Dissertations / Theses: 'Shock and Vibration'

1

Vijayan, Kiran. "Vibration and shock amplification of drilling tools." Thesis, University of Cambridge, 2012. https://www.repository.cam.ac.uk/handle/1810/283896.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Walter, Patrick L. "FILTERING CONSIDERATIONS WHEN TELEMETERING SHOCK AND VIBRATION DATA." International Foundation for Telemetering, 2001. http://hdl.handle.net/10150/607681.

Full text

Abstract:

International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada
The accurate measurement of shock and vibration data via flight telemetry is necessary to validate structural models, indicate off-nominal system performance, and/or generate environmental qualification criteria for airborne systems. Digital telemetry systems require anti-aliasing filters designed into them. If not properly selected and located, these filters can distort recorded time histories and modify their spectral content. This paper provides filter design guidance to optimize the quality of recorded flight structural dynamics data. It is based on the anticipated end use of the data. Examples of filtered shock data are included.

APA, Harvard, Vancouver, ISO, and other styles

3

SVOBODA, LADISLAV, LIBUŠE SMOLÍKOVÁ, VLADIMIL MUFF, DARINA HARTLOVÁ, and LADISLAV LOUDA. "IMPULSIVE VIBRATION AND EXPOSURE LIMIT." Nagoya University School of Medicine, 1994. http://hdl.handle.net/2237/16064.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Zheng, Wei, and 鄭偉. "Shock vibration resistance and direct tensile strength of concrete." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31242753.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Karshenas, Amir Masood. "Random vibration and shock control of an electrodynamic shaker." Thesis, Heriot-Watt University, 1997. http://hdl.handle.net/10399/1170.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Zheng, Wei. "Shock vibration resistance and direct tensile strength of concrete." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23273124.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Carwell, James W. "PYROTECHNIC SHOCK AND RANDOM VIBRATION EFFECTS ON CRYSTAL OSCILLATORS." International Foundation for Telemetering, 2001. http://hdl.handle.net/10150/607695.

Full text

Abstract:

International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada
Today’s telemetry specifications are requiring electronic systems to not only survive, but operate through severe dynamic environments. Pyrotechnic shock and Random Vibration are among these environments and have proven to be a challenge for systems that rely on highly stable, low phase noise signal sources. This paper will mathematically analyze how Pyrotechnic shock and Random Vibration events deteriorate the phase noise of crystal oscillators (XO).

APA, Harvard, Vancouver, ISO, and other styles

8

Walter, Patrick L. "OPTIMIZING FLIGHT SHOCK AND VIBRATION MEASUREMENT BY RF LINKS." International Foundation for Telemetering, 1998. http://hdl.handle.net/10150/609222.

Full text

Abstract:

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California
Acquiring shock and vibration data from flight vehicles through rf telemetry links has numerous associated challenges. Yet, these measurements are important to establish environmental specifications to provide a basis for system or component design and testing. The principal limitation in acquiring these measurements is the frequency bandwidth available for data transmission. This limited bandwidth is often responsible for invalid data being accepted as valid. This work provides a brief review of time and frequency division multiplexing to identify the potential error contributors to shock and vibration measurements. Its focus is on the design of acceleration measurement systems to eliminate these errors and optimize individual measurement channel performance.

APA, Harvard, Vancouver, ISO, and other styles

9

Eshleman, Eric D. "Vibration and shock isolation through use of passive, nonlinear mounts." Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/20019.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Son, Lovely. "STUDIES ON SHOCK VIBRATION CONTROL BY MOMENTUM EXCHANGE IMPACT DAMPER." 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/49140.

Full text

Abstract:

学位授与大学：京都大学 ; 取得学位: 博士(工学) ; 学位授与年月日: 2007-09-25 ; 学位の種類: 新制・課程博士 ; 学位記番号: 工博第2859号 ; 請求記号: 新制/工/1420 ; 整理番号: 25544
Kyoto University (京都大学)
0048
新制・課程博士
博士(工学)
甲第13388号
工博第2859号
新制||工||1420(附属図書館)
25544
UT51-2007-Q789
京都大学大学院工学研究科精密工学専攻
(主査)教授松久寛, 教授吉村允孝, 教授松原厚
学位規則第4条第1項該当

APA, Harvard, Vancouver, ISO, and other styles

11

Powell, John Anthony. "Electrorheological fluids and other nonlinearities in shock and vibration isolation." Thesis, University of Aberdeen, 1993. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU046769.

Full text

Abstract:

This thesis investigated the use of electrorheological fluids in shock and vibration isolation. An electrorheological fluid (ER) is a suspension of semiconducting particles in a nonconducting carrier fluid. The novel feature of this fluid is its ability to change its rheological properties upon the application of an external electric field. To investigate the properties of activated ER fluids an experimental oscillatory electroviscometer was commissioned and the fluid tested. Conclusions drawn from the results were that the activated ER fluid changed from a viscous system, to one with a yield stress, elasticity and enhanced viscosity. These rheological changes were catalogued for a variety of electric field strengths, oscillatory frequencies and amplitudes. The fluid was also incorporated into a damper in an experimental single degree of freedom base excited system (SDOF). It was shown that the relative displacement between the base and the isolated mass could be significantly reduced on application of an electric field. The feasibility of a 'switched' semi-active vibration isolation scheme was also demonstrated with the SDOF apparatus. This system aimed to reduce isolated mass acceleration. Numerical analysis was carried out which involved successfully modelling the response of the SDOF system incorporating the ER damper. This model used a 'softening' spring element, a 'nonreversible' Coulomb friction characteristic and viscous damping to represent ER material behaviour. A theoretical comparison was also made between activated ER systems and systems with hardening spring characteristics, for steady state and transient responses. It was shown theoretically that the semi-active scheme described can give major improvements in isolation performance for frequencies much greater than resonance. The numerical integration of the models was carried out using a fourth order Runge-Kutta algorithm with the aid of a novel smoothing function to overcome problems associated with modelling friction phenomena.

APA, Harvard, Vancouver, ISO, and other styles

12

Smedley, Mark, and Gary Simpson. "SHOCK & VIBRATION TESTING OF AN AIRBORNE INSTRUMENTATION DIGITAL RECORDER." International Foundation for Telemetering, 2000. http://hdl.handle.net/10150/606747.

