Browse Topic: Reliability

Items (423)

Short-Term Prediction of Highway Visibility Level Based on Attention Mechanism LSTM

2025-01-721202/21/2025

To improve the accuracy and reliability of short-term prediction of highway visibility level in key scenarios such as short duration and fast changing speed, this paper proposes a short-term prediction method for highway visibility level based on attention mechanism LSTM. Firstly, XGBoost and SHAP methods are used to analyze the factors affecting highway visibility, determine the importance ranking of different influencing factors, and select the factors that have a greater impact on visibility as inputs for the visibility level prediction model. Secondly, based on LSTM as the model foundation network and innovative coupling attention mechanism, a visibility level prediction model based on attention mechanism LSTM is constructed, which can dynamically update the correlation between meteorological feature information at each historical time point and the visibility level at the current prediction time, thereby dividing the importance of information and flexibly capturing important

Ding, Shanshan, Xiong, Zhuozhi, Huang, Xu, Li, Yurong

Intelligent Courier Delivery Scheduling Based on XGBoost Feature Selection and Reinforcement Learning: A Case Study Using Chongqing Cainiao Express Data

2025-01-717602/21/2025

This study tackles the issue of order delays in logistics using XGBoost for feature analysis and reinforcement learning for intelligent courier scheduling. Pickup order data from May 1 to October 31, 2023, in Chongqing is analyzed using spatio-temporal statistical methods. Key findings include that order placement peaks at 9:00 a.m., delays peak at 10:00 a.m., and the delay rate is 8.6%. A significant imbalance exists between the regional daily average of dispatchable couriers and order volumes.XGBoost is employed to predict order delays, revealing that pickup location is the most influential factor (27%), followed by courier pickup location (22%). These factors and their relationships are identified as key drivers of delays.To address these issues, a reinforcement learning-based courier scheduling optimization model is developed. The model defines courier location, current time, and pending orders as state variables and adopts an epsilon-greedy strategy for action selection

Wang, Manjun, Yu, Xinlian

Advancing Implantable Medical Device Reliability with Enhanced Laser Joining Technology

TBMG-5217712/01/2024

DC-DC Converters for High Reliability eVTOL Auxiliary Power Systems

TBMG-5214712/01/2024

SAE TOMORROW TODAY: What Role Do Electric Utilities Have in the EV Space?

1336811/17/2022

As demand for EVs grows, so too does the role of electric utilities. From powering the grid to ensuring the reliability of EV charging stations, the electric utility industry plays a pivotal role in accelerating EV adoption. For more than a century, Duquesne Light Company (DLC) has delivered electricity to more than 600,000 customers in the Pittsburgh region. Currently, there are more than 6,000 EVs in DLC's service territory -- and they expect that number to grow to more than 23,000 by the end of 2025. With this projected growth, DLC is not only providing reliable power, but EV information analysis and incentives like a Community Charging Program and Electric Fleet Advisory Service Program. We sat down with Sarah Olexsak, Senior Manager, Transportation Electrification, to discuss the role of electric utilities and how DLC is supporting EV adoption in Western Pennsylvania.

Hineman, Marcie

Development of a Built-in Type Dashboard Camera with Reliability and Usability

2022-01-012003/29/2022

Dashcam, which is considered essential parts of vehicles in Korea, are installed in most vehicles for reasons such as accidents, evidence of threatened driving of other vehicles, and insurance premiums. Aftermarket dashcam have been developed with many improvements such as higher resolution camera and LCD application, but still have problems in usability and durability. The first problem is a separate device mounted on the top of the windshield, which obstructs the driver's view and may injure the driver due to a collision impact. In addition, the connection of the power supply may cause a vehicle breakdown such as a fire due to a worker's mistake or a product defect. Secondly, in order to view the stored video, it is troublesome to remove the SD card and check it on the computer. Moreover, since the LCD is so small, it is difficult to search and play the desired video from the list in many saved files. The third problem is durability and reliability, when operating in the high

Jeong, DongHyuk

Computation integration

2022-01-094703/29/2022

This invention combines optical technology of nanotechnology to produce accessible and reliable data processing. The invention increase security by demanding three key chips to access it. The key chips are the central controls and powersouce of the invention. The invention will revolutionize the way computers are used. The technology suggests advancement of previous computer technology to simplicity. It uses wireless technology to provide greater accessibility. The main claim of this invention is to provide simple data processing. Images (2)

