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Technical Paper

Comparing stress gradient and other concepts for fatigue analysis of notched components

2022-03-29
2022-01-0252
Nowadays simulation of the fatigue life is an essential part of the development of components in the automotive and machinery industry. Weak points can be identified fast and reliable with respect to stiffness, strength and lightweight. A pure virtual optimization of the design can be performed without the need of prototypes. Only for the production release a final test is necessary. A lot of parameters influence the fatigue life as the local stress, material, surface roughness, size of the component, temperature etc. Notches have the strongest impact on fatigue life, depending on radius and shape. Stresses at the notch base are increased because the load flow is forced through a reduced cross section, or changes its direction around an inwardly curved edge. But notches cause not only an increase of the local stress. Also, the local fatigue strength is increased because of a support effect from the neighboring areas, where the stress is already reduced.
Technical Paper

The investigation of a contact and element-based approach for Cohesive zone modelling in the simulation of Delamination propagation

2022-03-29
2022-01-0259
The CAE industry always moves towards new ways to improve the productivity, efficiency and to reduce the solution times. Conventional method of Cohesive Zone Modelling has drawback of higher computation and modelling time. Due to this problem, sometimes Engineers need to avoid simulations and rely only on some sort of approximation of crack from previous designs. This approximation can lead to either product failure or overdesign of the product. A new approach is discussed in this paper to simulate crack initiation and propagation with Cohesive Zone Modelling. Conventional method uses Cohesive zone modelling with Hex or Penta elements by assigning material with cohesive properties, which increases computation and modelling time. The new approach models Cohesive zone as contact between two bodies, thus eliminating the need to use cohesive elements which will essentially reduce the computation time as well as modelling time.
Technical Paper

A quick method to evaluate fuel chemistry on vehicle particulate emissions

2022-03-29
2022-01-0489
Fuel chemistry plays a crucial role in the continued reduction of particulate emission (PE) and cleaner air quality while using internal combustion engines (ICE). Over the past ten years, there has been great improvements in the measurements of particulate formation indices. Examples of these indices would be the Honda Particulate Matter Index (PMI) equation and the General Motors Particulate Evaluation Index (PEI), among others. Even though there have been improvements in particulate index (PI) measurement tools, the method analysis within these tools are still very time-consuming. These methods can include the use of chromatography separation techniques such as detailed hydrocarbon analysis (DHA), which have become very popular in the petrochemical industry. A review of historical PI methods will be discussed, along with a PE comparison to a less time-consuming simulated distillation method analysis.
Technical Paper

A Review of Current Understanding of the Underlying Physics Governing the Interaction, Ignition and Combustion Dynamics of Multiple-injections in Diesel Engines

2022-03-29
2022-01-0445
This work is intended to be a comprehensive technical review of existing literature and a synthesis of current understanding of the governing physics behind the interaction of multiple fuel injectio ns, ignition and combustion behavior of multiple-injections in diesel engines. Multiple-injection is a widely adopted operating strategy applied in modern compression-ignition engines, which involves various combinations of small pre-injections and post-injections of fuel before and after the main injection and splitting the main injection into multiple smaller injections. This strategy has been conclusively shown to improve fuel economy in diesel engines while achieving simultaneous NOx, soot, and combustion noise reduction in addition to a reduction in the emissions of unburned hydrocarbons and CO by preventing fuel wetting and flame quenching at the piston wall.
Technical Paper

Modeling the Effects of Drop Impingement Frequency on Heated Walls at Engine Conditions

2022-03-29
2022-01-0508
Understanding the fundamental details of drop/wall interactions is important to improving engine performance. Most of the drop-wall interactions studies are based on the impact of a single drop on the wall. To accurately mimic and model the real engine conditions, it is necessary to characterize spray/wall interactions with different impingement frequencies at a wide range of wall temperatures. In this study, a numerical method, based on Smoothed Particle Hydrodynamics (SPH), is used to simulate consecutive droplet impacts on a heated wall both below and above Leidenfrost temperature. Impact regimes are identified for various impact conditions by analyzing the time evolution of the post-impingement process of n-heptane drops at different impingement frequencies and wall surface temperatures. At low temperature, crown propagation and merging are dominant at low K-number whereas at high K-number there is significant splashing with the traces of liquid film on the surface.
Technical Paper

