Markov Matrix gives non-integer number of cycles
Category: Post Processing
Problem
I'm calculating Markov Matrix from rainflow with 128 bins, plotting Number of cycles vs. Cycle Range but I get a table with number of cycles with decimal numbers. Why do I not get integer numbers for the number of cycles?
Solution
The Rainflow cycle counting algorithm in Bladed counts whole numbers of cycles, therefore you would end up with integers after a cycle count. This can be seen for example in the results of a single channel rainflow cycle run. However, when summing the results over a lifetime, a scaling factor is calculated for each load case and the rainflow cycle count of each load case is multiplied by its corresponding scaling factor.
The scaling factor is based on the weighting factor (e.g. user defined hours per year or Weibull distribution) and the scaling up/down to a whole year of simulation time. Therefore if the total number of hours entered into a rainflow calculation does not exactly equal the number of hours in a year, then the distribution that you provide will be scaled to match the number of hours in a year. This can lead to the non integer values for the number of cycles.
The scaling factor is based on the weighting factor (e.g. user defined hours per year or Weibull distribution) and the scaling up/down to a whole year of simulation time. Therefore if the total number of hours entered into a rainflow calculation does not exactly equal the number of hours in a year, then the distribution that you provide will be scaled to match the number of hours in a year. This can lead to the non integer values for the number of cycles.
Keywords Rainflow Cycle; Markov Matrix; Integer