Primous, Matthew

SAE TOMORROW TODAY: Cummins Innovating Engines to Power the Global Food Economy

1315407/16/2021

Whether it's gas, electric or hydrogen-fueled, engines serving the agriculture industry are dynamic. Cummins engines power everything from the farm to the field to the future. Ann Schmelzer, General Manager, Global Ag Business for Cummins, is passionate about problem solving through the lens of technology. Building on Cummins' reputation of reliability, Schmelzer is leading the charge to get their engines into the growing demand of autonomous agriculture. Listen as she shares insights on the current economics of agriculture and ways Cummins is stepping up to meet the needs of the global food economy.

Hineman, Marcie

GUIDANCE FOR DISTRIBUTED RADIO ARCHITECTURES

ARINC678 (Current)07/15/2021

The purpose of this document is to evaluate Communication, Navigation, and Surveillance (CNS) Distributed Radio architectures and the feasibility of distributing the RF and systems processing sections to ensure the following: Reduce cost of equipment Reduce Size, Weight, and Power (SWaP) Ease of aircraft integration Growth capability built into the design Maintain or improve system availability, reliability, and maintainability It provides a framework to determine whether it is feasible to develop ARINC Standards that support CNS distributed radio architectures.

Airlines Electronic Engineering Committee

Quality and Reliability in the Assembly and Manufacturing of Medical Electronics PCBs

TBMG-3807511/01/2020

With COVID-19 continuing to rage across the United States and the world, hospitals and medical centers are relying on their medical electronics equipment, including ventilators, to help improve COVID-19 patients’ health. EMS providers, contract manufacturers (CMs), and printed circuit board (PCB) fabricators are the strongest link in the supply chain critical for building medical electronics equipment, including ventilators. These PCB companies help design, assemble, and manufacture the PCBs that are at the heart of these life-saving medical instruments.

Reliability Program Standard for Systems Design, Development, and Manufacturing

GEIASTD0009A-TEST-REC (Historical)05/27/2020

This standard requires the developers and customer/users working as a team to plan and implement a reliability program that provides systems/products that satisfy the user’s requirements and expectations. The user’s requirements and needs are expressed in the form of the following four reliability objectives: The developer shall solicit, investigate, analyze, understand and agree to the user’s requirements and product needs. The developer, working with the customer and user, shall include the activities necessary to ensure that the user’s requirements and product needs are fully understood and defined, so that a comprehensive design specification and Reliability Program Plan can be generated. The developer shall use well-defined reliability- and systems-engineering processes to develop, design, and verify that the system/product meets the user’s documented reliability requirements and needs. The developer shall implement a set of engineering activities (included in this standard as

G-41 Reliability

Reliability Program Standard for Systems Design, Development, and Manufacturing

GEIASTD0009A (Current)

05/27/2020

This standard requires the developers and customer/users working as a team to plan and implement a reliability program that provides systems/products that satisfy the user’s requirements and expectations. The user’s requirements and needs are expressed in the form of the following four reliability objectives: The developer shall solicit, investigate, analyze, understand and agree to the user’s requirements and product needs. The developer, working with the customer and user, shall include the activities necessary to ensure that the user’s requirements and product needs are fully understood and defined, so that a comprehensive design specification and Reliability Program Plan can be generated. The developer shall use well-defined reliability- and systems-engineering processes to develop, design, and verify that the system/product meets the user’s documented reliability requirements and needs. The developer shall implement a set of engineering activities (included in this standard as

G-41 Reliability

Understanding vapor and solution phase corrosion of lubricants used in electrified transmissions

2020-01-056104/14/2020

In this study, the corrosion rates of commercially available lubricants that are found in electrified and conventional transmissions are measured in the vapor and solution phase across a range of operating temperatures using the wire corrosion test. The results of this study demonstrate the importance of performing vapor and solution phase corrosion measurements in real time across a range of temperatures and offers an efficient and cost-effective way to screen fluid chemistries over a range of potential corrosion situations. Corrosion measurements such as these, when interpreted correctly provide reliable data on which to base appropriate safety margins during the design phase.

