Untitled

% Step 1: Load data from Excel
filename = 'your_file.xlsx'; % Replace with your actual file name
data = readtable(filename, 'VariableNamingRule', 'preserve'); % Preserve original column names

% Step 2: Assign correct column names
time = data.('Time (s)'); % Replace with the actual name of the time column
abs_accel = data.('Absolute Acceleration (m/s^2)'); % Replace with the actual name of the absolute acceleration column

% Step 3: Find peaks in the absolute acceleration data
[peaks, peak_times] = findpeaks(abs_accel, time);

% Step 4: Calculate logarithmic decrement
num_cycles = length(peaks) - 1; % Number of cycles
log_dec = zeros(num_cycles, 1); % Preallocate array for log decrement

for i = 1:num_cycles
    log_dec(i) = log(peaks(i) / peaks(i+1));
end

% Step 5: Plot the results
figure;

% Plot absolute acceleration vs. time
subplot(2, 1, 1);
plot(time, abs_accel, '-b', 'DisplayName', 'Absolute Acceleration');
hold on;
plot(peak_times, peaks, 'ro', 'DisplayName', 'Peaks');
xlabel('Time (s)');
ylabel('Absolute Acceleration');
title('Absolute Acceleration vs. Time');
legend show;
grid on;

% Plot logarithmic decrement vs. cycle number
subplot(2, 1, 2);
cycle_numbers = 1:num_cycles; % Cycle numbers
plot(cycle_numbers, log_dec, '-k', 'LineWidth', 1.5);
xlabel('Cycle Number');
ylabel('Logarithmic Decrement (\delta)');
title('Logarithmic Decrement vs. Cycle Number');
grid on;

% Display calculated values
disp('Logarithmic Decrement for each cycle:');
disp(log_dec);

% Optional: Save the figure
saveas(gcf, 'logarithmic_decrement_analysis.png');