Improvement Of Crashworthiness Research Articles

Axial Crushing and Energy Absorption Integrated Design of Modular Filled Double-Hat Beam Composite Structures.

In order to study the influence of modular filled and composite material forms on the axial crushing and energy absorption properties of structures, modular filled composite structures were constructed, and innovatively applied to the inner side of double-hat beam (DHB) structures in automobiles. The modular filled structures comprise hexagonal, quadrilateral, and triangular sections. By analyzing the collision performance of modular filled DHB structures, significant enhancements were observed in both the sectional characteristics and the specific Mean Crushing Force of modular filled DHBs compared to the conventional double-hat beam structure. These advancements notably improved the plastic deformation characteristics of the structures. Additionally, dynamic weightlessness experiments were conducted to validate the accuracy of the simulation model. Among the proposed schemes, namely QU-5, HE-5, and TR-5, notable improvements in crashworthiness were identified. Specifically, crashworthiness indicators increased by 32.54%, 78.9%, and 116.53%. Compared with other thin-walled structures, modular filled composite DHBs have advantages in axial crushing and energy absorption. By optimizing layout characteristics, the modular filled structures will achieve significant lightweight and energy absorption performance improvements. This work has clear reference value for automotive engineers and scholars to further explore the axial crash safety, platform modularization, and lightweight design of vehicles.

Energy Absorption Characteristics and Parameter Optimization of Anti-Climb Energy-Absorbing Devices for Subway Vehicles under Impact Loads

To further enhance the crashworthiness of subway vehicle anti-climb energy-absorbing devices, this paper proposes a novel collapsible structure, which is embedded with honeycomb aluminum blocks and consists of an inner and outer double-layer square tube. An impact finite element model of the subway vehicle’s anti-climb energy-absorbing device was established using LS-DYNA (v.17.2). The effects of the connecting diaphragm thickness, the inner and outer tube thicknesses of the thin-walled tubes, and the yield strength of the honeycomb aluminum on the energy absorption and impact force of the anti-climb energy-absorbing device were investigated. The results indicate that changes in the inner and outer tube thicknesses of the thin-walled tubes significantly affect the energy absorption and impact force of the anti-climb energy-absorbing device. However, changes in the connecting diaphragm thickness only increase the maximum energy absorption by up to 7.5% but have a significant impact on the maximum peak force. It was also found that the difference in energy absorption due to changes in the yield strength of the honeycomb aluminum is only 3.6%, suggesting that the yield strength of the honeycomb aluminum and the connecting diaphragm thickness have a limited influence on the crashworthiness design of the anti-climb energy-absorbing device. Furthermore, a multi-objective surrogate model characterizing the specific energy absorption and maximum peak force was established for the aforementioned four influential parameters using the response surface method. The model was then optimized using a genetic algorithm, resulting in optimal parameters that increased the energy absorption and specific energy absorption by 27.3% and 13.8%, respectively, compared to the original values, leading to a significant improvement in crashworthiness. The findings provide valuable references for and insights into the crashworthiness design and optimization of subway vehicles’ anti-climb energy-absorbing devices.

Optimization design of crashworthiness of polyurethane foam filled Origami thin wall square tube based on an surrogate model

Rigid polyurethane foam, due to its low density, light weight and effective energy absorption, can be used as a new filling material to improve the energy absorption capacity of pipe fittings, thus improving the overall crashworthiness of automobiles. In this paper, numerical simulations on rigid polyurethane foam-filled origami thin-walled pipe fittings are carried out. The effects of interlayer dihedral angle, number of layers of creased pipe, and filling of foam with different densities on the crashworthiness of the pipe fittings are compared and analyzed. Additionally, an surrogate model is established to predict the correlation between the above three factors and the model. Taking the specific absorption energy (SEA) and the initial peak force (PCF) as optimization objectives, the NSGA-II algorithm and the CHC algorithm were used for optimization analysis respectively. Simulation experiments were conducted to validate the accuracy of the optimized structural parameters. The results show that the CHC algorithm provides more accurate optimization results compared to the NSGA-II algorithm. The optimized optimal interlayer dihedral angle is 150°, the number of creased tube layers is 8, and the foam density is 0.3 g/cm3. Consequently, the tubing’s specific absorption energy is enhanced by 10.3 % compared to ordinary straight tubing, demonstrating the significant improvement in crashworthiness achieved through foam filling. This study proves that the filling of tubing with foam has excellent impact resistance, and the results provide a certain reference value for future research.

