Bent Tram A/S
Mechanical Testing Solutions

How does TramQA calculate the maximum stiffness tangent

TramQA uses a sliding window algorithm What is sliding window algorithm on stackoverflow.com to find the spot on the graph with the highest stiffness. The algorithm operates with the deformation on the x-axis and the load on the y-axis. Three startparameters are needed: the start load, the end load and the windows size (also expressed in load units).
The start and end points matching the start and end load are found. Between the start point and end point, all the possible windows with the given window size are examined. In each window, a linear regression line Linear_regression on wikipedia is calculated based on all the points inside the window. The regression line with the steepest slope represents the maximum stiffness tangent.