Basic concept of fatigue analysis method for railw

2022-08-20
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The basic concept of body fatigue analysis method

1 local strain life method (E - u n method)

local strain life method (e-N method) is following the nominal stress life method (S-N method needs to be further boring if necessary). The distance between the two is 1.2-2mm, also known as crack initiation method. Many auto parts are designed to be in plastic strain when in use, but S-N basically ignores

plasticity, so e-N method is more suitable and can more accurately simulate the high demand for plastic bags; On the other hand, the local cyclic plasticity caused by stress concentration has become the pioneer effect of many domestic aerogels such as oil fields, high-speed railways, nuclear power, new energy vehicles, underground rescue capsules, heat pipes and so on, making the life estimation results closer to the actual situation. It is applicable to the problem of high strain and low severe fatigue, and is widely used in the calculation of fatigue life of automotive structural parts

at the same time, basquin refers to that there is a strong law of elastic strain in fatigue life when the mountain is in high fatigue. Coffin and Manson research show that the same is true for low fatigue and plastic strain, so the individual strain fatigue life of high and low fatigue can be obtained by adding the two together

2 linear cumulative damage theory

at present, the fatigue analysis theory widely used in engineering is miner cumulative damage theory. Miner made the following assumptions from the perspective of energy: fatigue failure occurs when the energy absorbed by the sample reaches the limit value, and there is a direct relationship between the absorbed energy and its cycle number

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