Managing Trust along the CAN Bus

2022-03-29
2022-01-0119
Multiple approaches have been created to enhance intra-vehicle communications security over the past three decades since the introduction of CAN. The twin pair differential-mode communications bus is tremendously robust in the face of interference, yet physical access to the bus offers a variety of potential attack vectors whereby false messages and/or denial of service are easy to achieve. This paper seeks to evaluate extensions of a common-mode watermark-based authentication technique recently developed to improve authentication on the CAN bus by considering the watermark as a side-channel communications means for high value information. We also describe a variety of higher layer algorithms, with benefits and pitfalls, for employing the watermark as a physical-layer firewall. All of these results are backed by a software-defined radio (SDR) based hardware testbed.
Technical Paper

Visualization of Frequency Response Using Nyquist Plots

2022-03-29
2022-01-0753
Nyquist plots are a classical means to visualize a complex vibration frequency response function. By graphing the real and imaginary parts of the response, the dynamic behavior in the vicinity of resonances is emphasized. This allows insight into how modes are coupling, and also provides a means to separate the modes. Mathematical models such as Nyquist analysis are often embedded in frequency analysis hardware. While this speeds data collection, it also removes this visually intuitive tool from the engineer’s consciousness. The purpose of this paper is to review the fundamentals of Nyquist plots and their application to structural vibration. The behavior of a single degree of freedom system will be shown to be well described by a circle on its Nyquist plot. This observation allows simple visual examination of the response of a continuous system, and the determination of quantities such as uncoupled natural frequencies, modal damping factors, and uncoupled modes shapes.
Technical Paper

Development of a Generalized Model to Predict Efficiency of Electrified Power Transmission Considering Optimal Driving Efficiency

2022-03-29
2022-01-0641
The expansion of electrified powertrain over the past decade due to strict fuel efficiency regulations has led to the development of various powertrain systems. While operating the engine at high efficiency using a multi-speed gearbox is a feature of existing powertrain system development, recent trends are being developed to improve system operation efficiency based on a multi-power source configured by mixing an engine and a motor in a simple gearbox. This situation makes it necessary to analyze the overall system efficiency to compare the competitiveness of each system from the early stages of powertrain system development. The prediction of powertrain system efficiency is a process to understand how the system is composed and what strategy can be used for the system in driving cycle.
Technical Paper

A Work in Synthesizing Planetary Gear Trains for Plug-in Hybrid Electrical Powertrain Systems for Automotive Vehicles

2022-03-29
2022-01-0654
Planetary gear trains (PGT) are widely used in automatic transmissions (AT), hybrid electric powertrains (HEP) and plug-in hybrid electrical powertrains (PHEP) for automotive vehicles. Plenty PGTs have been developed by the industry throughout the history of automotive vehicles. To name few which includes 6, 7, 8, 9 or 10 speeds automatic transmissions (AT) for internal combustion engine (ICE) power train systems; PGTs with two electrical machines (EM) and an ICE for single mode or multi-mode HEP systems; PGTs with single EM and an ICE for PHEP systems. Facing the new competitive challenges in motor vehicle electrification, synthesizing the simplest PGTs for PHEP become an important task. The work reported in this article is a such effort which results in much simpler, if not simplest, PGT designs for PHEPs as well as for ATs. The methodology of the synthesis works, and the details of the results will be reported.
Technical Paper