Numerical simulation and theoretical analysis of the crashworthiness of a tree-like hierarchical multicellular bi-tube

Drawing inspiration from the branching structure of trees, a novel Tree-like Hierarchical Multi-cellular Bi-tube (THMBT) has been devised. This design merges the hierarchical distribution traits of tree branches with the superior crashworthiness of double square tube structures. Utilizing a validated finite element model, this study investigates the crashworthiness of THMBT, examining the impacts of wall thickness, bifurcation angle, and bifurcation length on its performance. The Simplified Super Folding Element theory is employed for theoretical analysis, facilitating the calculation of the mean crushing force of THMBT. Findings reveal that wall thickness exerts the most pronounced influence on crashworthiness. As wall thickness increases, THMBT-3 demonstrates a substantial 88.07% enhancement in specific energy absorption, accompanied by a notable increase in peak crushing force. Particularly noteworthy is the exceptional crashworthiness of THMBT-3 with a bifurcation angle (θ) of 60°. For instance, the crushing force efficiency of THMBT-3 with a wall thickness of 0.5 mm reaches 92.08%. Furthermore, when considering different bifurcation lengths under the same wall thickness and bifurcation coefficients (c) set to 1/3, both THMBT-2 and THMBT-3 exhibit superior impact resistance within their respective structures. This study marks a significant advancement by integrating biomimetic design with double square tubes, resulting in a substantial improvement in structural crashworthiness. The findings offer valuable insights for the further development of biomimetic and double square tubes.

Research on Optimization Design of Front and Side Structures under the 24th Edition of C-NACP Automotive Collision Standard

Structural crashworthiness plays a core role in vehicle safety design, mainly focusing on the maximum impact force that the body structure can withstand in collision accidents, and striving to maximize collision energy absorption to ensure that passengers have sufficient living space. The design of structural crashworthiness needs to consider the deformation mechanism and energy absorption characteristics of vehicles under different collision modes, and improve crashworthiness through material selection, structural optimization, and other means. In addition, the structural crashworthiness is closely connected to the passenger restraint system, which together constitute the key to the passive safety performance of the vehicle. In vehicle safety design, the improvement of structural crashworthiness can significantly enhance the vehicle's ability to protect passengers in collision accidents and reduce the risk of injury. Therefore, in-depth research on structural crashworthiness and the development of efficient crashworthiness structures are important directions for improving vehicle safety performance.

Optimizing functionally graded hexagonal crash boxes with honeycomb filler for enhanced crashworthiness

A crash box is typically designed to enhance crashworthiness by absorbing impact energy and reducing the crushing force that can cause injury or fatality to passengers. However, the structural integrity of conventional crash boxes is often compromised due to buckling deformations during collisions. This study introduces a novel approach utilizing functionally graded thickness (FGT) in hexagonal crash box design with honeycomb fillers to improve crashworthiness through multi-objective optimization. Finite element analysis using LS-DYNA was performed for axial and oblique impacts. Mesh sensitivity study indicated that constructing the FGT crash box with 41 layers yielded favourable outcomes, with simulation results differing by a mere 2.5% compared to experimental data. A surrogate model based on response surface methodology was employed to mathematically formulate the objective functions, which aimed to maximize specific energy absorption (SEA) and minimize initial peak crash force (IPF). Subsequently, a multi-objective particle swarm optimization was used to determine the optimal grading exponent of both outer and filler structures. The optimized FGT crash box demonstrated superior control over progressive deformation, exhibiting high SEA and reducing IPF compared to the uniform thickness crash box. Particularly, under oblique impact loads, using two grading exponents in optimizing the FGT crash box potentially achieved significant improvements in crashworthiness within the design procedure.

Multi-objective robust optimization of foam-filled double-hexagonal crash box using Taguchi-grey relational analysis

In this paper, a novel thin-walled double-hexagonal crash box is first proposed and then multi-objective robust optimized for better overall crashworthiness under multi-angle impact loading, using a proposed hybrid method combining aluminum foam-filling and Taguchi-grey relational analysis (GRA). Specifically, the finite element (FE) models of the regularly-shaped double-hexagonal column (DHC) extracted from original irregularly-shaped crash box under multi-angle impact loading, including hollow (H-DHC) and foam-filled (F-DHC), are first built and validated by experiments. On this basis, a comprehensive crashworthiness comparison is conducted to explore relative merits of F-DHC over original H-DHC under multi-angle impact loading. After that, the F-DHC is multi-objective robust optimized for maximizing overall specific energy absorption (SEAθ) and minimizing overall initial peak crushing force (IPCF0) simultaneously under multi-angle impact loading, using a hybrid method of Taguchi-GRA. At last, a bumper-crash box integrated crashworthiness analysis under multi-angle impact loading is executed to further verify the optimization. The optimal F-DHC and the optimized crash box within the optimal F-DHC demonstrate evident improvement of crashworthiness compared to their respective initial designs, indicating aluminum foam-filling combined with Taguchi-GRA could be an effective approach for multi-objective robust optimization of the novel crash box and other similar vehicle structures.

