Research on precise test method for switching performance of high speed SiC MOSFET

2016 ◽  
Author(s):  
Mei Liang ◽  
Yan Li ◽  
Trillion Q. Zheng
Keyword(s):  
High Speed ◽  
Test Method ◽  
Switching Performance

Round-Robin of High-Frequency Test Methods by IPC-D24C Task Group

2016 ◽  
Vol 13 (3) ◽  
pp. 77-94
Author(s):  
Glenn Oliver ◽  
Jonathan Weldon ◽  
Chudy Nwachukwu ◽  
John Andresakis ◽  
John Coonrod ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
High Frequency ◽  
High Speed ◽  
Test Methods ◽  
Round Robin ◽  
Standard Test ◽  
Test Method ◽  
Task Group ◽  
Circuit Board ◽  
Industry Standard

Currently, there is no industry standard test method for measuring dielectric properties of circuit board materials at frequencies greater than ~10 GHz. Various material vendors and test laboratories apply different approaches to determine these properties. It is common for these different approaches to yield varying values of key properties such as permittivity and loss tangent. The D-24C Task Group of IPC has developed this round-robin program to assess these various methods from the “bottom up” to determine if standardized methods can be agreed upon to provide the industry with more accurate and valid characteristics of dielectrics used in high-frequency and high-speed applications.

Investigation of the axial compressive behavior of Kevlar fibers using the dynamic loop test

2019 ◽  
Vol 89 (18) ◽  
pp. 3825-3838
Author(s):  
Ahmad Abuobaid ◽  
Raja Ganesh ◽  
John W Gillespie
Keyword(s):  
Strain Rate ◽  
High Speed ◽  
Failure Strain ◽  
Kink Band ◽  
Test Method ◽  
Strain Rates ◽  
Compressive Failure ◽  
Band Formation ◽  
Rate Dependent ◽  
Strain And Strain Rate

A dynamic loop test method for measuring strain rate-dependent fiber properties was developed. During dynamic loop testing, the fiber ends are accelerated at constant levels of 20.8, 50 and 343 m/s2. The test method is used to study Kevlar® KM2-600, which fails in axial compression due to kink band formation. The compressive failure strain and strain rate at the onset of kink band formation is calculated from the critical loop diameter ( D C), which is monitored throughout the test using a high-speed camera. The results showed that compressive failure strain increases with strain rates from quasi-static to a maximum strain rate of 116 s−1 by a factor of ∼3. Kink angles (φ) and kink band spacing ( D S) were 60 ° ± 2 ° and 16 ± 3 μm, respectively, over the strain rates tested. Rate-dependent mechanisms of compressive failure by kink band formation were discussed.

A new moving model test method for the measurement of aerodynamic drag coefficient of high-speed trains based on machine vision

2017 ◽  
Vol 232 (5) ◽  
pp. 1425-1436 ◽  
Author(s):  
Zhiwei Li ◽  
Mingzhi Yang ◽  
Sha Huang ◽  
Dan Zhou
Keyword(s):  
Machine Vision ◽  
Drag Coefficient ◽  
Model Test ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Full Scale ◽  
Test Method ◽  
Test Accuracy ◽  
Friction Resistance ◽  
Aerodynamic Drag Coefficient

A moving model test method has been proposed to measure the aerodynamic drag coefficient of a high-speed train based on machine vision technology. The total resistance can be expressed as the track friction resistance and the aerodynamic drag according to Davis equation. Cameras are set on one side of the track to capture the pictures of the train, from which the line marks on the side surface of the train are extracted and analyzed to calculate the speed and acceleration of the train. According to Newton’s second law, the aerodynamic drag coefficient can be resolved through multiple tests at different train speeds. Comparisons are carried out with the full-scale coasting test, wind tunnel test, and numerical simulation; good agreement is obtained between the moving model test and the full-scale field coasting test with difference within 1.51%, which verifies that the method proposed in this paper is feasible and reliable. This method can accurately simulate the relative movement between the train, air, and ground. The non-contact measurement characteristic will increase the test accuracy, providing a new experimental method for the aerodynamic measurement.

