scholarly journals Design and Research of Bearing Reliability Test Bed Based on Multi-Dimensional Vibration Loading

2021 ◽  
Vol 2101 (1) ◽  
pp. 012045
Author(s):  
Yanzhong Wang ◽  
E Shiyuan
Keyword(s):  
Test Chamber ◽  
Reliability Test ◽  
Test Bed ◽  
External Excitation ◽  
Rolling Bearings ◽  
Dynamic Reliability ◽  
External Vibration ◽  
Vibration Loading ◽  
Flexible Material ◽  
Vibration Excitation

Abstract Rolling bearings are widely used in aviation, aerospace and other important fields, and their reliability is greatly affected by external vibration excitation during service. Due to the large volume and high cost of the combined structure of shaking table and test chamber, this paper designed a dynamic reliability test bed specially for rolling bearings to study the influence of external vibration excitation with different directions, frequencies and amplitudes on vibration signals and service life of rolling bearings. The test bed is loaded with external excitation by means of electromagnetic shakers in two directions, and the flexible material is used to realize the displacement of the test chamber under two external excitation directions at the same time. The bearing vibration loading life test carried out by this test bed has important guiding significance for the design of rolling bearing. The experimental results show that the test bed can apply axial and radial vibration loads of 1-800Hz sinusoidal waveform, and the vibration acceleration can reach 1g, which can simulate the effect of actual working conditions.

scholarly journals Thermal loads of a piston in a diesel engine during startup

2008 ◽  
Vol 133 (2) ◽  
pp. 20-25
Author(s):  
Janusz MYSŁOWSKI ◽  
Krzysztof TALAGA
Keyword(s):  
Combustion Engine ◽  
Direct Injection ◽  
Test Chamber ◽  
Thermal Loads ◽  
Engine Test ◽  
Test Bed ◽  
Simulation Research ◽  
Ambient Temperatures ◽  
Theoretical Assumptions ◽  
Temperature Test

The paper presents the issue of thermal loads of a piston in a combustion engine with direct injection during startup. Theoretical assumptions have been described as well as the programme of engine test bed and simulation research based on the previous results of tests in the low temperature test chamber. Differences taking place in the piston thermal loads have been discussed as well as their influence on an efficient startup at low ambient temperatures

A Test Bed for Small Aero Gas Turbines for Education and for University: Industry Collaboration

2004 ◽  
Author(s):  
A. J. B. Jackson ◽  
P. Laskaridis ◽  
P. Pilidis
Keyword(s):  
Experimental Data ◽  
Gas Turbines ◽  
Large Scale ◽  
Test Chamber ◽  
Engine Performance ◽  
Correction Factors ◽  
Test Bed ◽  
Ongoing Research ◽  
Test Beds ◽  
Static Conditions

Engine testing is a necessary but nonetheless expensive and time consuming process. Most of the facilities used to test an engine at sea level static conditions are enclosed test beds. In these facilities the existence of secondary mass flow within the test chamber and around the engine gives rise to various drag components that affect the thrust measurements. For this reason, the net thrust measured in an indoor test bed is lower than the true gross thrust delivered by the engine and measured during outdoor tests. Thrust correction factors, therefore, need to be calculated and applied. For the past five years Cranfield University has been involved in a research study evaluating the performance of gas turbines in test beds, and this work continues. Recently, Cranfield purchased a small gas turbine and invested in the design and construction of a small test bed facility that provides experimental data for the support of the analytical computational fluid dynamics (CFD) analysis. The purpose of this micro-turbojet and test bed facility is to mimic large scale facilities and provide appropriate experimental data for calculating thrust correction factors. The data are also used together with three dimensional CFD models to provide a better understanding of the aerodynamic and engine performance issues involved. Tests have been completed successfully and the facility is capable of detecting the small thrust differences between indoor and outdoor test. Thrust correction factors have been derived through a back to back process. This is an excellent result showing that the equipment is performing as designed. In addition to providing useful results and conclusions in support of ongoing research the facility is also used for postgraduate projects focusing on the performance of small engines in test beds. Analytical design tolls such as commercial CFD and in house engine performance programs are used to predict engine performance and parameters. The results are then validated against the test data. This paper describes the present state of technical progress, which is under development. Its other purpose is to describe the educational value of the analytical and experimental techniques, the objective of which is to mimic the overall engine development process.