Hunt, Gregory, Prengaman, Christopher

Experimental Study on Stress State of a Car Wheel under Typical Working Conditions

2020-01-122904/14/2020

Wheel stress state is one of the important factors determining wheel reliability. The nonlinear influence of the tire on the wheel during actual use makes it difficult to obtain the multi-axial stress of the wheel through simulation calculation. This paper proposes a method based on bench test to study the stress state of car wheels. Firstly, starting from the two typical working condition of straight running and turning, the wheel dangerous point position is obtained. Then strain gauges are attached to the dangerous point of the wheel to analyze the stress changes of it under these two load conditions. The variation rules corresponding to different loading conditions are analyzed. Finally, the load conditions affecting the stress state of the wheel are found through comparative analysis. Through the above research, the measurement method and influencing factors of the stress state of the wheel during use are obtained. It provides guidance for wheel structure optimization and

Cheng, Liu, Zu, Ren, Chao, Cheng, Wei, Liu

Report on Unmanned Ground Vehicle Reliability

J2958_202002 (Current)02/24/2020

This information report is applicable to the reliability characteristics of unmanned ground vehicles.

G-41 Reliability

A Methodology of Design for Fatigue Using an Accelerated Life Testing Approach with Saddlepoint Approximation

2019-01-015904/02/2019

We present an Accelerated Life Testing (ALT) methodology along with a design for fatigue approach, using Gaussian or non-Gaussian excitations. The accuracy of fatigue life prediction at nominal loading conditions is affected by model and material uncertainty. This uncertainty is reduced by performing tests at a higher loading level, resulting in a reduction in test duration. Based on the data obtained from experiments, we formulate an optimization problem to calculate the Maximum Likelihood Estimator (MLE) values of the uncertain model parameters. In our proposed ALT method, we lift all the assumptions on the type of life distribution or the stress-life relationship and we use Saddlepoint Approximation (SPA) method to calculate the fatigue life Probability Density Functions (PDFs). Finally, a design for fatigue is performed where a Reliability-Based Design Optimization (RBDO) process is developed to optimize the system’s characteristics (model parameters, fatigue and/or material

Tsianika, Vasiliki, Geroulas, Vasileios, Papadimitriou, Dimitrios, Mourelatos, Zissimos, Hu, Zhen, Majcher, Monica

Self-Stabilizing, Distributed, Symmetric, Fault-Tolerant Synchronization

TBMG-3392303/01/2019

Distributed systems have become an integral part of safety-critical computing applications, necessitating system designs that incorporate complex fault-tolerant resource management functions to provide globally coordinated operations with ultra-reliability. As a result, robust clock synchronization has become a required fundamental component of fault-tolerant, safety-critical distributed systems. Since physical oscillators are inherently imperfect, local clocks of nodes of a distributed system, driven by these oscillators, do not keep perfect time and can drift with respect to real time and one another. Thus, the local clocks of the nodes must periodically be re-synchronized. As a result, a fault-tolerant system needs a clock synchronization algorithm that tolerates imprecise local clocks and faulty behavior by some processes.

Separable and Standard Monte Carlo Simulation of Linear Dynamic Systems Using Combined Approximations

02-12-02-000801/25/2019

Reliability analysis of a large-scale system under random dynamic loads can be a very time-consuming task since it requires repeated studies of the system. In many engineering problems, for example, wave loads on an offshore platform, the excitation loads are defined using a power spectral density (PSD) function. For a given PSD function, one needs to generate many time histories to make sure the excitation load is modeled accurately. Global and local approximation methods are available to predict the system response efficiently. Each way has their advantages and shortcomings. The combined approximations (CA) method is an efficient method, which combines the advantages of local and global approximations. This work demonstrates two methodologies that utilize CA to reduce the cost of crude or separable Monte Carlo simulation (MCS) of linear dynamic systems when the excitation loads are defined using PSD functions. The system response is only calculated at a few frequencies within the

Norouzi, Mahdi, Nikolaidis, Efstratios

Photonic Radiation Sensors Survive Huge Doses Undamaged

TBMG-3355801/01/2019

Landmark test results suggest a promising class of sensors can be used in high-radiation environments and to advance important medical, industrial, and research applications.

