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Photogrammetry and Analysis of Digital Media

2021-09-01
Photographs and video recordings of vehicle crashes and accident sites are more prevalent than ever, with dash mounted cameras, surveillance footage, and personal cell phones now ubiquitous. The information contained in these pictures and video provide critical information to understanding how crashes occurred, and in analyzing physical evidence. This course teaches the theory and techniques for getting the most out of digital media, including correctly processing raw video and photographs, correcting for lens distortion, and using photogrammetric techniques to convert the information in digital media to usable scaled three-dimensional data.
Technical Paper

An Experimental Setup for Investigations on the Boundary Layer Dynamics

2020-10-05
2020-01-1617
The frictional behavior of a tribological contact is influenced by the dynamics in the forming boundary layer. Recurring structures, built up through self-organizing effects, were found in various frictional systems. To investigate those phenomena on a macroscopic scale and to better understand dynamical processes such as the formation and decay of contact patches, the first revision of the Wear Debris Investigator (WDI) was introduced in 2017. A friction gap is formed between two coaxial horizontally arranged discs. To mimic the presence of particles, artificial wear dust is fed into the gap. With a camera the formation of the boundary layer is recorded in situ. An implemented normal force and torque sensor enables to recognize correlations between the formed boundary layer and the occurring frictional forces. Numerous measurements revealed an insufficient precision of the previous WDI.
Technical Paper

Micro-Macro Acoustic Modeling of Heterogeneous Foams with Nucleation Perturbation

2020-09-30
2020-01-1526
The properties of a polyurethane foam are greatly influenced by the addition of graphite particles during the manufacturing process, initially used as a fire retardant. These thin solid particles perturbate the nucleation process by generating bubbles in its immediate vicinity. The preponderance of work so far has focused on foams that are locally relatively homogeneous. We propose a model for locally inhomogeneous foams (including membrane effects) consisting of a random stack of spheres that permits one to represent certain pore size distribution functions. The cellular structure of the foam is obtained through a Laguerre tessellation and the solid skeleton determined from the minimization of surface energy (Surface Evolver). The structure of real foam samples is analyzed using X-ray computed tomography and scanning electron microscopy followed by image processing to create computerized three-dimensional models of the samples.
Technical Paper

Numerical Analysis of the Influences of Wear on the Vibrations of Power Units

2020-09-30
2020-01-1506
Numerical Analysis of the Influences of Wear on the Vibrations of Power Units Yashwant Kolluru, Rolando Doelling eBike Department Robert Bosch GmbH Kusterdingen, Germany yashwant.kolluru@de.bosch.com rolando.doelling@de.bosch.com Lars Hedrich Institute of Informatics Goethe University Frankfurt Frankfurt, Germany hedrich@em.informatik.uni-frankfurt.de The prime factor, which influences vibrations of electro-mechanical drives, is wear at the components. This paper discusses the numerical methods developed for abrasion, vibration calculations and the coupling between wear and NVH models of drive unit. Wear is a complex process and understanding it is essential for vibro-acoustics. The paper initially depicts finite element static model used for wear calculations. The special subroutines developed, aids in coupling the wear equations, various contact and friction formulations to the numerical model.
Technical Paper

Inverse Vibration Problem Used for the Characterization of the Damping Added by a Trim Foam on a Plate

2020-09-30
2020-01-1580
Many solutions exist to insure the NVH comfort of ground and air vehicles, like heavy mass (bitumen pads), viscoelastic treatments and absorbing foams. The trim foam is an alternative to heavy solutions. To know the potential of the foam, a study of its capacity to damp vibration is done. A system, composed by a suspended plate, with a foam on it, is characterized in different cases of contact at the foam-plate interface (glued or not) and with different types of foam. An experimental test facility is developed to identify the global damping of the structure: a laser vibrometer measures the displacement field of the foam-plate structure, an inverse method is used to determine the structural parameters. By changing the contact at the interface, it is possible to identify the contribution of the friction forces to the global damping of the structure. Another type of damping is the viscoelastic damping due to the intrinsic characteristics of the trim foam.
Technical Paper

Thermal Imaging of a Li-Ion Battery for the Estimation of the Thermal Parameters and Instantaneous Heat Dissipated

