Damage accumulation comparison for various vibration test profile generation methods applied to a complex payload

2021 ◽  
pp. 107754632110105
Author(s):  
Mark Warren ◽  
Keith F Joiner ◽  
Murat Tahtali
Keyword(s):  
Damage Accumulation ◽  
Acceptance Test ◽  
Vibration Testing ◽  
Damage Potential ◽  
Power Spectral ◽  
Amplitude Vibration ◽  
Predicted Values ◽  
Vibration Tests ◽  
Time Waveform ◽  
Development Methods

There are potential sources of uncertainty when using default or generic profiles for vibration testing, particularly for large and complex payloads ( Warren and Joiner, 2019 ). Replacing these severities with custom profiles generated using measured data offers one alternative; however, care must be taken not to select an inappropriate or inaccurate method. This research details the methodology and results of a trial which involved the design and implementation of a series of vibration tests, each to simulate a mixed-terrain environment applied to a complex payload. A systematic approach was used to develop and execute a test plan via the design of experiments method. An estimate of the damage potential for each was formed using Miner’s rule (linear damage accumulation) applied to direct strain gauge data. This approach was compared with damage measured during a time waveform replication style test to be used as a baseline. The results of this test can be used to guide test specifiers and programme-level acceptance test guidelines and may be useful in implementing or guiding standards in this space. In addition, the damage measured in a series of increasing amplitude vibration tests (with an identical power spectral density) was compared with predicted values to assess the gain linearity assumptions often used in accelerated vibration testing. The research is unique as the authors could not source a thorough trial comparing the damage produced using a range of different profile development methods with a complex, real-world payload. Test houses and test specifiers seeking to improve the accuracy of their tests should consider the key findings and guidance in this article.

An Investigation of the Vibration Testing Method for Small Diameter Endmills

2014 ◽  
Vol 625 ◽  
pp. 134-139
Author(s):  
Takenori Ono
Keyword(s):  
Small Diameter ◽  
Milling Process ◽  
Modal Parameters ◽  
Vibration Testing ◽  
Function Generator ◽  
Testing Method ◽  
Milling Tool ◽  
Compliance Curve ◽  
Vibration Tests ◽  
The Impact

This paper introduced about the in-process vibration testing method for small diameter endmill. By this method, the natural frequency and modal parameters such as mass, damping, and stiffness of the milling tool can be determined in the milling process. An oscillation of the vibrator is controlled by the function generator to apply the impact force at the appropriate cutting period. The measurement setup can determine the compliance curve by the measurement signals of the exiting force and tool deformation. To evaluate the feasibility of the new method, vibration tests were performed on a square endmill which has the diameter of 4 mm in the milling on brass material. Results of vibration tests show that modal parameters of the specific vibration mode can be determined by the new developed method.

scholarly journals Analysing Random Vibration of KLT Box during Transporting by Finite Element Method

10.29007/b1th ◽  
2022 ◽  
Author(s):  
Cong Hoa Vu ◽  
Ngoc Thien Ban Dang
Keyword(s):  
Finite Element ◽  
Spectral Density ◽  
Power Spectral Density ◽  
Automotive Industry ◽  
Random Vibration ◽  
Element Model ◽  
Vibration Testing ◽  
Time Data ◽  
Power Spectral ◽  
The Impact

Today, freight is an extremely important industry for the world we are living. Fast transportation, large volume...will optimize the cost, time and effort. Besides, ensuring the products safety is a matter of concern. During transporting, it is inevitable that the vibration caused by the engine, rough road surface...the cargo inside can be damaged. Automobile industries have prime importance to vibration testing. Sine vibration testing is performed when we have been given with only one frequency at given time instant. Trend to perform random vibration testing has been increased in recent times. As random vibration considers all excited frequencies in defined spectrum at known interval of time, it gives real-time data of vibration severities. The vibration severity is expressed in terms of Power Spectral Density (PSD). KLT box is an industrial stacking container conforming to the VDA 4500 standard that was defined by German Association of the Automotive Industry (VDA) for the automotive industry. The aim of this paper is study about random vibration and power spectral density analysis, how it can be used to predict the impact of hash road to the KLT box on container / truck during transportation. Finite element model is developed in ANSYS, modal analysis and random vibration analysis were done.

