IMPACT CRUSHING BEHAVIORS OF FUNCTIONALLY GRADED HONEYCOMB STRUCTURES WITH DEFECTS

摘要

Due to the superior characteristics, honeycombs are extensively used as energy absorption and noise reduction devices. In this work, the concept of functionally graded materials is introduced to the honeycomb structures by changing the thickness of cell walls. On the other hand, it is rather difficult to avoid the defects in manufactured honeycombs because of the processing technique. The imperfections of missing cell walls are introduced to illustrate the influences of defects on the impact crushing of the functionally graded honeycombs. Both the deformation modes and energy absorption of the functionally graded honeycombs with defects are studied. The results show that there always is a critical value for the compression strain. When the compression strain is less than the critical value, the energy absorption abilities for the positive density gradient are much stronger than those for the negative ones. Nevertheless, the honeycombs with the negative density gradient will absorb more energy when the compression strain is larger than the critical value. Moreover, the energy absorption capacity would be weakened with the increasing of the defect ratio. The deformation modes are sensitive to the defect location, the concentrated defects always results in the local deformation bands.