Value of Information for Comparing Dependent Repairable Assemblies and Systems

2018-01-110304/03/2018

This article presents an approach for comparing alternative repairable systems and calculating the value of information obtained by testing a specified number of such systems. More specifically, an approach is presented to determine the value of information that comes from field testing a specified number of systems in order to appropriately estimate the reliability metric associated with each of the respective repairable systems. Here the reliability of a repairable system will be measured by its failure rate. In support of the decision-making effort, the failure rate is translated into an expected utility based on a utility curve that represents the risk tolerance of the decision-maker. The algorithm calculates the change of the expected value of the decision with the sample size. The change in the value of the decision represents the value of information obtained from testing. The approach uses a Bayesian probability model, which allows the decision-maker to incorporate subjective

Capser, Shawn P., Nikolaidis, Efstratios

High-Power Solid-State Power Amplifier System

TBMG-2871504/01/2018

NASA Marshall Space Flight Center (MSFC) has developed a High-Power Solid-State Power Amplifier System that combines 1-KW modules (16 amps total) to generate up to 16KW of radio frequency (RF) power from 230 MHz. The NASA device is a first step toward increasing the power of solid-state power amp devices so that they might replace the more cumbersome vacuum tube amps for some applications. Also, when vacuum tube amps fail, a total power failure occurs. Since the NASA device is a system of amplifiers, it enables graceful failure, meaning one or more stages can fail and the system will continue to operate, although at reduced power.

Safe2Ditch Technology

TBMG-2871304/01/2018

Highly capable small Unmanned Aerial Vehicles (UAVs) provide substantial business opportunity, especially if allowed to operate in the suburban market. Reliability issues force the use of a safety pilot for each vehicle in operation, which is cost-prohibitive for large-scale commercial applications, and limits the use of these vehicles to line-of-site (LOS) operation. Extending the use of small UAVs to beyond visual line-of-sight (BVLOS) and to fleet operations requires a vehicle system to autonomously perform emergency management activities as a replacement for the human pilot to maintain safety to people and property in populated areas.

AMMOS-PDS Pipeline Service (APPS)

TBMG-2815001/01/2018

APPS provides a multi-mission instrument data and metadata (i.e. label) transformation service that interfaces local or remote Mission Data provider’s data processing pipeline/end-products and the PDS (Planetary Data System) data archive to ensure compliance to standards in a schedule/cost-efficient manner (i.e. streamline the delivery of data between the missions and the PDS). In turn, this supports data format independence for instrument data (including, but not limited to, imaging), which improves data access and discovery for instrument Principal Investigators, scientists, and general users within the PDS4 architecture.

Microwave-Based Test Method for Computer Chips

TBMG-2814101/01/2018

A new approach was developed that overcomes the limitation of conventional chip-testing methods on 3D chips, which include many thin horizontal “floors” connected to one another by vertical pathways called through-substrate vias (TSVs). TSVs help 3D chips do three essential things: speed up, shrink down, and cool off. By allowing elements on different floors to communicate with each other, signals no longer need to travel all the way across a comparatively sprawling 2D chip, meaning calculations go faster and electrons heat up far less conducting material as they move.

Test System Ensures Flawless Performance of Military RF Devices

TBMG-2765510/01/2017

Communication on the battlefield is a life-or-death matter. You can't take chances with RF devices or power units malfunctioning or failing. A soldier's life may depend on how well you designed and tested your product. Will it function in temperature extremes, after physical shocks, and with low battery power? Where will it break or fail, and why? How can that be prevented?

Metallic Materials Properties Development and Standardization (MMPDS) Handbook - 12

B-98407/01/2017

The Metallic Materials Properties Development and Standardization (MMPDS) Handbook is an accepted source for metallic material and fastener system allowables, recognized by the Federal Aviation Administration (FAA), all departments and agencies of the Department of Defense (DoD), and the National Aeronautics and Space Administration (NASA), within the limitations of the certification requirements of the specific government agency. 2017 saw the release of MMPDS-12, superseding MMPDS-11 and prior editions of the MMPDS, as well as all editions of its predecessor MIL-HDBK-5. The MMPDS Handbook is revised regularly to ensure that reliable, statistically-based design properties are available for as many mature materials and/or product forms as possible. Changes specific to this version, MMPDS-12, include: • Revision of modulus (chapter 5) • Re-evaluation of some fatigue curves (chapter 6) • Update of shear strength basis footnotes (chapter 8) • Changes in strain rate requirement for full

