This research will focus on understanding the physics behind chip formation during machining metal syntactic foams through development of a 2D finite element (FE) model which will enable to predict cutting forces using AdvantEdge FE software. Cutting tests were conducted on the aluminium syntactic foam with varying cutting velocity and undeformed chip thickness. From the FE results, it is shown that the increase in cutting speed results in reduction of cutting force due to thermal softening of matrix alloy. However, the measured cutting force increased with increasing undeformed chip thickness is primarily due to increasing chip load. Increase in shear strength of the material is noticed with increasing volume fraction and finer hollow microsphere size which contributes to a higher magnitude of cutting force. The AdvantEdge FE model shows comparable results with the validation experiments within an error of 15%.
Transmissive CPVs (Concentrated Photovoltaics) are investigated for their ability in increasing the overall potential of CPV technology by collecting diffuse sunlight and reducing the cost associated with large tracking mechanisms for the main aim of integrating them in greenhouses. Simulation results conducted on SAM (System Advisory Model) and the experimental plan are briefly outlined in this paper.
The 3D graphene structures were expected to exhibit optimum mechanical, electrical, and multifunctional properties which can be exploited in various applications. The graphene TPMS structures have higher potential to generate such properties. A graphene gyroid 3D lattice was fabricated in this study using a self-assembly assisted hydrothermal technique. A polymer 3D printed gyroid lattice of 5% relative density was used as a sacrificial template. The SEM images of the initial polymer and output rGO lattices showed successful 3D printing and preservation of the gyroid structure after the fabrication process. The micro CT-scan images confirmed the polymer removal from the hollow internal tubes. The rGO composition was proved using Raman, EDS, and XRD. The mechanical properties were calculated from the developed compressive stress-strain curve. The measured Young's modulus was 0.23 MPa, while the measured electrical conductivity was 6.95 S/m.
Passive radiative cooling has obtained growing attention because of its potential for subambient cooling with no extra energy and zero greenhouse gas emission. This work studies the structural effect of truncated pyramid, conical, cylindrical and cubic microarrays based radiative coolers using full-wave electromagnetic simulations. It was found that the truncated pyramid microstructure not only enhanced the long wavelength infrared emissivity but also contributed to improved solar light reflection. Besides, we also propose a novel facial and scalable method to fabricate the microstructure using 3D printing.
Novel AZ91 magnesium syntactic foams are a potential choice for temporary biomedical implants.In this study, the drilling performance of biodegradable grade AZ91-magnesium foam is investigated under different lubrication methods. Drilling experiments were carried out using titanium aluminium nitride (TiAlN) (PVD) coated and uncoated twist drills on varying volume fractions of AZ91 magnesium syntactic foams (5%, 10%, and 15%) reinforced with hollow alumina microspheres. Test results showed a 30%-60% higher thrust forces generated with cryogenic machining. while cutting AZ91-15% hollow alumina foam. Higher volume fraction syntactic foam recorded higher machining forces, which increased by almost 200% as the volume fraction of hollow alumina increased from 5% to 15% during dry machining.A three-dimensional, thermo-mechanical finite element-based model for drilling magnesium syntactic foam using AdvantEdgeTM is presented for different lubrication conditions. Based on the analysis carried out, cryogenic machining is recommended as a sustainable drilling process for AZ91-magnesium syntactic foams.
The influence of independent process variables of Pulsed metal inert gas welding (P-MIG) such as current, weld speed, and wire feed speed for welding dissimilar metals stainless steel 304 and mild steel were examined. The L9 Taguchi array was used to optimize the input parameters with the necessary quality factors being ultimate tensile strength (UTS), and mass deposition rate (MDR). The Taguchi approach and Grey relational analysis have been used to optimize and identify the best P-MIG process parameters. Taguchi Desirability tests were used to interpret, explore, and evaluate the experimental results from UTS, and MDR. To determine the effect of each variable, ANOVA has been used. Wire feed rate and weld current were found to be the most contributing variables, while weld speed was the least important. Bending distortion and buckling are observed on the weld plate and detailed analysis of distortion will be done in the future.
CO2 capture is not only important to reduce CO2 footprints, but also it can be attractive for enhanced oil recovery. However, costs for CO2 capture are still expensive. Rotating packed beds can intensify the capture process using HiGee technology, cutting down capture costs. In this study, the dry pressure drop is validated and compared against three modified geometric designs. Pressure-drop at free rotational zone exhibits comparable value to the packing. However, modifying the area design at the packing's inner edge shows a reduction in total pressure drop by 30%. This accounts for a 36 to 46 % reduction in free rotational zone pressure drop. As a result, this can save 30% of compression power.
Most studies of phononic crystals (PnC) mainly focus on creating mechanical properties contrast between two phases in a unit cell. However, large contrast in dimension and configuration of different components of the same phase could also induce wide phononic band gap. In our research, simple cubic (SC) lattice on mesoscopic scale is studied and two groups of eigenmode (bulk-mode and interaction mode) are found to be the reason for the opening of Phononic band gap.
Complex and lightweight lattice-based structures could be manufactured using Additive manufacturing (AM) processes. Triply periodic minimal surfaces (TPMS) are cellular structures with mathematically defined architectures in which surface area for a given boundary is locally minimized. Material usage, cost and part weight could be optimized by combining additive manufacturing with TPMS structures. This paper introduces a methodology for generating variable density TPMS lattice structure by mapping the output of topology optimization. As an example, the proposed methodology is implemented for structural and heat conduction optimization problem
An experimental investigation on a horizontal hydraulic loop with a transparent test zone is employed to study the interaction of a circular bluff body with a two-phase swirl flow. Using high speed camera the gaseous phase is analyzed. The air core is studied with instantaneous and average images. Which are then processed using Matlab image processing toolbox to capture some relevant information about the air core for different Gas-Liquid Ratio (GLR) in steady state. Further information addressing the interaction with the circular bluff body is embodied on a flow regime map is also reported.