Inadequacies in Uniaxial Stress Screen Vibration Testing

2001 ◽  
Vol 44 (4) ◽  
pp. 20-23 ◽  
Author(s):  
Wayne Whiteman ◽  
Morris Berman
Keyword(s):  
Fatigue Failure ◽  
Uniaxial Stress ◽  
Test Methods ◽  
Operating Conditions ◽  
Triaxial Tests ◽  
Vibration Testing ◽  
Uniaxial Test ◽  
Multiaxial Testing ◽  
The Difference ◽  
Vibration Tests

Validating the design and reliability of equipment prior to fielding is a critical step in the materiel development and manufacturing process. Success requires that the new equipment undergo and survive testing. Stress screen vibration testing determines the equipment's design capability. Traditionally, stress screen vibration tests have been conducted by sequentially applying uniaxial excitation to test articles along three orthogonal axes. Simultaneous multiaxial excitation is an advanced method of vibration testing with the goal of more closely approximating real-world operating conditions. Multiaxial testing achieves the synergistic effect of exciting all modes simultaneously and induces a more realistic vibrational stress loading condition. This research begins an effort to explore the difference in predicting fatigue failure between sequentially applied uniaxial and simultaneous triaxial tests. The research plan starts with simple cantilever beam structures. Once initial results are complete, more complex and typical components in actual vehicles will be tested. This paper provides results that reveal inadequacies in traditional uniaxial test methods. It is shown that the order in which orthogonal uniaxial excitation is applied has a significant effect on fatigue failure.

Shaker Testing with Simultaneous Control of PSD and FDS

2020 ◽  
Vol 63 (1) ◽  
pp. 21-34
Author(s):  
Alexander Steinwolf
Keyword(s):  
Excitation Frequency ◽  
Scaling Up ◽  
Excitation Level ◽  
Accelerated Testing ◽  
Random Testing ◽  
Frequency Range ◽  
Damage Potential ◽  
Simultaneous Control ◽  
Power Spectral ◽  
Phase Manipulation

Abstract The fatigue damage spectrum (FDS) model characterizes how the damage potential is distributed over the excitation frequency range, similarly to how the power spectral density (PSD) characterizes the distribution of the excitation level. However, reproducing the operational PSD during in-house shaker testing does not necessarily mean that the FDS would be also reproduced because some unusually distinctive peaks, higher than those in a signal generated from the PSD, occur in vibrations of automobiles and railway vehicles. Presence of these peaks in real operational vibrations and their absence in the PSD-based random testing is the reason why the shaker testing FDS obtained by the ordinary PSD control is different in shape and usually lies below the operational FDS. It is shown in this paper that the FDS shape as a function of frequency can be controlled by manipulating some of the IFFT phases instead of making all of them random. Since the phase manipulation does not affect the excitation PSD, the FDS and the PSD can be controlled simultaneously, which is demonstrated for an example of operational vibrations of an automobile. This new concept of shaker testing with the PSD+FDS control can also be used for accelerated testing when the FDS target needs to be artificially increased. It can be done without scaling up the PSD, thereby avoiding concerns about the test exaggeration factor being too high.

