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To better evaluate the crash performance of the guardrail and reduce the number of actual vehicle crash tests, this paper uses mechanical analysis and finite element simulation technology to evaluate the typical movable guardrail and optimize the structure. It’s of great significance for improving the crashworthiness of this type of guardrail and enhancing its safety performance. Firstly, the vehicle-barrier mechanical model was established to calculate the vehicle collision force on the barrier. Secondly, the collision force model was used to calculate the collision of a 10-ton truck, and a finite element model of a typical movable barrier was established for a collision simulation. Finally, the wall thickness and column spacing were optimized according to the results. The simulation results show that the maximum lateral dynamic deformation of the barrier was 1,818 mm, which agrees with the actual vehicle test results (1,600 mm). When the wall thickness of the barrier increases by 2 mm, the maximum lateral dynamic deformation was 1,419 mm; When the spacing of strengthened columns was reduced to 15 m, the deformation was 1,364 mm; After optimization, the deformation was reduced by more than 20%, and the crashworthiness of barrier was improved obviously.

Finite element-based crashworthiness optimization is extensively used to improve the safety of motor vehicles. However, the responses of crash simulations are characterized by a high level of numerical noise, which can hamper the blind use of surrogate-based design optimization methods. It is therefore essential to account for the noise-induced uncertainty when performing optimization. For this purpose, a surrogate, referred to as Non-Deterministic Kriging (NDK), can be used. It models the noise as a non-stationary stochastic process, which is added to a traditional deterministic kriging surrogate. Based on the NDK surrogate, this study proposes an optimization algorithm tailored to account for both epistemic uncertainty, due to the lack of data, and irreducible aleatory uncertainty, due to the simulation noise. The variances are included within an extension of the well-known expected improvement infill criterion referred to as Modified Augmented Expected Improvement (MAEI). Because the proposed optimization scheme requires an estimate of the aleatory variance, it is approximated through a regression kriging, which is iteratively refined. The proposed algorithm is tested on a set of analytical functions and applied to the optimization of an Occupant Restraint System (ORS) during a crash.

An explicit dynamic simulation of the vertical crash of a regional airliner’s middle fuselage section has been conducted to investigate its crashworthiness. The simulation result shows that there a...

For structural bending crashworthiness, previous studies mostly focused on thin-walled tubes with multi-cell cross-sections, while the double-tube configuration was seldom studied. In this paper, the bending crashworthiness of thin-walled tubes with multi-cell and double-tube configurations was compared based on three-point bending tests conducted using the ABAQUS/Explicit code. The numerical results reveal that the reinforcements significantly improve the bending crashworthiness beyond the conventional empty tube according to the two indicators: specific energy absorption (SEA) and crash load efficiency (CLE). For the ratio of cross-sectional width to wall thickness b/t = 100, the double-tube configuration has a similar bending crashworthiness performance to the multi-cell configuration. The asymmetric multi-cell configurations are found to demonstrate more excellent SEA performance than their symmetric counterparts in most cases. For the case b/t = 50, the double-tube configuration significantly prevails over the multi-cell configuration.

Many hierarchical structures have good mechanical properties, which can better improve the energy absorption characteristics and achieve lightweight. This article proposed a novel circumferential s...

Frontal impacts are the most frequent crash types and may generate extreme body in white (BIW) deformations. Vehicles are subjected to impact evaluation rating protocols such as 100 % Front Rigid Barrier (FRB) impact, 40 % Offset Deformable Barrier (ODB) impact and 25 % overlap (small overlap) impact. This paper proposes a collaborative optimization process using optimal Latin hypercube design (Opt LHD) and response surface methodology (RSM), to improve the vehicle crashworthiness in the frontal impacts, by considering displacement oriented structure (DOS). Upper and lower engine bay structure were considered herein to increase the lateral vehicle displacement during small overlap impact and decrease the impact force that transferred to the passenger compartment in the frontal impacts. The optimal results indicated that the acceleration of the B-pillar was reduced 0.4g in the FRB impact, the intrusion of the firewall was reduced by 55.13 % in the ODB impact, and the intrusion of passenger compartment during small overlap impact was decreased by an average of 53.88 %, with a maximum percentage of 71.41 % around left toepan, leading to an IIHS rating to acceptable from poor. The proposed crashworthiness design approach is effective in vehicle structure optimization for better frontal impacts performance.

