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Journal Article

Uncertainty Assessment of Octane Index Framework for Stoichiometric Knock Limits of Co-Optima Gasoline Fuel Blends

2018-10-25
Abstract This study evaluates the applicability of the Octane Index (OI) framework under conventional spark ignition (SI) and “beyond Research Octane Number (RON)” conditions using nine fuels operated under stoichiometric, knock-limited conditions in a direct injection spark ignition (DISI) engine, supported by Monte Carlo-type simulations which interrogate the effects of measurement uncertainty. Of the nine tested fuels, three fuels are “Tier III” fuel blends, meaning that they are blends of molecules which have passed two levels of screening, and have been evaluated to be ready for tests in research engines. These molecules have been blended into a four-component gasoline surrogate at varying volume fractions in order to achieve a RON rating of 98. The molecules under consideration are isobutanol, 2-butanol, and diisobutylene (which is a mixture of two isomers of octene). The remaining six fuels were research-grade gasolines of varying formulations.
Journal Article

Turbulent Flow Pressure Losses in Gasoline Particulate Filters

2019-08-19
Abstract Gasoline Particulate Filter (GPF) technology is the key method of meeting the new regulations for particulate matter emissions from gasoline cars. Computer-Aided Engineering is widely used for the design of such systems; thus the development of accurate models for GPFs is crucial. Most existing pressure loss models require experimental calibration of several parameters. These experiments are performed at room temperatures, or on an engine test bench, where gas properties cannot be fully controlled. This article presents pressure loss measurements for clean GPF cores performed with uniform airflow and temperatures up to 680°C. The flow regime in GPF is shown to be different to that in the Diesel Particulate Filters (DPF) due to high flow rates and temperatures. Therefore, most of the existing models are not suitable for design of the new generation of aftertreatment devices. To separate pressure loss contribution from different sources, unplugged filter cores are tested.
Journal Article

The Impacts of Pd in BEA Zeolite on Decreasing Cold-Start NMOG Emission of an E85 Fuel Vehicle

2018-10-25
Abstract In the development of hydrocarbon (HC) traps for E85 fuel vehicle emission control, the addition of palladium (Pd) to BEA zeolite was studied for trapping and decreasing cold-start ethanol emissions. BEA zeolite after a laboratory aging at 750°C for 25 hours released nearly all of the trapped ethanol as unconverted ethanol at low temperature, and some ethene was released at a higher temperature by a dehydration reaction. The addition of Pd to BEA zeolite showed a decrease in the release of unconverted ethanol emissions even after the lab aging. The release of methane (CH4), acetaldehyde (CH3CHO), carbon monoxide (CO), and CO2 from Pd-BEA zeolite during desorption (temperature programmed desorption (TPD)) demonstrated that multiple ethanol reaction mechanisms were involved including dehydrogenation and decomposition reactions.
Journal Article

Study of Temperature Distribution and Parametric Optimization during FSW of AA6082 Using Statistical Approaches

2019-02-01
Abstract In this article, Al-Mg-Si-Mn alloy (AA6082) is butt joined by employing friction stir welding (FSW). The mechanical and metallurgical properties of joints are analyzed by conducting tensile and microhardness testing, respectively. To measure the temperature at different locations, eight thermocouples (L-shaped k-type) are placed at equal distance from the centerline. Least square method attempts to calculate the temperature at the centerline of joints. The process parameters are also optimized using Taguchi’s five-level experimental design. The optimum process parameters are determined, employing ultimate tensile strength (UTS) as a response parameter. A statistical test “analysis of variance” is used to check the adequacy of the model. It has been observed that rotational speed and feed rate are the predominant factors for UTS and microhardness.
Journal Article

Response of Austempering Heat Treatment on Microstructure and Mechanical Property in Different Zones of As-Welded Ductile Iron (DI)

2018-05-08
Abstract Sound ductile iron (DI) welded joints were performed using developed coated electrode and optimized welding parameters including post weld heat treatment (PWHT).Weldments consisting of weld metal, partially melted zone (PMZ), heat affected zone (HAZ) and base metal were austenitized at 900 °C for 2 hour and austempered at 300 °C and 350 °C for three different holding time (1.5 hour, 2 hour and 2.5 hour). In as-weld condition, microstructures of weld metal and PMZ show ledeburitic carbide and alloyed pearlite, but differ with their amount. Whereas microstructure of HAZ shows pearlite with some ledeburitic carbide and base metal shows only ferrite.
Journal Article

