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 21

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.
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.
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.
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.
Static and Dynamic Solutions of Functionally Graded Micro/Nanobeams under External Loads Using Non-Local Theory
(MDPI, 2020-04) Moheimani, Reza; Dalir, Hamid; Mechanical and Energy Engineering, School of Engineering and Technology
Functionally graded materials (FGMs) have wide applications in different branches of engineering such as aerospace, mechanics, and biomechanics. Investigation of the mechanical behaviors of structures made of these materials has been performed widely using classical elasticity theories in micro/nano scale. In this research, static, dynamic and vibrational behaviors of functional micro and nanobeams were investigated using non-local theory. Governing linear equations of the problem were driven using non-local theory and solved using an analytical method for different boundary conditions. Effects of the axial load, the non-local parameter and the power index on the natural frequency of different boundary condition are assessed. Then, the obtained results were compared with those obtained from classical theory. These results showed that a non-local effect could greatly affect the behaviors of these beams, especially at nano scale.
Design and Analysis of an Optimized Formula 3 Nosecone Structure
(ASC, 2019) Deshpande, Archit; Venugopal, Naveen; Dalir, Hamid; Mechanical and Energy Engineering, School of Engineering and Technology
In order to ensure the driver safety in motorsport crashes, special crash structures are designed to absorb the race car’s kinetic energy and limit the decelerations acting on the human body. The use of Carbon fibre epoxy as a primary structural material has been evident in the motorsport industry. By utilizing monolithic structure for crash, large amount of energy can be absorbed. However, the energy absorbing capacity, unlike metals, is highly dependent on the geometry, number of layups and layup orientation angles. By optimizing the plies and the orientation along the geometric cross-section, the deceleration of the vehicle can be controlled. For the FIA crash test regulations, the deceleration was limited to 5g’s for the first 150mm of crushing and the average deceleration was limited to 25g’s. By dividing the geometry into sections, the ply orientation, and number of plies were varied. This resulted in a nosecone structure weighing around 2.1 kgs, but able to meet the above requirements. From the research1 it is evident that the Specific Energy Absorption (SEA) is not only a function of geometric cross-section (φ) but also the angle of attack (β). The angles of attack were varied from 5.5° to 32.5° and the effects on SEA were observed. The dynamic simulations were conducted in explicit solver LS-DYNA using Mat_ENHANCED_COMPOSITE_DAMAGE material model (MAT54). The simulation results were validated with crush test data for energy absorbed.
Specific Energy Absorption Improvement of Rear Crash Attenuator by Numerical Modelling for Various Angles of Impact
(ASC, 2019) Venugopal, Naveen; Deshpande, Archit Milind; Dalir, Hamid; Mechanical and Energy Engineering, School of Engineering and Technology
This research* aims on developing a reliable finite element framework to investigate the Specific Energy Absorption (SEA) of the rear crash attenuator of an open-wheel type Indycar vehicle. A meshed model representing the crash structure was designed and its failure behaviour was learnt on the basis of various non-linear finite element modelling techniques to simulate a crash as per regulations from the governing body of Indycar. All the numerical analysis was performed utilizing the LS-DYNA software with the Progressive Failure Model (PFM) and Continuum Damage Model (CDM) of MAT058_LAMINATED_COMPOSITE_FABRIC card. The sandwich structure material characterization for the tuning of the material model was done by the means of a correlation with experimental data and adjusting the non-physical input parameters in the software. Post calibration, the development of the rear impact attenuator was performed with the model. A combined failure mode was observed with a gradual crushing phenomenon during the analysis on head-on impacts (0°) while in case of oblique impacts performed at 30° off axis shows the structure failing at its rear attachment points to the bulkhead. The specific energy absorption was determined at different configurations of impact of this reinforced sandwich structure by evaluating the force over a crushed displacement. The layup was adjusted, the sensitive points at the attachments were stiffened, and the core thickness was varied throughout the structure to improve the overall specific energy absorption by 27.8% with a gradual deceleration value to that of the prescribed. Finally, the results were compared to the previous Indycar structure and the rear crash attenuator was redesigned with highlights of the refreshed results.

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