Time-Dependent Reliability-Based Design Optimization of Vibratory Systems

2017-01-019403/28/2017

A methodology for time-dependent reliability-based design optimization of vibratory systems with random parameters under stationary excitation is presented. The time-dependent probability of failure is computed using an integral equation which involves up-crossing and joint up-crossing rates. The total probability theorem addresses the presence of the system random parameters and a sparse grid quadrature method calculates the integral of the total probability theorem efficiently. The sensitivity derivatives of the time-dependent probability of failure with respect to the design variables are computed using finite differences. The Modified Combined Approximations (MCA) reanalysis method is used to reduce the overall computational cost from repeated evaluations of the system frequency response or equivalently impulse response function. The method is applied to the shape optimization of a vehicle frame under stochastic loading. The novelty of the proposed work lies in the integration of

Papadimitriou, Dimitrios, Mourelatos, Zissimos, Patil, Santosh

Closed Wheel Race Vehicle Aerodynamic Lift-Off

2017-01-151603/28/2017

Although, the implementation of lift-off prevention devices such as the NASCAR roof flaps have greatly reduced the frequency and severity of race vehicle aerodynamic lift-off incidents, airborne incidents still occur occasionally in motorsports. The effectiveness of existing lift-off prevention measures and future trends in lift-off prevention are addressed in this paper. The results and analysis presented in this paper will be of paramount interest to race vehicle designers and sanctioning bodies because the effects of aerodynamics on vehicle lift-off need to be comprehended, but there exists a scarcity of reliable data in this area.

Honeycutt, Daniel B., Uddin, Mesbah

Time-Dependent Reliability Analysis Using a Modified Composite Limit State Approach

2017-01-020603/28/2017

Recent developments in time-dependent reliability have introduced the concept of a composite limit state. The composite limit state method can be used to calculate the time-dependent probability of failure for dynamic systems with limit-state functions of input random variables, input random processes and explicit in time. The probability of failure can be calculated exactly using the composite limit state if the instantaneous limit states are linear, forming an open or close polytope, and are functions of only two random variables. In this work, the restriction on the number of random variables is lifted. The proposed algorithm is accurate and efficient for linear instantaneous limit state functions of any number of random variables. An example on the design of a hydrokinetic turbine blade under time-dependent river flow load demonstrates the accuracy of the proposed general composite limit state approach.

Majcher, Monica, Mourelatos, Zissimos, Tsianika, Vasiliki

Aerospace & Defense Technology: February 2017

17AERP0202/02/2017

Open Standard Middleware Enables New HPEC Solutions Cooling Your Embedded System What Can Your Open Standard Architecture Handle? Evaluating Key Certification Aspects of Multicore Platforms for Safety Critical Avionics Applications Simulating and Analyzing Flow for an Air-to-Air Refueling System The Ins and Outs of Spaceflight Passive Components and Assemblies Development of High Quality 4H-SiC Thick Epitaxy for Reliable High Power Electronics Using Halogenated Precursors Silicon Based Mid-Infrared SiGeSn Heterostructure Emitters and Detectors Reconfigurable Electronics and Non-Volatile Memory Research Energy-Filtered Tunnel Transistor: A New Device Concept Toward Extremely Low Energy Consumption Electronics

GUIDANCE FOR ASSIGNMENT, ACCOMPLISHMENT, AND REPORTING OF SPECIAL (ENGINEERING) INVESTIGATION FOR AIRCRAFT COMPONENTS

ARINC676 (Current)12/19/2016

The purpose of this document is to provide guidance for the assignment, accomplishment, and reporting of investigations which exceed the regular workshop analysis and repair process for components. The operator, repair shop, and the component manufacturer should use this guideline to support a special investigation for aircraft components where additional attention is needed to fulfill reliability and authority requirements. This includes the process of assignment, the scope of accomplishment, and the content/style of the final report.

Avionics Maintenance Committee

Metallic Materials Properties Development and Standardization (MMPDS) Handbook - 11

B-98306/01/2016

The Metallic Materials Properties Development and Standardization (MMPDS) Handbook is an accepted source for metallic material and fastener system allowables, recognized by the Federal Aviation Administration (FAA), all departments and agencies of the Department of Defense (DoD), and the National Aeronautics and Space Administration (NASA), within the limitations of the certification requirements of the specific government agency. 2016 saw the release of MMPDS-11, superseding MMPDS-10 and prior editions of the MMPDS, as well as all editions of its’ predecessor MIL-HDBK-5. The MMPDS Handbook is revised regularly to ensure that reliable, statistically-based design properties are available for as many mature materials and/or product forms as possible. Changes specific to this version, MMPDS-11, include: • Guidance on the use of Stress-Strain curves. • The addition of or update to alloy sections Ferrium M54, MLX19, 2024, 2029 Alclad, 2050, 2055, 2824, 6151, 6061, 7050, 7065, 7136, 7140

