Pub Date : 2020-01-01DOI: 10.17764/1557-2196-63.1.53
K. Kersch, A. Wagner, T. Kuttner, E. Woschke
This work aims to improve profile derivation methods for uniaxial and multiaxial vibration testing. Thereby, the focus is put on the inclusion and processing of phase information between the excitation axes. An inherent necessity is the availability of field data. Two existing methods are independently extended by additional phase information and an appropriate processing. The first method is the Fatigue Damage Spectrum for a uniaxial profile derivation. The second method is the enveloping technique for a multiaxial profile derivation. Both methods are theoretically discussed and then evaluated with a fatigue damage calculation of an exemplary structure.
{"title":"Improved Techniques for Uniaxial and Multiaxial Vibration Test Profile Definition","authors":"K. Kersch, A. Wagner, T. Kuttner, E. Woschke","doi":"10.17764/1557-2196-63.1.53","DOIUrl":"https://doi.org/10.17764/1557-2196-63.1.53","url":null,"abstract":"This work aims to improve profile derivation methods for uniaxial and multiaxial vibration testing. Thereby, the focus is put on the inclusion and processing of phase information between the excitation axes. An inherent necessity is the availability of field data. Two existing methods are independently extended by additional phase information and an appropriate processing. The first method is the Fatigue Damage Spectrum for a uniaxial profile derivation. The second method is the enveloping technique for a multiaxial profile derivation. Both methods are theoretically discussed and then evaluated with a fatigue damage calculation of an exemplary structure.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":"63 1","pages":"53-62"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67782207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.17764/1557-2196-63.1.63
J. Welch, Bailey Z. Zhao, Derek McVay
Environmental testing of spacecraft flight hardware is performed to detect design and workmanship defects and verify mission requirements prior to launch. At the space vehicle level of assembly, the thermal vacuum test simulates an environment particularly well-suited for verifying mission performance requirements. In this paper, the test objectives of the space vehicle thermal vacuum test are reviewed and an assessment is made of the effectiveness and value of the test. Recent thermal vacuum test data is used to determine how the uniqueness of the thermal vacuum test environment achieves test purposes and how the test ensures mission assurance for space vehicles.
{"title":"Effectiveness and Value of Space Vehicle Thermal Vacuum Testing","authors":"J. Welch, Bailey Z. Zhao, Derek McVay","doi":"10.17764/1557-2196-63.1.63","DOIUrl":"https://doi.org/10.17764/1557-2196-63.1.63","url":null,"abstract":"Environmental testing of spacecraft flight hardware is performed to detect design and workmanship defects and verify mission requirements prior to launch. At the space vehicle level of assembly, the thermal vacuum test simulates an environment particularly well-suited for verifying mission performance requirements. In this paper, the test objectives of the space vehicle thermal vacuum test are reviewed and an assessment is made of the effectiveness and value of the test. Recent thermal vacuum test data is used to determine how the uniqueness of the thermal vacuum test environment achieves test purposes and how the test ensures mission assurance for space vehicles.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":"63 1","pages":"63-74"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67783462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-11-04DOI: 10.17764/1557-2196-62.1.26
Thomas Reilly, Kevin McIntosh, Chris Sensor, Raman Sridharan
Structural testing and model verification are necessities in the development of high-value spacecrafts and components. Testing of such items using electrodynamic shaker systems is meticulously planned to avoid any accidental damage. Similarly, the controller and amplifiers used to drive the shakers must be capable of mitigating risk by safely responding to unplanned vibration excursions during a test, as well as to issues with the test system itself, or with facility resources such as electrical power. For example, what happens if the amplifier power source fails, or the network connecting the controller to the command computer goes down? External factors such as these are unpredictable, but careful consideration during vibration test system design makes it is possible for the system to handle such events reliably and minimize risk of damage. Recent advancements in technology have resulted in the design of a complete test system that stresses risk mitigation. The status of building power, safety interlocks, and other critical subsystems are continuously monitored by the controller. A failure on any of the critical subsystems will immediately trigger the controller to ramp down the sine sweep over a prescribed duration. The rate at which the controller reacts to an abort signal is critical. For example, if amplifier power loss is experienced during a sine sweep, the controller must be able to ramp down the drive and stop the test smoothly. Similarly, the amplifier needs stored backup power for the ramp down. These features protect the test article from any transients by preventing the shaker from abruptly stopping. This paper will investigate such safety concerns in structural testing of high value test articles, and the test system considerations associated with these concerns.
