5/Single-Walled Carbon Nanotubes Integrated into Nanostructured Composites as Cathode Materials in High Performance Lithium-Ion Batteries
(MDPI, 2022) Aliahmad, Nojan; Biswas, Pias Kumar; Dalir, Hamid; Agarwal, Mangilal; Mechanical and Energy Engineering, School of Engineering and Technology
Vanadium pentoxide (V2O5)-anchored single-walled carbon nanotube (SWCNT) composites have been developed through a simple sol–gel process, followed by hydrothermal treatment. The resulting material is suitable for use in flexible ultra-high capacity electrode applications for lithium-ion batteries. The unique combination of V2O5 with 0.2 wt.% of SWCNT offers a highly conductive three-dimensional network. This ultimately alleviates the low lithium-ion intercalation seen in V2O5 itself and facilitates vanadium redox reactions. The integration of SWCNTs into the layered structure of V2O5 leads to a high specific capacity of 390 mAhg−1 at 0.1 C between 1.8 to 3.8 V, which is close to the theoretical capacity of V2O5 (443 mAhg−1). In recent research, most of the V2O5 with carbonaceous materials shows higher specific capacity but limited cyclability and poor rate capability. In this work, good cyclability with only 0.3% per cycle degradation during 200 cycles and enhanced rate capability of 178 mAhg−1 at 10 C have been achieved. The excellent electrochemical kinetics during lithiation/delithiation is attributed to the chemical interaction of SWCNTs entrapped between layers of the V2O5 nanostructured network. Proper dispersion of SWCNTs into the V2O5 structure, and its resulting effects, have been validated by SEM, TEM, XPS, XRD, and electrical resistivity measurements. This innovative hybrid material offers a new direction for the large-scale production of high-performance cathode materials for advanced flexible and structural battery applications.
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.
Thermoplastic polyurethane flexible capacitive proximity sensor reinforced by CNTs for applications in the creative industries
(Springer Nature, 2021-01-13) Moheimani, Reza; Aliahmad, Nojan; Aliheidari, Nahal; Agarwal, Mangilal; Dalir, Hamid; Mechanical and Energy Engineering, School of Engineering and Technology
Wearable sensing platforms have been rapidly advanced over recent years, thanks to numerous achievements in a variety of sensor fabrication techniques. However, the development of a flexible proximity sensor that can perform in a large range of object mobility remains a challenge. Here, a polymer-based sensor that utilizes a nanostructure composite as the sensing element has been presented for forthcoming usage in healthcare and automotive applications. Thermoplastic Polyurethane (TPU)/Carbon Nanotubes (CNTs) composites are capable of detecting presence of an external object in a wide range of distance. The proximity sensor exhibits an unprecedented detection distance of 120 mm with a resolution of 0.3%/mm. The architecture and manufacturing procedures of TPU/CNTs sensor are straightforward and performance of the proximity sensor shows robustness to reproducibility as well as excellent electrical and mechanical flexibility under different bending radii and over hundreds of bending cycles with variation of 4.7% and 4.2%, respectively. Tunneling and fringing effects are addressed as the sensing mechanism to explain significant capacitance changes. Percolation threshold analysis of different TPU/CNT contents indicated that nanocomposites having 2 wt% carbon nanotubes are exhibiting excellent sensing capabilities to achieve maximum detection accuracy and least noise among others. Fringing capacitance effect of the structure has been systematically analyzed by ANSYS Maxwell (Ansoft) simulation, as the experiments precisely supports the sensitivity trend in simulation. Our results introduce a new mainstream platform to realize an ultrasensitive perception of objects, presenting a promising prototype for application in wearable proximity sensors for motion analysis and artificial electronic skin.