Approaches to Achieving High Reliability and Confidence Levels with Small Test Sample Sizes

2015-01-275809/29/2015

In product design and development stage, validation assessment methods that can provide very high reliability and confidence levels are becoming highly demanded. High reliability and confidence can generally be achieved and demonstrated by conducting a large number of tests with the traditional approaches. However, budget constraints, test timing, and many other factors significantly limit test sample sizes. How to achieve high reliability and confidence levels with limited sample sizes is of significant importance in engineering applications. In this paper, such approaches are developed for two fundamental and widely used methods, i.e. the test-to-failure method and the Binomial test method. The concept of RxxCyy (e.g. R90C90 indicates 90% in reliability and 90% in confidence) is used as a criterion to measure the reliability and confidence in both the test-to-failure and the Binomial test methods. For the test-to-failure method, high reliability and confidence levels are achieved by

Wei, Zhigang, Rebandt, Robert, Start, Michael, Gao, Litang, Hamilton, Jason, Luo, Limin

Automotive Engineering: June 2, 2015

15AUTP0606/02/2015

Balancing GDI fuel economy and emissions Will OEMs have to adopt gasoline particulate filters to comply with stringent new emissions regulations? Top engineers discuss current developments. Cameras look to go the distance Automakers seek vision systems with greater distances, improved reliability, and more functionality, thanks to ruggedized complementary metal-oxide semiconductor technologies. Mixing metals Cadillac pursues aluminum/steel mix for new CT6 luxury sedan, leading to advances in body assembly.

Spotlight on Design Insight: Diagnostics and Prognostics: Telematics Deep Dive

SOD-005/1S05/04/2015

“Spotlight on Design: Insight” features an in-depth look at the latest technology breakthroughs impacting mobility. Viewers are virtually taken to labs and research centers to learn how design engineers are enhancing product performance/reliability, reducing cost, improving quality, safety or environmental impact, and achieving regulatory compliance. Telematics, the convergence of telecommunications and informatics, uses electronic and computer technology built in to the vehicle to provide vehicle tracking, satellite navigation, wireless technology, and diagnostic information. In the episode “Diagnostics and Prognostics: Telematics Deep Dive” (8:09), an engineer from Delphi’s Telematics program discusses the advantages and challenges of telematics devices for the automotive industry, demonstrates the installation of an aftermarket telematics device, and shows how telematics can enhance diagnostics and preventative maintenance. This episode highlights multiple areas of interest

Researchers Improve Magnetic-Field Detector

TBMG-2195404/15/2015

A Massachusetts Institute of Technology team has developed a new, ultrasensitive magnetic-field detector. The device could lead to miniaturized, battery-powered devices for medical imaging.

Spotlight on Design: Composite Materials: Advanced Materials and Lightweighting

SOD-002S04/15/2015

“Spotlight on Design” features video interviews and case study segments, focusing on the latest technology breakthroughs. Viewers are virtually taken to labs and research centers to learn how design engineers are enhancing product performance/reliability, reducing cost, improving quality, safety or environmental impact, and achieving regulatory compliance. In the episode “Composite Materials: Advanced Materials and Lightweighting” (30:20), Molded Fiber Glass Companies, known for its deep involvement in the creative development of the molded fiberglass process for the Corvette, demonstrates the manufacturing of sheet molded composite for fiberglass parts. Tanom Motors introduces the Tanom Invader, a blend between an automobile and a motorcycle made exclusively with composite materials. Finally, Euro-Composites demonstrates the manufacturing of honeycomb core material made out of aramid paper and phenolic resin used in aircraft structures. This episode highlights multiple areas of

Bootstrapping and Separable Monte Carlo Simulation Methods Tailored for Efficient Assessment of Probability of Failure of Structural Systems

2015-01-042004/14/2015

There is randomness in both the applied loads and the strength of systems. Therefore, to account for the uncertainty, the safety of the system must be quantified using its reliability. Monte Carlo Simulation (MCS) is widely used for probabilistic analysis because of its robustness. However, the high computational cost limits the accuracy of MCS. Smarslok et al. [2010] developed an improved sampling technique for reliability assessment called Separable Monte Carlo (SMC) that can significantly increase the accuracy of estimation without increasing the cost of sampling. However, this method was applied to time-invariant problems involving two random variables. This paper extends SMC to problems with multiple random variables and develops a novel method for estimation of the standard deviation of the probability of failure of a structure. The method is demonstrated and validated on reliability assessment of an offshore wind turbine under turbulent wind loads. The results show the method