In the automotive structure, there are different components that utilise aluminium alloy (AA) sheets and it is used widely in the car body-in-white which comprise bumpers and the crash box structure at the front end of the car which specifically designed to withstand the event of collision. As the structures are also experiencing dynamic loading, it were also a concern for the structures to show satisfied modal properties. In this study, the modal properties of the crash box structures are investigated along with the effect of the modal properties towards the crashworthiness behaviour of the structure itself with the approach of finite element analysis. Experimental modal analysis was also done to further validating the finite element analysis of the modal properties. Three different designs of trigger mechanisms are applied towards the crash box structure to observe on both findings. For the connector element, equivalent nodes of both parts of the crash box structures are used. For the results, the correlation from both findings did show that the presence of trigger mechanism did decreased the magnitude of natural frequencies as well as the mode shape as shown by crash box type 3 by 9.50% and for the crashworthiness output, the crashworthiness behaviour of the crash box with trigger mechanisms were better in term of the collisions phases indicated by the primary peak force and the secondary peak force from the force-displacement curve as also shown by crash box structure type 3 with the percentage of 22.59%. The study does shows that the stiffness and mass distribution due to the presence of trigger mechanism do affect the modal properties of a structure as well as its crashworthiness output.

The continuing efforts of automotive technology aim to deliver even greater safety benefits and reduce the weight of a vehicle. Thin-walled beams (TWB) are widely used as strengtheners or energy absorbers in vehicle bodies due to their lightweight and excellent energy absorption capacity. Thus, researchers are interested in the collapse behaviour and mechanical properties of thin-walled beams under static and dynamic loadings. Circular TWB is commonly used in vehicle side doors. In the event of a side collision, this beam deforms and absorbs the greatest amount of impact energy. In this study, the energy absorption capability and crashworthiness of polygonal cross-section TWBs subjected to lateral impact was investigated using numerical simulations. Polygonal TWB ranging from square to dodecagon, as well as circular cross section, were selected for this study. Energy absorption (EA), specific energy absorption (SEA) and crash force efficiency (CFE) crashworthiness indicators are employed to evaluate the bending collapse performance. Because TWB thickness and weight have a greater impact on bending performance, they were kept constant across all polygons. In ABAQUS explicit dynamic software, finite element simulations are performed, and plastic hinges and flattening patterns of all polygons are examined. The results show that heptagon, octagon, and nonagon cross-section TWB perform better in crashworthiness than square and circular TWB.

Due to the low manufacture cost and easy installation, tubal structures are common utilized as energy absorbers in automotive and other engineering industries. In the present work, four novel reinf...

Thin-walled tubes are widely used as energy absorbers due to their high crashworthiness performance. This study aims to evaluate the effect of plastic forming history carried out for thickness optimization on crashworthiness performance of thin-walled square tube (TWST). Within the scope of the study, a series of numerical analyses were conducted for the TWST using a commercial finite element (FE) software. In order to determine individual effect of optimization, FG thickness of TWST was first obtained using LS-OPT software. Later, thickness gradient was achieved by performing rolling process to consider individual plastic forming effect Afterwards, deep drawing process was carried out to shape TWST by considering springback and trimming effects. Finally, crash responses were obtained under axial high velocity impact loading to determine the coupled effect of optimization and plastic forming on the crashworthiness performance of the TWST. It was determined that the coupled effect, which takes plastic forming and optimization effects into account, reduced the peak crush force of the TWST by 24% and increased the absorbed energy value by 39%. The results obtained from this study showed that coupled effect of optimization and plastic forming processes has significant effect on the crashworthiness performance of the TWST and otherwise either overestimated or underestimated results are obtained.

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.

