# How to rainflow counting?

## How to rainflow counting?

The rainflow cycle counting algorithm is summarized as follows:

1. Rotate the loading history 90° such that the time axis is vertically downward and the load time history resembles a pagoda roof.
2. Imagine a flow of rain starting at each successive extremum point.

What is rainflow cycle counting method?

The rainflow-counting algorithm is used in calculating the fatigue life of a component in order to convert a loading sequence of varying stress into an equivalent set of constant amplitude stress reversals.

### What is rainflow counting fatigue?

The rainflow method is a method for counting fatigue cycles from a time history. The fatigue cycles are stress-reversals. The rainflow method allows the application of Miner’s rule in order to assess the fatigue life of a structure subject to complex loading.

What is the Goodman line?

Goodman criteria (Goodman Line) :- Used for brittle Materials. A straight line joining Se on the stress amplitude axis and Sat on the mean stress axis is called the Goodman’s line, According to the Goodman criteria , the triangular region below this line is considered to be safe.

## What is Goodman line equation?

Within the branch of materials science known as material failure theory, the Goodman relation (also called a Goodman diagram, a Goodman-Haigh diagram, a Haigh diagram or a Haigh-Soderberg diagram) is an equation used to quantify the interaction of mean and alternating stresses on the fatigue life of a material.

What is fatigue limit of steel?

According to GOST 25502–79, the fatigue limit is found by testing not less than 6–8 specimens to determine the highest stress at which the material does not fracture at a preset number of cycles (the test base). The fatigue limit for steels is determined on a base of 5–10 million cycles.

### How can I improve my fatigue life?

Fatigue life is improved by reducing the stress concentration on the weld joint, softening the weld toe shape, improving the metal structure of the weld zone, and adequately changing the pin shape and treatment conditions of friction stir welding as shown in Figure 2.

What is basquin model?

Basquin’s equation is a power law relationship which describes the linear relationship between the applied stress cycles (S) in the y-axis and the number of cycles to failure in the x-axis plotted on a log-log scale.