Jehan, Musarrat, Nikolaidis, Efstratios

Advantages of Simulation Based Reliability Growth Planning

2015-01-043904/14/2015

The current reliability growth planning model used by the US Army, the Planning Model for Projection Methodology (PM2), is insufficient for the needs of the Army. This paper will detail the limitations of PM2 that cause Army programs to develop reliability growth plans that incorporate unrealistic assumptions and often demand that infeasible levels of reliability be achieved. In addition to this, another reliability growth planning model being developed to address some of these limitations, the Bayesian Continuous Planning Model (BCPM), will be discussed along with its own limitations. This paper will also cover a third reliability growth planning model that is being developed which incorporates the advantageous features of PM2 and BCPM but replaces the unrealistic assumptions with more realistic and customizable ones. The internal workings of this new Tank Automotive Research Development and Engineering Center (TARDEC) developed simulation-based model will be delved into with a focus

Kosinski, Daniel B.

Photo-Thermo-Refractive Glass Co-Doped with Luminescent Agents for All-Solid-State Microchip Lasers

02/01/2015

A proposed solid-state technology possesses photosensitivity that enables volume hologram recording and a high efficiency of luminescence, enabling stimulated emission. These features were used to record volume Bragg gratings and to demonstrate lasing under laser diode pumping for the same volume of glass. Moreover, a combination of dopants provides extremely wide luminescence bands, which enables both wideband optical processing and extremely short laser pulse generation. It is important that the whole design be incorporated in a single, monolithic piece of glass that excludes the opportunity for misalignment and sensitivity to vibrations. If developed, the compactness and reliability of such laser devices would find wide use in space or aeronautical applications.

Components Durability, Reliability and Uncertainty Assessments Based on Fatigue Failure Data

2014-01-230809/30/2014

Road vibrations cause fatigue failures in vehicle components and systems. Therefore, reliable and accurate damage and life assessment is crucial to the durability and reliability performances of vehicles, especially at early design stages. However, durability and reliability assessment is difficult not only because of the unknown underlying damage mechanisms, such as crack initiation and crack growth, but also due to the large uncertainties introduced by many factors during operation. How to effectively and accurately assess the damage status and quantitatively measure the uncertainties in a damage evolution process is an important but still unsolved task in engineering probabilistic analysis. In this paper, a new procedure is developed to assess the durability and reliability performance, and characterize the uncertainties of damage evolution of components under constant amplitude loadings. The linear and two nonlinear probabilistic damage accumulation models are briefly described

Wei, Zhigang, Lin, Shengbin, Luo, Limin, Gao, Litang

Components Durability, Reliability and Uncertainty Assessments Based on Fatigue Failure Data

2014-01-2308-TEST-REC09/30/2014

Road vibrations cause fatigue failures in vehicle components and systems. Therefore, reliable and accurate damage and life assessment is crucial to the durability and reliability performances of vehicles, especially at early design stages. However, durability and reliability assessment is difficult not only because of the unknown underlying damage mechanisms, such as crack initiation and crack growth, but also due to the large uncertainties introduced by many factors during operation. How to effectively and accurately assess the damage status and quantitatively measure the uncertainties in a damage evolution process is an important but still unsolved task in engineering probabilistic analysis. In this paper, a new procedure is developed to assess the durability and reliability performance, and characterize the uncertainties of damage evolution of components under constant amplitude loadings. The linear and two nonlinear probabilistic damage accumulation models are briefly described

Wei, Zhigang, Lin, Shengbin, Luo, Limin, Gao, Litang

TBMG-2018908/01/2014

Heraeus Precious Metals (West Conshohocken, PA) is pleased to announce the continuing performance growth and reliability of CelcionTM. CelcionTM is a thick film material system designed to produce electronic circuits for LED lighting on aluminum substrates. It is a highly efficient alternative to traditional metal core printed circuit boards (MCPCBs).

