An Avionics Integrity Program Approach to Preventing Aircraft Electronics Humidity and Moisture Problems

2009 ◽  
Author(s):  
Charles Lide ◽  
Stefan Glista
Keyword(s):  
Development Process ◽  
Test Methods ◽  
Operating Conditions ◽  
Process Improvements ◽  
Standard Procedures ◽  
Technical Issues ◽  
Verification Process ◽  
Improved Methods ◽  
Moisture Resistant ◽  
Field Failure

Analysis of the causes of airborne electronics field failures indicates that humidity, moisture, and corrosion are significant contributors to the total field failure population. In spite of this fact, analysis methods, test methods and standard procedures to address these problems are less mature than those for other electronics failure mechanisms such as low and high cycle fatigue. An Avionics Integrity Program (AVIP) approach to address humidity and moisture issues is outlined. Programmatic and technical issues associated with achieving humidity and moisture resistance are discussed. The paper focuses on the steps to be taken at each stage of the development and verification process to reduce the probability of moisture related problems escaping to later stages of development and verification. Design and development process improvements are discussed along with areas of need for improved methods. Sources of moisture including the influence of cooling interface temperatures are presented along with mitigations to moisture sources. Examples of moisture-related failures are discussed along with corrective actions to the electronic equipment. Design criteria to prevent moisture-related failures and achieve a moisture-resistant design are presented. Limitations of humidity test methods are covered along with suggested improvements to increase realism of testing to match the severe environmental and operating conditions. Finally, field life management moisture screening is proposed.

scholarly journals Comprehensive Parameters Identification and Dynamic Model Validation of Interior-Mount Line-Start Permanent Magnet Synchronous Motors

Machines ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 4 ◽  
Author(s):  
Luqman S. Maraaba ◽  
Zakariya M. Al-Hamouz ◽  
Abdulaziz S. Milhem ◽  
Ssennoga Twaha
Keyword(s):  
Mathematical Model ◽  
Permanent Magnet ◽  
High Efficiency ◽  
Experimental Tests ◽  
Induction Machines ◽  
Test Methods ◽  
Operating Conditions ◽  
Test Method ◽  
Permanent Magnet Synchronous Motors ◽  
Synchronous Motors

The application of line-start permanent magnet synchronous motors (LSPMSMs) is rapidly spreading due to their advantages of high efficiency, high operational power factor, being self-starting, rendering them as highly needed in many applications in recent years. Although there have been standard methods for the identification of parameters of synchronous and induction machines, most of them do not apply to LSPMSMs. This paper presents a study and analysis of different parameter identification methods for interior mount LSPMSM. Experimental tests have been performed in the laboratory on a 1-hp interior mount LSPMSM. The measurements have been validated by investigating the performance of the machine under different operating conditions using a developed qd0 mathematical model and an experimental setup. The dynamic and steady-state performance analyses have been performed using the determined parameters. It is found that the experimental results are close to the mathematical model results, confirming the accuracy of the studied test methods. Therefore, the output of this study will help in selecting the proper test method for LSPMSM.

Demonstration of the Benefits of SAE 30 Stationary Gas Engine Oil in Full Scale Engine Tests

2021 ◽  
Author(s):  
Thijs Schasfoort ◽  
Zoe Fard ◽  
Torsten Gehrmann ◽  
Steffen Hollatz
Keyword(s):  
Positive Impact ◽  
Fuel Efficiency ◽  
Test Methods ◽  
Operating Conditions ◽  
Engine Oil ◽  
Gas Engine ◽  
Fuel Consumption Rate ◽  
Efficiency Performance ◽  
Endurance Testing ◽  
Efficiency Test

Abstract This paper evaluates the benefits of an SAE 30 monograde stationary gas engine oil (SGEO) in comparison with SAE 40 monograde SGEOs with the focus on two main areas. First, to demonstrate and quantify the positive impact of lower viscosity on the fuel consumption rate, and second to demonstrate the faster lubrication of hard to reach points in the engine during startup. The current industry recognized fuel efficiency test methods for passenger car and on-road diesel engine sectors are not suitable for evaluating the fuel efficiency performance of a gas engine oil because of the significant differences in fuel type, engine operating conditions, and oil formulations. This paper, therefore, describes comparative studies of three different gas engine oils in a modern MAN E3262 E302 gas engine that was carefully adapted and fully instrumented. The performance of each oil with respect to fuel efficiency was assessed in an extensive program comprising endurance testing, stationary tests on various load/speed points and dynamic tests running the engine fired as well as non-fired (motored). Another part of the test program explores the lubrication of hard to reach points in the engine, e.g. valve guide. The paper describes how the SAE 30 monograde oil results in faster lubrication of these parts during startup in comparison with the SAE 40 oils.