Experimental and numerical study on crashworthiness of bionic hedgehog spine thin-walled structures

Natural impact-resistant biomaterials, with ingenious and exquisite geometric configurations, have resistance to external impact, and thus provide a perfect bionic example for the optimization design and crashworthiness improvement of new thin-walled structures. Based on the configuration characteristics of hedgehog spine, this paper designed the bulkheaded hedgehog spine thin-walled structure and studied the dynamic behavior of thin-walled structures under axial and oblique impact compression by combining 3D metal printing, quasi-static compression test and finite element simulation. The results show that the combined effect of the ribs, inner walls and bulkheads of the bulkheaded hedgehog spine thin-walled structure effectively improves its deformation coordination ability and crashworthiness. The specific energy absorption of the bulkheaded hedgehog spine thin-walled structure under axial or oblique impact is about 4.1, 2.1 and 1.4 times that of the single-wall cylinder, spider web and simplified hedgehog spine thin-walled structures, respectively.

The investigation on dynamic damage evolution and energy absorption of FML pin joints with different ply stacking sequences

With fiber reinforced composites widely applied in aerospace, the crashworthiness aspects for aircraft have been an important part of the design. Fiber metal laminate (FML) is a kind of hybrid composite fabricated by fiber reinforced plastic composites and metal layers, showing a potential application on energy absorption. In this work, the damage evolution and energy absorption of FML pin joints are investigated comprehensively. The configurations of FML pin joints with constant geometric parameters are designed to avoid net-tension damage failure in the experiments. The damage evolution processes of specimens are captured by a high-speed camera, and the surface strain is calculated by Digital Image Correlation (DIC) method. Abaqus/Explicit solver is adopted to simulate the mechanical responses of FML pin joint considering ductile damage of metal, damage evolution of composites, and delamination of the interface. The results indicate that the initial dynamic ultimate bearing strength of FML incorporate notable contribution from inertia effects. The average bearing strength associated with energy absorption efficiency is related to the ply stacking sequence of composites. The fiber direction of laminates should be perpendicular to the movement direction of pin as much as possible under the premise that the initial ultimate bearing strength satisfies the design requirement. The results obtained in this work provide comprehensive design guidance for the improvement of crashworthiness in the composite fuselage.

Crashworthiness analysis and design of a sandwich composite electric bus structure under full frontal impact

The transition toward sustainable transportation includes adopting ecofriendly electric vehicles in public transport, which reduces greenhouse gas emissions and increases energy efficiency. One of the critical features in fuel economy improvement of electric vehicles lies in lightweight structural design. Nevertheless, the crashworthiness of the structures of the vehicles and the safety of passengers must be guaranteed in the attempt of mass reduction because the crash of large vehicles such as buses usually costs many lives. This paper, therefore, aims to present an in-depth analysis of the impact behavior of a lightweight monocoque sandwich composite microbus body under full-frontal crash conditions. The bus structure, made of a high-density polyurethane foam core and woven glass fabric-epoxy face sheets, was modeled and simulated via LS-DYNA dynamic analysis using strength-based Chang-Chang criteria to characterize the failure mechanism of the structure and investigate intrusion into the passenger survival space. Under front collision, the front panel, A-pillars, and front sidewalls of the original bus were found to be extensively damaged in the compressive fiber mode. Based on the 50th percentile male dummy anthropometric parameters, injury indices of 0-5 intervals were proposed to evaluate occupant injury risks. The maximum front and side intrusion into the specified safety space under a maximum impact speed of 50 km/h is 208 mm at the front panel and 221 mm at the sidewall, indicating high injury indices of 3.59 and 4.81, respectively. The effects of stiffeners reinforced in the front panel and foam core thicknesses in the sidewalls, floor, and bottom parts on crashworthiness improvement were thoroughly discussed. The improved bus design can significantly enhance the safety of the occupants with a minimal increase in structural weight of merely 35.6 kg. An effective vehicle safety design under full frontal collision is presented.

