Small sample data method for testing fatigue performance
A fatigue performance, small sample technology, applied in electrical digital data processing, special data processing applications, instruments, etc., can solve the problems of high test consumption and cost, and achieve the effect of saving the number of samples, test time, and low cost
Active Publication Date: 2017-02-15
北京堂仁翔科技有限公司
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Problems solved by technology
Due to the dispersion of fatigue damage, it is often necessary to conduct a large number of fatigue tests to obtain the data of the fatigue performance test of a large sample, so as to infer its statistical characteristics. Therefore, the test consumption and cost are huge
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specific Embodiment approach
[0027] figure 1 It is a flowchart of the method of the present invention, and the specific implementation is as follows:
[0028] Step 1: Input fatigue performance test data
[0029] Enter the small sample data of the fatigue life test under different fatigue stress levels (S i ,N i )(i=1,2,...,n), where S i Is the fatigue stress level, N i Is the fatigue life.
[0030] Step two, fatigue performance S-N curve parameter estimation
[0031] The fatigue performance S-N curve expression is
[0032]
[0033] Where, S ∞ , Α and A are all material constants.
[0034] From the fatigue performance test data in step 1, linear regression method is used to estimate the material constants α, A, S of formula (1) ∞ , which is
[0035]
[0036]
[0037]
[0038] In the formula, σ is the sub-sample standard deviation of the fatigue performance test data.
[0039] From formula (2) to formula (4), it can be seen that the undetermined constants α, A, and σ are all parameters S ∞ The function of, by solving ...
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The invention provides a small sample data method for testing fatigue performance. The small sample data method comprises the steps of performing fatigue performance S-N curve parameter estimation by small sample data (Si and Ni) of a fatigue lifetime test under different stress levels and by a liner regression method; and performing reliability estimation on the fatigue performance S-N curve according to a normal distribution theory and a t distribution theory and by a parameter estimation result to acquire a fatigue performance S-N curve expression considering reliability and confidence. The small sample data method has the advantages of simpleness, practicability, low cost and the like. The fatigue performance reliability S-N curve required by application of test engineering can be acquired only by single-point tests of a few samples, no grouped fatigue performance test is needed, and the sample quantity and the test time are greatly reduced. The small sample data method has important academic significance and engineering application value.
Description
Technical field [0001] The invention provides a small sample data method for measuring fatigue performance, which belongs to the technical field of testing. Background technique [0002] The fatigue S-N curve is a key performance index of materials and structures, and it is also one of the preconditions for fatigue life assessment. Due to the dispersibility of fatigue damage, it is often necessary to conduct a large number of fatigue tests to obtain the fatigue performance test data of a large sample to infer its statistical characteristics. Therefore, the test consumption and cost are huge. In engineering practice, sometimes only a few specimens can be provided for fatigue testing due to conditions. At the same time, in order to save the cost and time of the specimens, the present invention proposes a small sample data method for measuring fatigue performance. The fatigue performance test of a small number of samples can determine the fatigue performance reliability SN curve th...
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IPC IPC(8): G06F17/50
CPCG06F30/20
Inventor 熊峻江万傲霜刘牧东
Owner 北京堂仁翔科技有限公司