Experimental Investigation Into the High Altitude Relight of a Three-Cup Combustor Sector

2018 ◽  
Author(s):  
Michael J. Denton ◽  
Samir B. Tambe ◽  
San-Mou Jeng
Keyword(s):  
Pressure Drop ◽  
High Altitude ◽  
High Speed ◽  
Development Process ◽  
Recirculation Zone ◽  
Operating Conditions ◽  
Pressure Drops ◽  
High Speed Video ◽  
Air Jet ◽  
Flame Development

The altitude relight of a gas turbine combustor is an FAA and EASA regulation which dictates the successful re-ignition of an engine and its proper spool-up after an in-flight shutdown. Combustor pressure loss, ambient pressure, ambient temperature, and equivalence ratio were all studied on a full-scale, 3-cup, single-annular aviation combustor sector to create an ignition map. The flame development process was studied through the implementation of high-speed video. Testing was conducted by placing the sector horizontally upstream of an air jet ejector in a high altitude relight testing facility. Air was maintained at room temperature for varying pressure, and then the cryogenic heat exchanger was fed with liquid nitrogen to chill the air down to a limit of −50 deg F, corresponding with an altitude of 30,000 feet. Fuel was injected at constant equivalence ratios across multiple operating conditions, giving insight into the ignition map of the combustor sector. Results of testing indicated difficulty in achieving ignition at high altitudes for pressure drops greater than 2%, while low pressure drops show adequate performance. Introducing low temperatures to simulate the ambient conditions yielded a worse outcome, with all conditions having poor results except for 1%. High-speed video of the flame development process during the relight conditions across all altitudes yielded a substantial effect of the pressure drop on ignitability of the combustor. An increase in pressure drop was associated with a decrease in the likelihood of ignition success, especially at increasing altitudes. The introduction of the reduced temperature effect exacerbated this effect, further hurting ignition. High velocity regions in the combustor were detrimental to the ignition, and high area, low velocity regions aided greatly. The flame tended to settle into the corner recirculation zone and recirculate back into the center-toroidal recirculation zone (CTRZ), spreading downstream and likewise into adjacent swirl cups. These tests demonstrate the need for new combustor designs to consider adding large recirculation zones for combustor flame stability that will aid in relight requirements.

Review of Test Methods for Evaluating Hydrogen Embrittlement Susceptibility of Materials

2004 ◽  
Author(s):  
Deanna J. Burwell ◽  
Michiel P. H. Brongers ◽  
John A. Beavers
Keyword(s):  
Hydrogen Embrittlement ◽  
Constant Load ◽  
Test Methods ◽  
Standard Test ◽  
Operating Conditions ◽  
General Motors ◽  
Hydrogen Fuel Cell ◽  
The Government ◽  
American Society ◽  
Safe Transport

For several decades, engineers and technicians responsible for safe transport and storage of hydrogen, in both the government and industry sectors, have had to contend with the problem of hydrogen embrittlement. Today, the problem of hydrogen embrittlement must be considered anew with the systems and environments emerging with the developing hydrogen fuel cell industry. This paper discusses several methods to test for the susceptibility of metallic materials to hydrogen embrittlement. The objective of this review is to assist engineers and designers in selecting hydrogen embrittlement test methods to simulate actual manufacturing and/or operating conditions while using appropriate specimen geometries. Reviewed are standard test methods from American Society for Testing and Materials (ASTM) International, British Aerospace Series (BSEN), and General Motors Engineering sources. These include constant load, rising step load, slow strain rate, inclined wedge, bend, disk pressure, and cantilever beam test methods. Information is provided on load and displacement characteristics, uses, a brief description, and required equipment for each test.

