software and waves current profiles damping coefficients and energy attenuation along the riser have to be predetermined subjectively based on metocean data and other sources the method of the present invention only assesses the measured data and true riser responses with unknown damping and attenuation effects as well as travelling history of the stress signals under real world environmental conditions this invention employs an analytical method without any fea model that has to be meshed for elements the analytical method considers the riser string as a beam and anything attached to the beam such as buoyant modules is modelled as added mass or external loads an unknown variable in the method is the mass due to u201c added mass u201d added mass represents the mass of the surrounding water that must be moved under lateral motion the added mass coefficients to use are determined from field tests or lab experiments alternatively it can be calibrated in the field if direct strain measurements are also available for an ordinary euler bernoulli beam the bending stiffness el where e is the young 39 s modulus and l is the second moment of area of the beam 39 s cross section and mass are key parameters for beam responses while the beam in this invention refers to a modified beam with additional considerations for axial tension shear stiffness rotational inertia and cross section shape which is termed.