In this research, influence of foam filling technique in honeycomb cores by using lightweight rigid polyurethane foam is investigated. Plastic mechanical behaviors of honeycomb cores are studied by mean of numerical method. Four types of Aluminum honeycombs (Al 5052 alloy) both bare and foam-filled were subjected to unidirectional compression. Analyses were carried out for different impact velocities to survey quasi-static and dynamic crushing response of the honeycomb cores. Crushing strengths and specific absorbed energy were obtained for honeycomb cores which have different relative densities. FEM results showed that foam filling technique can increase crushing strength of honeycomb core up to 24 times, and its specific absorbed energy up to 11 times. However, it was found that in heavier honeycombs the effect of foam filling technique decreases significantly. Furthermore, it was found that in quasi-static situation, foam filling technique can enhance desired core mechanical properties’. Meanwhile, in dynamic states of impact it was illustrated that polyurethane foam have not significant role in improving crushing strength and specific absorbed energy of honeycomb cores. For instance, in crushing with impact velocity of 100 m/s, amount of specific absorbed energy for bare and foam-filled cores were approximately equal.