检索结果-内蒙古大学图书馆

Evolution of Anand parameters with elevated temperature aging for sac leadfree alloys

Evolution of Anand parameters with elevated temperature agin...

ASME 2020 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems, InterPACK 2020

作者： Lall, Pradeep Yadav, Vikas Suhling, Jeff Locker, David NSF-CAVE3 Electronics Research Center Department of Mechanical Engineering Auburn University AuburnAL36849 United States Us Army Combat Capabilities Development Command Armament Center United States

ISBN: (纸本)9780791884041

Electronic equipment in automotive, agricultural and avionics applications may be subjected to temperatures in the range of-55 to 200°C during storage, operation and handling in addition to high strain-rates. Strain rates in owing to vibration and shock may range from 1-100 per sec. Temperature in electronic assemblies depends typically on location, energy dissipation and thermal architecture. Some investigators have indicated that the required operating temperature is between-40 to 200°C for automotive electronics located underhood, on engine, on transmission. Prior data indicates the evolution of mechanical properties under extended exposures to high temperatures. However, the constitutive models are often only available for pristine materials only. In this paper, effect of low operating temperatures (-65°C to 0?C) on Anand-model parameters at high strain rates (10-75 per sec) for aged SAC (SAC105 and SAC-Q) solder alloys has been studied. Stress-Strain curves have been obtained at low operating temperatures using tensile tests. The SAC leadfree solder samples were subjected to isothermal-aged up to 4-months at 50°C before testing. Anand Viscoplastic model has been used to describe the material constitutive behavior. Evolution of Anand Model parameters for SAC solder has been investigated. The computed parameters of the experimental data were used to simulate the tensile test and verified the accuracy of the model. A good correlation was found between experimental data and Anand predicted data. Copyright © 2020 ASME.

关键词： Stress-strain curves

来源：评论

学校读者我要写书评

暂无评论

High strain rate low temperature properties for sac-r after exposure to isothermal aging

High strain rate low temperature properties for sac-r after ...

引用

ASME 2020 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems, InterPACK 2020

作者： Lall, Pradeep Saha, Mrinmoy Suhling, Jeff Blecker, Ken Electronic Research Center Department of Mechanical Engineering Auburn University NSF-CAVE3 AuburnAL36849 United States Us Army Combat Capabilities Development Command Armament Center United States

ISBN: (纸本)9780791884041

Electronic parts in military, automotive, avionics and space applications may be subjected to sustained operation at high temperature in addition to high strain-rate loads. Parts may be stored in non-climate-controlled enclosures prior to deployment. Earlier studies on undoped SAC alloys have shown that the material properties evolve after prolonged period of storage at even modest temperatures. In order to mitigate the aging effects, a number of alloy formulation have been proposed. Data of the mechanical properties of lead-free solder alloys which is used for interconnection in the electronic packaging at high strain rates and at high storage temperature is very essential for design optimization of electronic package sustainability at extreme temperature environment because the SAC solders have shown to have degradation in mechanical properties at prolonged exposure to storage temperature. Industries have come up with a solution to reduce the degradation using dopants in SAC solder. In this study, a doped SAC solder called SAC-R has been subjected to high strain rate testing after extended storage at temperature of 50°C for 1 month, 2 months and 3 months. Samples with no aging and aged samples for up to 3-months have been subjected to uniaxial tensile tests to measure the mechanical properties of SAC-R for High and Low operating temperature ranging from-65°C to +200°C. The material data has been used to compute the constants for the Anand Visco-Plasticity model. The ability of the model to represent the material constitutive behavior has been quantified by comparing the model predictions of the uniaxial tensile test with the experimental data. Copyright © 2020 ASME.

关键词： Tensile testing

来源：评论

学校读者我要写书评

暂无评论

Multi-Task Multi-Fidelity Learning of Properties for Energetic Materials

arXiv

引用

arXiv 2024年

作者： Appleton, Robert J. Klinger, Daniel Lee, Brian H. Taylor, Michael Kim, Sohee Blankenship, Samuel Barnes, Brian C. Son, Steven F. Strachan, Alejandro School of Materials Engineering Birck Nanotechnology Center Purdue University West LafayetteIN47907 United States School of Mechanical Engineering Purdue University West LafayetteIN47907 United States Department of Mechanical Engineering New Mexico Institute of Mining and Technology SocorroNM87801 United States Department of Computer Sciences Purdue University West LafayetteIN47907 United States U.S. Army Combat Capabilities Development Command Army Research Laboratory Proving Ground AberdeenMD21005 United States

