Equivalent inter-phase model of dynamic response to thin layer of different mechanical properties in engineering structures

The dynamic response of an infinite long elastic rod with a thin layer of different mechanical properties has been investigated. Three equivalent inter-phase models of elastic thin layer have been used: simple spring, spring plus mass and modified spring. The dynamic response of the rod has been simulated effectively by last two models: the reflection and transmission coefficients of longitudinal waves are in good agreement with the exact results in a rather wide low frequency region. The modified spring model proposed in this work is better than common spring plus mass model: the inertia has been considered, and its form is as simple as simple spring.