Full text

Abstract:

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California
Shock and vibration testing was performed on the Metrum-Datatape Inc. 32HE recorder to determine its viability as an airborne instrumentation recorder. A secondary goal of the testing was to characterize the recorder operational shock and vibration envelope. Both flight testing and laboratory environmental testing of the recorder was performed to make these determinations. This paper addresses the laboratory portion of the shock and vibration testing and addresses the test methodology and rationale, test set-up, results, challenges, and lessons learned.

APA, Harvard, Vancouver, ISO, and other styles

13

Yuill, Gavin John. "Simulation of the generation and propagation of blast induced shock waves." Thesis, University of Leeds, 2003. http://etheses.whiterose.ac.uk/907/.

Full text

Abstract:

Hybrid modelling of blast vibration uses the signal produced from a single hole test shot to simulate the vibration that would be produced by a full-scale production blast. This simulation can be used to determine optimum hole timings to minimise the vibration generated at a point of interest. This thesis studies the assumptions that are made to facilitate the use of hybrid modelling with emphasis placed on near to mid field applications. A highly accurate seismograph is developed and used to monitor a series of test blasts carried out in limestone and chalk. The repeatability of single hole test shots is investigated. It is shown that in the near field single holes are generally highly repeatable even with relatively major differences in design. It is also shown that an inversion of the radial and transverse vibration traces may occur. The factors which affect the vibration magnitude are also explored, showing that the level of confinement can have a large effect on the magnitude of vibration. Two, three and five hole production blasts are examined to determine the signal generated by each hole in the blast. It is shown that in a two hole blast the second hole can produce an inverted signal in the radial and transverse components. The three and five hole are disassembled by using a computer program to test every possible combination of convolved single holes and select the best. It is concluded that the complex interaction of the vibration generated by each blast hole makes it very difficult to model the vibration generated by a production blast in the near field.

APA, Harvard, Vancouver, ISO, and other styles

14

De, Alwis Pahansen. "METHODS FOR SHOCK ANDVIBRATION EVALUATION APPLIEDON OFFSHORE POWER BOATS." Thesis, KTH, Marina system, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-162066.

Full text

Abstract:

Vibration is a part of human life. People use vibrations in many useful ways but eventually human exposure to vibration has become an impediment to human life. Health problems due to exposure to vibration and shock are common among the crew operating high speed craft (HSC). Whole body vibration and repeated shocks have been identified as one of the major causes for health effects among HSC crew. Whole body vibration can affect health, comfort and performance depending on the magnitude, waveform and time of exposure. Therefore it is prudent the significance of consideration of human exposure to vibration and shock when deciding the operational envelope of an offshore HSC. This report addresses this question in two correlated parts where it identifies the interrelationship between the human exposure to vibration and shock and the operational envelope of HSC. The first part consists of a state of the art review on methods and measures for evaluation of workplaces exposed to vibrations containing multiple shocks and select a suitable method to be used in the second part. The second part is a case study of a Swedish Coast Guard HSC, KBV 476, which describes crew exposure to shock and vibration using the method selected from the state of the art review, and discusses the results in relation to the risks involved with the crew in the perspective of short and long term exposure. Nature of the vibration exposure and the corresponding risk involved is then discussed with respect to the operational envelope of the craft.

APA, Harvard, Vancouver, ISO, and other styles

15

Choudhary, Prakriti Lall Pradeep. "Health monitoring for damage initiation & progression during mechanical shock in electronic assemblies." Auburn, Ala., 2007. http://repo.lib.auburn.edu/2006%20Fall/Theses/CHOUDHARY_PRAKRITI_26.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Petrusa, Douglas C. "Evaluation and analysis of DDG-81 simulated athwartship shock response." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Jun%5FPetrusa.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Jain, Priyank P. "Explicit dynamic analysis of computer motherboards subjected to mechanical shock." Diss., Online access via UMI:, 2005.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

18

Haas, Anna C. "Carbon fiber substitution in shipboard instrument structural mounts for vibration and shock isolation." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/69776.

Full text

Abstract:

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 27).
Insufficient support and isolation of rotating and non-rotating shipboard equipment and instruments may cause damage to the components or the ship itself. Reduction of noise emissions to the ship's hull and protection of equipment from outside disturbances may be attained through isolator mounting systems. The objective of this thesis is to investigate and analyze the effects of substituting carbon fiber reinforced polymer (CFRP) for use in the structural mounts on rotating marine diesel engines and on sensitive, nonrotating Electronic Chart Display and Information Systems (ECDIS). The high specific stiffness of CFRP make it an interesting candidate for mounting material substitution. The shipboard components were modeled with mounts made of steel, rubber and CFRP and their step response, impulse response and transmissibility behavior were analyzed. It was concluded that the choice in appropriate mounting materials depends on the application, but CFRP was found in many cases to display similar vibration isolation behavior to steel while being much less dense.
by Anna C. Haas.
S.B.

APA, Harvard, Vancouver, ISO, and other styles

19

Davies, David Bradley. "Analysis of active compensation for shock, vibration, and wind-up in disk drives." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/13301.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

MAEDA, SETSUO. "TEMPORARY THRESHOLD SHIFTS IN FINGERTIP VIBRATORY SENSATION FROM HAND-TRANSMITTED VIBRATION AND REPETITIVE SHOCK." Nagoya University School of Medicine, 1994. http://hdl.handle.net/2237/16066.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Tanner, Edward Troy. "Combined Shock and Vibration Isolation Through the Self-Powered, Semi-Active Control of a Magnetorheological Damper in Parallel with an Air Spring." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/29541.