Data science and artificial intelligence are playing an increasingly important role in the physical sciences. Unfortunately, in the field of energetic materials data scarcity limits the accuracy and even applicability of ML tools. To address data limitations, we compiled multi-modal data: both experimental and computational results for several properties. We find that multi-task neural networks can learn from multi-modal data and outperform single-task models trained for specific properties. As expected, the improvement is more significant for data-scarce properties. These models are trained using descriptors built from simple molecular information and can be readily applied for large-scale materials screening to explore multiple properties simultaneously. This approach is widely applicable to fields outside energetic materials. © 2024, CC BY.

关键词： Data Science

来源：评论

学校读者我要写书评

暂无评论

Three rotor hub flow prediction workshops (2016-2020) - What did we learn & What's next ? 77

Three rotor hub flow prediction workshops (2016-2020) - What...

引用

77th Annual Vertical Flight Society Forum and Technology Display: The Future of Vertical Flight, FORUM 2021

作者： Schmitz, Sven Tierney, Charles Reich, David Jaffa, Nicholas Centolanza, Louis R. Thomas, Mathew L. Dept. of Aerospace Engineering Pennsylvania State University University ParkPA16802 United States Applied Research Laboratory Pennsylvania State University University ParkPA16802 United States U.S. Army Combat Capabilities Development Command Aviation Missile Center Fort EustisVA23604 United States

ISBN: (纸本)9781713830016

The 'Rotor Hub Flow Prediction Workshops' have been productive collaborations between experimental and computational efforts in the important area of high-Reynolds number model testing of rotor hubs and associated complex interactional aerodynamics in the long-age wake as relevant to current and future rotorcraft. As such the hub flow workshops have joined the ranks of past successful collaborations such as the UH-60 Airloads and HART-II workshops. This paper begins by describing the basic physics of rotor hub flows and gives a brief summary of recent water-tunnel test campaigns. Following, the evolution of the hub flow workshops is summarized, with emphasis on the productive interactions between experimentalists and computational participants. A compilation of computational blind comparison results against measured data for all three workshops thus far is presented. Challenges associated with uncertainties in both experiments and computations and their effect on quantitative comparisons are discussed. In particular, emphasis is given to the 'Lessons Learned' on both sides and an outlook into remaining challenges and next research steps in the area of rotor hub flows is provided. © 2021 by the Vertical Flight Society.

关键词： Reynolds number

来源：评论

学校读者我要写书评

暂无评论

Comparisons of fully coupled aeroelastic fuselage simulations to UH-60A airloads program data 76

Comparisons of fully coupled aeroelastic fuselage simulation...

引用

Vertical Flight Society's 76th Annual Forum and Technology Display

作者： Reveles, Nicolas D. Pierce, Tyler J. Blades, Eric L. Yeo, Hyeonsoo ATA Engineering Inc. HuntsvilleAL United States ATA Engineering Inc San DiegoCA United States US Army Combat Capabilities Development Command Aviation and Missile Center Ames Research Center Moffett FieldCA United States

An aeroelastic coupling framework is applied to the UH-60A platform to examine aerodynamic-induced vibrations at four advance ratios spanning the flight envelope. Both one-way and two-way aeroelastic coupling results are examined at each condition. The two-way coupled results are observed to generally predict closer values to measured flight test data on the lifting surfaces of the empennage, and a less pronounced effect is seen in stiffer, nonlifting structure. The effect of aeroelastic coupling subiterations is examined, and they are found to further refine the two-way coupled results, generally improving prediction quality. © 2020 by the Vertical Flight Society.

关键词： Flight envelopes

来源：评论

学校读者我要写书评

暂无评论

High strain rate mechanical properties of sac-q between-65 oc and +200 oc after exposure to isothermal aging

High strain rate mechanical properties of sac-q between-65 o...

