Vergleichende Untersuchung der Verschleißbilder von Steckverbindern aus Reibverschleiß- und Vibrationsprüfungen mit unterschiedlichen Prüfrichtungen

2021 ◽  
Vol 68 (5) ◽  
pp. 41-49
Author(s):  
Dirk Hilmert ◽  
Kevin Krüger ◽  
Jian Song
Keyword(s):  
Corrosion Test ◽  
Direct Relationship ◽  
Measurement Techniques ◽  
Excitation Amplitude ◽  
Vibration Test ◽  
Fretting Corrosion ◽  
Vergleichende Untersuchung ◽  
Similarities And Differences ◽  
Vibration Tests ◽  
Electrical Connectors

In this study a comparison between the wear patterns of electrical connectors resulting from two different test types, namely fretting corrosion test and vibration test, is conducted. In both tests, the excitation directions include the mating direction as well as the orthogonal directions corresponding to the mating direction. Different measurement techniques are used to identify similarities and differences between the wear resulting from these test types. The results show fundamentally different critical directions with regard to wear for the respective test types. Furthermore, it is shown that the induced movement of the fretting tests lead to a higher degree of wear than the vibration tests. Also, it is not adequately possible to establish a direct relationship between the induced movement and the excitation amplitude caused by the attached wires since there is a superposition of several movements in the case of real applications.

Damping in LMFBR Pipe Systems

1985 ◽  
Vol 107 (4) ◽  
pp. 366-372 ◽  
Author(s):  
M. J. Anderson ◽  
D. A. Barta ◽  
M. R. Lindquist ◽  
E. J. Renkey ◽  
J. A. Ryan
Keyword(s):  
Excitation Amplitude ◽  
Test Facility ◽  
Seismic Events ◽  
Seismic Loads ◽  
Modal Damping ◽  
Water Plant ◽  
Pipe Systems ◽  
Vibration Tests ◽  
Recent Laboratory

Liquid Metal Fast Breeder Reactor pipe systems typically utilize a thicker insulation package than that used on water plant pipe systems. They are supported with special insulated pipe clamps. Mechanical snubbers are employed to resist seismic loads. Recent laboratory testing has indicated that these features provide significantly more damping than presently allowed by Regulatory Guide 1.61 for water plant pipe systems. This paper presents results of additional in-situ vibration tests conducted on Fast Flux Test Facility pipe systems. Pipe damping values obtained at various excitation levels are presented. Effects of filtering data to provide damping values at discrete frequencies and the alternate use of a single equivalent modal damping value are discussed. These tests further confirm that damping in typical LMFBR pipe systems is larger than presently used in pipe design. Although some increase in damping occurred with increased excitation amplitude, the effect was not significant. Recommendations are made to use increased damping values for seismic events in design of heavily insulated pipe systems.

Modal Analysis of Ring-Plate of Double Crank Four Ring-Plate-Type Cycloid Reducer

2010 ◽  
Vol 139-141 ◽  
pp. 2364-2367
Author(s):  
Bing Yang ◽  
Wen Liu ◽  
Yan Liu
Keyword(s):  
Natural Frequencies ◽  
Three Dimensional ◽  
Vibration Test ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Distribution Rules ◽  
Ring Plate ◽  
Analysis System ◽  
Vibration Tests ◽  
Plate Type

The vibration tests of the double crank ring-plate-type cycloid reducer driven by three gears are tested and analyzed with the HEAD acoustics multi-channel vibration test and analysis system. The tests of the reducer are completed under the condition of different rotational speeds and different loads. The vibration distribution rules of the reducer are obtained. The three dimensional model of the ring-plates of the double crank four ring-plate-type cycloid reducer with Pro/E are established, the modality analysis are carried out on the model by the use of ANSYS. The natural frequencies and the corresponding vibration models of the ring-plates are gained. The results are well consistent with that of the vibration tests which provide the basis for further study of vibration and noise reduction.