Response Surface Methodology (RSM) in Optimization of Performance and Exhaust Emissions of RON 97, RON 98, and RON 100 (Motor Gasoline) and AVGAS 100LL (Aviation Gasoline) in Lycoming O-320 Engine

2019-08-19
Abstract Federal Aviation Administration (FAA)’s 20 years of research and development with 200 unleaded blends and full-scale engine tests on 45 high-octane unleaded blends has not found a “drop-in” unleaded replacement for aviation gasoline (AVGAS) 100 low lead (100LL) fuel. In this study, analysis of compatibility via optimization of Lycoming O-320 engine fuelled with RON 97, RON 98, RON 100, and AVGAS was conducted using the Response Surface Methodology (RSM). Test fuels were compositionally characterized based on Gas Chromatography (GC) analysis and were categorized based on types of Hydrocarbon (HC). Basic fuel properties of fuels in this research were analyzed and recorded. For optimization analysis, engine speed and fuel were considered as the input parameters.
Journal Article

Residual Stresses and Plastic Deformation in Self-Pierce Riveting of Dissimilar Aluminum-to-Magnesium Alloys

2018-05-08
Abstract In this work, the complex relationship between deformation history and residual stresses in a magnesium-to-aluminum self-pierce riveted (SPR) joint is elucidated using numerical and experimental approaches. Non-linear finite element (FE) simulations incorporating strain rate and temperature effects were performed to model the deformation in the SPR process. In order to accurately capture the deformation, a stress triaxiality-based damage material model was employed to capture the sheet piercing from the rivet. Strong visual comparison between the physical cross-section of the SPR joint and the simulation was achieved. To aid in understanding of the role of deformation in the riveting process and to validate the modeling approach, several experimental measurements were conducted. To quantify the plastic deformation from the piercing of the rivet, micro hardness mapping was performed on a cross-section of the SPR joint.
Journal Article

Parameter Sensitivity and Process Time Reduction for Friction Element Welding of 6061-T6 Aluminum to 1500 MPa Press-Hardened Steel

2018-12-14
Abstract Conventional fusion joining techniques pervasive in the automotive industry are unable to effectively join aluminum and steel. To solve this problem, a technique termed friction element welding (FEW) has been developed, which is able to join any nonferrous top sheet material to a base steel layer, independent of the base layer strength. FEW works on the same principles as friction welding, as a steel element is pushed and rotated against a nonferrous top sheet to create frictional energy which softens and flows the material around the fastener shaft and under the fastener head, exposing the steel below. The element then contacts the steel and bonds through traditional friction welding. FEW is a four-step process (penetration, cleaning, welding, compression), with two to four parameters (endload, spindle speed, displacement transition, time transition) controlling each step.
Journal Article

Optimization of WEDM Cutting Parameters on Surface Roughness of 2379 Steel Using Taguchi Method

2018-04-07
Abstract Surface roughness is one of the important aspects in producing quality die. Wire Electrical Discharge Machine (WEDM) is commonly used in tool and die fabrication, since the die material is usually difficult to cut using traditional metal removal processes. Selection of optimal WEDM cutting parameters is crucial to obtain quality die finish. In this study, 2379 steel which equivalent to SKD 11 is selected as the die material. Four main WEDM cutting parameters, namely, pulse duration (A), pulse interval (B), servo voltage (C), ignition pulse current (D), were experimentally evaluated for both main cut and multiple trim cuts using Taguchi Method. Taguchi’s L9 orthogonal array is employed for experimental design and analysis of variance (ANOVA) was used in recognizing levels of significance of WEDM cutting parameters.
Journal Article

Numerical Prediction of Various Failure Modes in Spotweld Steel Material

2018-05-11
Abstract Crash simulation is targeted mainly carried out by the collision regulations FMVSS simulation to identify problems in vehicle structures. A modern car structure consist of several thousand weld-type connections, and failure in these connections plays an important role for the crashworthiness of the vehicle. Therefore accurate modeling of these connections is important for the automotive industry in order to improve Vehicle collision characteristics. In pursuit of this key requirement, we introduced a proper methodology for the development detailed weld model to study structural response of the weld when the applied load range is beyond the yield strength. Three-dimensional finite element (FE) models of spot welded joints are developed using the LS-Dyna FE code. In this process the force estimation model of spot welds is explained. The results from this paper shows good agreement between the simulations and the tests.
Journal Article

