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In a rainflow classification, DIAdem first divides the load-time function into n classes. Classes are half-open intervals, which means that a value on the class boundary is included in the next higher class. Rainflow classification includes a value from the load-time function only if the absolute difference between the value and the preceding value in time is greater than a hysteresis Eps and the two values are in different classes (condition A).
If the setting Use the first and last value as reversal points is disabled, the first reversal point which crosses a class limit is counted as the first valid value in the load time function (X1). The last value of the load-time function is invalid. If the setting is enabled, DIAdem uses the first and the last value as reversal points. DIAdem uses the valid values from the load-time function to construct the residue vector Xi. The closed load cycles are eliminated from the residue vector and are counted to the rainflow matrix (rain). Additionally all class cycles (from => to) are counted to the transition matrix (trans).
If there are no more valid values in the load-time function (EOF = true), the non-closed load cycles remain in the residue vector. In DIAdem you select whether residues are closed and are counted. If there is an odd number of remaining values in the residue vector, the last value is not included, because there is no target class.
The following graphic shows the flow chart of the rainflow classification in DIAdem.
Characteristic Statistical Values | Process Capability | Classifications | Single Classification | Reducing Classification | Compound Classification | Rainflow Classification | Example Rainflow Classification | Algorithm Rainflow Classification