Mobility Boundaries for the Wheel Normal Reaction

2022-03-29
2022-01-0360
When a vehicle moves over uneven ground, motion of the sprung and unsprung masses causes dynamic shifting in the load transmitted to the ground, making the normal reaction in the tire-soil patch a continuously changing wheel parameter that may affect vehicle performance. At high loads, sinkage of the wheel can become high as the wheel digs into the soil. At low loads, the wheel can have difficulty acquiring sufficient traction. Additionally, steerability of the wheel can be diminished at very low loads. Controlling the damping forces in the suspension that is usually used to improve ride quality and stabilize motion of the sprung mass can result in an increase in the dynamic variation of the wheel normal reaction and cause vehicle performance deterioration. In this paper, a method is developed to establish boundary constraints on the dynamic normal reaction to maintain reasonable tire-terrain mobility characteristics.
Technical Paper

HD-Map Based Ground Truth to Test Automated Vehicles

2022-03-29
2022-01-0097
Over the past decade there has been significant development in Automated Driving (AD) with continuous evolution towards higher levels of automation. Higher levels of autonomy increase the vehicle Dynamic Driving Task (DDT) responsibility under certain predefined Operational Design Domains (in SAE level 3, 4) to unlimited ODD (in SAE level 5). The AD system should not only be sophisticated enough to be operable at any given condition but also be reliable and safe. Hence, there is a need for Automated Vehicles (AV) to undergo extensive open road testing to traverse a wide variety of roadway features and challenging real-world scenarios. There is a serious need for accurate ground truth to locate the various roadway features which helps in evaluating the perception performance of the AV at any given condition. The results from open road testing provide a feedback loop to achieve a mature AD system.
Technical Paper

Approaches for Simulation Model Reuse in Systems Design — A Review

2022-03-29
2022-01-0355
In this paper, we review the literature related to the reuse of computer-based simulation models in the context of systems design. Models are used to capture aspects of existing or envisioned systems and are simulated to predict the behavior of these systems. However, developing such models from scratch requires significant time and effort. Researchers have recognized that the time and effort can be reduced if existing models or model components are reused, leading to the study of model reusability. In this paper, we review the tasks necessary to retrieve and reuse model components from repositories, and to prepare new models and model components such that they are more amenable for future reuse. Model reuse can be significantly enhanced by carefully characterizing the model, and capturing its meaning and intent so that potential users can determine whether the model meets their needs.
Technical Paper

Evolution and Redistribution of Residual Stress in Welded Plates During Fatigue Loading

2022-03-29
2022-01-0257
The presence of residual stresses affect the fatigue response of welded components. In the present study of a thick welded cantilever specimen, residual stresses were measured in an as-welded A36 steel sample and in a sample subjected to a short history of bending loads where substantial local plasticity is expected at the fatigue hot-spot weld toe. Extensive XRD measurements describe the residual stress state in a large region in front of the weld toe both in an untested as-welded sample and in a sample subjected to a short load history that generated an estimated 0.01 strain amplitude at the stress concentration zone at the weld toe. The results show that such a test will significantly alter the welding induced residual stresses. Fatigue life prediction methods need to be aware that such alterations are possible and incorporate the effects of such cyclic stress relaxation in life computations.
Technical Paper

Performance and activity Characteristics of Zero Emission Battery-Electric Cargo Handling Equipment at a Port Terminal

2022-03-29
2022-01-0576
Off-road equipment makes some of the most important contributions to the emissions inventory for both urban pollutants and greenhouse gases. Reducing the emissions contribution from these sources has been a focus of regulations and incentive programs over the past few years. The number of plug-in and electric vehicle/equipment models in the medium-duty and heavy-duty off-road categories have significantly expanded in recent years. A growing number of fleets are deploying or are interested in deploying electric vehicles such as port-related equipment, transit buses, school buses, trucks, and other off-road equipment. Reliable operational and performance data on electric vehicles/equipment is needed with the rapid growth and use of electric vehicles/equipment to provide insights on their performance and to support the ongoing research into the future deployment of this equipment.
Technical Paper

Identifying Cybersecurity Focus Areas in Connected Cars Based on United Nations Regulation No. 155 Attack Vectors and Beyond

