Performance assessment of 3D printed multi-material energy absorber for automotive bumper: pedestrian lower extremity protection

Komal Chawla; Ahmed Arabi Hassen; Nikhil Garg; Deepak Kumar Pokkalla; Tyler Smith; Brittany Rodriguez; Desheng Yao; Rayne Zheng; Ellen Lee; Iskander Farooq; Matthew Rebandt; Asim Khan; Seokpum Kim

doi:10.1016/j.compstruct.2026.120056

Performance assessment of 3D printed multi-material energy absorber for automotive bumper: pedestrian lower extremity protection

Komal Chawla
, Ahmed Arabi Hassen
, Nikhil Garg
, Deepak Kumar Pokkalla
, Tyler Smith
, Brittany Rodriguez
, Desheng Yao
, Rayne Zheng
, Ellen Lee
, Iskander Farooq
, Matthew Rebandt
, Asim Khan
, Seokpum Kim

Research output: Contribution to journal › Article › peer-review

Abstract

Designing an energy absorber for automotive bumpers involves balancing low-speed and high-speed impacts to ensure safety, reduce repair costs, and meet regulatory standards. This study explores a novel design using multi-material 3D printing and structural optimization to fabricate a lightweight and cost-efficient energy absorber. The design effectively dissipates energy in low-speed collisions and minimizes force transmission in high-speed pedestrain impacts, helping to meet both safety and performance requirements. The energy absorber design combines 20% carbon fiber-reinforced acrylonitrile butadiene styrene (CF-ABS) and thermoplastic polyurethane (TPU) for optimal stiffness and flexibility. It uses 3D-printed lattice structures optimized through finite element simulations to help meet both low-speed and high-speed impact requirements. Full-scale energy absorbers were 3D-printed using optimized CF-ABS/TPU blends and tested under high-speed impact using the Flexible Pedestrian Legform Impactor (Flex-PLI). For fair comparison, a baseline bumper with a traditional triangular lattice structure, also 3D-printed from the same CF-ABS/TPU materials, was similarly tested. Interestingly, both the optimized and baseline 3D-printed energy absorbers showed nearly identical performance, successfully meeting injury limits. Their performances were also benchmarked against an injection-molded energy absorber. While both 3D-printed and injection-molded designs met injury limits, the 3D-printed absorber exhibited a higher tibia bending moment, indicating an opportunity for further optimization. A Techno-Economic Analysis compared the costs of producing energy absorbers using traditional manufacturing and 3D printing. The analysis highlighted that 3D printing offers cost benefits for low to medium production volumes, with the total cost per energy absorber at ∼ $74, compared to traditional methods that become economical beyond 2000 units.

Original language	English
Article number	120056
Journal	Composite Structures
Volume	381
DOIs	https://doi.org/10.1016/j.compstruct.2026.120056
State	Published - Apr 1 2026

Funding

Notice: This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05- 00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the work for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, world-wide license to publish or reproduce the submitted manuscript version of this work, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( https://energy.gov/downloads/doe-public-access-plan ). The research is sponsored by the Vehicle Technologies Office in the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Industrial Technologies Program , under contract DE-AC05-00OR22725 with UT-Battelle, LLC.

Keywords

Additive manufacturing
Automotive bumper
Energy absorber
Low and high-speed impacts
Techno-economic analysis

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10.1016/j.compstruct.2026.120056

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Chawla, K., Hassen, A. A., Garg, N., Pokkalla, D. K., Smith, T., Rodriguez, B., Yao, D., Zheng, R., Lee, E., Farooq, I., Rebandt, M., Khan, A., & Kim, S. (2026). Performance assessment of 3D printed multi-material energy absorber for automotive bumper: pedestrian lower extremity protection. Composite Structures, 381, Article 120056. https://doi.org/10.1016/j.compstruct.2026.120056

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abstract = "Designing an energy absorber for automotive bumpers involves balancing low-speed and high-speed impacts to ensure safety, reduce repair costs, and meet regulatory standards. This study explores a novel design using multi-material 3D printing and structural optimization to fabricate a lightweight and cost-efficient energy absorber. The design effectively dissipates energy in low-speed collisions and minimizes force transmission in high-speed pedestrain impacts, helping to meet both safety and performance requirements. The energy absorber design combines 20\% carbon fiber-reinforced acrylonitrile butadiene styrene (CF-ABS) and thermoplastic polyurethane (TPU) for optimal stiffness and flexibility. It uses 3D-printed lattice structures optimized through finite element simulations to help meet both low-speed and high-speed impact requirements. Full-scale energy absorbers were 3D-printed using optimized CF-ABS/TPU blends and tested under high-speed impact using the Flexible Pedestrian Legform Impactor (Flex-PLI). For fair comparison, a baseline bumper with a traditional triangular lattice structure, also 3D-printed from the same CF-ABS/TPU materials, was similarly tested. Interestingly, both the optimized and baseline 3D-printed energy absorbers showed nearly identical performance, successfully meeting injury limits. Their performances were also benchmarked against an injection-molded energy absorber. While both 3D-printed and injection-molded designs met injury limits, the 3D-printed absorber exhibited a higher tibia bending moment, indicating an opportunity for further optimization. A Techno-Economic Analysis compared the costs of producing energy absorbers using traditional manufacturing and 3D printing. The analysis highlighted that 3D printing offers cost benefits for low to medium production volumes, with the total cost per energy absorber at ∼ \$74, compared to traditional methods that become economical beyond 2000 units.",