Electrospun Thermosetting Carbon Nanotube–Epoxy Nanofibers
(ACS, 2021-02) Aliahmad, Nojan; Biswas, Pias Kumar; Wable, Vidya; Hernandez, Iran; Siegel, Amanda; Dalir, Hamid; Agarwal, Mangilal; Mechanical and Energy Engineering, School of Engineering and Technology
This paper represents the process of fabrication and characterization of submicron carbon nanotube (CNT)–epoxy nanocomposite filaments through an electrospinning process. Electrospinning is one of the most versatile, inexpensive, and environmentally well-known techniques for producing continuous fibers from submicron diameter all the way to tens of nanometer diameter. Here, electrospinning of submicron epoxy filaments was made possible by partial curing of the epoxy by mixing the hardener and through a thermal treatment process without the need for adding any plasticizers or thermoplastic binders. This semicuring approach makes the epoxy solution viscous enough for the electrospinning process, that is, without any solidification or nonuniformity caused by the presence of the hardener inside the mixture. The filaments were spun using a CNT/epoxy solution with a viscosity of 65 p using 16 kV and a collector distance of 10 cm. The diameter of these filaments can be tuned as low as 100 nm with adjustment of electrospinning parameters. By incorporating a low amount of CNT into epoxy, better structural, electrical, and thermal stabilities were achieved. The CNT fibers have been aligned inside the epoxy filaments because of the presence of the electrostatic field during the electrospinning process. The modulus of the epoxy and CNT/epoxy filaments were found to be 3.24 and 4.84 GPa, respectively. The presence of the CNT can lead up to 49% improvement on modulus. Accordingly, using a commercially available epoxy suitable for industrial composite productions makes the developed filament suitable for many applications.
Mathematical Model and Experimental Design of Nanocomposite Proximity Sensors
(IEEE, 2020-08) Moheimani, Reza; Pasharavesh, Abdolreza; Agarwal, Mangilal; Dalir, Hamid; Engineering Technology, School of Engineering and Technology
A mathematical model of fringe capacitance for a nano-based proximity sensor, which takes the presence of different resistivities into account, is developed. An analytical solution obtained for a rectangular-shape sensor with applying of Gauss, Conversation of Charge and Ohm laws into Laplace's equation ∇2V (x, y, z, t) = 0 gives the electric potential distribution by which the fringe capacitance in a 2D domain area can be calculated. The calculated capacitance evidently decreases drastically due to the fringe phenomena while object moves toward the polymeric sensor. The model also asserts that the change of capacitance is under a noticeable influence of sensor resistivity, particularly in the range of 103-105Ω.m, the initial capacitance varies from 0.045pF to 0.024 pF. The fabricated flexible nanocomposite sensors, Thermoplastic Polyurethane (TPU) reinforced by 1wt.% Carbon Nanotubes (CNTs) having resistivity 105Ω.m, are capable of detecting presence of an external object in a wide range of distance and indicating remarkable correlation with the mathematical solution. Our proximity sensor fabrication is straightforward and relatively simple. An unprecedented detection range of measurement reveals promising ability of this proximity sensor in applications of motion analysis and healthcare systems.
Higher strength carbon fiber lithium-ion polymer battery embedded multifunctional composites for structural applications
(Wiley Online Library, 2022-03-17) Biswas, Pias Kumar; Liyanage, Asel Ananda Habarakada; Jadhav, Mayur; Agarwal, Mangilal; Dalir, Hamid
This study proposes and evaluates the structural integrity of a carbon fiber reinforced polymer (CFRP) composite containing encapsulated lithium-ion polymer (Li-Po) batteries. A comparison of various composite structures made of CFRP having the core of lithium-ion batteries is conducted. Electrospinning is globally recognized as a flexible and cost-effective method for generating continuous nanofilaments. In this study, epoxy-multiwalled carbon nanotubes (CNT/epoxy) were electrospun onto CFRP layers, which improved interfacial bonding and strong adhesion between the layers which ultimately worked as an effective packaging for Li-ion batteries. This composite structure showed enhanced mechanical strength compared to the standard CFRP laminate structure due to incorporating electrospun CNT/epoxy nanofibers in between the layers. An alternate method was proposed for comparison where CNT/epoxy was air sprayed onto the CFRP layers. CFRP structure containing airsprayed CNT/epoxy was found to be stronger than standard CFRP laminate structure, although not as strong as electrospun CNT/epoxy enhanced CFRP laminates. Finally, the design validation, manufacturing method, and electromechanical characterization of multifunctional energy storage composites (MESCs) were examined and compared. Electrochemical characterization showed that MESCs with electrospun CNT/epoxy nanofibers enhanced CFRP laminate under loading conditions had similar performance to the standard lithium-ion pouch cells without any loading. The mechanical robustness of the proposed CFRP composite structures enables their manufacturing as multifunctional energy-storage devices for electric vehicles and other structural applications.
