Your Selections

Risk assessments
Show Only

Collections

File Formats

Content Types

Dates

Sectors

Topics

Authors

Publishers

Affiliations

Committees

Events

Magazine

 

Exploration of Cavitation-suppressing Orifice Designs for a Heavy-duty Diesel Injector Operating with Straight-Run Gasoline

Aramco Research Center - Detroit-Yuanjiang Pei, Michael L. Traver
Argonne National Laboratory-Roberto Torelli, Gina M. Magnotti, Sibendu Som
  • Technical Paper
  • 2019-24-0126
To be published on 2019-09-09 by SAE International in United States
The occurrence of cavitation inside injectors is generally undesirable since it can cause material erosion and result in deviations from the expected operating conditions and performance. Previous numerical work employing an injector geometry measured with x-ray diagnostics and operating with a high-volatility straight-run gasoline has shown that: (1) most of the cavitation is generally observed at low needle lifts, (2) needle motion is responsible for asymmetric structures in the internal flow as well as large pressure and velocity gradients that trigger phase transition at the orifice inlets, and (3) cavitation affects the injector discharge coefficient and distribution of injected fuel. To explore the potential for material damage within the injector orifices due to cavitation cloud collapse, the cavitation-induced erosion risk assessment (CIERA) tool has been applied for the first time to the realistic geometry of a heavy-duty injector using the CONVERGE software. Critical locations with high erosive potential matched qualitatively well with x-ray scans of an eroded injector sample that underwent a durability test with straight-run gasoline. This motivated a CFD exploration of a series…
 
new

Flammability of Polymeric Interior Materials - Horizontal Test Method

Textile and Flexible Plastics Committee
  • Ground Vehicle Standard
  • J369_201908
  • Current
Published 2019-08-08 by SAE International in United States
This SAE Standard pertains to automotive vehicles and off-road, self-propelled work machines used in construction, general purpose industrial, agriculture, forestry, and specialized mining machinery. This standard does not address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this document to establish safety and health practices and determine the applicability of regulatory limitations prior to use. Fire testing is inherently hazardous. Adequate safeguards for personnel and property shall be employed when conducting this test.
Datasets icon
Annotation icon
 

Scaling Evaluation of Ice-Crystal Icing on a Modern Turbofan Engine in PSL Using the COMDES-MELT Code

Ohio Aerospace Institute-Jen-Ching Tsao
Published 2019-06-10 by SAE International in United States
This paper presents preliminary ice-crystal icing (ICI) altitude scaling evaluation results of a Honeywell Uncertified Research Engine (HURE) that was tested in the NASA Glenn Research Center Propulsion Systems Laboratory (PSL) during January of 2018. This engine geometry features a hidden core design to keep the core less exposed. The engine was fitted with internal video cameras to observe various ice buildup processes at multiple selected locations within the engine core flow path covering the fan stator, the splitter-lip/shroud/strut, and the high pressure compressor (HPC) variable inlet guide vane (IGV) regions. The potential ice accretion risk was pre-determined to occur by using NASA’s in-house 1D Engine Icing Risk assessment code, COMDES-MELT. The code was successful in predicting the risk of ice accretion in adiabatic regions like the fan-stator of the HURE at specific engine operating points. However at several operating points during the test, liquid water was observed running along the shroud toward the variable IGV of the HPC regions with an air temperature well below freezing, thus no particle melting could have occurred due…
Datasets icon
Annotation icon
 

DO -326A and ED-202A : An Introduction to the New and Mandatory Aviation Cyber-Security Essentials

  • Professional Development
  • C1949
Published 2019-06-10

The international standards D-326A (U.S.) and ED-202A (Europe) titled "Airworthiness Security Process Specification" are the cornerstones of the "DO-326/ED-202 Set" and they are the only Acceptable Means of Compliance (AMC) by FAA & EASA for aviation cyber-security airworthiness certification, as of 2019. The "DO-326/ED-202 Set" also includes companion documents DO-356A/ED-203A: "Airworthiness Security Methods and Considerations" & DO-355/ED-204: "Information Security Guidance for Continuing Airworthiness" (U.S. & Europe) and ED-201: "Aeronautical Information System Security (AISS) Framework Guidance" & ED-205: "Process Standard for Security Certification / Declaration of Air Traffic Management / Air Navigation Services (ATM/ANS) Ground Systems“ (Europe only).

