Sandwich structures are widely used in many technical applications, because their composition combines high rigidity and strength with a good energy absorption, keeping low weights. Their static and dynamic behaviour can be studied by performing series of experi-mental tests, which, however, are expensive and require much setting and execution times. For this reason, it is common to use Finite Element (FE) simulation models, achieving good static and dynamic accuracy. However, difficulties in defining and modifying a complex mod-el led to the development of simplified models, such as 3D equivalent models. These homoge-neous models are based on specific laws and have geometric and stiffness characteristics equivalent to those of complex models. Many efforts have been spent to obtain models resem-bling the characteristics of honeycomb structures. These models have reached accurate static prediction performance, but obtaining a good accuracy for dynamic loads is still a challenge. Concept modelling approaches proved very useful for defining equivalent reduced models, able to reduce computational resources as well as the time needed for model modifications. In this paper, a dynamic FE-based method is used to obtain a concept model of honeycomb sandwich beams, that can reproduce accurately their static and dynamic behaviours. The method consists of two steps. First, a detailed FE model of one honeycomb beam-structure is developed and validated against experimental data obtained from literature. Its natural fre-quencies are estimated by means of a modal analysis in free-free conditions. Then, the analyt-ical modal model of the beam is used to derive cross-sectional stiffness properties of the equivalent 1D concept beam from the frequencies estimated by analysing the original 3D model. The analysis of a sandwich beam with a honeycomb aluminium core is presented as an application case to assess the accuracy of the proposed method.