使用MATLAB写一个雨流计数法程序
时间: 2023-08-24 19:10:05 浏览: 71
下面是一个简单的MATLAB雨流计数法程序:
```matlab
function [cycle_range, cycle_count] = rainflow(data)
% RAINFLOW Rainflow counting method for fatigue analysis.
%
% Syntax:
% [cycle_range, cycle_count] = rainflow(data)
%
% Inputs:
% data - Time history data
%
% Outputs:
% cycle_range - Cycle range array
% cycle_count - Cycle count array
%
% Example:
% data = sin(linspace(0, 10*pi, 1000));
% [range, count] = rainflow(data);
% plot(range, count);
%
% References:
% ASTM E1049 - 85(2012) Standard Practices for Cycle Counting in Fatigue Analysis
% ASTM E606 - 15 Standard Test Method for Strain-Controlled Fatigue Testing
% Initialize variables
n = length(data);
cycle_range = [];
cycle_count = [];
% Find extrema
[maxima, max_loc] = findpeaks(data);
[minima, min_loc] = findpeaks(-data);
minima = -minima;
% Sort extrema by location
extrema = sort([max_loc, min_loc]);
extrema_type = zeros(size(extrema));
extrema_type(max_loc) = 1;
extrema_type(min_loc) = -1;
% Find half cycles
half_cycles = zeros(n, 1);
half_cycles(extrema(1:end-1)) = extrema_type(1:end-1);
half_cycles(extrema(2:end)) = half_cycles(extrema(2:end)) + extrema_type(2:end);
% Find full cycles
full_cycles = find(half_cycles == 0);
full_cycles_range = diff(data(full_cycles));
% Find partial cycles
half_cycles = half_cycles(full_cycles(1):full_cycles(end));
half_cycles_range = full_cycles_range(1:end-1) + full_cycles_range(2:end);
% Combine full and partial cycles
cycle_range = [full_cycles_range; half_cycles_range];
cycle_count = [ones(length(full_cycles_range), 1); 0.5*ones(length(half_cycles_range), 1)];
% Remove cycles below 2*sigma
sigma = std(data);
below_sigma = cycle_range < 2*sigma;
cycle_range(below_sigma) = [];
cycle_count(below_sigma) = [];
% Remove cycles with negative mean
mean_data = mean(data);
negative_mean = cycle_range + mean_data < 0;
cycle_range(negative_mean) = [];
cycle_count(negative_mean) = [];
end
```
这个程序输入一个1D向量(例如一个时间信号),输出雨流计数法中的循环范围和循环次数。雨流计数法的具体实现方式可以参考ASTM E1049-85和ASTM E606-15的标准。注意,这个程序只是一个简单的实现,需要根据具体的应用场景进行修改和优化。