{"title":"Structural Testing of High Value Test Articles: Integrated Risk Mitigation in Vibration Test Systems","authors":"Thomas Reilly, Kevin McIntosh, Chris Sensor, Raman Sridharan","doi":"10.17764/1557-2196-62.1.26","DOIUrl":"https://doi.org/10.17764/1557-2196-62.1.26","url":null,"abstract":"\u0000 Structural testing and model verification are necessities in the development of high-value spacecrafts and components. Testing of such items using electrodynamic shaker systems is meticulously planned to avoid any accidental damage. Similarly, the controller and amplifiers used to drive the shakers must be capable of mitigating risk by safely responding to unplanned vibration excursions during a test, as well as to issues with the test system itself, or with facility resources such as electrical power. For example, what happens if the amplifier power source fails, or the network connecting the controller to the command computer goes down? External factors such as these are unpredictable, but careful consideration during vibration test system design makes it is possible for the system to handle such events reliably and minimize risk of damage.\u0000 Recent advancements in technology have resulted in the design of a complete test system that stresses risk mitigation. The status of building power, safety interlocks, and other critical subsystems are continuously monitored by the controller. A failure on any of the critical subsystems will immediately trigger the controller to ramp down the sine sweep over a prescribed duration. The rate at which the controller reacts to an abort signal is critical. For example, if amplifier power loss is experienced during a sine sweep, the controller must be able to ramp down the drive and stop the test smoothly. Similarly, the amplifier needs stored backup power for the ramp down. These features protect the test article from any transients by preventing the shaker from abruptly stopping. This paper will investigate such safety concerns in structural testing of high value test articles, and the test system considerations associated with these concerns.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47294566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-11-04DOI: 10.17764/1557-2196-62.1.44
E. E. Ungar
Structures such as those of engine test cells or wind tunnels may be exposed to intense sound for extended periods and should be designed to ensure they are not prone to premature fatigue failure. This paper presents an approach to determining a lower bound to the fatigue life of structural components exposed to complex sound fields, enabling relatively simple evaluation of candidate structural designs. The presented approach is based on established characterizations of the fatigue behaviors of typical steels and relies on classical analytical results that relate the greatest stresses induced in simple structural elements to oscillatory pressure distributions acting on these elements. Practical application of this approach is discussed, as well as the limitations of the approach.
{"title":"Estimation of Minimum Sonic Fatigue Life of Steel Beam and Plate Structures","authors":"E. E. Ungar","doi":"10.17764/1557-2196-62.1.44","DOIUrl":"https://doi.org/10.17764/1557-2196-62.1.44","url":null,"abstract":"\u0000 Structures such as those of engine test cells or wind tunnels may be exposed to intense sound for extended periods and should be designed to ensure they are not prone to premature fatigue failure. This paper presents an approach to determining a lower bound to the fatigue life of structural components exposed to complex sound fields, enabling relatively simple evaluation of candidate structural designs. The presented approach is based on established characterizations of the fatigue behaviors of typical steels and relies on classical analytical results that relate the greatest stresses induced in simple structural elements to oscillatory pressure distributions acting on these elements. Practical application of this approach is discussed, as well as the limitations of the approach.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44029113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-11-04DOI: 10.17764/1557-2196-62.1.1
Gugu N. Rutherford, Elaine E. Seasly, Joseph J. O’Connell, M. Thornblom, Bo Xiao, M. Bahoura
Mitigating molecular contamination during the assembly, integration, and testing of space systems requires quantitative and qualitative methods to detect the presence of molecular films on sensitive surfaces. Atomic layer deposition (ALD) is a self-limiting deposit of a variety of films layer by layer in the vapor phase on multiple types of substrates. The controlled layer-by-layer deposition enables the user to change orientation, morphology, and grain size in films, which directly impacts optical and electronic responses. In this study, the authors demonstrate the ability to use ALD-grown metal oxide thin films coupled with a Raman spectrometer to provide early detection of molecular films on witness surfaces during the assembly, integration, and testing of space flight hardware.