Flatwise Young’s modulus and flatwise shear modulus of plywood measured by flexural vibration test

Holzforschung ◽  
2013 ◽  
Vol 67 (6) ◽  
pp. 683-690 ◽  
Author(s):  
Hiroshi Yoshihara
Keyword(s):  
Finite Element Analysis ◽  
Shear Modulus ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Flexural Vibration ◽  
Vibration Test ◽  
Specimen Length ◽  
Element Analysis ◽  
Flexural Vibration Test ◽  
Vibration Tests

Abstract The flatwise Young’s modulus and the flatwise shear modulus of 3-, 5-, and 7-ply plywoods made of Lauan (Shorea sp.) veneers have been determined by conducting flexural vibration tests with various specimen lengths and by finite element analysis. The results indicate that the flatwise Young’s modulus decreases with decreasing specimen length, whereas the opposite is true for the flatwise shear modulus.

Vibration Tests With a 1/13-Scaled 3-D Model of the Folsom Dam Tainter-Gate and Its Prediction by Theory

2006 ◽  
Author(s):  
Keiko Anami ◽  
Noriaki Ishii ◽  
Charles W. Knisely ◽  
Robert V. Todd ◽  
Tatsuya Oku
Keyword(s):  
Dynamic Instability ◽  
Vibration Test ◽  
Test Results ◽  
Bending Vibration ◽  
Coupled Mode ◽  
Basic Assumptions ◽  
Vibration Tests ◽  
D Model ◽  
Theoretical Analyses ◽  
Made In

This study presents 3-D model gate vibration test results demonstrating violent spontaneous vibrations and validating the basic assumptions made in previously published theoretical analyses. First, the design of a 1/13-scaled 3-D model of Folsom dam Tainter-gate is presented, in which the streamwise natural bending vibration mode of the skinplate, measured in the field vibration tests on the remaining Folsom gate, is shown to be correctly replicated with the aid of FEM simulations. Secondly, in-air and in-water vibration test results with the 1/13-scaled 3-D model are presented, reproducing the intense coupled-mode self-excited vibrations. Thirdly, test results are plotted on a theoretically calculated stability criterion diagram to confirm the validity of the theoretical analysis. Finally, the intense dynamic instability of the Folsom gate, which could have caused its failure, is presented.

scholarly journals Distant motions from a building vibration test

1970 ◽  
Vol 60 (6) ◽  
pp. 2037-2043 ◽  
Author(s):  
Paul C. Jennings
Keyword(s):  
Ground Motion ◽  
Vertical Component ◽  
Excitation Level ◽  
Vibration Test ◽  
Multistory Buildings ◽  
Dynamic Forces ◽  
Horizontal Ground Motion ◽  
Vibration Tests

Abstract Horizontal ground motion generated by vibration tests of the nine-story Millikan Library Building on the Caltech campus was recorded on the surface of the ground in the Pasadena area at distances up to 3 miles from the building. Later it was learned that the vertical component of the motion also was recorded by the seismograph on Mt. Wilson, 6.7 miles from the Library and 4,800 ft higher in elevation. The magnitude of the acceleration varied from 2.04 × 10-2g at the excitation level on the ninth floor of the building to 3.2 × 10-7g at Mt. Wilson. Simple calculations show that multistory buildings are particularly well-suited for inducing large dynamic forces in the ground with relatively small equipment.

scholarly journals SOME PARTICULAR ASPECTS OF THE AUTOMOTIVE INDUSTRY CONNECTORS

2021 ◽  
Vol XXVIII (4) ◽  
pp. 44-51
Author(s):  
Titu-Marius I. Băjenescu ◽  
Keyword(s):  
Automotive Industry ◽  
Electronic System ◽  
Operating Conditions ◽  
Fretting Corrosion ◽  
Corrosion Prevention ◽  
Design Technology ◽  
Performance Factors ◽  
Actual Meaning ◽  
Contact Unit ◽  
Electrical Connectors