Lumen Maintenance of Ternary Ag-Alloy Wire Bonded LED Package after Reliability Tests

2020 ◽  
Vol 1003 ◽  
pp. 275-280 ◽  
Author(s):  
Jui Hung Yuan ◽  
Tung Han Chuang ◽  
Ju Hui Chuang
Keyword(s):  
High Temperature ◽  
White Light ◽  
Electrical Resistance ◽  
Oxidation Reaction ◽  
Reliability Test ◽  
Bonding Wire ◽  
Dynamic Reliability ◽  
Alloy Wire ◽  
Brightness Decay ◽  
Maintenance Performance

In this investigation, ternary Ag-alloy wires were doped with different Pd and Au concentrations, and each wire was encapsulated in an LED package. The static and dynamic reliability were tested, and the lumen maintenance performance was examined. The static reliability tests included the sulfur test, LTSL, HTSL, and WHTSL. According to the sulfur test data, higher Pd and Au contents led to better lumen maintenance. Furthermore, the bonding wire of the LED with better lumen maintenance in the sulfur test had higher electrical resistance. The brightness decay rate of the white light LEDs was low in low-and high-temperature environments, but it was significantly higher after the WHTSL test. The dynamic reliability test after 1,000 hours of HTOL and WHTOL showed that the lumen maintenance improved with higher Pd and Au contents, indicating that doping Ag-alloy wires with sufficient amounts of Pd and Au can retard degradation due to thermal and humidity aging and oxidation reaction. Therefore, ternary Ag-Pd-Au alloy wires produced with specific drawing and annealing processes are suitable for application to mid-power white light LEDs.

Application with Theory of Vibration Equivalence on Reliability Test Bed of Train Brake System

2010 ◽  
Vol 34-35 ◽  
pp. 1978-1982 ◽  
Author(s):  
Xiao Yan Wang ◽  
Meng Ling Wu ◽  
Zhong Kai Chen
Keyword(s):  
Random Vibration ◽  
Brake System ◽  
Quantitative Relation ◽  
Reliability Test ◽  
Test Bed ◽  
Sinusoidal Vibration ◽  
Equivalency Theory ◽  
Environmental Vibration ◽  
Circular Frequency ◽  
Vibrating Table

In order to design a reliability test bed for train brake system, theory of vibration equivalence was used to represent in laboratory the environmental vibration. Firstly, the root mean square (RMS) value of the acceleration was calculated for train brake system according to IEC 61373. Then, a configuration of vibrostand was proposed for the reliability test bed, which was mainly composed of vibrating table-board, vibrator motor, damp and four vibrating springs, as shown in figure 2. After that, an equation was got according to the RMS equivalency theory. Finally, the equation was solved according to the feature of the vibrostand. And the quantitative relation was got for exciting force F0, shock excitation circular frequency ω and spring rate k. The method can also be used on other occasions where sinusoidal vibration is needed to replace random vibration.

Fatigue Life Analysis of Shaking Table’s Exciting Beam Based on Finite Element Analysis

2011 ◽  
Vol 421 ◽  
pp. 208-211
Author(s):  
Hai Bin Gong ◽  
Jian Su ◽  
Dong Lin Zhang ◽  
Li Wang ◽  
Xing Yu Wang
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Large Scale ◽  
Time History ◽  
Shaking Table ◽  
Reliability Test ◽  
Test Bed ◽  
Element Analysis ◽  
Exciting Beam ◽  
Fatigue Life Analysis

With large scale increases of the train speed, the development of one reliability test bed which can simulate vibration environment becomes the extremely urgent task. The shaking table is one of key reliability test equipments, and its design and development is in needs immediately. The fatigue strength is basic design index of shaking table. Based on the load time history acquired by track spectrum, combined with finite element model of exciting beam and material properties, the fatigue life of exciting beam is predicted by Miner cumulative damage rule method in this paper.

Study on Simulation Reliability Test of Machining Center

2010 ◽  
Vol 34-35 ◽  
pp. 360-364
Author(s):  
Xiang Po Zhang ◽  
Jian Zhong Shang ◽  
Zhuo Wang
Keyword(s):  
Quality Improvement ◽  
Reliability Test ◽  
Test Bed ◽  
Long Cycle ◽  
Machining Center ◽  
Mechanical Products

Reliability research on machining center has great significance for the quality improvement of the machining center and its mechanical products. The long cycle and insufficient accuracy of collecting data is the main problem of the current reliability research on machining center. By means of building a test-bed and simulating the environment and running conditions of live using in the specialized laboratory, the simulation reliability tests, accelerated and enhancement tests are carried out. This paper aims to solve the above mentioned limitations and offer a more effective method for reliability tests on machining center.

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