Full text

Abstract:

Combining shock and vibration isolation into a single isolation system package is explored through the use of an air spring in parallel with a controlled magnetorheological fluid damper. The benefits of combining shock and vibration isolation into a single package is discussed. Modeling and control issues are investigated and test and simulation results are discussed. It is shown that this hybrid isolation system provides significantly increased performance over current state-of-the-art passive systems. Also explored is the feasibility of scavenging and storing ambient shipboard vibration energy for use in powering the isolation system. To date the literature has not adequately explored the direct design of a combined shock and vibration isolation system. As shock and vibration isolation are typically conflicting goals, the traditional approach has been to design separate shock and vibration isolation systems and operate them in parallel. This approach invariably leads to compromises in terms of the performance of both systems. Additionally, while considerable research has been performed on magnetorheological fluids and devices based on these fluids, there has been little research performed on the use of these fluids in devices that are subjected to high velocities such as the velocity seen by a ship exposed to underwater near-miss explosive events. Also missing from the literature is any research involving the scavenging and storage of ambient shipboard vibration energy. While the focus of this work is on the use of this scavenged energy to power the subject isolation system, many other uses for this energy can be envisioned. Experimental and analytical results from this research clearly show the advantages of this hybrid isolation system. Drop tests show that inputs as great as 167 g's were reduced to 3.42 g's above mount at 1.11 inches of deflection using a Velocity Feedback controller suggested by the author. When contrasted with typical test results with similar inputs, the subject isolation system achieved reductions in above mount accelerations of 300% and reductions in mount deflections of 200% over current state-of-the-art passive shipboard isolation systems. Furthermore, simulations using a validated model of the isolation system suggest that this performance improvement can be achieved in multi-degree-of-freedom isolation systems as well. It was shown that above mount accelerations in the vertical and athwartship directions could be effectively limited to a predefined value, while achieving the absolute minimum mount defections, using an Acceleration Limiting Bang-Bang controller suggested by the author. Further experimentation suggests that the subject isolation system could be entirely self-powered from scavenged ambient shipboard vibration energy. An experiment using an energy scavenging and storage system consisting of a Piezoelectric Stack Generator and a bank of ultracapacitors showed that enough energy could be harvested to power the isolation system though several shock events.
Ph. D.

APA, Harvard, Vancouver, ISO, and other styles

22

Van, der Merwe Andre Francois. "An air suspension cushion to reduce human exposure to vibration." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/473.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Schneider, Nathan A. "Prediction of surface ship response to severe underwater explosions using a virtual underwater shock environment." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Jun%5FSchneider.pdf.

Full text

Abstract:

Thesis (Mechanical Engineer and M.S. in Mechanical Engineering)--Naval Postgraduate School, June 2003.
Thesis advisor(s): Young S. Shin. Includes bibliographical references (p. 161-162). Also available online.

APA, Harvard, Vancouver, ISO, and other styles

24

Olausson, Katrin. "On Evaluation and Modelling of Human Exposure to Vibration and Shock on Planing High-Speed Craft." Licentiate thesis, KTH, Marina system, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-159168.

Full text

Abstract:

High speed in waves, necessary in for instance rescue or military operations, often result in severe loading on both the craft and the crew. To maximize the performance of the high-speed craft (HSC) system that the craft and crew constitute, balance between these loads is essential. There should be no overload or underuse of crew, craft or equipment. For small high-speed craft systems, man is often the weakest link. The human exposure to vibration and shock results in injuries and other adverse health effects, which increase the risks for non-safe operations and performance degradation of the crew and craft system. To achieve a system in balance, the human acceleration exposure must be considered early in ship design. It must also be considered in duty planning and in design and selection of vibration mitigation systems. The thesis presents a simulation-based method for prediction and evaluation of the acceleration exposure of the crew on small HSC. A numerical seat model, validated with experimental full-scale data, is used to determine the crew's acceleration exposure. The input to the model is the boat acceleration expressed in the time domain (simulated or measured), the total mass of the seated human, and seat specific parameters such as mass, spring stiffness and damping coefficients and the seat's longitudinal position in the craft. The model generates seat response time series that are evaluated using available methods for evaluation of whole-body vibration (ISO 2631-1 \& ISO 2631-5) and statistical methods for calculation of extreme values. The presented simulation scheme enables evaluation of human exposure to vibration and shock at an early stage in the design process. It can also be used as a tool in duty planning, requirements specification or for design of appropriate vibration mitigation systems. Further studies is proposed within three areas: investigation of the actual operational profiles of HSC, further development of seat models and investigation of the prevailing injuries and health problems among the crew of HSC.

QC 20150126

APA, Harvard, Vancouver, ISO, and other styles

25

Yadur, Balagangadhar Nakul. "Field Load Data Acquisition with regard to Vibration, Shock and Climate including Self-heating of ECUs." Master's thesis, Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-161558.

Full text

Abstract:

For the reliability design of Engine Control Unit devices in motor vehicles, the knowledge of stresses occurring in the field within the product service life is essential. In addition to the environmental influences such as temperature, moisture and humidity, vibration and shock issues are in focus. To ensure the robustness of the products and they are still easily and inexpensively made, they must be interpreted appropriately in the development process. For this, the load spectra for the mechanical influences of road conditions and operating conditions are to be determined. Work will also include temperature and humidity values examined on typical installation locations. The essential everyday situations (commuters, taxi, farmer, ...) should be considered. Existing measurement technology must be combined to this end a comprehensive logger system with communication to the vehicle.

APA, Harvard, Vancouver, ISO, and other styles

26

Aye, S. A. (Sylvester Aondolumun). "Evaluation of operator whole-body vibration and shock exposure in a South African open cast mine." Diss., University of Pretoria, 2009. http://hdl.handle.net/2263/27920.