Crash-worthiness studies on multistage stiffened honeycomb core sandwich structures under dynamic impact loads

The high-velocity impact performance of honeycomb sandwich structures is enhanced by adopting multi-stage structures with varying cell wall thickness, and cell wall inclination, after preserving the structural mass. The performance of the enhanced structures is simulated considering bullet penetration tests. The penetration is observed to be reduced by 4.82% in case of two stage sandwich structures, as compared to the single stage sandwich structures. Furthermore, the reduction in penetration is estimated to be up to 11.34% when the cell wall thickness is increased from 0.05 mm to 0.15 mm. Moreover, honeycomb cores are stiffened using ribs in two different configurations, within the available space. The improvement in crash-worthiness is estimated by measuring the penetration of the single and two stage hybrid sandwich structures. The penetration distance of stiffened single and two stage structures is found to be reduced by 28.4% and 31.97%, respectively, as compared to the corresponding structures without stiffeners. On the other hand, inclination of the cell walls at an angle to the normal of the face plates is found to enhance the stiffness, and hence the penetration resistance. The honeycomb sandwich structure with oblique unit cells is estimated to dissipate three times more energy as compared to a regular structure. As a result, the impactor is unable to pierce through the sandwich structure. Therefore, two stage hybrid sandwich structures with oblique hexagonal unit cells are recommended for energy absorption in impact applications.

Numerical analysis of origami-ending crash tubes

A crash tube is an essential component in assuring the safety of a vehicle. In a low-speed accident, crash tubes avoid damage to passengers and goods. They are mounted at the vehicle's front end and are designed to disperse kinetic energy and lessen impact loads during a collision. A novel origami-ending crash tube (OET) is presented in this study. FEA tool ABAQUS EXPLICIT was used for validation, design, and simulation studies. The dihedral angle and thickness of the tube were varied to optimize the crashworthiness. Crashworthiness measures, like mean force, specific energy absorbed, and peak force, were used to conduct comparative investigations. A dihedral angle of 1650 was found to optimize all the crashworthiness parameters, and a thickness of 2mm was found to be significant for better crashworthiness of the tube. OETs are suitable for engineering applications due to substantial improvements in the structure's crashworthiness.

The association between data collected in IIHS side crash tests and real-world driver death risk

Objective The Insurance Institute for Highway Safety (IIHS) side crash test has led to crashworthiness improvements, and both overall and component ratings have been shown to be associated with real-world death risk. The objective of the current study was to investigate how crash test measurements, on which component ratings are based, are associated with real-world death risk. Methods Driver deaths and police-reported crash involvements were extracted from national crash databases for left-impact crashes of passenger vehicles with standard-feature, head-protecting side airbags for calendar years 2000–2016. Risk of driver death in left-impact crashes was estimated as the number of driver deaths divided by the number of driver police-reported crash involvements. Logistic regression was used to estimate the association between crash test measurements and death risk, controlling for driver and vehicle information. Results All crash test measurements investigated were associated with driver death risk. For instance, a 10 cm reduction in B-pillar intrusion, a measure of post-crash occupant survival space, was associated with 30% lower driver death risk. For most measures, at least 75% of study vehicles were within the good rating boundary for that measure, and still these measures were associated with driver death risk. Fewer than half of study vehicles earned a good rating for B-pillar intrusion. Conclusion Because performance in measures collected in the IIHS side crash test are strongly associated with real-world driver death risk, one of the ways the crash test program could continue to encourage crashworthiness improvements is by requiring stronger performance on these measures.

Study of Tailored Hot Stamping Process on Advanced High-Strength Steels

Ultra-high-strength steels (UHSS) combined with tailor-stamping technologies are increasingly being adopted in automotive body production due to crashworthiness improvements and part weight reduction, which meet safety and energy saving demands. Recently, USIBOR®2000 (37MnB5) steel has been added to the family of UHSS. This new material allows higher performance with respect to its predecessor USIBOR®1500 (22MnB5). In this work, the two steels are compared for the manufacturing of an automotive B-Pillar by press-hardening with a tailored tool tempering approach. A Finite Element (FE) model has been developed for the numerical simulation of thermomechanical cycles of the press-hardening process. The FE-simulations have been performed with the aim of obtaining soft zones in the part, by varying the quenching time and the temperature of heated tools. The effects of these parameters on the mechanical properties of the part have been experimentally evaluated thanks to hardness and tensile tests performed on specimens subjected to the numerical thermo-mechanical cycles using the Geeble-3180 physical simulator. The results show that for both UHSS, an increase in quenching time leads to a decrease in hardness up to a threshold value, which is lower for the USIBOR®1500. Moreover, higher mechanical resistance and lower elongation at break values are derived for the USIBOR®2000 steel than for USIBOR®1500 steel.