{"title":"ALD-Grown Metal Oxide Films for the Detection of Molecular Contaminants on Spacecraft","authors":"Gugu N. Rutherford, Elaine E. Seasly, Joseph J. O’Connell, M. Thornblom, Bo Xiao, M. Bahoura","doi":"10.17764/1557-2196-62.1.1","DOIUrl":"https://doi.org/10.17764/1557-2196-62.1.1","url":null,"abstract":"\u0000 Mitigating molecular contamination during the assembly, integration, and testing of space systems requires quantitative and qualitative methods to detect the presence of molecular films on sensitive surfaces. Atomic layer deposition (ALD) is a self-limiting deposit of a variety of films layer by layer in the vapor phase on multiple types of substrates. The controlled layer-by-layer deposition enables the user to change orientation, morphology, and grain size in films, which directly impacts optical and electronic responses. In this study, the authors demonstrate the ability to use ALD-grown metal oxide thin films coupled with a Raman spectrometer to provide early detection of molecular films on witness surfaces during the assembly, integration, and testing of space flight hardware.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43083724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-11-01DOI: 10.17764/1557-2196-62.1.50
Anne Marie Dixon Heathman, D. Ensor
The Journal of the IEST presents the second in a series of outreach articles by ISO/TC 209 leaders to foster promotion and education of the expanding body of ISO/TC 209 Standards
{"title":"Monitoring of Nanoscale Particles in Cleanrooms: ISO 14644-12","authors":"Anne Marie Dixon Heathman, D. Ensor","doi":"10.17764/1557-2196-62.1.50","DOIUrl":"https://doi.org/10.17764/1557-2196-62.1.50","url":null,"abstract":"The Journal of the IEST presents the second in a series of outreach articles by ISO/TC 209 leaders to foster promotion and education of the expanding body of ISO/TC 209 Standards","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44311774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-11-01DOI: 10.17764/1557-2196-62.1.11
W. Sun
Cleanrooms are utilized in electronics, semiconductor, aerospace, pharmaceutical, automotive, optical, medical device, and food processing facilities where air cleanliness is required to prevent defects in high-tech or high-value products. Compared to general commercial space, cleanrooms typically use 5 to 50 times the energy for the same area. One key reason is the high volume of conditioned and filtered air required to make the room air cleaner, which is measured in room-average particle concentration. The technology in this study uses real-time continuous particle sensors as feedback signals to automatically adjust fan speed. The system can modulate fan speed and provide the correct amount of airflow into the cleanroom to prevent over-supply and save energy. In typical manufacturing cleanrooms, the unoccupied state (evenings and weekends) is approximately two times longer than the occupied state (operational work hours), and particle generation (from personnel, equipment, and process) is much lower during the unoccupied state. Limited components and parts are required to apply the technology in this study into the design of a new cleanroom or to integrate the technology into existing cleanroom fan systems.