Full text

Abstract:

This study quantifies whole-body vibration on a range of mine machinery typically used in a South African open cast mine. The ISO 2631-1 (1997) standard was used in the computation of weighted root mean square (WRMS) and vibration dose values (VDVs) whereas the ISO 2631-5 (2004) standard was used in the computation of daily static compressive stress (Sed) and R factor values. Two methods have been used to evaluate the whole-body vibration on a wide range of equipment used in an open cast mine. There are two main parameters for each of the standards. The ISO 2631-1 (1997) standard utilises the daily exposure A(8) and VDV, whereas the new ISO 2631-5 (2004) standard methodology uses the parameters Sed and R factor. ISO 2631-1 (1997) is poor in taking account of transient shocks. This led to the development of ISO 2631-5 (2004). Signals were therefore generated in the laboratory to further explore the parameters of the two standards. Vibration signals of more-or-less steady periodic processes can be approximated by superposition of sinusoids. To investigate the effect of shocks on the WBV response parameters used in the two standards, a series of investigations were conducted using very simplified simulations to capture the essential nature of various operational conditions, and qualitatively explain the trends in the response parameters. Pure sinusoidal data was first generated without shocks and investigated. Subsequently, sinusoidal signals with higher amplitudes were generated and investigated. Sinusoidal signals with increasing shock amplitude up to and exceeding the crest factor of 9 based on ISO 2631-1 (1997) were generated and analyzed. Finally, simulated data with different shock magnitude for five typical example cases were then generated and analyzed. The pure sinusoidal data was artificially generated using the signal generator at different amplitudes and frequencies, which are similar to field observed frequencies to enable numerical investigation of parameters to be carried out. A subset of the data was selected based on frequencies and amplitudes obtained on the field so as to have a representative data set on which investigations were carried out. The two parameters of the two standard methodologies were computed using simulated sinusoidal signal data. The trends in each of the parameters corresponding to each of the standards were monitored using various scenarios obtained by varying the signal parameters and compared against each other. There was approximate proportional correlation between the two parameters (VDV and Sed) with varying degrees of slope for each scenario. The Sed and VDV parameters are plotted on the x- and y-axes respectively. The graphs with slope greater than 1 corresponded to signals with low or no shock content; whereas the graphs with slope less than 1 corresponded to high shock content. The shock parameters (VDV and Sed) corresponding to the ISO 2631-1 (1997)and ISO 2631-5 (2004) standard methodologies were computed from field data and compared to see if the same trend obtained from the numerically obtained sinusoidal signals could be validated. It was found that the there was a gradual band correlation with slope less than 1 between the VDV and Sed parameters corresponding to signals of high shock content thereby validating the numerical findings. Since little or no extensive epidemiological studies have been carried out on the new methodology; it is recommended that more epidemiological studies be done to determine the exposure action and exposure limit values with respect to shocks in the Sed parameter for the new ISO 2631-5 (2004) standard methodology. It is advisable that caution is taking when using the new ISO 2631-5 (2004) standard methodology in evaluating whole-body vibration measurements until the limits are properly established. It is suggested that the new standard be used along with the established ISO 2631-1 (1997) standard methodology. Copyright
Dissertation (MSc)--University of Pretoria, 2009.
Mechanical and Aeronautical Engineering
Unrestricted

APA, Harvard, Vancouver, ISO, and other styles

27

Julie, Fagerudd. "Stress simulation of the SEAM CubeSat structure during launch." Thesis, KTH, Hållfasthetslära (Inst.), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-168324.

Full text

Abstract:

A spacecraft is subjected to dynamic and static loads during launch. These loads are deterministic and of random nature and cannot be tested under the real conditions due to cost considerations. The spacecraft must therefore sustain certain mechanical loads without permanent deformation with a certain safety factor due to the uncertainties in the actual loading values during launch. The applicable mechanical test requirements and load combination have been first determined for the structure of interest: the SEAM CubeSat. These requirements are found to be steady-state accelerations, random vibration and shock response spectrum loadings. They have been simulated onto the structure globally and locally in order to extract stress values, amend design features when necessary and determine adequate material properties in order for the final design to fulfill the mechanical requirements during launch.
En satellit utsätts för dynamiska och statiska belastningar under uppskjutningen. Dessa laster är av deterministisk och av slumpmässig natur och kan inte testas under verkliga förhållanden på grund av kostnadsskäl. Satellitens konstruktion måste därför klara att utsättas för utan permanent deformation med en viss säkerhetsfaktor på grund av osäkerheter i de faktiska belastningarna under uppskjutningen. Mekaniska provningskrav och lastkombinationer har bestämts för en utvald struktur: SEAM CubeSat. Dessa krav visar sig vara accelerationer, slumpmässiga vibrationer och stötar. Strukturen har simulerats globalt och lokalt för att få fram de mekaniska belastningarna. Baserat på resultat från simuleringarna har konstruktionen modifierats och lämpliga material egenskaper har bestämts för att den slutliga konstruktionen ska uppfylla de mekaniska kraven under uppskjutningen.

APA, Harvard, Vancouver, ISO, and other styles

28

Ibrahim, Mahmoud Ibrahim. "An investigation into the effect of electrostatic actuation and mechanical shock on microstructures." Diss., Online access via UMI:, 2009.

Find full text

Abstract:

Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Mechanical Engineering, 2009.
Includes bibliographical references.

APA, Harvard, Vancouver, ISO, and other styles

29

Anandito, Akhsanto. "Dynamic Analysis of Sinusoidal, Random and Shock Vibration according to Launch Environment for Small Spacecraft Development to Asteroid 2016-HO3." Thesis, KTH, Lättkonstruktioner, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-244221.

Full text

Abstract:

The investment of space commerce is skyrocketing and it is predicted to be a nascent business in the future. The spacecraft demand has been growing not only for NASA and other space agency’s mission but also collaboration business between small space industries, academia, and scientific community. This glimpse brought an interest to a new investor, government, military, and manufacturing company to deliver their objectives efficiently. Nowadays, many startups compete embracing innovation and pioneering the novelty of space project beyond prodigious vision in an unprecedented way. Many players foresee that decreasing size of the rocket is an important key to survive and succeed in the space business. One of the efficient acts is lowering the launch cost. This can be achieved by designing a small size, lightweight and affordable spacecraft. Within this context, a Beyond Atlas Spacecraft which will be sent to Asteroid 2016-HO3, has achieved a wet mass of 20.85 kg with the size of 24.7 x 42.2 x 40.8 cm in stowed mode and 84 x 399 x 40.8 cm in unstowed mode. However, the drawback being light and small may lead to catastrophic failure due to resonance frequency events. According to past experience, the gyro of the Swedish national satellite was damaged during ground testing and it was suspected due to high amplification when the natural frequency coincides to the main structure resonance. Therefore, this work is focusing on a spacecraft development and a non-destructive structural analysis. The coupled-load analysis of a preliminary spacecraft design including sinusoidal, random vibration and shock analysis are calculated using FEM. This effort can reduce the risk of component destruction before laboratory testing as well as understand better the dynamic behavior of the spacecraft. The critical frequency in each orthogonal axis with base input from launch environment of the LM-3A Launch Vehicle was devised. The maximum stress, amplitude, and acceleration in accordance of qualification test criteria were evaluated and discussed.
Investeringen av rymdhandeln är skyrocketing och det förväntas bli en växande verksamhet i framtiden. Efterfrågan på rymdfarkoster har ökat inte bara för NASA och andra rymdorganisationens uppdrag utan även samarbete mellan små rymdindustrier, akademin och det vetenskapliga samfundet. Denna glimt väckte intresse för en ny investerare, regering, militär och tillverkningsföretag för att effektivt kunna leverera sina mål. Idag konkurrerar många startups om att omfatta innovation och banbrytande rymdprojektets nyhet bortom en fördärvad vision på ett aldrig tidigare skådat sätt. Många spelare förutser att minskad storlek på raketen är en viktig nyckel för att överleva och lyckas i rymdverksamheten. En av de effektiva handlingarna sänker lanseringskostnaden. Detta kan uppnås genom att utforma en liten storlek, lätt och prisvärd rymdfarkost. Inom detta sammanhang har en Beyond Atlas Spacecraft som skickas till Asteroid 2016-HO3, uppnått en våt massa på 20,85 kg med storleken 24,7 x 42,2 x 40,8 cm i stuvningsläge och 84 x 399 x 40,8 cm i ostoppat läge. Nackdelen som är ljus och liten kan emellertid leda till katastrofalt fel på grund av resonansfrekvenshändelser. Enligt tidigare erfarenhet skadades gyroen i den svenska nationella satelliten under marktestning och det misstänktes på grund av hög förstärkning när den naturliga frekvensen sammanföll med huvudstrukturen resonans. Därför fokuserar detta arbete på rymdskeppsutveckling och en icke-destruktiv strukturanalys. Den kombinerade belastningsanalysen av en preliminär rymdfarkostkonstruktion inklusive sinusformad, slumpvibration och chockanalys beräknas med användning av FEM. Denna insats kan minska risken för komponent förstörelse före laboratorietestning samt förstå bättre rymdskeppets dynamiska beteende. Den kritiska frekvensen i varje ortogonal axel med basinmatning från startmiljön för LM-3A-startkärlet utformades. Den maximala spänningen, amplituden och accelerationen i enlighet med kvalifikationstestkriterierna utvärderades och diskuterades.

APA, Harvard, Vancouver, ISO, and other styles

30

Hideblad, Daniel. "Equipment for Accelerated Vibration Testing." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-62587.

Full text

Abstract:

The increasing complexity with the decrease in size of EEE – components (Electronic, electric and electromagnetic) raises the question on how higher energy frequencies will affect the components and their continuous development. The most common vibration testing equipment currently in use within the automotive industry and SCANIA CV AB are the electrodynamic shaker (ED system). This thesis covers the characteristics of different vibration testing equipment while analysing their strengths and weaknesses, not only for the automotive industry but also including equipment more commonly handled within the aero and space industry. The project aims to find a complement for the ED system and study the possibility for its replacement in the automotive industry.In particular, experiments are carried out and documented on a so-called “Repeatable shaker system” (RS system) for the purpose to get a better understanding on the functions of the equipment and its overall differences compared to the electrodynamic system when it comes to random vibration testing.It became clear that complementing or replacing the ED system is difficult and that the RS system work fundamentally different in comparison. Accordingly, the RS system is not a potential replacement for our purpose and it cannot perform at the same level of precision but instead is able to achieve higher energy frequencies overall, making it still ideal for its intended purposes, but not as a replacement of the ED system.

APA, Harvard, Vancouver, ISO, and other styles

31

Budd, Chris. "HOW TO MAKE A RUGGEDIZED SSD." International Foundation for Telemetering, 2016. http://hdl.handle.net/10150/624195.

Full text

Abstract:

SSDs are now commonplace in all types of computing from consumer laptops to enterprise storage systems. However, most of those SSDs would not survive in environments with extreme temperatures or high shock and vibration such as found in embedded and military systems. The problems in this space are more than just mechanical; they involve all aspects of the design including electrical and even firmware. A combination of all three engineering disciplines is needed to provide a robust ruggedized SSD product.

APA, Harvard, Vancouver, ISO, and other styles

32

Florence, Dennis E. "Time and frequency domain synthesis in the optimal design of shock and vibration isolation for large structural systems." Monterey, California. Naval Postgraduate School, 1997. http://hdl.handle.net/10945/9078.

Full text

Abstract:

Approved for public release; distribution is unlimited
The dynamic analysis of large, complex structural systems is computationally intensive and therefore prohibits the use of optimization procedures, which are both iterative and complex with respect to variable search patterns. The solution to this problem is through the use of time and frequency synthesis techniques. They provide a means of rapidly recalculating a system's changed response due to structural modifications, as dictated by the optimization procedure. The efficiency is gained through the fact that the synthesis methods are independent of model size, in that only those model degrees of freedom where changes are made are required in the analysis. Furthermore, these methods are exact in their formulation, including the treatment of non- proportional damping. These structural synthesis techniques are developed in the context of optimal design of shock and vibration isolation systems. Their utility and value is demonstrated in the optimal design of an isolation system for a 109 dof non-proportionally damped structural system. In the course of the optimization, the synthesis techniques make possible 80 transient, frequency response, and static analyses in 2 hours and 39 minutes (desktop computer), while yielding an isolation design which satisfies all design constraints

APA, Harvard, Vancouver, ISO, and other styles

33

Li, Amei. "Real-time signal processing for flying height measurement and control in hard drives subject to shock and vibration." Thesis, University of Plymouth, 2008. http://hdl.handle.net/10026.1/1991.

