A method for corrosion crack growth performance characterization and life estimation
A technique for crack growth and life estimation, applied in the direction of testing material strength by applying repetitive force/pulsation force
Active Publication Date: 2017-09-15
北京睦邦仁科技有限公司
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At present, there is still a lack of a more accurate and practical corrosion crack growth performance characterization model and life estimation method. Therefore, a simple and practical method for corrosion crack growth performance characterization and life estimation is invented. According to the constant load crack growth performance curve and the measured flight load spectrum, the corrosion crack growth performance characterization model can be constructed, and the spectrum-loaded crack growth life of the material can be estimated. The invention has important academic significance and engineering application value
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[0064] Figure 6 For the flow chart of the method of the present invention, the present invention is realized in three steps, specifically:
[0065] Step 1. Corrosion crack growth performance da / dN-ΔK curve
[0066] figure 1 is the schematic diagram of the loading of the central crack tensile M(T) specimen, according to figure 1 The loading form and the national standard "Metallic Materials Fatigue Crack Growth Rate Test Method" (GB-T6398), the crack growth test is carried out in a corrosive environment. Apply the specified stress ratio R, observe and record the left and right crack lengths during the crack growth process, and calculate the average crack growth length a according to the left and right crack lengths, and obtain the constant load crack growth a-N data of aluminum alloy materials, using the secant method data processing
[0067]
[0068] In the formula, a i and a i+1 is the crack growth length adjacent to two points, N i and N i+1 is the corresponding ...
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A method for characterization and life estimation of corrosion crack growth performance, the method has three steps: step 1, obtain the corrosion crack growth performance da / dN-ΔK curve of the material through a constant load test; step 2, consider the effect of corrosion on the fracture threshold influence, modify the Walker formula, and combine the binary linear regression theory to fit the da / dN-ΔK surface to construct a corrosion crack growth performance characterization model; Step 3, considering the hysteresis effect under the spectral load and the interaction between loads, The Willenborg-Chang model and cumulative summation method were used to estimate the corrosion spectrum-loaded crack growth life of materials. The invention is simple and practical. It only needs the constant-load crack growth performance curve and the measured flight load spectrum of the material in the corrosive environment to build a corrosion crack growth performance characterization model and estimate the spectrum-loaded crack growth life, which has important academic significance and engineering application value. .
Description
technical field [0001] The invention provides a corrosion crack propagation performance characterization and life estimation method, which belongs to the technical field of metal structure fatigue fracture reliability. Background technique [0002] In engineering practice, materials are often damaged by alternating loads and fatigue cracks appear; when the damage accumulation exceeds the allowable limit of the material, fracture failure occurs, thus posing a threat to the safety of the structure. Corrosion is an inevitable environmental factor in the use of materials. For example, aircraft serving in coastal areas are often corroded by the ocean atmosphere; oil pipelines are corroded by acidic substances in crude oil; in corrosive environments, the macroscopic properties and microstructure of materials often change. , the crack growth behavior is also different, therefore, the research on the corrosion crack growth behavior of materials has important practical significance. ...
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IPC IPC(8): G01N3/32
Inventor熊峻江刘牧东王池权
Owner北京睦邦仁科技有限公司