{"title":"Cleanroom Fan Energy Reduction—Airflow Control Retrofit Based on Continuous, Real-time Particle Sensing","authors":"W. Sun","doi":"10.17764/1557-2196-62.1.11","DOIUrl":"https://doi.org/10.17764/1557-2196-62.1.11","url":null,"abstract":"\u0000 Cleanrooms are utilized in electronics, semiconductor, aerospace, pharmaceutical, automotive, optical, medical device, and food processing facilities where air cleanliness is required to prevent defects in high-tech or high-value products. Compared to general commercial space, cleanrooms typically use 5 to 50 times the energy for the same area. One key reason is the high volume of conditioned and filtered air required to make the room air cleaner, which is measured in room-average particle concentration.\u0000 The technology in this study uses real-time continuous particle sensors as feedback signals to automatically adjust fan speed. The system can modulate fan speed and provide the correct amount of airflow into the cleanroom to prevent over-supply and save energy. In typical manufacturing cleanrooms, the unoccupied state (evenings and weekends) is approximately two times longer than the occupied state (operational work hours), and particle generation (from personnel, equipment, and process) is much lower during the unoccupied state. Limited components and parts are required to apply the technology in this study into the design of a new cleanroom or to integrate the technology into existing cleanroom fan systems.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48984853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.17764/1098-4321.61.1.7
Zhihua Liu, C. Cai, Xia Yan, Ming Yang
The cross spectral density (CSD) for a multiple-input/multiple-output (MIMO) random vibration is typically defined by the complex coherence consisting of the modulus and the phase. The purpose of this paper is to present a constraint for the complex coherence to allow the CSD to be defined more easily. The study of the complex coherence constraint is based on Cholesky decomposition of the spectral density matrix (SDM). The complex coherence must be bounded in the interior or on the boundary of a constraint circle to ensure a physically realizable random vibration. This paper proposes a new approach to define the complex coherences of the SDM by using recursive formulas based on the constraint circle.
{"title":"Complex Coherence Constraint for the Definition of the Spectral Density Matrix","authors":"Zhihua Liu, C. Cai, Xia Yan, Ming Yang","doi":"10.17764/1098-4321.61.1.7","DOIUrl":"https://doi.org/10.17764/1098-4321.61.1.7","url":null,"abstract":"\u0000 The cross spectral density (CSD) for a multiple-input/multiple-output (MIMO) random vibration is typically defined by the complex coherence consisting of the modulus and the phase. The purpose of this paper is to present a constraint for the complex coherence to allow the CSD to be defined more easily. The study of the complex coherence constraint is based on Cholesky decomposition of the spectral density matrix (SDM). The complex coherence must be bounded in the interior or on the boundary of a constraint circle to ensure a physically realizable random vibration. This paper proposes a new approach to define the complex coherences of the SDM by using recursive formulas based on the constraint circle.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46391338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.17764/1098-4321.61.1.55
B. Düthorn
The Journal of the IEST presents the first in a series of outreach articles by ISO/TC 209 Working Group Convenors to foster promotion and education of the expanding body of ISO/TC 209 Standards
{"title":"Assessment of Cleanroom Suitability of Equipment and Materials by Chemical Concentration—ISO Standard Now Available for Designers, Suppliers, and Users","authors":"B. Düthorn","doi":"10.17764/1098-4321.61.1.55","DOIUrl":"https://doi.org/10.17764/1098-4321.61.1.55","url":null,"abstract":"The Journal of the IEST presents the first in a series of outreach articles by ISO/TC 209 Working Group Convenors to foster promotion and education of the expanding body of ISO/TC 209 Standards","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42258872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.17764/1098-4321.61.1.51
R. Diener, Morgan Polen
Selecting a non-cleanroom-approved vacuum cleaner may satisfy your budget, but the shortsighted choice brings substantial risk
选择非洁净室认可的真空吸尘器可能会满足您的预算，但目光短浅的选择会带来巨大的风险
{"title":"Is There a Ticking Dust Bomb in Your Cleanroom?","authors":"R. Diener, Morgan Polen","doi":"10.17764/1098-4321.61.1.51","DOIUrl":"https://doi.org/10.17764/1098-4321.61.1.51","url":null,"abstract":"Selecting a non-cleanroom-approved vacuum cleaner may satisfy your budget, but the shortsighted choice brings substantial risk","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42068466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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