2020-09-27
2020-24-0014
The electrochemical performance of a lithium-ion battery is strongly affected by the temperature. During charge and discharge cycles, batteries are subjected to an increment of temperature that can accelerate aging and loss of efficiency if critical values are reached. Knowing the thermal parameters that affect the heat exchange between the battery surface and the surrounding environment (air, cooling fins, plates, etc…) is fundamental to their thermal management. In this work, thermal imaging is applied to a laminated lithium-ion battery as a non-invasive temperature-indication method. Measurements are taken during the discharge phase and the following cooling down until the battery reaches the ambient temperature. The 2d images are used to analyze the homogeneity of the temperature distribution on the battery surface. Then, experimental results are coupled with mathematical correlations.
Technical Paper

CFD Numerical Reconstruction of the Flash Boiling Gasoline Spray Morphology

2020-09-27
2020-24-0010
The numerical reconstruction of the liquid jet generated by a multi-hole injector, operating in flash-boiling conditions, has been developed by means of an Eulerian- Lagrangian CFD code and validated thanks to experimental data collected with schlieren and Mie scattering imaging techniques. The model has been tested with different injection parameters in order to recreate various possible engine thermodynamic conditions. The work carried out is framed in the growing interest present around the gasoline direct-injection systems (GDI). Such technology has been recognized as an effective way to achieve better engine performance and reduced pollutant emissions. High-pressure injectors operating in flashing conditions are demonstrating many advantages in the applications for GDI engines providing a better fuel atomization, a better mixing with the air, a consequent more efficient combustion and, finally, reduced tailpipe emissions.
Technical Paper

Free Vibrational Characteristics of Dual Side Nd: YAG Laser Welded Stainless Steel 304 joints Reinforced with Al2O3 Micro Powder Particles

2020-09-25
2020-28-0393
Nd: YAG Laser Welding Process (LWP) is the most efficient method commonly used for the joining of different kinds of materials, whether it can be a sheet or plate.LWP in general,uses high power density, frequency and travel speed or feed rate as primary process parameters in order to perform a joining process across the metals. This paper investigates the effect on free vibrational characteristics for Stainless Steel 304 (SS 304) joints which are reinforced with Al2O3 micro particles processed by dual side (welding performed on the top and bottom surface of sheets) Nd: YAG LWP. The inclusion of micro particles was inserted directly across the weld pool region, by fabricating drills with a constant gap between each drilled holes. Totally 12 samples were fabricated with different laser power, travel speed and by keeping the frequency level as constant for all the experiments.
Technical Paper

Recyclability of Particulate Natural Fiber Composite Waste on Hemp/Epoxy composite- Mechanical and Drilling Characterization.

2020-09-25
2020-28-0398
In automobile industries, the usage of natural fiber composites (NFC) becomes one of the most inevitable materials in engineering applications because of its better properties such as less expensive, high strength to weight ratio and stiffness. In recent days door trim panels, wheel arch, rear hatch, roof liner and bonnet insulation in vehicles were fabricated by NFC. Once the vehicle attains ELV (end-of-life vehicles) metals from the vehicle were recycled but the NFC’s were not recycled and dumped as scrap. Hence the main objective of the present research was to recycle the NFC waste as reinforcement in the hemp/epoxy composite. This work examines the effect of reinforcing the composite waste in hemp fiber in various weight percentages (0, 5, 10 and 15). The mechanical characteristics such as tensile, flexural, impact and hardness were carried out for the prepared composite as per ASTM standards.
Technical Paper

Investigation on the Effect of Pulsed Frequency on Microstructure and Hardness of Alloy C-2000 by Current Pulsing

2020-09-25
2020-28-0420
The objective of the study is to investigate the effect of current pulsation frequency on the weld bead microstructure, segregation, and hardness of Hastelloy C-2000 weldments. Bead on Plate (BoP) welds was made by using the Pulsed Current Gas Tungsten Arc Welding method (PCGTAW) at eleven different frequencies. The weld bead width and depth of penetration was measured with the help of Dinolite macro analyzer. The microstructure of weldments is further examined through an optical microscope and Scanning Electron Microscopy (SEM) to identify the type of grain, grain coarsening and extent of the Heat Affected Zone (HAZ). The grain structure turns into finer and equiaxed in all cases and there was an optimum frequency range over which the significant grain refinement was observed. Microsegregation of alloying elements was computed with the aid of Energy Dispersive X-ray Spectroscopy (EDS). Vickers Hardness Tester was used to measure the hardness of the weld samples at ambient conditions.
Technical Paper

Nd: YAG Laser Welding of Stainless Steel 304: The effects of Al2O3 micro particles addition

