Axial Crushing Behavior of EPP Foam-Filled Nested GFRP Tubes
- 1Department of Mechanical Engineering, Faculty of Engineering, Sakarya University, 54187 Sakarya, Türkiye
Abstract
Polymer matrix composites are used in many components in the automotive sector due to their high specific mechanical properties, and their use in energy-absorbing structures provides significant reductions in vehicle weight. In this study, the energy absorption behavior and load-carrying capacity of nested glass fiber reinforced epoxy composite (GFRP) tubes with and without expanded polypropylene (EPP) foam filling were investigated under quasi-static axial loading. Three nesting arrangements of three concentric tubes were tested: equal-length, short-to-long and long-to-short. Foam filling increased the load-carrying capacity and the absorbed energy of all nested configurations. For the equal-length configuration, EPP foam filling increased the mean crushing force and absorbed energy by approximately 34%, while the specific energy absorption (SEA) improved by about 12%. In the short-to-long configuration, foam filling increased the absorbed energy by approximately 30%, whereas in the long-to-short configuration the increase was approximately 19%; however, the SEA increased by only 6% in the short-to-long configuration and remained practically unchanged in the long-to-short configuration, and the maximum force increased by 24–40% with foam filling. Among the investigated arrangements, the equal-length nested tubes exhibited the highest energy absorption, while the short-to-long configuration provided the lowest initial force and a stepwise load progression due to sequential tube activation. The long-to-short configuration demonstrated intermediate behavior with relatively higher force levels and moderate energy absorption. The results indicate that both foam filling and nesting arrangement govern the quasi-static crushing response of nested composite tubes and that the gain in absorbed energy due to foam filling must be weighed against the added mass and the higher transmitted force.
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BibTeX
@article{ozsoy2026axial,
title = {{Axial Crushing Behavior of EPP Foam-Filled Nested GFRP Tubes}},
author = {Mehmet İskender Özsoy and Muhammet Muaz Yalçın},
journal = {Polymers},
year = {2026},
month = oct,
doi = {10.3390/polym18212661},
url = {https://www.mdpi.com/2073-4360/18/21/2661},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Axial Crushing Behavior of EPP Foam-Filled Nested GFRP Tubes
AU - Mehmet İskender Özsoy
AU - Muhammet Muaz Yalçın
PY - 2026
DA - 2026/10/27
JO - Polymers
DO - 10.3390/polym18212661
UR - https://www.mdpi.com/2073-4360/18/21/2661
AB - Polymer matrix composites are used in many components in the automotive sector due to their high specific mechanical properties, and their use in energy-absorbing structures provides significant reductions in vehicle weight. In this study, the energy absorption behavior and load-carrying capacity of nested glass fiber reinforced epoxy composite (GFRP) tubes with and without expanded polypropylene (EPP) foam filling were investigated under quasi-static axial loading. Three nesting arrangements of three concentric tubes were tested: equal-length, short-to-long and long-to-short. Foam filling increased the load-carrying capacity and the absorbed energy of all nested configurations. For the equal-length configuration, EPP foam filling increased the mean crushing force and absorbed energy by approximately 34%, while the specific energy absorption (SEA) improved by about 12%. In the short-to-long configuration, foam filling increased the absorbed energy by approximately 30%, whereas in the long-to-short configuration the increase was approximately 19%; however, the SEA increased by only 6% in the short-to-long configuration and remained practically unchanged in the long-to-short configuration, and the maximum force increased by 24–40% with foam filling. Among the investigated arrangements, the equal-length nested tubes exhibited the highest energy absorption, while the short-to-long configuration provided the lowest initial force and a stepwise load progression due to sequential tube activation. The long-to-short configuration demonstrated intermediate behavior with relatively higher force levels and moderate energy absorption. The results indicate that both foam filling and nesting arrangement govern the quasi-static crushing response of nested composite tubes and that the gain in absorbed energy due to foam filling must be weighed against the added mass and the higher transmitted force.
SN - 2073-4360
ER -