2022-03-29
2022-01-0116
The arrival of 5G will enable vehicles to become better connected. In order to allow this evolution to manifest safely, the UNECE World Forum for Harmonization of Vehicle Regulations (WP.29) introduced the United Nations Regulation No. 155(UN-R155) on January 2021, with expectations that at least 54 countries will mandate it starting July 2022. This regulation provides 69 attack vectors manufacturers are required to secure against, although it does not include specific countermeasures. Security methods and corresponding technologies change with time and are influenced by evolving connected car technologies as well as the threat landscape. Implementing effective cybersecurity means conducting a thorough risk analysis and prioritizing what needs to be achieved. Trend Micro Research conducted a risk analysis on each of the 69 attack vectors from a current and future perspective. In addition, we went beyond the attack vectors listed in UN-R155.
Technical Paper

High-Speed Thermographic Analysis of Diesel Injector Nozzle Tip Temperature

2022-03-29
2022-01-0495
The temperature of fuel injectors can affect the flow inside nozzles and the subsequent spray and liquid films on the injector tips. These processes are known to impact fuel mixing and combustion and the formation of deposits that can cause engines to go off calibration. However, there is a lack of experimental data for the transient evolution of nozzle temperature throughout engine cycles and the effect of operating conditions on injector temperature. Although some measurements of engine surface temperature exist, they have relatively low temporal resolutions and cannot be applied to production injectors due to the requirement for a specialist coating which can interfere with the orifice geometry. To address this knowledge gap, we have developed a high-speed infra-red imaging approach to measure the temperature of the nozzle surface inside an optical diesel engine.
Technical Paper

Evaluation of Fretting Phenomenon in Gearbox and Allied Failures

2022-03-29
2022-01-0648
This paper takes a review of fretting phenomenon on splines of the engaging gears and corresponding splines on shaft of automotive transmission and how it leads to failure of other components in the gearbox. Fretting is a special wear process which occurs at the contact area of two mating metal surfaces when subject to minute relative oscillating motion under vibration. In automotive gearbox, which is subjected to torsional vibrations of the powertrain, the splines of engaging gears and corresponding shaft may experience fretting, especially when the subject gear pair is not engaged. The wear debris formed under fretting process when oxidizes becomes very hard and more abrasive than base metal. These oxidized wear particles when comes in mesh contact with nearby components like bearings, gears etc. may damage these parts during operation and eventually lead to failure.
Technical Paper

Effects of Thermodynamic Conditions and Nozzle Geometry on the Methane Direct Injection Process in Internal Combustion Engines

2022-03-29
2022-01-0505
It's known direct injection of gaseous methane can involve the presence of under-expanded jets. Understanding the physics of such process is imperative for developing Direct Injection (DI) internal combustion engines fueled indeed by gaseous fuels. The paper presents an experimental-numerical characterization of the spray issued from an innovative multi-hole injector designed for application in heavy-duty engines. The experimental characterization of the jet evolution was recorded by means of schlieren imaging technique and then, using such measurements for the validation, a numerical simulation procedure was assessed. A high-order and density-based solver, capable of reproducing the most relevant features of the under-expanded jets, was developed within OpenFOAM framework. Both early and late injection configurations were investigated.
Technical Paper

Development and Validation of a Magnetoelastic Torque Sensor for Motorsport Applications

2022-03-29
2022-01-0375
First introduced around the year 2000, magnetoelastic torque sensors are now used by a majority of the teams competing in racing series such as Formula 1, WEC P1 class, and Formula E, in which torque is commonly measured on half-shafts, engine output shafts, as well as high speed motor generator shafts (MGU). The teams using torque sensors are able to benefit by using the information provided from the torque sensor to improve performance and reliability. Regulating bodies employ the information to assist with regulation ranging from monitoring for control loops to balancing performance. This paper will describe the torque sensor architecture used when installed on the half-shafts for a GT motorsport application. This description will include a discussion of suitable transducer materials and stress criteria, provide an overview of the limitations of the technology such as errors associated with temperature, and hysteresis, and how these limitations are addressed.
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