Hamid Dalir

Permanent URI for this collection

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.

Browse

Now showing 1 - 10 of 25

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.
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.
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.
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.
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.
Electrospun Nanofibers for Label-Free Sensor Applications
(MDPI, 2019-08-17) Aliheidari, Nahal; Aliahmad, Nojan; Agarwal, Mangilal; Dalir, Hamid; Engineering Technology, School of Engineering and Technology
Electrospinning is a simple, low-cost and versatile method for fabricating submicron and nano size fibers. Due to their large surface area, high aspect ratio and porous structure, electrospun nanofibers can be employed in wide range of applications. Biomedical, environmental, protective clothing and sensors are just few. The latter has attracted a great deal of attention, because for biosensor application, nanofibers have several advantages over traditional sensors, including a high surface-to-volume ratio and ease of functionalization. This review provides a short overview of several electrospun nanofibers applications, with an emphasis on biosensor applications. With respect to this area, focus is placed on label-free sensors, pertaining to both recent advances and fundamental research. Here, label-free sensor properties of sensitivity, selectivity, and detection are critically evaluated. Current challenges in this area and prospective future work is also discussed.
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.
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.
Failure study of fiber/epoxy composite laminate interface using cohesive multiscale model:
(SAGE, 2020-03-18) Moheimani, Reza; Sarayloo, Reza; Dalir, Hamid; Mechanical and Energy Engineering, School of Engineering and Technology
In this study, finite element modeling is performed to investigate the compressive failure of the composite sandwich structures with layered composite shells. An embedded debond area between the layered composite shell and the foam core is assumed as a defect. The composite shells are several plies of equal thickness Kevlar, carbon fiber composite, and E-glass composite with epoxy resin. Three different lay-ups, namely, (0°/90°/0°/90°/0°/90°), (45°/−45°/0°/90°/60°/−30°), and (60°/−30°/90°/0°/30°/90°) are considered for symmetric and asymmetric sequences. The work focuses on the importance of cohesive zone model versus the previously conducted numerical simulation and experimental results for buckling of sandwich composite structures. This enables one to account for delamination growth between shells and core and improve the correlation results with those of experiments. It has been shown that not only the cohesive model is capable of demonstrating delamination propagation, but it also correlates very well with the experimental data. By compiling user-defined cohesive mesoscale model in Abaqus simulation, the local and global buckling of the face-sheets can be precisely detected and response of sandwich structure becomes mesh independent, while mesh size is reduced.
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.

Browse

Browsing Hamid Dalir by Author "Dalir, Hamid"

Results Per Page

Sort Options