The article proposes the method of comparative analysis of mechanical behavior stages of two types of materials which are used for forming monolithic outer layers and inner cellular layers of sandwich panels. Fiber reinforced polymer composite has been explored as monolithic systems and a polymer compound, that’s based on a methacrylate oligomer and created by additive technology, has been researched as an inner cellular fiberfill. The model cellular samples had an inner square cell. The samples have been tested in compression at different strain rates and temperatures. To analyze specific stages of deformation response of studied systems, have been applied the intensity parameters of specific energy absorption by energy samples of external influence on the development of successive steps of deformation processes. Property parameters of the researched samples have been examined depending on parameters of fiberfill material cells and parameters of fiber filler as part of composite.