2020-09-25
2020-28-0418
In the present work, fabrication of similar Stainless Steel (SS) 304 joints by Nd-YAG Laser Welding Process (LWP). A novel approach was attempted in this study, welding was performed on dual sides of the plate (top and bottom) for a better mixture of micro powder particles in the weld pool region and to achieve maximum depth of penetration, which is not easily possible in a single-sided (LWP). High depth of penetration during fabrication of joints, significantly improved the mixture ratio of molten steel with reinforced micro powder particles. Al2O3 micro powder particles were reinforced in the weld pool region through the drilling process with varying depth ratios, and a moderate gap was maintained between each hole. The effects of Al2O3 on the microstructure and mechanical properties were studied and elaborated in brief. Totally 12 samples were fabricated, here joining was performed by keeping the frequency as constant and varying laser power, travel speed for all the trials.
Technical Paper

Effect of Austenitic Filler Wires on Duplex Stainless Steel 2205 Weldment Made by Gas Tungsten Arc Welding

2020-09-25
2020-28-0431
Duplex stainless steel (DSS) contained with dual phase such as austenite and ferrite exhibit higher strength and resistance to corrosion in numerous environmental conditions over several decades. The need of duplex stainless steel is increased gradually in the field of petrochemical, powerplant, marine and other engineering applications, where the dual phase steels are being espoused that need welding for production of components. These duplex alloys are challenging to weld due to the formation of various embrittling precipitates and variations in the metallurgy. The imbalance phase ratio of ferrite/austenite due to welding leads to solidification cracking. DSS 2205 is in need of welding with proper welding processes and consumables for corrosive environments such as shipbuilding and pipeline. In this connection, to achieve the desired requirements, austenitic filler wires (ERNiCrMo-3 and ERNiCrMo-4) are utilized for welding DSS 2205 grade using gas tungsten arc welding technique.
Technical Paper

Self-assembled ZnO nanostructure by one step emulsion combustion synthesis

2020-09-25
2020-28-0510
Self- assembled ZnO nanostructures were synthesized by a simple, rapid and costeffective emulsion combustion method. The synthesized ZnO nanostructures have a hexagonal wurtzite structure. TEM micrographs of the sample consisted of looped chains that were <1μm in length and consisted of 30-120 isometric 13-16 nm sized nanoparticles. The assembling of nanoparticles transforms from branched chain to linear network by increasing the molar concentration of oleic acid from 0.5 to 1.5. The linear network was <700 nm in length and width varies from 15-35 nm respectively. The optical band gap (Eg) of 3.34, 3.38 and 3.43 eV based on the absorption edge 371, 367 and 361 nm respectively. Magnetization study reveals that the ZnO sample exhibits diamagnetic behavior.
Technical Paper

Optical surface roughness evaluation of ground specimens using speckle line images

2020-09-25
2020-28-0514
A well-established method of surface roughness measurement is of stylus-based. The filtering effect of the stylus tip is the major lacuna of the process. So in the present study, a vision based 100% inspection procedure is proposed for the characterisation of ground specimens. A CMOS camera, and monochromatic line laser source were used for capturing speckle line images of the ground specimens. Signal vectors were generated from each of the surface images of ground specimens using MATLAB software. On the other hand the roughness of the ground specimens, particularly the Ra & Rda were computed using a stylus instrument. It was found that standard deviation and kurtosis having good correlation with the image pixel intensity of the signal vectors with the correlation coefficient of 0.96 & 0.89 for Ra and 0.86 & 0.82 for Rda respectively. So we conclude that the speckle line images can be used for in-situ surface roughness evaluation of the ground specimens.
Technical Paper

Experimental study on fuel transcritical injection characteristics about macroscopic and near-nozzle microscopic structure

2020-09-15
2020-01-2118
The supercritical fluid combustion technology was regarded as an effective method to increase fuel gas mixing rate and performance. During the transcritical injection and combustion process, critical characteristics dominate the jet development to behave as different spray structure. Due to the limited researches about fuel transcritical injection characteristics, macroscopic and near-nozzle microscopic spray structure was observed respectively. In this work, a transcritical injection device was designed able to heat the fuel temperature up to 773 K and maintain the fuel injection pressure stable at 4 MPa. The experiment was conducted with the fuel injecting from supercritical condition to atmosphere condition. As a comparison, two fluids were selected to conduct transcritical injection experiment. The n-heptane was used to represent the surrogate of the supercritical diesel, while the cryogenic nitrogen was selected to represent the ideal gas.
Technical Paper