Shock and Vibration Survivability Prediction Using Failure Envelopes for Electronic and MEMS Packaging

2005 ◽  
Author(s):  
Pradeep Lall ◽  
Dhananjay Panchagade ◽  
Prakriti Choudhary ◽  
Jeff Suhling ◽  
Sameep Gupte
Keyword(s):  
Electronic Packaging ◽  
Wavelet Transforms ◽  
High Speed ◽  
Damage Index ◽  
Test Method ◽  
System Level ◽  
Failure Envelope ◽  
Ball Grid Arrays ◽  
Cost Constraints ◽  
Damage Progression

Product level assessment of drop and shock reliability relies heavily on experimental test methods. Prediction of drop and shock survivability is largely beyond the state-of-art. However, the use of experimental approach to test out every possible design variation, and identify the one that gives the maximum design margin is often not feasible because of product development cycle time and cost constraints. Presently, one of the primary methodologies for evaluating shock and vibration survivability of electronic packaging is the JEDEC drop test method, JESD22-B111 which tests board-level reliability of packaging. However, packages in electronic products may be subjected to a wide-array of boundary conditions beyond those targeted in the test method. In this paper, a failure-envelope approach based on wavelet transforms and damage proxies has been developed to model drop and shock survivability of electronic packaging. Data on damage progression under transient-shock and vibration in both 95.5Sn4.0Ag0.5Cu and 63Sn37Pb ball-grid arrays has been presented. Component types examined include — flex-substrate and rigid substrate ball-grid arrays. Dynamic measurements like acceleration, strain and resistance are measured and analyzed using high-speed data acquisition system capable of capturing in-situ strain, continuity and acceleration data in excess of 5 million samples per second. Ultra high-speed video at 150,000 fps per second has been used to capture the deformation kinematics. The concept of relative damage index has been used to both evaluate and predict damage progression during transient shock. The failure-envelope provides a fundamental basis for development of component integration guidelines to ensure survivability in shock and vibration environments at a user-specified confidence level. The approach is scalable to application at system-level. Explicit finite-element models have been developed for prediction of shock survivability based on the failure envelope. Model predictions have been correlated with experimental data for both leaded and leadfree ball-grid arrays.

Experimental Study on Cavitation Motion of Underwater Vehicle With Protrusions

2020 ◽  
Author(s):  
Zhaoyu Qu ◽  
Ning Gan ◽  
Yingyu Chen ◽  
Nana Yang
Keyword(s):  
High Speed ◽  
Underwater Vehicle ◽  
Test Method ◽  
Scale Model ◽  
Small Scale ◽  
Reduced Pressure ◽  
Local Flow ◽  
Bubble Generation ◽  
Scale Characteristics ◽  
Motion Characteristics

Abstract For underwater vehicles with protrusions (external structure), the geometric shape of the protrusions is bound to affect the local flow field of the vehicles during the moving process of the vehicles, thus affecting the generation, development and collapse of cavitation around the vehicles. The cavitation may break, fall off and collapse randomly, and other local movements may affect the motion attitude of the underwater vehicle. It is an effective method to study fluid dynamics to simulate prototype cases with small scale models. In this paper, we mainly use the small scale model test method to explore the cavitation motion characteristics of the vehicle in water with protrusions. Through the establishment of a set of vehicle motion test equipment under reduced pressure, a series of experiments were conducted on this basis to explore the motion characteristics of vehicle cavitation under different bump shapes. In this study, two high-speed cameras were used to simultaneously record cavitation generation, development, collapse and other characteristics, to analyze the bubble generation mechanism and scale characteristics caused by the bulge, and then to study the influence of cavitation induced by the bulge on the motion attitude of the vehicle.

