Papers

@article{lopez_assessment_2025,

title = {Assessment of foam-filled carbon-fiber reinforced thermoplastic tubes under impact loading for energy absorption structures},

author = {Carmen López-Chao and Luis E. Romera-Rodríguez and Jacobo Díaz-García},

url = {https://www.sciencedirect.com/science/article/pii/S0263822325007020},

doi = {10.1016/j.compstruct.2025.119537},

issn = {0263-8223},

year  = {2025},

date = {2025-12-01},

urldate = {2025-12-01},

journal = {Composite Structures},

volume = {373},

pages = {119537},

abstract = {Structures composed of multiple materials can leverage the advantages of each constituent to enhance the overall performance of energy-absorbing components. This research investigates the axial crushing behavior of foam-filled carbon-fiber reinforced thermoplastic energy absorbers. The studied components consist of thin-walled circular tubes filled with polymeric foam to enhance energy absorption capabilities. A material testing campaign is conducted on the polymeric foam to calibrate the numerical model. Finite element analyses are performed to evaluate the crashworthiness behavior, failure mechanisms, and energy absorption metrics of the full components under dynamic impact conditions. Two components are subjected to axial impact tests to validate the numerical predictions. The experimental results reveal a progressive crushing process, governed by brittle fracture and delamination. The numerical predictions demonstrate good agreement with the experimental findings, capturing both failure mechanisms and crashworthiness metrics. Specific energy absorption values of up to 40 kJ/kg and absorbed energies up to 15 kJ are achieved, indicating adequate structural performance. Furthermore, interaction effects between the foam and the composite tube are analyzed and compared to empty tubes tested in a previous study. The results show that the foam significantly enhances crashworthiness, with foam-filled tubes absorbing approximately 43% more energy than the equivalent empty tubes.},

keywords = {Crashworthiness, Finite element analysis, Foam-filled, Impact testing, Thermoplastic composite},

pubstate = {published},

tppubtype = {article}

}

@article{paz_analytical_2020,

title = {Analytical and numerical crashworthiness uncertainty quantification of metallic thin-walled energy absorbers},

author = {Javier Paz-Méndez and Jacobo Díaz-García and Luis E. Romera-Rodríguez},

url = {https://www.sciencedirect.com/science/article/pii/S0263823120308971},

doi = {10.1016/j.tws.2020.107022},

issn = {0263-8231},

year  = {2020},

date = {2020-12-01},

urldate = {2026-08-06},

journal = {Thin-Walled Structures},

volume = {157},

pages = {107022},

abstract = {Thin-walled tubular components are featured in transport structures for increased occupant protection in the event of a crash. However, when the limits of their design are sought through deterministic procedures, components often become unreliable due to uncertainties which may cause them to underperform or even fail. Seeking a deeper understanding of the effect of incertitudes on the thin-walled tubes' performance, this research focuses on the crashworthiness quantification of diverse sources of uncertainties in the progressive collapse of these components under axial loads. For a broader insight on the tubes’ behavior, diversity is considered and scrutinized on all the main fields involved in the research; studying two cross-sections, three sources of uncertainties, and the two epitomical crashworthiness metrics, namely the average and peak crushing loads. The process is undertaken via three different methods, combining analytical formulas, numerical simulations, and surrogate modeling. Results show that the best approximation is offered by the multivariate adaptive regression splines metamodel, yielding similar mean values as with the statistical propagation of the analytical formulas, while the standard deviation is overestimated by 1%–3%. The numerical noise quantified for the simulations results shows oscillation frequencies below 40% and a breadth of three-sigma under 9% for both metrics. The uncertainty quantification of both tubes offers a similar response when studying geometric uncertainties, with the plate thickness having a more relevant effect on the results than diameter or edge length. However, material uncertainties affect the absorbers in an opposite manner, as variations in the elastic modulus contribute the most to the square section metrics, while the circular tube is more affected by variations in the equivalent flow stress. Incertitudes in the operational conditions lead to reduced peak load values when the impact angle varies from a perfect axial collision, consequently delivering reduced mean values and high standard deviations.},

keywords = {Crashworthiness, Crushable energy absorbers, Surrogate models journal: thin-walled structures, Uncertainty quantification},

pubstate = {published},

tppubtype = {article}

}

@article{paz_optimisation_2020,

title = {Optimisation of thin-walled hybrid vertical struts for crashworthy aircraft designs},

author = {Javier Paz-Méndez and Jacobo Díaz-García and Luis E. Romera-Rodríguez and F. Teixeira-Dias},

url = {https://doi.org/10.1007/s00158-019-02350-3},

doi = {10.1007/s00158-019-02350-3},

issn = {1615-1488},

year  = {2020},

date = {2020-01-01},

urldate = {2026-08-06},

journal = {Structural and Multidisciplinary Optimization},

volume = {61},

number = {1},

pages = {141–158},

abstract = {This research concerns the crashworthiness enhancement of a model of a Boeing 737-200 fuselage section. Using a validated numerical specimen, four thin-walled crushable hybrid energy absorbers are added to the aircraft to work as vertical struts. The absorbers are composed of a hollow aluminium tube, a star-shaped glass fibre–reinforced polymer inner matrix and foam extrusions. The absorbers—with variable tube edge and thickness, composite thickness and core height—are single- and multi-objectively optimised. Surrogate models and genetic algorithms are used for the minimisation of acceleration loads, injury levels and the strut’s weight. Results yield a more efficient frames’ collapse evolution with plastic dissipation increased by over 50%. Consequently, acceleration peaks are up to 50% lower at the two measured locations while maintaining low mass values. Injury levels were also reduced from severe to moderate according to an Eiband diagram.},

keywords = {Aircraft design, Biometric criteria, Crashworthiness, Genetic algorithms, Hybrid energy absorbers, Multi-objective optimisation, Surrogate models},

pubstate = {published},

tppubtype = {article}

}