Broadband multi-axis random vibration life prediction method in frequency domain
A random vibration and life prediction technology, applied in vibration testing, testing of machine/structural components, measuring devices, etc., can solve errors, multi-axis cannot guarantee that there is only one dangerous point, stress tensor at one point cannot be fully reflected, etc. problem, to achieve the effect of accurate prediction results
Pending Publication Date: 2021-07-09
BEIJING UNIV OF TECH
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Nowadays, most methods for multi-axis vibration are to measure a point stress tensor at the dangerous point and then extend it to multi-axial stress. The stress tensor at one point cannot fully reflect the multi-axis and cannot guarantee that there is only one dangerous point. This calculation method An error occurs when entering parameters
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[0033] The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.
[0034] A method for predicting the fatigue life of broadband random multi-axis vibration in the frequency domain, the method specifically includes the following steps, step 1) performing a multi-axis random vibration test on a test piece, the multi-axis test piece is a symmetrical design, and four strain gauges are respectively pasted on At the largest arc of the four edges, if cracks appear on the edge corresponding to the excitation direction, the data recorded on this edge will be used in the calculation. If there are cracks on both edges, the data in this direction will be numerically averaged in the frequency domain.
[0035] Step 2) Acquisition of the power spectrum of the stress response signal in two excitation directions. The stress in these two directions is the main cause of specimen failure. We take the strain time-domain data and convert i...
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The invention discloses a broadband multi-axis random vibration life prediction method in a frequency domain, relates to data acquisition, processing and life calculation of a broadband random vibration test, and belongs to the field of fatigue performance of a material under a random vibration load. According to the method, a previous method for calculating a multi-axis stress power spectrum matrix through dangerous point stress tensor extension is abandoned, a new stress power spectrum density matrix is combined through vibration direction corresponding response, meanwhile, a narrow-band approximation method is corrected, an over-conservative service life estimation result is given for the broadband Gaussian stress process, and a bandwidth correction coefficient is introduced. According to the method, the broadband multi-axis random vibration life can be well calculated.
Description
technical field [0001] The invention is applied to the field of fatigue life prediction of broadband random multi-axis vibration in the frequency domain, and particularly refers to a fatigue life prediction method considering the response of each vibration direction. Background technique [0002] Whether it is a ship, heavy machinery or a hypersonic vehicle that has recently attracted much attention, it is required that the fatigue life of many components is within 10 7 As mentioned above, using the traditional time-domain method will bring about a long time investment in design, experimentation, and testing, which is too time-consuming; the frequency-domain method requires small data samples, less data processing, and has wider practicability in engineering. [0003] Many structures bear not only one-directional loads during their working life, but also bear more multi-axial loads due to the randomness and complexity of the external environment and the diversity of loading ...
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IPC IPC(8): G06F17/14G06F17/18G06F17/15G01M7/06
CPCG06F17/14G06F17/18G06F17/15G01M7/06Y02T90/00
Inventor 尚德广王松光吴少东苗彬侯庚夏禹尹翔
Owner BEIJING UNIV OF TECH