Noncontact DC and AC Magnetostrictive Current Sensor

TBMG-2032608/01/2014

At the time of this reporting, there have been no effective methods of monitoring current in conductors in space without breaking the circuit or making contact with the conductor. In space, reliability rules all designs, and breaking a circuit to insert a sensor to monitor current would reduce reliability of the system. Hall effect sensors provide a noncontact DC measurement technique, but they are relatively expensive and not rugged enough for the space environment.

Chip-on-Board (COB) LEDs

TBMG-1965205/01/2014

Everlight Electronics Co. Ltd. (Taipei, Taiwan) has expanded its high performance JU series of chip-on-board (COB) LEDs to include 7, 10 and 15 W types in addition to the existing 4W version. The JU series now consists of four JU1215 (15×12×1.6mm) and one JU2024 (20×24×1.6mm) type/s with powers ranging from 4 watts to 15 watts. All types provide an efficacy of 110lm/W or more at 3000K CCT, a CRI of >80Ra and 25° C substrate temperature, and are available in versions ranging from ANSI bin 2,700 K to 6,500 K.

Flexible Design and Operation of a Smart Charging Microgrid

2014-01-071604/01/2014

The reliability theory of repairable systems is vastly different from that of non-repairable systems. The authors have recently proposed a ‘decision-based’ framework to design and maintain repairable systems for optimal performance and reliability using a set of metrics such as minimum failure free period, number of failures in planning horizon (lifecycle), and cost. The optimal solution includes the initial design, the system maintenance throughout the planning horizon, and the protocol to operate the system. In this work, we extend this idea by incorporating flexibility and demonstrate our approach using a smart charging electric microgrid architecture. The flexibility is realized by allowing the architecture to change with time. Our approach “learns” the working characteristics of the microgrid. We use actual load and supply data over a short time to quantify the load and supply random processes and also establish the correlation between them. The quantified processes are then used

Pandey, Vijitashwa, Skowronska, Annette, Mourelatos, Zissimos, Gorsich, David, Castanier, Matthew

Protective Sleeve for a Pyrotechnic Reefing Line

TBMG-1924203/01/2014

A metallic sleeve provides protection and guidance for the actuating lanyard pull of a parachute system reefing line cutter. This device ensures that the reefing line cutter is not damaged during packing or deployment. In addition, the device ensures that the actuating lanyard that initiates the cutter is pulled within the device’s specification cone angle. Combined, these features increase the durability of the reefing line cutter used in parachute reefing systems, and significantly increases the reliability of the underlying reefing cutter. Protecting such a critical element of the controlled deployment of parachutes significantly improves the operation of the parachute reefing system.

Boeing's CST-100 Unveiled to the World

1171307/25/2013

NASA astronauts Serena Aunon and Randy Bresnik conducted flight suit evaluations inside a fully outfitted test version of The Boeing Company's CST-100 spacecraft July 22, the first time the world got a glimpse of the crew capsule's interior. Boeing is one of three American companies working with the agency's Commercial Crew Program (CCP) to develop safe, reliable and cost-effective crew transportation systems during the Commercial Crew Integrated Capability (CCiCap) initiative, which is intended to make commercial human spaceflight services available for government and commercial customers.

Automotive Engineering International 2013-07-16

13AEID071607/16/2013

Gearing up for long lifetimes For transmission control engineers, a greater focus on reliability is prompting a shift to standards such as ISO 26262 and an improved diagnostics function that takes a broader view, looking at the overall system vs. individual components.

A Comparison of Methods for Representing and Aggregating Uncertainties Involving Sparsely Sampled Random Variables - More Results

2013-01-094604/08/2013

This paper discusses the treatment of uncertainties corresponding to relatively few samples of random-variable quantities. The importance of this topic extends beyond experimental data uncertainty to situations involving uncertainty in model calibration, validation, and prediction. With very sparse samples it is not practical to have a goal of accurately estimating the underlying variability distribution (probability density function, PDF). Rather, a pragmatic goal is that the uncertainty representation should be conservative so as to bound a desired percentage of the actual PDF, say 95% included probability, with reasonable reliability. A second, opposing objective is that the representation not be overly conservative; that it minimally over-estimate the random-variable range corresponding to the desired percentage of the actual PDF. The presence of the two opposing objectives makes the sparse-data uncertainty representation problem an interesting and difficult one. The performance of

Romero, Vicente, Mullins, Joshua, Swiler, Laura, Urbina, Angel

Items per page:

1 – 50 of 423