引用

ASME 2020 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems, InterPACK 2020

作者： Lall, Pradeep Mehta, Vishal Suhling, Jeff Blecker, Ken NSF-CAVE3 Electronics Research Center Department of Mechanical Engineering Auburn University AuburnAL36849 United States Us Army Combat Capabilities Development Command Armament Center Picatinny ArsenalNJ United States

ISBN: (纸本)9780791884041

In many industries, such as automotive, oil and gas, aerospace, medical technologies, electronic parts can often be exposed to high strain loads during shocks, vibrations and dropimpact conditions. Such electronic parts can often be subjected to extreme low and high temperatures ranging from-65oC to 200oC. Also, these electronic devices can be subjected to strain rates of 1 to 100 per second in the critical environment. Recently, many doped SAC solder alloys are being introduced in the electronic component including SAC-Q, SAC-R, Innolot. SAC-Q is made with addition of Bi in Sn-Ag-Cu composition. Mechanical characteristic results and data for lead-free solder alloys are extremely important for optimizing electronic package reliability, at high temperature storage and elevated strain rates. Furthermore, the mechanical properties of solder alloys can be changed significantly due to a thermal aging, which is causing modification of microstructure. Data for the SAC-Q solder alloy with a high temp aging and testing at extreme low to high operating temperatures are not available. SAC-Q material was tested and analyzed for this study at range of operating temperatures of-65oC to 200oC and at a strain rate up to 75 per second. After the specimens were manufactured and reflowed, specimens were stored at 100oC for the isothermal aging for up to 90 days, before tensile tests were carried out at different operating temperatures. For the wide range of strain rates and test temperatures, stress-strain curves are established. In addition, the measured experimental results and data were fitted to the Anand viscoplasticity model and the Anand constants were calculated by estimating the stress-strain behavior measured in the wide range of operating temperatures and strain rates Copyright © 2020 ASME.

关键词： Strain rate

来源：评论

学校读者我要写书评

暂无评论

Effect of 100C Aging for Periods of up to 120-days on High Strain Rate Properties of SAC305 Alloys

Effect of 100C Aging for Periods of up to 120-days on High S...

引用

19th InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITherm 2020

作者： Lall, Pradeep Mehta, Vishal Suhling, Jeff Blecker, Ken Auburn University NSF-CAVE3 Electronics Research Center Department of Mechanical Engineering AuburnAL36849 United States Us Army Combat Capabilities Development Command - Armament Center NJ United States

ISBN: (纸本)9781728197647

In the applications like automotive, military applications and in oil/gas exploration, the electronic parts can be exposed to vibrations, impact, shocks and high temperatures, as well. In these harsh environments, electronic components may experience strain rates of 1 to 100 per seconds and environmental temperature up to 200C. The published literature available for lead-free solder alloys at high aging temperature and at high strain rates is scarce. Previous published and available studies for SAC305 lead-free solder alloys are restricted to either low strain rates or lower storage temperatures in the region of 50C. High temperature, high strain-rate properties of SAC305 are not available for prolonged periods of isothermal storage. In this paper, lead- free solder alloy SAC305 has been tested and examined at numerous surrounding temperatures from 25C up to 200C, with high strain rates and elevated thermal aging temperature. The specimens were stored at 100C for the duration of 3 months and 4 months for thermal aging. These thermally aged SAC305 lead-free solder specimen, which have been made using reflow profiles indicative of solder-joint manufacturing assemblies, have been tested at strain rates of 10, 35, 50, and 75 per sec at multiple operating temperatures ranging from 25C to 200C. Stress-strain curves are prepared for the wide range of operating temperatures and strain rates for thermally aged specimens for 3 months and 4 months durations. The experimental results have been fit to the Anand Viscoplastic model for SAC305 and the Anand constants are established by estimating the measured stress-strain behavior for the wide range of temperatures and strain rates, after high temperature storage of specimens. © 2020 IEEE.

关键词： Strain rate

来源：评论

学校读者我要写书评

暂无评论

Hybrid Integration of Semiconductor Lasers: Impact of Matching Laser AR Coatings to Photonic Wire Bonds

Hybrid Integration of Semiconductor Lasers: Impact of Matchi...

引用

Conference on Lasers and Electro-Optics (CLEO)

作者： Omid Esmaeeli Matthew Mitchell Justin Bickford Frederic Grillot Lukas Chrostowski Sudip Shekhar Department of Electrical and Computer Engineering The University of British Columbia Vancouver BC Canada Stewart Blusson Quantum Matter Institute The University of British Columbia Vancouver BC Canada Dream Photonics Inc. Vancouver BC Canada Army Research Laboratory US Army Combat Capabilities Development Command Adelphi MD USA LTCI Telecom Paris Institute Polytechnique de Paris Palaiseau France Center for High Technology Materials University of New Mexico Albuaueraue NM USA Dream Photonics Inc. Woodinville WA USA

We investigate the influence of anti-reflection (AR) coating index on the per-formance of distributed feedback (DFB) lasers when integrated to a fiber using photonic wire bonds (PWBs). We compare the performance of ai... 详细信息

ISBN: (纸本)9798350369311

关键词： Semiconductor lasers Refractive index Distributed feedback devices Laser feedback Reflection Wire Coatings Polymers Fiber lasers Photonics

来源：评论

学校读者我要写书评

暂无评论

High fidelity code-to-code comparison of rotor performance in hover and forward flight 76

High fidelity code-to-code comparison of rotor performance i...