 

Oxygen Cylinder Installation Guide

A-10 Aircraft Oxygen Equipment Committee
  • Aerospace Standard
  • ARP5021B
  • Current
Published 2019-04-11 by SAE International in United States
This document provides guidance for oxygen cylinder installation on commerical aircraft based on airworthiness requirements, and methods practiced within aerospace industry. It covers considerations for oxygen systems from beginning of project phase up to production, maintenance, and servicing. The document is related to requirements of DOT-approved oxygen cylinders, as well to those designed and manufactured to standards of ISO 11119. However, its basic rules may also be applicable to new development pertaining to use of such equipment in an oxygen environment. For information regarding oxygen cylinders itself, also refer to AIR825/12.
Datasets icon
Annotation icon
 

Potential Risk Assessment Algorithm in Car Following

Tongji University-Rui Liu, Jingwei He, Xichan Zhu
Published 2019-04-02 by SAE International in United States
In this paper, a potential risk assessment algorithm is proposed. The obvious risk assessment measure is defined as time to collision (TTC), whereas the potential risk measure is defined as the time before the host vehicle has to decelerate to avoid a rear-end collision assuming that the target vehicle brakes, i.e. time margin (TM). The driving behavior of the human driver in the dangerous car following scenario is studied by using the naturalistic driving data collected by video drive record (VDR), which include 78 real dangerous car following dangerous scenarios. A potential risk assessment algorithm was constructed using TM and the dangerous car following scenarios. Firstly, the braking starting time during dangerous car following is identified. Next, the TM at brake starting time of the 78 dangerous car following scenarios is analyzed. In the last, the thresholds of the potential risk levels are achieved. It is found that the potential risk assessment algorithm can detect the possibility of danger earlier than that using TTC. And the potential risk assessment algorithm can describe the danger when…
Annotation icon
 

An Analytical Methodology for Engine Gear Rattle and Whine Assessment and Noise Simulation

FEV North America, Inc.-Joern Baumann, Brian Campbell
Ford Motor Company-Mohammad Moetakef, Abdelkrim Zouani, Mario Felice
Published 2019-04-02 by SAE International in United States
In this paper, a CAE methodology based on a multiphysics approach for engine gear noise evaluation is reviewed. The method comprises the results and outputs from several different analytical domains to perform the noise risk assessment. The assessment includes the source-path analysis of the gear-induced rattling and whining noise. The vibration data from the exterior surface of the engine is extended through acoustic analysis to perform the engine noise simulation and to identify acoustic hot spots contributing to the noise. The study includes simulations under different engine loading conditions with results presented in both time and frequency domains. Various sensitivity analyses involving different gear geometries and micro-geometries are investigated as well. Finally, the simulation results from three different engines are compared vis-a-vis.
Datasets icon
Annotation icon
 

Determination of Validation Testing Scenarios for an ADAS Functionality: Case Study

ZF-Oleg Kirovskii
Published 2019-04-02 by SAE International in United States
As the engineering community continues working on automated driving (AD) functionalities, the topic of safety validation still provides fuel for discussions. Despite the vehicles equipped with higher level AD functionalities ready to enter service on public roads, there is still no state-of-the-art process created for safety validation procedures. In this situation, vehicles with similar functionalities may end up coming through fundamentally different validation procedure, and the public may be exposed to additional risks.This paper fist formulates requirements which safety validation process needs to fulfill. The requirements are based on ISO 26262, PAS 21448 (SOTIF), and the state of the art requirements typical for safety applications. Then, the process of implementation of those requirements is sketched.
Datasets icon
Annotation icon
 

Simulation and Its Contribution to Evaluate Highly Automated Driving Functions

BMW Group-Korbinian Groh
BMW Technology Office USA-Thomas Kuehbeck
Published 2019-04-02 by SAE International in United States
A key criterion for launching autonomous vehicles on real roads is the knowledge of their capability to ensure traffic safety. In contrast to ADAS, deriving this measure of safety is difficult to achieve as the functional scope of an autonomous driving function exceeds by far the one of ADAS. As a consequence, real-world testing solely is not sufficient enough to cover the required test volume. This assessment problem imposes new requirements on a valid test concept for automated driving. A possible solution represents simulation by enabling it to generate reliable test kilometers. As a first step, we discuss in this paper the feasibility of simulation frameworks to re-simulate a real-world test in certain scenarios. We will demonstrate that even with ground truth information of the vehicle odometry and corresponding environment model an acceptable accordance of functional behavior is not guaranteed. Hence, to yield a reliable degree of confidence in a risk assessment a single scenario has to be represented by an ensemble generated from a local variation considering both, ground truth information and odometry including…
Annotation icon
 

A Fault Tolerant Time Interval Process for Functional Safety Development

Ford Motor Co., Ltd.-Daniel Denomme, Sam Hooson
kVA-James Winkelman
Published 2019-04-02 by SAE International in United States
During development of complex automotive technologies, a significant engineering effort is often dedicated to ensuring the safe performance of these systems. An important aspect to consider when assessing the viability of different safety designs or strategies is the time period from the occurrence of a fault to the violation of a Safety Goal (SG). This time period is commonly referred to as the Fault Tolerant Time Interval (FTTI). In Automotive Safety, ISO 26262 [1] calls for the identification and appropriate partitioning of the FTTI, however very little guidance is provided on how to do this. This paper presents a process, covering the entire safety development lifecycle, for the identification of timing constraints and the development of associated requirements necessary to prevent Safety Goal violations.
Annotation icon