This work presents a simple method for vibration analysis of a composite structure with viscoelastic heterogeneities.The method is in frequency domain and uses numerical homogenization technique in multiscale approach.Thus it allows a fast and flexible modeling of complex composite micro-structure.The main objective is to reduce the vibrations levels of structures at low frequency band; therefore we enhance the material microstructure with viscoelastic components in order to increase the structure ability to damp the flexural vibrations.At low frequency band, the structures main material (Matrix) is considered to be a homogeneous and purely elastic meanwhile the material of the heterogeneities (inclusions) has a frequency dependent viscoelastic behavior.