Full text

Abstract:

Three readback signal detection methods are investgated for real-time flying height or headd isk spacingv ariation measuremenut nder vibration conditions. This is carried out by theoretical analysis, numerical simulation, and experimental study. The first method (amplitude detection) provides a simple way to study the head disk spacing change. The second method (PW50 parameter estimation) can be used effectively for real-time spacing variation measurement in normally operated hard disk drives, primarily in low frequency spacing variation conditions. The third method (thermal signal detection), on the other hand, is more effective and suitable for high frequency spacing variation measurement. By combining the PW50 estimation and thermal signal detection methods, a noval spacing variation detection method for the whole frequency range is constructed. This combined signal detection method not only has been used to study the head disk spacing variation itself, but also has the potential of being used for real time flying height control. Analytical models are developed for head disk assembly and head position servo control mechanisms to analyse the operation failure of hard disk drives under vibration conditions. Theoretical analysis and numerical simulation show their good agreement with experimental results. A novel active flying height control method is proposed to suppress the flying height or head-disk spacing variation in hard disk drives under vibration conditions. Simulation results show that this active flying height control can effectively suppress the head-disk spacing variation, therefore the perfon-nance and reliability of HDDs can be well improved when working in vibration conditions. * The method has a good potential to be applied to future ruggedized hard disk drives.

APA, Harvard, Vancouver, ISO, and other styles

34

Murthy, Aravind N. "Investigation of the effect of shock, vibration, surface texture and surface pattern on the dynamics of the head disk interface." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2007. http://wwwlib.umi.com/cr/ucsd/fullcit?p3277954.

Full text

Abstract:

Thesis (Ph. D.)--University of California, San Diego, 2007.
Title from first page of PDF file (viewed October 29, 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.

APA, Harvard, Vancouver, ISO, and other styles

35

Farshidianfar, A. "Optimisation of torsional vibrations in driveline systems : an investigation into the sensitivity of a driveline system when subjected to shock torque and optimisation of high and low frequency vibration." Thesis, University of Bradford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.632856.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Didoszak, Jarema M. "Parametric studies of DDG-81 ship shock trial simulations." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Mar%5FDidoszak.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Rehn, Börje. "Musculoskeletal disorders and whole-body vibration exposure among professional drivers of all-terrain vehicles /." Umeå : Univ, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-216.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Rehn, Börje. "Musculoskeletal disorders and whole-body vibration exposure among professional drivers of all-terrain vehicles." Doctoral thesis, Umeå universitet, Yrkesmedicin, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-216.

Full text

Abstract:

Musculoskeletal disorders are common among professional driver groups. Ergonomic risk factors at work are often suggested as causative, aggravating or preserving. The general aim with this thesis is to investigate the association between musculoskeletal disorders and physical exposure with special with special focus on whole-body vibration (WBV), among professional drivers of all-terrain vehicles (ATVs). Drivers of ATVs are expsosed to high magnitudes of WBV and shock. This thesis included drivers of forest machines, snowgroomers and snowmobiles. A cross-sectional study revealed that ATV drivers had an increased risk of musculoskeletal symptoms in the neck-shoulder and thoracic regions, even after adjusting for age, smoking habits and psychosocial stress. Prevalence rates were in the range of 1.5-2.9 (CI:1.2-5.2) compared to an age-matched group from the general population. No group of ATV drivers had a significantly increased risk of low back pain. Trend analysis showed no association between symptoms and exposure time. A clinical investigation of a subgroup found that it was for ATV drivers with neck pain to have assymetrical and focal neuropathies, pure or in mix with a nociceptive disorder, in the neck and upper extremities (47-79%), which was in contrast to referents with neck pain who had more nociceptive disorders (27% prevalence of neuropathy). Two studies measured characteristics of seated WBV exposure in forest machines (forwarders), snowgroomers and snowmobiles. The magnitudes of WBV in ATVs, measured and analyzed according to ISO 2631-1, were between 0.5-3.5 m/s2 (frequency weighted vector sum), which was considered high compared to limits suggested by the international standard ISO 2631-1 and the physical agent directive from the Euoropean Union (0.5 m/s2, rms). Drivers of ATVs were exposed to horizontally directed WBV and shocks. Non-neutral neck postures are ergonomic risk factors that occured infrequently and with short duration. The magnitude of seated WBV in forwarder vehicles varied substantiálly depending on model, terrain condition and driver. This may result in different conclusions regarding health risk assessments. The main conclusion from this thesis is that musculoskeletal symptoms and disorders in the neck and upper extremities, among drivers of ATVs, may be a result of long-time exposure to shock-type and horisozontally oriented seated WBV.

APA, Harvard, Vancouver, ISO, and other styles

39

Hallak, Yanina Soledad. "DESIGN, MANUFACTURE, DYNAMIC TESTING, AND FINITE ELEMENT ANALYSIS OF A COMPOSITE 6U CUBESAT." DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1572.

Full text

Abstract:

CubeSats, specially the 6U standard, is nowadays the tendency where many developers point towards. The upscaling size of the standard and payloads entail the increase of the satellite overall mass. Composite materials have demonstrated the ability to fulfill expectations like reducing structural masses, having been applied to different types of spacecraft, including small satellites. This Thesis is focused on designing, manufacturing, and dynamic testing of a 6U CubeSat made of carbon fiber, fiberglass, and aluminum. The main objective of this study was obtaining a mass reduction of a 6U CubeSat structure, maintaining the stiffness and strength. Considering the thermal effects of the used materials an outgassing test of the used materials was performed and the experimental results are presented. The CubeSat structure was entirely manufactured and tested at Cal Poly Aerospace Engineering Department facilities. A mechanical shock test and random vibration test were performed using a shock table and a shake table respectively. Results of both tests are presented. A correlation between the Experimental data and the Finite Element Model of the satellite was carried out. Finally, a comparison between 6U structure studied and aluminum 6U structures available in the market is presented.

APA, Harvard, Vancouver, ISO, and other styles

40

Veta, Jacob E. "Analysis and Development of a Lower Extremity Osteological Monitoring Tool Based on Vibration Data." Miami University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=miami1595879294258019.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Kerber, Thierry. "Réponse à un impact localisé d'une structure coque composite multicouche rotationnelle : études théoriques et mise au point de méthodes numériques." Châtenay-Malabry, Ecole centrale de Paris, 1995. http://www.theses.fr/1995ECAP0383.