The Effect of Joints on the Transverse Vibration of a Simple Structure

1990 ◽  
Vol 204 (1) ◽  
pp. 37-42 ◽  
Author(s):  
F P E Dunne ◽  
M Heppenstall
Keyword(s):  
Mild Steel ◽  
Compressive Stress ◽  
Transverse Vibration ◽  
Reasonable Agreement ◽  
Simple Structure ◽  
Natural Frequencies ◽  
Theoretical Models ◽  
Experimental Results ◽  
Predicted Values ◽  
Vibration Tests

Transverse vibration tests were carried out on a cold-drawn mild steel tubular beam containing annular metal-to-metal joints. The tests were also carried out on an unjointed beam of the same dimensions. An axial compressive preload was applied giving a compressive stress in the range of 0–80 N/mm2. Joints between rough turned surfaces, between ground surfaces and mixed joints between both types of surface were used. Dynamic bending stiffnesses of the joints over the range of compressive stress were determined. Stiffness of the turned and mixed joints was found to be proportional to preload. Stiffness of ground joints increased with preload, but not proportionally. Theoretical models were developed to determine joint bending siffness and natural frequencies of transverse vibration of the jointed beams. Predicted values of joint bending stiffness for ground and turned joints were in reasonable agreement with the experimental results.

Vibration Testing as a Tool to Optimize the Configuration of the PCBs

2014 ◽  
Vol 2014 (1) ◽  
pp. 000050-000054
Author(s):  
I. Szendiuch ◽  
B. Psota ◽  
A. Otáhal ◽  
M. Klapka
Keyword(s):  
Mechanical Stress ◽  
Design Process ◽  
High Density ◽  
Harsh Environment ◽  
Vibration Testing ◽  
Stress Optimization ◽  
New Construction ◽  
Vibration Tests ◽  
Eu Project ◽  
The Impact

This paper is linked to the EU project Euripides Eureka BOB (Board on Board) which is a joint solution for companies from four European countries. Its goal is the development, design, implementation and validation of an innovative configuration of the PCBs in 2.5D arrangement, which is designed for applications with a high density of components, and must meet the requirements for reliability in harsh environment and the ability to repair. To minimize the effect of mechanical stress is one of the priorities of this new construction, where a high density of components occurs on both sides of the PCB configuration. Therefore, any new solution, especially in 2.5D configuration, designed for harsh environment, requires mechanical stress optimization, already in the board's design process. Shock and vibration tests are also essential steps to reliability and quality assurance. This paper suggests as a simple example of one possible way to achieve this goal using vibration testing, including vibration simulations in ANSYS, to optimize the layout during the PCB design process. The optimization process consists of a sequence of necessary steps that need to be performed. The main contribution of this work is to show the first approach in the simulation of vibrations, and demonstrate that this path can help you choose the best design and layout of PCB, so as to avoid later problems caused by mechanical influences. In summary, specific rules are provided for verification of mechanical reliability by vibration testing and the most important properties of PCBs are defined. This procedure is in general suitable for use primarily in the design of any PCB, where you can prevent possible complications due to the impact of mechanical stress on the reliability of newly developed products.

Growth of spectral components in a wind-generated wave train

1968 ◽  
Vol 33 (3) ◽  
pp. 545-560 ◽  
Author(s):  
Alex J. Sutherland
Keyword(s):  
Growth Rates ◽  
Linear Growth ◽  
Wave Train ◽  
Surface Displacement ◽  
Research Facility ◽  
Power Spectral ◽  
Spectral Components ◽  
Order Of Magnitude ◽  
Wave Research ◽  
Predicted Values

Power spectral density measurements were made of the water surface displacement in a wind-generated wave train in the Stanford wind, water-wave research facility. Growth rates of different components were determined from the measured spectra. The resulting values were compared with those predicted by the viscous Reynolds stress mechanism of energy transfer from wind to wave which was proposed by Miles. Where the growth was exponential the theory could be made to predict growth rates successfully at wave frequencies less than 3·5 c/s. At higher frequencies the theory predicted values an order of magnitude larger than those measured. Limited regions of linear growth were found at the lowest wind speed for components with frequencies less than 2·5 c/s. The scatter in the data did not permit a quantitative comparison with theory to be made for this range.

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