引用

Vertical Flight Society's 76th Annual Forum and Technology Display

作者： Lim, Joon W. Jain, Rohit K. Potsdam, Mark A. Fitzgibbon, T.A. Barakos, G.N. Widjaja, Ronny U.S. Army Combat Capabilities Development Command Aviation Missile Center Ames Research Center Moffett FieldCA United States CFD Laboratory School of Engineering University of Glasgow Glasgow United Kingdom Australia Defence Science and Technology Group Fishermans BendVIC Australia

High fidelity code-to-code comparisons have been made between the University of Glasgow HMB3 code and the HPCMP CREATETM-AV Helios code under The Technical Cooperation Program collaboration project, Next Generation Rotor Blade Design. The comparisons are made for two model-scale rotors - Langley baseline (LBL) rotor and Pressure Sensitive Paint (PSP) rotor. Hover and forward flight performance results are compared against test data. For the LBL rotor, hover performance is in a good agreement between the test data and HMB3 results over a full range of CT. However, the comparison between the HMB3 and Helios results at a CT of 0.0084 shows the difference in Figure of Merit (FM) by approximately 2 counts (2.2-3.2%). In forward flight, the HMB3 and Helios performance results overpredict the test data at the low advance ratios but improve the predictions at the high advance ratios. At an advance ratio of 0.31, the code-to-code comparison indicated that the Helios torque was lower by 2.8-3.1% compared with the HMB3 torque. For the PSP rotor, the FM trend computed using the Helios-OVERFLOW code agrees well with the fully-turbulent test data. The Helios-OVERFLOW result shows that the fuselage interaction effect is favorable for rotor performance. For a code-to-code comparison, the HMB3 FM result shows about 3.0 counts (4.0%) lower than the Helios-OVERFLOW result at a CT/σ of 0.091. In forward flight, the HMB3 rotor result agrees well with the test data whereas the Helios rotor result underpredicts by 2-3 counts in CP/σ (3.5-5.7%) at the high advance ratios although it was significantly improved at the low advance ratio. Overall, the code-to-code comparisons are successfully conducted for both the LBL and PSP rotors. © 2020 by the Vertical Flight Society.

关键词： Frequency modulation

来源：评论

学校读者我要写书评

暂无评论

Assessing bias of expert solicited parameters for simulation based costing

Assessing bias of expert solicited parameters for simulation...

引用

2016 Industrial and Systems engineering research Conference, ISERC 2016

作者： Farr, John V. Faber, Isaac J. Richards, James E. Department of Systems Engineering United States Military Academy West PointNY10996 United States US Army Cyber Command Fort BelvoirVA22060 United States Engineer Research and Development Center US Army Corps of Engineers HanoverNH03753 United States

Early in a project life cycle (concept development and early design) subject matter expert (SME) elicitation and historical data are the most common means for producing cost estimates. There is a large and growing body of knowledge on using historical data. However, while there is a robust set of literature surrounding how to elicit specific information from SMEs there is little work done on the inherent bias's that individuals may be contributing and how it may impact a given estimate. Cost estimates are forecasts derived from requirements, architectures, economic environment, level of competence of the developers, etc. Inherent uncertainties produce estimates that can be inaccurate or have little credibility with decision makers. One approach often championed is cost risk analysis, which evaluates and quantifies the variability in the cost estimate. Cost risk analysis involves assigning a probability distribution over a range of estimates and is accomplished using simulation. Cost risk analysis using simulation is often referred to as simulation based costing (SBC). This research is focused on how to develop input data for SBC. Specifically, we present how bias affects the results of research input behavior (i.e., probability distributions) based upon SME elicitation focused on early stage life cycle cost estimating using SBC. © 2016 Proceedings of the 2016 Industrial and Systems engineering research Conference, ISERC 2016. All rights reserved.

关键词： Uncertainty analysis

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：