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AU - Chawla, Komal

AU - Hassen, Ahmed Arabi

AU - Garg, Nikhil

AU - Pokkalla, Deepak Kumar

AU - Smith, Tyler

AU - Rodriguez, Brittany

AU - Yao, Desheng

AU - Zheng, Rayne

AU - Lee, Ellen

AU - Farooq, Iskander

AU - Rebandt, Matthew

AU - Khan, Asim

AU - Kim, Seokpum

PY - 2026/4/1

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N2 - Designing an energy absorber for automotive bumpers involves balancing low-speed and high-speed impacts to ensure safety, reduce repair costs, and meet regulatory standards. This study explores a novel design using multi-material 3D printing and structural optimization to fabricate a lightweight and cost-efficient energy absorber. The design effectively dissipates energy in low-speed collisions and minimizes force transmission in high-speed pedestrain impacts, helping to meet both safety and performance requirements. The energy absorber design combines 20% carbon fiber-reinforced acrylonitrile butadiene styrene (CF-ABS) and thermoplastic polyurethane (TPU) for optimal stiffness and flexibility. It uses 3D-printed lattice structures optimized through finite element simulations to help meet both low-speed and high-speed impact requirements. Full-scale energy absorbers were 3D-printed using optimized CF-ABS/TPU blends and tested under high-speed impact using the Flexible Pedestrian Legform Impactor (Flex-PLI). For fair comparison, a baseline bumper with a traditional triangular lattice structure, also 3D-printed from the same CF-ABS/TPU materials, was similarly tested. Interestingly, both the optimized and baseline 3D-printed energy absorbers showed nearly identical performance, successfully meeting injury limits. Their performances were also benchmarked against an injection-molded energy absorber. While both 3D-printed and injection-molded designs met injury limits, the 3D-printed absorber exhibited a higher tibia bending moment, indicating an opportunity for further optimization. A Techno-Economic Analysis compared the costs of producing energy absorbers using traditional manufacturing and 3D printing. The analysis highlighted that 3D printing offers cost benefits for low to medium production volumes, with the total cost per energy absorber at ∼ $74, compared to traditional methods that become economical beyond 2000 units.

AB - Designing an energy absorber for automotive bumpers involves balancing low-speed and high-speed impacts to ensure safety, reduce repair costs, and meet regulatory standards. This study explores a novel design using multi-material 3D printing and structural optimization to fabricate a lightweight and cost-efficient energy absorber. The design effectively dissipates energy in low-speed collisions and minimizes force transmission in high-speed pedestrain impacts, helping to meet both safety and performance requirements. The energy absorber design combines 20% carbon fiber-reinforced acrylonitrile butadiene styrene (CF-ABS) and thermoplastic polyurethane (TPU) for optimal stiffness and flexibility. It uses 3D-printed lattice structures optimized through finite element simulations to help meet both low-speed and high-speed impact requirements. Full-scale energy absorbers were 3D-printed using optimized CF-ABS/TPU blends and tested under high-speed impact using the Flexible Pedestrian Legform Impactor (Flex-PLI). For fair comparison, a baseline bumper with a traditional triangular lattice structure, also 3D-printed from the same CF-ABS/TPU materials, was similarly tested. Interestingly, both the optimized and baseline 3D-printed energy absorbers showed nearly identical performance, successfully meeting injury limits. Their performances were also benchmarked against an injection-molded energy absorber. While both 3D-printed and injection-molded designs met injury limits, the 3D-printed absorber exhibited a higher tibia bending moment, indicating an opportunity for further optimization. A Techno-Economic Analysis compared the costs of producing energy absorbers using traditional manufacturing and 3D printing. The analysis highlighted that 3D printing offers cost benefits for low to medium production volumes, with the total cost per energy absorber at ∼ $74, compared to traditional methods that become economical beyond 2000 units.

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KW - Low and high-speed impacts

KW - Techno-economic analysis

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M3 - Article

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JO - Composite Structures

JF - Composite Structures

M1 - 120056

ER -

Performance assessment of 3D printed multi-material energy absorber for automotive bumper: pedestrian lower extremity protection

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