Fatigue life assessment of a four-rotor swather based on rainflow cycle counting

Publication Type

Journal contribution (peer reviewed)

Authors

D.S. Paraforos, H.W. Griepentrog, S.G. Vougioukas, D. Kortenbruck

Year of publication

2014

Published in

Biosystems Engineering

Pubisher

Elsevier

Band/Volume

127/

DOI

10.1016/j.biosystemseng.2014.08.006

Page (from - to)

1-10

Assessing the fatigue life of agricultural machinery is a challenging task, especially when
the machine assumes different configurations in various operating modes. In such cases,
assessing fatigue life requires the recording of loads at high stress points on the machine
chassis during every possible mode of operation. In this paper strain data were recorded at
critical, high-stress points of a four-rotor swather, along with acceleration data on the
main axle. All data were georeferenced using a global navigation satellite system (GNSS).
Measurements were performed while the machine was transported on asphalt and along
unmade roads that are typically used by farmers. Additionally, data were acquired during
swathing operations in grass fields with different conditions and speeds. For each experiment
performed the rainflow cycle counting method was used to extract load cycles from
stress data, and the Palmgren-Miner method was used to determine the fatigue damage
from each individual cycle, as well as the total accumulated fatigue damage. The results
indicated the ability of the system to identify and quantify the damage that was accumulated
in every operation mode of the swather. The transition between these operating
modes, e.g. lifting the rotors for headland turning, proved to have a high impact on machine
fatigue life. Fatigue damage under working conditions in grass fields was also
increased by surface irregularities.