Mixture Distributions in Autonomous Decision-Making for Industry 4.0

2019-05-29
Abstract Industry 4.0 is expected to revolutionize product development and, in particular, manufacturing systems. Cyber-physical production systems and digital twins of the product and process already provide the means to predict possible future states of the final product given the current production parameters. With the advent of further data integration coupled with the need for autonomous decision-making, methods are needed to make decisions in real time and in an environment of uncertainty in both the possible outcomes and in the stakeholders’ preferences over them. This article proposes a method of autonomous decision-making in data-intensive environments, such as a cyber-physical assembly system. Theoretical results in group decision-making and utility maximization using mixture distributions are presented. This allows us to perform calculations on expected utility accurately and efficiently through closed-form expressions, which are also provided.
Journal Article

Machining Quality Analysis of Powertrain Components Using Plane Strain Finite Element Cutting Models

2018-05-07
Abstract Finite Element Analysis (FEA) of metal cutting is largely the domain of research organizations. Despite significant advances towards accurately modelling metal machining processes, industrial adoption of these advances has been limited. Academic studies, which mainly focused on orthogonal cutting, fail to address this discrepancy. This paper bridges the gap between simplistic orthogonal cutting models and the complex components typical in the manufacturing sector. This paper outlines how to utilize results from orthogonal cutting simulations to predict industrially relevant performance measures efficiently. In this approach, using 2D FEA cutting models a range of feed, speed and rake angles are simulated. Cutting force coefficients are then fit to the predicted cutting forces. Using these coefficients, forces for 3D cutting geometries are calculated.
Journal Article

Joint Mechanism and Prediction of Strength for a Radial Knurling Connection of Assembled Camshaft Using a Subsequent Modeling Approach

2018-06-25
Abstract Knurling joint applied in assembled camshaft has developed rapidly in recent years, which have exhibited great advantages against conventional joint methods in the aspects of automation, joint precision, thermal damage, noise, and near net shape forming. Both quality of assembly process and joint strength are the key requirements for manufacturing a reliable assembled camshaft. In this article, a finite element predictive approach including three subsequent models (knurling, press-fit and torsion strength) has been established. Johnson-Cook material model has been used to simulate the severe plastic deformation of the material. The residual stress field calculated from the knurling process was transferred as initial condition to the press-fit model to predict the press-fit load. The predicted press-fit load, torque strength and displacement of cam profile before failure were calculated.
Journal Article

Investigation of a Six-Phase Interior Permanent Magnet Synchronous Machine for Integrated Charging and Propulsion in EVs

2018-04-17
Abstract Merits such as reduced weight, overall and operational costs of the electric vehicle (EV) while providing level 3 charging capability, are propelling research on integrated charging (IC) technology for EVs. Since the same interior permanent magnet synchronous machine (IPMSM) is used during IC and traction conditions, it is important to understand the behavior of the machine during these conditions and optimally design the machine. Hence, firstly, this paper presents a case study on performance of a laboratory 3-phase IPMSM under IC and traction conditions. Thereafter, understanding the challenges such as low magnet operating point, losses and torque oscillation in 3-phase IPMSM during IC, a 6-phase IPMSM with an unconventional configuration is investigated to yield traction characteristics like that of the 3-phase IPMSM and mitigate challenges during IC. In the process, mathematical model of the 6-phase IPMSM is developed employing the dq-axis theory.
Journal Article

Investigation of Residual Stresses in Cold-Formed Steel Sections with Nonlinear Strain-Hardened Material Model

2018-09-17
Abstract In this article, forming residual stresses in cold-formed small-radius corner sections are analytically predicted with the consideration of the shift in the neutral axis and the nonlinear strain-hardened material model. The predicted forming stress results in the transverse direction show a trend of increased compressive residual stress in the outer surface and reduced tensile residual stress in the inner surface as the corner radius-to-thickness ratio increases in small-radius bends. In the longitudinal direction, there is no significant change in the residual stress values observed in the inner and outer surfaces with respect to an increase in corner radius-to-thickness ratios. But a considerable decrease in compressive residual stress and an increase in tensile stress values are observed in the midsection areas with an increase in the corner radius-to-thickness ratio.
Journal Article