Multi-nozzle electrospinning optimization of carbon nanotube/epoxy submicron filaments – A numerical study
(American Chemical Society, 2021-08-26) Liyanage, Asel Habarakada; Biswas, Pias Kumar; Cumbo, Eric; Siegel, Amanda P.; Agarwal, Mangilal; Dalir, Hamid
Electrospinning is the process of spinning a polymer melt or solution through a nozzle in the presence of a high-voltage electric field, which causes it to coalesce into a continuous filament. Diameter of the filament is anywhere from tens of nanometers to a few microns, depending on the materials being spun, viscosity, electric field, and other experimental conditions. This process has gained attention because of its versatility, low cost, and ease of processing for many polymers. Thermosetting reinforced epoxy is particularly challenging because of the variability in viscosity caused by temperature changes and induced by the electrospinning process itself. Nevertheless, our research group previously developed the fabrication and characterization of submicron carbon nanotube (CNT)–epoxy nanocomposite filaments through an electrospinning process via a single nozzle, horizontal spray process. In this study, electric fields and other parameters were simulated using COMSOL Multiphysics® software to understand the induced surface charges that cause the Taylor cone of the CNT-epoxy solution.. Optimization of the simulation results coupled with those of experiments enabled us to achieve stability and fabricate smaller but more uniform diameter fibers with enhanced structural, electrical, and thermal properties. The main challenge addressed in this paper is the use of the COMSOL models to understand the effect of different geometries on the electric field in the presence of multi-nozzle systems.
Fabrication of Submicron Thermosetting Carbon Nanotube-Epoxy Fibers Using Electrospinning
(American Society for Composites, 2020-09-20) Aliahmad, Nojan; Wable, Vidya; Biswas, Pias Kumar; Hernadez, Iran; Dalir, Hamid; Agarwal, Mangilal
Recently epoxy-based nanocomposites are gaining tremendous attention in many structural applications such as those in aerospace, automotive and motorsports. This research represents a new approach to fabricate submicron thermoset epoxy filaments enhanced with carbon nanotubes (CNT), through optimized curing followed by an electrospinning process. The optimized curing process is based on the uniform mixing of CNT with epoxy, and partial curing of the CNT/epoxy mixture with the hardener through a thermal treatment without adding any plasticizers or thermoplastic binders. Later the fibers have been made by electrospinning of the semi-cured mixture. Fig 1 shows the fabrication process of the described filaments. The key goal is to make the thermosetting epoxy without adding any thermoplastic to keep the integrity and quality of the fibers. The diameters of these filaments can be tuned between 100 nm to 500nm. Further, the CNT structure has been aligned inside the filament structure by the presence of the electrostatic field during the electrospinning process results in better stability and smaller diameters for the fibers. The fabricated filaments show that adding a low amount of CNT in the epoxy structure, better structural, electrical and thermal stability, has been achieved.
Nonlinear energy harvesting from vibratory disc-shaped piezoelectric laminates
(Elsevier, 2020-04) Pasharavesh, Abdolreza; Moheimani, Reza; Dalir, Hamid; Mechanical and Energy Engineering, School of Engineering and Technology
Implementing resonators with geometrical nonlinearities in vibrational energy harvesting systems leads to considerable enhancement of their operational bandwidths. This advantage of nonlinear devices in comparison to their linear counterparts is much more obvious especially at small-scale where transition to nonlinear regime of vibration occurs at moderately small amplitudes of the base excitation. In this paper the nonlinear behavior of a disc-shaped piezoelectric laminated harvester considering midplane-stretching effect is investigated. Extended Hamilton’s principle is exploited to extract electromechanically coupled governing partial differential equations of the system. The equations are firstly order-reduced and then analytically solved implementing perturbation method of multiple scales. A nonlinear finite element method (FEM) simulation of the system is performed additionally for the purpose of verification which shows agreement with the analytical solution to a large extent. The frequency response of the output power at primary resonance of the harvester is calculated to investigate the effect of nonlinearity on the system performance. Effect of various parameters including mechanical quality factor, external load impedance and base excitation amplitude on the behavior of the system are studied. Findings indicate that in the nonlinear regime both output power and operational bandwidth of the harvester will be enhanced by increasing the mechanical quality factor which can be considered as a significant advantage in comparison to linear harvesters in which these two factors vary in opposite ways as quality factor is changed.

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