Injury risks and crashworthiness benefits for females and males: Which differences are physiological?

Objective Previous research has found elevated injury risk for females relative to males in passenger vehicle crashes but has not accounted for ways the crashes themselves differ between these populations. Vehicle curb weight, ride height, safety rating, airbag deployment, and crash configuration all influence injury outcome and often are not well-represented by delta-V alone. This study evaluated the effect of occupant sex on injury risk in front and side crashes while limiting or controlling for non-physiological crash differences. Additionally, the effects of crashworthiness improvements are compared for females and males. Methods NASS-CDS cases from 1998–2015 calendar years involving a belted driver in a front crash or a struck-side driver or right front passenger in a side crash were analyzed. Case vehicle model years were 1989–2016. Logistic regression was used to estimate the risk of MAIS ≥ 2 and MAIS ≥ 3 injury outcomes for females relative to males as well as the change in risk due to improved crashworthiness. Sex-based differences in occupant age, mass, and stature; crash test rating; delta-V; crash configuration; and vehicle-to-vehicle compatibility were considered either through case selection or the inclusion of additional regression covariates. Results Before controlling for crash and vehicle differences, female drivers in front crashes had higher estimated overall and body-region-specific risks of MAIS ≥ 2 and MAIS ≥ 3 injury, as consistent with previous findings. After accounting for such differences, all ratios of injury odds for females relative to males were reduced. Females remained at higher risk of MAIS ≥ 2 injury (OR, 2.23; 95% CI, 1.42–3.51), especially extremity injury, but had similar odds for MAIS ≥ 3 non-extremity injury (OR, 0.98; 95% CI, 0.56–1.7). While controlling for crash differences in side impacts, none of the estimated injury risk differences by sex were significant at the p ≤ 0.05 level. Estimated benefits of improved crashworthiness were similar or greater for females than for males for most injury outcomes. Conclusions Female-specific crashworthiness improvements may be required to provide additional protection against AIS 2 extremity injury. Much of the remaining discrepancy in sex-based injury risk can be attributed differences between vehicles and crashes, not to physiological differences. Addressing these differences will require other types of countermeasures.

Crashworthiness improvements of multi-cell thin-walled tubes through lattice structure enhancements

Taking advantage of multi-cell tubes and lattice structures on improving crashworthiness performances, a novel multi-cell thin-walled tube filled with uniform and graded lattice structures is explored in this paper. The body-centered cubic lattice structure is employed as the uniform lattice filler, while the graded lattice filler is constructed by varying the diameter of lattice rods in each layer. Several geometric parameters are investigated numerically, which include the cell number of tube, the dimension of tube and lattice, the height-to-width ratio of the enhanced tube, and the configuration of graded lattices. These parameters are then compared for their crushing load-displacement curves, deformation modes, and energy-absorbing mechanisms. It is observed that the multi-cell tubes exhibit significant improvements to the absorbed energy and crushing force efficiency over the single-cell tubes. In addition, the specific energy absorption (SEA) of the hybrid multi-cell tube structures is improved by 78.6% with respect to the sum of its individual constituents. Furthermore, the multi-cell tube structure filled with graded lattices can present larger energy-absorbing capacity than its uniform lattice counterpart, and the strong end at its top provides better SEA performance. Overall, the hybrid lattice-enhanced tube structure provides an optimal strategy for the crashworthiness design of multi-cell tubes, which can serve as a potential candidate for future crashworthiness applications.

Developing an aluminum honeycomb barrier to represent a striking SUV in a side impact crash test