Full text

Abstract:

Résoudre des problèmes d'impacts localises sur des coques composites multicouches reste à l'heure actuelle un véritable défi. Les couts informatiques, en stockages et en calculs, s'avèrent en effet gigantesques des qu'on s'intéresse à des cas industriels. De plus, les problèmes de fiabilité des résultats se posent de façon cruciale. Parmi ces difficultés, dominent la modélisation des coques et la résolution des problèmes d'impacts, incluant les choix délicats des discrétisations spatio-temporelles. Lorsque les structures étudiées présentent des symétries, en particulier axiales, de nouvelles opportunités se créent. Elles consistent à développer des procédures spécifiques pour tirer parti des propriétés du solide, afin de réduire les couts de traitement informatique. Ces procédés, reposant typiquement sur des développements en séries de Fourier ou des décompositions par la théorie des groupes, posent cependant de nouveaux problèmes, tant théoriques que pratiques, et les performances publiées jusqu'à présent semblent rester assez modestes. Les particularités de comportement liées aux symétries, les risques de sensibilité extrême aux imperfections, avec les phénomènes de localisation de mode et de revirement de fréquences, mettent également à jour des difficultés théoriques encore non surmontées. Traiter des impacts localises sur des structures coques composites multicouches rotationnelles (c'est à dire admettant des symétries axiales) renferme donc plusieurs sujets indépendants bien qu'interagissant. C'est pourquoi on a partagé l'étude en trois grands thèmes fondamentaux : la résolution numérique d'impacts localisés, la modélisation des coques, en particulier composites multicouches, et l'exploitation théorique et numérique des symétries axiales incluant l'influence d'imperfections. Afin de mettre en évidence leurs interconnexions, on a ensuite combiné les connaissances, acquises indépendamment et validées numériquement, en résolvant un problème industriel représentatif

APA, Harvard, Vancouver, ISO, and other styles

42

Bierworth, Rick Daniel. "Design of a rear-wheel after-market suspension system for manual wheelchairs." [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0001964.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Unal, Ugur. "Optomechanical Analysis And Experimental Validation Of Bonding Based Prism And Mirror Mounts In A Laser System." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614161/index.pdf.

Full text

Abstract:

In this thesis, different optomechanical design and adhesive configurations for mounting mirrors and prisms used in a laser system are investigated. Maintaining stability and strength of optical components of a laser device is difficult especially if the system is to be used in military environment. In order to determine the strength of prism mounts to high acceleration levels, mathematical correlations derived by Yoder are used. By use of these mathematical correlations, safety factor of different prism mounts and adhesive configurations are calculated for an acceleration level of 40g. So as to decide most stable mirror mount and adhesive configuration, several experiments are conducted. For the experiments, 5 different optomechanical mounts are designed. Then, 25 mirrors are bonded to the designed mounts with 5 different adhesives. These experiments are done to simulate harsh military environmental conditions such as thermal shock, mechanical vibration and mechanical shock. In the experiments, angular movement of mirrors due to adhesive cure, thermal shock, mechanical vibration and mechanical shock are monitored. Thermal shock is applied between -40º
C and 70º
C with a temperature change of 22º
C/min. On the v other hand, mechanical vibration of 14 grms and mechanical shock of 40g for 6 ms is applied in the experiments. Shortly, this study is done for determination of the most stable mirror and prism mount design and adhesive combination of a laser system subjected to extremely harsh environments.

APA, Harvard, Vancouver, ISO, and other styles

44

Ghaleb, Marie-Josèphe. "Vibrations d'une plaque élastique infinie couplée avec un fluide sous l'effet d'un impact ponctuel." Grenoble 1, 1987. http://www.theses.fr/1987GRE10150.

Full text

Abstract:

Cette etude porte sur les vibrations dans le vide ou en contact avec un fluide, d'une plaque elastique infinie soumise a un impact ponctuel normal a sa surface. La reponse, en deplacement et en deformation, a un impact de bille a ete calculee dans le vide par une methode analytique de transformees integrales dans le temps et l'espace, parallelement a des mesures d'extensometrie. Dans le cas du couplage, le deplacement sous l'effet d'une force harmonique ponctuelle a ete etudie en fonction de la frequence

APA, Harvard, Vancouver, ISO, and other styles

45

Abu, Hanieh Ahmed. "Active isolation and damping of vibrations via stewart platform." Doctoral thesis, Universite Libre de Bruxelles, 2003. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211336.

Full text

Abstract:

In this work, we investigate the active vibration isolation and damping of sensitive equipment. Several single-axis isolation techniques are analyzed and tested. A comparison between the sky-hook damper, integral force feedback, inertial velocity feedback and LagLead control techniques is conducted using several practical examples.

The study of single-axis systems has been developed and used to build a six-axis isolator. A six degrees of freedom active isolator based on Stewart platform has been designed manufactured and tested for the purpose of active vibration isolation of sensitive payloads in space applications. This six-axis hexapod is designed according to the cubic configuration; it consists of two triangular parallel plates connected to each other by six active legs orthogonal to each other; each leg consists of a voice coil actuator, a force sensor and two flexible joints. Two different control techniques have been tested to control this isolator :integral force feedback and Lag-Lead compensator, the two techniques are based on force feedback and are applied in a decentralized manner. A micro-gravity parabolic flight test has been clone to test the isolator in micro-gravity environment.

ln the context of this research, another hexapod has been produced ;a generic active damping and precision painting interface based on Stewart platform. This hexapod consists of two parallel plates connected to each other by six active legs configured according to the cubic architecture. Each leg consists of an amplified piezoelectric actuator, a force sensor and two flexible joints. This Stewart platform is addressed to space applications where it aims at controlling the vibrations of space structures while connecting them rigidly. The control technique used here is the decentralized integral force feedback.

Doctorat en sciences appliquées
info:eu-repo/semantics/nonPublished

APA, Harvard, Vancouver, ISO, and other styles

46

Mariano, Silvio Luiz. "Analise numerica e experimental do indice de vibro-impacto em alavancas de transmissão mecanica." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264950.

