MATLAB Implementation of Rainflow Counting Method for Fatigue Analysis

The Rainflow Counting Method is a cycle counting technique based on stress-strain hysteresis behavior. By systematically counting closed stress-strain hysteresis loops, it completely captures the full spectrum of random loading processes, thereby determining the equivalent fatigue damage from load-time history data. This method is widely employed in engineering for damage accumulation calculations, with applications spanning multiple fields including mechanical, civil, aerospace, and automotive engineering. When implementing the Rainflow Counting Method in MATLAB, key considerations include load magnitude, loading direction, frequency characteristics, and load history patterns. The algorithm typically involves four main steps: peak-valley extraction, cycle counting using the rainflow principle, range-pair identification, and damage calculation based on Miner's rule. The implementation requires careful handling of signal preprocessing, cycle extraction logic, and damage accumulation algorithms. MATLAB's built-in functions like rainflow in the Signal Processing Toolbox can be utilized, while custom implementations often employ matrix operations and loop structures for efficient cycle identification. In summary, the Rainflow Counting Method serves as a crucial engineering practice that enables engineers to accurately predict and evaluate structural fatigue life through systematic load cycle analysis.