Effects of Internal Geometry on High-Pressure Gasoline Sprays using High-Speed Imaging

2020-09-15
2020-01-2111
High-pressure gasoline injection can be utilized for improved combustion efficiency and lower engine-out emissions. The objective of this study was to quantify the effects of injector geometry on high-pressure gasoline transient spray development in a constant volume chamber. Five injector nozzles were studied with controlled internal flow features including differences in inlet rounding, conicity, and outlet diameter. Effects of fuel injection pressure and chamber density on the spray characteristics were investigated. Reference grade gasoline was injected at pressures of 300, 600, 900, 1200, and 1500 bar. The chamber density was varied with pressurized nitrogen at 1, 5, 10 and 20 bar at a constant temperature of 298 K, corresponding to ambient densities of 1.13, 5.65, 11.31, and 22.61 kg/m3. The spray development was recorded using diffuse backlit shadowgraph and high-speed imaging methods.
Technical Paper

Multi-Plane PIV Measurements in a Gasoline Direct Injection Engine

2020-09-15
2020-01-2049
The flows in-cylinder have a profound effect on the mixture preparation and subsequent combustion in all engines. These flows are highly three-dimensional in nature and information from multiple planes is required to characterise the flow dynamics. The flow measurements reported here are from three orthogonal planes in an optical access engine that is based on the Jaguar Land Rover AJ200 Gasoline Direct Injection (GDI) engine. Particle Image Velocimetry (PIV) measurements have been taken every 5°ca from the start of induction to the end of compression. Data have been obtained from 300 cycles for separate experiments measuring flows in the tumble plane, the swirl plane and the cross tumble plane. Vector comparison metrics are used to quantitatively compare ensemble averaged PIV flow fields to Computational Fluid Dynamics (CFD) simulations across each plane in terms of both the velocity magnitude and direction.
Technical Paper

Numerical Investigation on GDI Spray Under High Injection Pressure Up to 100MPa

2020-09-15
2020-01-2108
In recent years the increase of injection pressure gasoline fuel is a way to improve thermal efficiency and lower engine-out emissions in GDI homogenous combustion concept. The challenge of controlling particulate formation as well in mass and number concentrations imposed by emissions regulations can be pursued improving the mixture preparation process and avoiding mixture inhomogeneities with ultra-high injection pressure values up to 100MPa. The increase of the fuel injection pressure meets the demand for increased injector static flow, while simultaneously improving the spray atomization and mixing characteristics that provide improvement of the combustion performance of GDI homogeneous systems. Few studies quantify the effects of high injection pressure on transient gasoline spray evolution.
Technical Paper

Technology for Obtaining Asymmetries of Stereometric Shapes of the Sealing Rings Sliding Surfaces for Selected Anti-Wear Coatings

2020-09-15
2020-01-2229
The article presents the methodology of obtaining asymmetric shapes of the sealing rings sliding surfaces. A very high product tolerance of 1 to 3 µm stereometric shape was taken into account for various types of wear-resistant materials that meet the requirements of adhe-sion of the anti-wear coating to the substrate. In particular, an analysis was made of the possi-bilities of using various product technologies, a modification of the grinder intended for profile grinding of the sliding surface of the rings was carried out, and the process of ring machining was determined. A very advanced stage of the production process is proper shaping, consistent with the-oretical assumptions based on the results of simulation tests. This shape should be maintained for all the rings in the experimental series both in cross-section and on the periphery of the ring.
Technical Paper

Comparison of the Diffusive Flame Structure for Dodecane and OMEX Fuels for Conditions of Spray A of the ECN

2020-09-15
2020-01-2120
A comparison of the flame structure for two different fuels, dodecane and oxymethylene dimethyl ether (OMEX), has been performed under condition of Spray A of the Engine Combustion Network (ECN). The experiments were carried out in a constant pressure vessel with wide optical access, at high pressure and temperature and controlled oxygen concentration. The flame structure analysis has been performed by measuring the formaldehyde and OH-radical distributions using Planar Laser-Induced Fluorescence (PLIF) techniques. To complement the analysis, this information was combined with that obtained with high speed imaging of natural luminosity and OH chemiluminescence radiation in the UV. Formaldehyde molecule is excited with the 355nm radiation from the third harmonic of a ND:YAG laser, whilst OH is excited with 281 nm wavelength from a dye laser.
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