Objective The Insurance Institute for Highway Safety (IIHS) introduced its side impact ratings test in 2003. Despite manufacturers' improvements to airbags and vehicle structures, 45% of 2018 side crash fatalities on U.S. roadways were in good-rated vehicles, suggesting that more crashworthiness improvements are necessary. Crash trends indicate that the most promising avenue to address the remaining real-world injuries is a higher severity vehicle-to-vehicle test using a barrier to represent a striking sport-utility vehicle (SUV). Laboratory tests comparing striking SUVs with the current IIHS moving deformable barrier (MDB) showed discrepancies in damage patterns and injury measures. The current study outlines the characteristics of a multi-stiffness aluminum honeycomb barrier to represent a modern SUV-striking vehicle in side impact crash tests. Methods Barrier size and shape were determined from a series of measurements taken from 21 modern SUVs. Barrier honeycomb stiffness characteristics were derived by comparing the damage profile of six different barrier prototypes against a baseline profile obtained from a high-severity SUV crash into a midsize car. Tests were conducted at 60 km/h with a 1,900 kg MDB. The best honeycomb design was tested against four additional vehicles to ensure it was representative of striking SUVs of different sizes and types. Results The final barrier has a 1,700-mm width by 600-mm height and 500-mm depth multi-stiffness design, with less stiffness on the top and more stiffness in the lower outside sections compared with the original IIHS barrier. For three struck vehicles, the redesigned barrier matched all performance criteria set by the striking-SUV tests. For two additional struck vehicles, there were some differences in intrusion patterns but overall, these matched the test trends of the striking SUVs. The new barrier in a higher severity test mode resulted in a range of performance for these good-rated vehicles. Conclusion A multi-stiffness aluminum honeycomb barrier was developed to represent the characteristics of striking SUVs in 60 km/h perpendicular side impact crash tests focusing on the occupant compartment. The redesigned barrier differentiates between currently good-rated vehicles, which will promote structural and restraint system improvements to the fleet relevant to the remaining real-world injuries.

Design for crash safety of electric heavy quadricycle structure

An electric small four-wheeler, categorized by the European Union as L7e so-called heavy quadricycle or microcar, is one of the solutions to eco-friendly and sustainable mobility for personal transport. Nonetheless, quadricycles typically do not offer the equivalent passive safety as larger passenger car models, in case of accidents, owing to the lack of energy absorption in the vehicle’s structure. This paper presents a proposed heavy quadricycle structure using plain weave carbon fibre-reinforced polymer in the passenger cell and aluminium alloy 6061-T6 in the crumple zone. The behaviors of electric heavy quadricycles under impact are simulated in accordance with the test guidelines of European New Car Assessment Programme using a non-linear finite element analysis via LS-DYNA to examine structural crashworthiness and characteristics. A full-frontal crash with a rigid wall at 30 km/h to 50 km/h shows that the front crush box, longerons and subframes in the crumple zone can efficiently absorb energy from a frontal crash up to 54.8%. The maximum damage in the structure occurs at the joints of the A-pillars and side beams to the front panel. Whilst the occupant safety space is safe under side collision by a 1350-kg moving deformable barrier at 50 km/h speed. However, the quadricycle tends to experience overturns from a side crash due to the vehicle’s lightweight and high center of gravity. Finally, suggestions for crashworthiness improvements to the composite passenger cell are provided based on the attained damage mechanism under a crash.

Crashworthy characteristics of sustainable thin-walled tubes: A study on recycled beverage cans

Thin-walled tubular structures are widely employed in applications. The current study proposes an innovative cost-saving and eco-friendly thin-walled cylinder concept using recycled beverage cans. Axial compression experiments are conducted to characterize the crushing performance under quasi-static and dynamic loading. Besides, the polyurethane foam (PUF)-filled beverage cans are fabricated to improve the compression resistance and energy absorption capacity. Experimental results show that empty beverage cans behave as a typical Type-II absorber and fail by local buckling of the cylinder belly. The initial peak force increases with deformation rates while the highest mean crushing force is obtained at compressive velocity of 50 mm/min. In contrast, PUF-filled beverage cans collapse with a progressive folding process and present significant improvement in crashworthiness. Experimental results are compared with theoretical analysis and conventional energy absorbers to clarify the crashworthiness. In addition, the interaction effect between the PUF fillings and the recycled beverage cans is discussed comprehensively.

A crashworthiness optimisation procedure for the design of full-composite fuselage section

Crashworthiness of composites is a key-point in the design of new aeronautical structures. Special attention has been addressed in the last years to the energy absorption mechanisms of dedicated components in order to limit the structural damages and to preserve the occupants’ safety. Remarkable progress has been made in this field. Despite this, to further improve the design of crashworthy composite structures, components modification, sensitivity analysis, design of experiments and optimisation procedures are needed. In this work, crashworthiness improvements, related to a simplified finite element model of a full-composite fuselage section subjected to a vertical drop-test, have been introduced. The genesis of the model has been described together with its main features and details and a high-speed vertical fall has been simulated, paying attention to velocity and payload. In addition, sensitivity analyses of some components and a discussion on the main crashworthiness characteristics have been carried out. Finally, the parent fuselage section and its simplified model have been compared under both energy and deformation points of view, showing a good results agreement.