Identification of physical parameters with memory in non-linear systems

A new technique called 'Reverse MI/SO' has been developed that greatly simplifies the identification of parameters in systems with amplitude non-linearities and frequency-dependent coefficients as described by non-linear integro-differential equations of motion. This paper illustrates the technique for single degree-of-freedom (SDOF) non-linear systems where linear and non-linear damping is described by memory functions of an exponential and exponential-cosine analytical form. Comparisons between analytical and numerical simulation results prove that the Reverse MI/SO technique is quite robust. A discussion is included outlining the importance of this new technique as applied to the (non-linear) dynamics of ships and stability studies.