The journal Complex component mode synthesis method using hybrid coordinates for generally damped systems with local nonlinearities solves a 10 DoF local nonlinear system with non proportional damping defined as C= alpha* M + beta* K+ R .

alpha, beta = Rayleigh damping coefficient

R= Stochastic diagonal matrix. Couldn't formulate this stochastic matrix, please help

Thanks in advance

Reference Journal: Article Complex component mode synthesis method using hybrid coordin...