Electrical connectors are very sensitive parts in an electronic system. The actual meaning of reliability and the problems associated with determining it, are often not right understood. The paper presents some particular aspects of the automotive industry connectors’ i.e. fretting, fretting corrosion prevention, aluminium connections. The performance factors governed by the operating conditions and design-technology factors determined by the manufacturing characteristics of a contact unit were analyzed.

scholarly journals The changes of physical properties in ‘Elsanta’ strawberries from the winter and summer cultivations after vibration tests

2020 ◽  
pp. 697-704
Author(s):  
Saowapa Chaiwong ◽  
Chris F. H. Bishop
Keyword(s):  
Electrical Conductivity ◽  
Physical Properties ◽  
Respiration Rate ◽  
Fruit Weight ◽  
Fragaria X Ananassa ◽  
Vibration Test ◽  
Compression Tests ◽  
Average Temperature ◽  
Postharvest Handling ◽  
Vibration Tests

Strawberries (Fragaria x ananassa Duchesne) cv. ‘Elsanta’ were grown in the greenhouse during the winter and summer seasons of 2014 and 2015. A vibration test of strawberry fruits from these cultivations was carried out at the two frequency levels of 3 Hz and 5 Hz for 150 sec plus a control of no vibration to simulate transport. The physical properties (fruit weight, puncture, compression, electrical conductivity (EC), and respiration rate) and bruise incidence of fruits were determined after the vibration test (day 0) and after storage at 10oC (±1oC) and 70% RH (±5% RH) for 3 days (day 3). A higher average temperature (21 as opposed 25oC) during strawberry growth and development of the summer crop gave a shorter period for harvesting, with a smaller fruit and a softer fruit as compared to a lower average temperature in the winter cultivation (8 to 21oC). The fruit from the summer cultivation when vibrated at a frequency of 5 Hz were observed to have significantly higher for wet bruise (50% of total fruits), electrical conductivity (EC) and respiration rate (63.78 mgCO2/kg.hr), as well as lower firmness values (puncture and compression tests) than other treatments (p≤0.05). The lower vibration level at 3 Hz of the winter strawberries did not affect the percentage of bruise and both firmness values (p>0.05), whilst the EC method could noticeably distinguish the bruise incidence, particularly for a frequency of 5 Hz (p≤0.05). The EC method gave a highly significant correlation with wet bruise (r = 0.854) and severity score (r = -0.499) when compared with either firmness tests (puncture and compression) or respiration rate (p≤0.01). The EC technique is suggested for use as a bruise indicator of strawberries and an application for a bruise assessment for a whole strawberry punnet during postharvest handling operation and transport.

scholarly journals Multi-Input-Multi-Output Continuous Swept-Sine Vibration Test Realization by Inverse Multistep Prediction Model

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Wei Zheng ◽  
Huaihai Chen ◽  
Zhengbo Luo ◽  
Amr A. Nassr
Keyword(s):  
Prediction Model ◽  
Time Domain ◽  
Original System ◽  
Inverse System ◽  
Vibration Test ◽  
System Method ◽  
Frequency Domain Methods ◽  
Vibration Tests ◽  
The Time Domain ◽  
Drive Signals

As frequency-varying sine excitations in rotating machines are always emerging during run-ups and shutdowns, the multi-input-multi-output (MIMO) swept-sine test is of utter significance in product validation. At present, swept-sine vibration tests are mostly conducted with frequency-domain methods, where drive spectra are generated and updated by frequency response function (FRF), and drive signals are then generated with sinusoid oscillators. In this paper, a time-domain approach using an inverse system method based on a multistep prediction model is developed to realize the MIMO continuous swept-sine vibration test. First, the multistep prediction model of the original system is estimated in the time domain. Then, the inverse multistep prediction model is derived. After that, this model is truncated to guarantee the robustness of the inverse system and the smoothness of the generated drive signals. At last, the proposed method is validated by a simulation example with a cantilever beam and an actual test by using a three-axis shaker. The results show that the MIMO continuous swept-sine vibration test can be operated effectively by the proposed method.

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