Interaction Between Wind Loading and Japanese Slates: Effect on Vibration and Scattering

2008 ◽  
Author(s):  
Satoru Okamoto
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Natural Frequencies ◽  
Basic Mechanism ◽  
Video Camera ◽  
Flow Speed ◽  
Test Method ◽  
Wind Loading ◽  
Natural Mode ◽  
Set Up

A series of wind tunnel tests was conducted on the vibration and scattering behavior of full-sized model of roof tiles, which were used widely for roofings of Japanese wooden dwellings. This study has investigated the nature and source of the vibrating and scattering behavior of roof tiles with the aim of providing a better insight to the mechanism. The roof tiles were set up on the pitched roof in the downstream of the flow from the wind tunnel. The vibrations for the roof tiles were measured by the Laser Doppler Vibrometry and the accelerometer, and the practical natural frequencies of the roof tiles were analyzed by the impulse force hammer test method. The motions of the vibration and scattering were observed by the high-speed video camera. Based on the consideration on the results of the measurements, there is a basic mechanism which can lead to flow-induced vibrations of the roof tiles. This mechanism is similar to that of the so-called fluttering instability, which appears as the self-excited oscillation in the natural mode of the structure at the certain critical flow speed. The values of the frequencies for the oscillating relate to the values of natural frequencies of the vibration.

Evaluation of the Scott bond test method

2012 ◽  
Vol 27 (2) ◽  
pp. 231-236 ◽  
Author(s):  
Christer Fellers ◽  
Sören Östlund ◽  
Petri Mäkelä
Keyword(s):  
Tensile Test ◽  
Total Energy ◽  
High Speed ◽  
Test Methods ◽  
Test Method ◽  
The Other ◽  
High Speed Photography ◽  
Tensile Tester ◽  
Delamination Resistance ◽  
Energy Consuming

Abstract The Scott bond test is the most commonly used test method for quantifying the delamination resistance of paper and board. The objective of this investigation was to validate the hypothesis that the Scott bond value would be dominated by the total energy under the force elongation curve in a z-directional tensile test. The investigation comprised three types of hand sheets with comparatively low strength values. Three test methods were used to obtain the energy for delamination: 1) Z-test, a z-directional tensile test, 2) Scott bond test, and 3) Simulated Scott bond test, a Scott bond type of test performed in a hydraulic tensile tester. The test data were expressed as a correlation between the failure energy obtained from the Z-test and the other two tests. The results showed that the Scott bond test gave slightly higher values than the Z-test for the weakest paper, but that the value tended to be much higher for the stronger papers. On the other hand the Simulated Scott bond test tended to give lower values than the Z-test. High speed photography was used to reveal several energy consuming mechanisms in the Scott bond test that can explain why this test gave higher values than the Ztest. The lower values from the Simulated Scott bond values are more difficult to explain. At this stage we can suggest that the failure mechanism is different if the paper is delaminated by pure tension or by a gradual delamination as in the Scott bond test.

scholarly journals Research on Fatigue Test Method of Car Body for High-speed trains

2018 ◽  
Vol 189 (6) ◽  
pp. 062011 ◽  
Author(s):  
Chao Wang ◽  
Chengqiang Wang ◽  
Chaotao Liu ◽  
Yongzhi Jiang
Keyword(s):  
Fatigue Test ◽  
High Speed ◽  
Test Method ◽  
Car Body ◽  
High Speed Trains

Rapid Non-Destructive Testing of Ceramic Multilayer Capacitors by a Resonance Method

1988 ◽  
Vol 142 ◽  
Author(s):  
O. Boser ◽  
P. Kellawon ◽  
R. Geyer
Keyword(s):  
Acoustic Waves ◽  
High Speed ◽  
Piezoelectric Materials ◽  
Resonance Method ◽  
Test Method ◽  
Test Set ◽  
Speed Test ◽  
Multilayer Capacitors ◽  
Set Up ◽  
Non Destructive

AbstractA rapid non-destructive test method for ceramic multilayer capacitors made from piezoelectric materials such as barium titanate or lead containing materials is described and evaluated. The test method is based on the internal excitation of standing acoustic waves in the capacitors. The standing waves are severely dampened by defects such as delaminations and pores. An undampened resonance is a good indication of a defect free ceramic multilayer capacitor. This finding was used in a nondestructive test set-up to evaluate about 1,000 capacitors. The test set-up has the potential to test over 100,000 capacitors an hour. Through metallographic (cross section) examination a sorting accuracy of 2% false accepts and 8% false rejects was determined for the high speed test set-up.

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