Full text

Abstract:

Orientador: Janito Vaqueiro Ferreira
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica
Made available in DSpace on 2018-08-04T09:11:42Z (GMT). No. of bitstreams: 1 Mariano_SilvioLuiz_M.pdf: 10538477 bytes, checksum: b5e594a3783a5571c8face1a74dae202 (MD5) Previous issue date: 2005
Resumo: Este trabalho apresenta a análise numérica e experimental do índice de vibro-impacto em alavancas de transmissão mecânica. Foram desenvolvidos modelos de alavanca que consideram não-linearidades na estrutura. Métodos para quantificação do vibro-impacto foram obtidos na literatura e implementados para o levantamento de curvas, as quais indicam a variação do índice de Vibro-impacto com relação à variação dos parâmetros dos modelos desenvolvidos. A técnica da Transformada de Hilbert também foi implementada para levantamento das forças não-lineares atuantes nos modelos. Foram utilizadas três bancadas para identificação das forças não-lineares atuantes e validação da técnica salientada, que utiliza sinais de força, deslocamento, velocidade e aceleração. As curvas de rigidez não-Hnear foram identificadas coerentemente, as quais tiveram validação pelo levantamento da rigidez das mesmas bancadas por medições estáticas. Dois modelos numéricos de alavanca, utilizando massas concentradas, foram estudados. Nestes identificaram-se curvas de força não-Hnear e levantaram-se curvas de sensibilidade do índice de Vibro-impacto à variação dos parâmetros dos modelos. Mostrou-se que a técnica da Transformada de Hilbert pode ser utilizada para a identificação de sistemas não-lineares e que o estudo de sensibilidade em modelos de vibro-impacto pode ser obtido sem muita dificuldade
Abstract: This work presents a study about a numerical and experimental vibro-impact level analisys in mechanical gearshift levers. It was developed gearshift lever models which consider nonlinearities in the structure. Methods to vibro-impact quantification were obtained in the available literature and were implemented to obtain curves which show the vibro-impact level change with the modification of the parameters of the developed models. Hubert Transform techniques were also implemented to obtain nonlinear forces implemented on the models. To verify the efficiency of these techniques, three test rigs with nonlinearities were developed and the nonlinear forces were identified. The techniques need the displacement, velocity and acceleration signals to calculate the forces. The nonlinear forces curves were identified and validated with the static forces measured. Two models of gearshift levers were developed, using lumped masses. In these models the nonlinear forces curves and the sensibility to the vibro-impact level with modifications in the model parameters were obtained. It was showed that the Hubert Transform techniques are reliable to identify nonlinear systems and that the sensibility study in vibro-impact can be obtained easily
Mestrado
Mecanica dos Sólidos e Projeto Mecanico
Mestre em Engenharia Mecânica

APA, Harvard, Vancouver, ISO, and other styles

47

Saïd, Didier. "Étude théorique et numérique des vibrations de structures soumises à des chocs pyrotechniques." Cachan, Ecole normale supérieure, 1998. http://www.theses.fr/1998DENS0020.

Full text

Abstract:

L'étude s'inscrit dans le cadre de la prévision des niveaux vibratoires induits par les chocs pyrotechniques lors de la phase de séparation des étages du lanceur Ariane 5, et plus particulièrement de la prévision des niveaux vibratoires dans la case a équipements. On développe une approche simplifiée permettant de déterminer la réponse dynamique de la structure à partir du calcul de matrices de rigidité dynamique exactes. Cette approche est réservée a des structures de type guides d'ondes dans lesquelles la direction de propagation des ondes est connue. On s'intéresse également a la prise en compte de liaisons entre structures ; on montre qu'il est possible de déterminer la matrice de rigidité dynamique des liaisons a partir de la connaissance des coefficients de réflexion et de transmission des ondes et des relations force-déplacement dans les éléments relies a la liaison.

APA, Harvard, Vancouver, ISO, and other styles

48

Selim, André Baroni. "Influência das forças de inércia e do balanceador de massas na dinâmica do motor de combustão interna." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264881.

Full text

Abstract:

Orientador: Airton Nabarrete
Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
Made available in DSpace on 2018-08-16T19:07:22Z (GMT). No. of bitstreams: 1 Selim_AndreBaroni_M.pdf: 8247651 bytes, checksum: 306a914d67d3207fb1d8f193b3bf7bd2 (MD5) Previous issue date: 2010
Resumo: Este trabalho visa estudar a influência do balanceador de massas e das forças de inércia dos componentes internos móveis do motor na dinâmica do motor de combustão interna apoiado sobre amortecedores de vibrações. Para o estudo da influência do balanceador de massas, diversas análises experimentais foram realizadas com um motor em dinamômetro. Chegam-se nas conclusões através da comparação dos deslocamentos medidos do motor com e sem balanceador de massas. Para que a influência das forças de inércia dos componentes internos móveis do motor fosse estudada, um modelo matemático foi criado. Neste modelo consideram-se as forças vindas dos componentes internos móveis atuando em um corpo rígido, neste caso o bloco do motor, apoiado sobre quatro amortecedores de vibrações com seis graus de liberdade. Variam-se dados construtivos como massas e geometria dos componentes internos móveis do motor observando a sua influência sobre o comportamento dinâmico do motor de combustão interna. A validação deste modelo matemático ocorre por meio da comparação de seus resultados com os resultados reais observados nas análises experimentais
Abstract: This work aims at studying the influence of mass balancer and inertia forces coming from engine internal components on internal combustion engine dynamics supported by vibration dampers. For mass balancer study several experimental analyses were performed with a dynamometer. The conclusions are obtained by comparison between measured engine displacements with and without mass balancer. To study the influence of inertia forces from engine internal components, a mathematical model was developed. In this model the inertia forces act on a rigid body, the engine crankcase, supported by four vibration dampers and with six degrees of freedom. Some modifications are made on engine internal components such as mass and geometry observing what is their influence on internal combustion engine dynamics. The mathematical model is validated by comparison against experimental analyses
Mestrado
Dinâmica
Mestre em Engenharia Automobilistica

APA, Harvard, Vancouver, ISO, and other styles

49

Motts, J. "Listening Beyond the Image: Toward a Trans-Sensory Cinema." Miami University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=miami1501099367573869.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Rashed, Tarek Ahmed. "Methods for Assessing Exposure to Whole-Body Vibration and Mechanical Shocks Induced During Forklift Operations." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1172597312.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Shock and Vibration'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles