CPA/STRESS makes the load combinations by combining the static vertical loads, the static lateral X and Y loads, the variable loads (vertical, lateral X & Y) at the specified positions plus the angled loads. It calculates stresses at each point for each load case and each variable
load position. The maximum interaction ratio for each load case is saved, and the overall maximum interaction ratio determined. The maximum compression and tension stress at each point is calculated as well as the corresponding stress at other section points.
CPA/STRESS reads Input and Spectrum files. The Input file contains the data for each member. The Spectrum file contains the data to calculate the forces on the members at each variable load position. A path is a series of steps and a spectrum is applying the path over a number of cycles.
The load combinations may be calculated by combining the static vertical loads, the static lateral X and Y loads, the moving loads at each position, the lateral moving load in the Y direction, the lateral moving
load X at each position, and the angled loads. CPA/STRESS calculates stresses at each point for each load combination in the path. The maximum fatigue damage is saved and the overall maximum fatigue damage determined.
BS2573, CMAA and FEM calculate fatigue damage based on a stress ratio. BS5400, BS7608 and JIS calculate fatigue damage based on a stress range.