Inadequacies in Uniaxial Stress Screen Vibration Testing

2001 ◽  
Vol 44 (4) ◽  
pp. 20-23 ◽  
Author(s):  
Wayne Whiteman ◽  
Morris Berman
Keyword(s):  
Fatigue Failure ◽  
Uniaxial Stress ◽  
Test Methods ◽  
Operating Conditions ◽  
Triaxial Tests ◽  
Vibration Testing ◽  
Uniaxial Test ◽  
Multiaxial Testing ◽  
The Difference ◽  
Vibration Tests

Validating the design and reliability of equipment prior to fielding is a critical step in the materiel development and manufacturing process. Success requires that the new equipment undergo and survive testing. Stress screen vibration testing determines the equipment's design capability. Traditionally, stress screen vibration tests have been conducted by sequentially applying uniaxial excitation to test articles along three orthogonal axes. Simultaneous multiaxial excitation is an advanced method of vibration testing with the goal of more closely approximating real-world operating conditions. Multiaxial testing achieves the synergistic effect of exciting all modes simultaneously and induces a more realistic vibrational stress loading condition. This research begins an effort to explore the difference in predicting fatigue failure between sequentially applied uniaxial and simultaneous triaxial tests. The research plan starts with simple cantilever beam structures. Once initial results are complete, more complex and typical components in actual vehicles will be tested. This paper provides results that reveal inadequacies in traditional uniaxial test methods. It is shown that the order in which orthogonal uniaxial excitation is applied has a significant effect on fatigue failure.

scholarly journals Fracture and Fatigue of Commercial Grade API Pipeline Steels in Gaseous Hydrogen

2010 ◽  
Author(s):  
Chris San Marchi ◽  
Brian P. Somerday ◽  
Kevin A. Nibur ◽  
Douglas G. Stalheim ◽  
Todd Boggess ◽  
...  
Keyword(s):  
Fracture Resistance ◽  
Structural Integrity ◽  
Standardized Test ◽  
Compact Tension ◽  
Test Methods ◽  
Gaseous Hydrogen ◽  
Operating Conditions ◽  
Sustained Load ◽  
Pipeline Steels ◽  
Integrity Assessment

Gaseous hydrogen is an alternative to petroleum-based fuels, but it is known to significantly reduce the fatigue and fracture resistance of steels. Steels are commonly used for containment and distribution of gaseous hydrogen, albeit under conservative operating conditions (i.e., large safety factors) to mitigate so-called gaseous hydrogen embrittlement. Economical methods of distributing gaseous hydrogen (such as using existing pipeline infrastructure) are necessary to make hydrogen fuel competitive with alternatives. The effects of gaseous hydrogen on fracture resistance and fatigue resistance of pipeline steels, however, has not been comprehensively evaluated and this data is necessary for structural integrity assessment in gaseous hydrogen environments. In addition, existing standardized test methods for environment assisted cracking under sustained load appear to be inadequate to characterize low-strength steels (such as pipeline steels) exposed to relevant gaseous hydrogen environments. In this study, the principles of fracture mechanics are used to compare the fracture and fatigue performance of two pipeline steels in high-purity gaseous hydrogen at two pressures: 5.5 MPa and 21 MPa. In particular, elastic-plastic fracture toughness and fatigue crack growth rates were measured using the compact tension geometry and a pressure vessel designed for testing materials while exposed to gaseous hydrogen.

scholarly journals Bio-oil yield potential of some tropical woody biomass

2017 ◽  
Vol 26 (2) ◽  
pp. 33 ◽  
Author(s):  
Edmund C Okoroigwe ◽  
Zhenglong Li ◽  
Shantanu Kelka ◽  
Christopher Saffron ◽  
Samuel Onyegegbu
Keyword(s):  
Mangifera Indica ◽  
Industrial Applications ◽  
Test Methods ◽  
Oil Yield ◽  
Yield Potential ◽  
Pyrolysis Products ◽  
Standard Procedures ◽  
Bio Oil ◽  
American Standard ◽  
Gas Chromatography Mass Spectroscopy

Six tropical biomass samples namely: Ogbono wood (Irvingia wombolu), Mango wood (Mangifera indica), Neem wood (Azadiracta indica), Ogbono shell (Irvingia wombolu), Ogirisi wood (Neubouldia laevis) and Tropical Almond wood (Terminalia catappa) were pyrolyzed in a bench scale screw reactor at 450oC. The physicochemical properties of the samples were determined prior to the pyrolysis experiments. The bio-oil and bio-char produced were similarly characterized using standard procedures established by American Standard and Test Methods (ASTM). The highest bio-oil yield of 66 wt% and least bio-oil yield of 53 wt% were obtained from Neem wood and Tropical Almond wood respectively. The characterization results of the products show that even though the moisture content of the bio-oil was quite higher than those of the original feedstock, their higher heating values were higher than those of the parent feedstock. Both characterization results show that the feedstock and their fast pyrolysis products are good materials for bioenergy production. The Gas Chromatography Mass Spectroscopy (GC-MS) analysis of the bio-oil shows the presence of useful chemicals such as phenols and levoglucosan, which could be harnessed for industrial applications.

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