Integrated Driving and Braking Control Unit for Electric Bikes

2018-10-04
Abstract In this research, an integrated driving and braking control unit was developed for electric bikes. The unit integrates the driving and braking circuits in a module. Alternate commutation was used to design the driving and braking unit of a customized brushless direct-current hub motor (BLDCHM). The braking torque for the braking section is generated through alternating the duty cycle of the pulse-width-modulated (PWM) commands of the switching elements and phase sequence arrangement of the current conduction loops. The current conduction loops in the motor and switching elements is arranged to adjust the braking torque in a sophisticated way. The integrated design has been successfully tested in a commercialized electric bike with a BLDCHM.
Journal Article

Influence of the Friction Coefficient in Self-Pierce Riveting Simulations: A Statistical Analysis

2018-05-08
Abstract In this work, optimal modeling parameters for self-pierce riveting (SPR) were determined using a factorial design of experiments (DOE). In particular, we show statistically how each of the calibrating parameters used in modeling the SPR process through nonlinear finite element modeling can drastically change the geometry of the joint. The results of this study indicate that the degree of interlock, which is a key feature of a sound joint, is largely influenced by the friction between the die and bottom sheet as well as the friction between the rivet and top sheet. Furthermore, this numerical study also helped elucidate the role of friction in SPR and sheds light on how coatings with diverse friction coefficients can affect material deformation and ultimately structural integrity of the joint.
Journal Article

Improving Hole Expansion Ratio by Parameter Adjustment in Abrasive Water Jet Operations for DP800

2018-09-17
Abstract The use of Abrasive Water Jet (AWJ) cutting technology can improve the edge stretchability in sheet metal forming. The advances in technology have allowed significant increases in working speeds and pressures, reducing the AWJ operation cost. The main objective of this work was to determine the effect of selected AWJ cutting parameters on the Hole Expansion Ratio (HER) for a DP800 (Dual-Phase) Advanced High-Strength Steel (AHSS) with s0 = 1.2 mm by using a fractional factorial design of experiments for the Hole Expansion Tests (HET). Additionally, the surface roughness and residual stresses were measured on the holes looking for a possible relation between them and the measured HER. A deep drawing quality steel DC06 with s0 = 1.0 mm was used for reference. The fracture occurrence was captured by high-speed cameras and by Acoustic Emissions (AE) in order to compare both methods.
Journal Article

Impact of Dynamic Characteristics of Wheel-Rail Coupling on Rail Corrugation

2019-07-02
Abstract To gain a better understanding of the characteristics of corrugation, including the development and propagation of corrugation, and impact of vehicle and track dynamics, a computational model was established, taking into account the nonlinearity of vehicle-track coupling. The model assumes a fixed train speed of 300 km/h and accounts for vertical interaction force components and rail wear effect. Site measurements were used to validate the numerical model. Computational results show that (1) Wheel polygonalisation corresponding to excitation frequency of 545-572 Hz was mainly attributed to track irregularity and uneven stiffness of under-rail supports, which in turn leads to vibration modes of the bogie and axle system in the frequency range of 500-600 Hz, aggregating wheel wear. (2) The peak response frequency of rail of the non-ballasted track coincides with the excitation frequency of wheel-rail coupling; the resonance results in larger wear amplitude of the rail.
Journal Article

Filled Rubber Isolator’s Constitutive Model and Application to Vehicle Multi-Body System Simulation: A Literature Review

2018-06-05
Abstract Rubber elements present highly nonlinear mechanical properties affected by frequency and amplitude of excitation, prestrain and temperature, etc. Finite element (FE) models and lumped parameter models can be distinguished in the development of constitutive models of rubbers. Based on the concept of overlay model, different kinds of viscoelastic, or frequency-dependent models, and elastoplastic/friction, or amplitude-dependent models, are compared in terms of their modelling approach, parameters identification process and applications. Prestrain-dependent models and temperature-dependent thermo-mechanical models are also reviewed, including some special models which are not based on the concept of the overlay model. Experimental and computational studies of cylindrical bushings subjected to coupled deformation modes are analyzed and discussed.
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