The bending crashworthiness performance of thin-walled structures is affected by several factors such as the end-clamping constraints. The end-clamping configuration should be carefully investigated since it is an important part of the real working condition of a structure under bending loading. End-clamping fixtures (pads) can be used intentionally as complementary energy dissipating mechanisms to trigger new plastic deformation. The present article explores the use of pads to improve the crashworthiness of square tubes under lateral loads. For this purpose, internal, external, and combined pads were located at the profile ends which were subjected to a modified three-point bending test using finite element simulations. The effect of assembly force (fN) and pad length (lp) on the energy absorption was investigated. The structures were made of aluminum 6063-T5 and modeled with elasto-plastic properties considering ductile and shear damage criteria with evolution. Additionally, the numerical results were validated by an experimental three-point bending test on a square profile with constrained and free ends. Our results for a structure with end-clamping fixtures show an improvement of crashworthiness performance in a range from 42.38 – 57.89% relative to a structure with free-ends. The best crush force efficiency (CFE) of 0.78 was obtained when external pads were implemented. Moreover, the importance of fN on the end-clamping pads was noticed since CFE is increased by 9.30% when a normalized force of 0.109 is applied. The importance of pad length was also demonstrated. An improvement of 69.38% in CFE was achieved when a normalized length $$ {\overline{L}}_p $$ = 0.138 was implemented. Finally, with the findings of our work, a design of end-clamping fixtures for an automobile’s side-door impact beam is presented and analyzed.

In this paper, the effects of various design options for improving the crashworthiness performance of a rectangular crash absorber with diaphragms are explored. These design options include (i) optimal tube and diaphragm dimensioning, (ii) optimal diaphragm placement, and (iii) tapering of the crash absorber. The wall thicknesses of the absorber and the diaphragms, the locations of the diaphragms, and the taper angle are taken as design variables to optimize the crashworthiness performance of the absorber. Before the optimization study, a finite element model is generated and validated with experimental results available in the literature. The effect of each design variable on crashworthiness performance is evaluated by solving a series of design optimization problems, and compared with the baseline design. A successive iterative approach is used in this study, where the optimum design variables obtained from a previous optimization problem are used as the initial design of the next optimization problem. Maximum specific energy absorption (SEA) is sought in these optimization problems. A surrogate-based optimization approach is used, where radial basis functions and response surface models are utilized. Optimal tube and diaphragm dimensioning resulted in 59.2% increase, optimum diaphragm placement led to 7.7% additional increase, and tapering resulted in 2.5% further increase in SEA. Overall, the design changes considered in this paper provided 69.4% increase in SEA.

This paper takes into consideration the excellent energy absorption ability of hierarchical honeycombs and auxetic structures and proposes a novel auxetic hierarchical crash box assembled by the auxetic hierarchical filling cores and the outer square thin-walled tube. The crushing performance of the auxetic hierarchical crash box is systematically investigated. The comparisons of energy absorption ability are made among the auxetic hierarchical crash box, aluminum foam-filled crash box, and the traditional crash box. In addition, a multi-objective optimization design is conducted based on the surrogate model with higher accuracy. The non-dominated sorting genetic algorithm (NSGA-II) and archive-based micro genetic algorithm (AMGA) are, respectively, employed to obtain the pareto sets. The results show that the optimum solution with AMGA has a smaller relative error, and the multi-objective optimization successfully improves the crushing performance of the auxetic hierarchical crash box. The electric vehicle crashworthiness is remarkably improved by the application of the auxetic hierarchical crash box. The conclusions of this paper can provide a new solution for the design of the crash box.

New products based on a structure that represents a combination of known elements in a higher quality set, as well as products that refer to new shapes, new curves, new surfaces can be obtained logically - analytically - deductively or by methods specific to the optimal calculation. The present paper focuses on the method of analyzing tridimensional morphology, some possible solutions being evaluated on value criteria. Of course, these methods can be applied in the field of engineering with very good results. The focus of this study is to obtain new thin walled tubular structures - such as car crash members - which in the case of axial shock loads have a higher predictable behavior compared to those already used in various technical fields. Following the study, it can be said that depending on the amount of absorbed energy in the case of axial collisions and the absorption of kinetic energy developed at the time of impact, the optimal crashworthiness solution could be tubular structures with a circular support base and rectangular deformable area for impact.

Multi-wall profile as one of the most widely approaches can enhance the crashworthiness properties in thin-walled tubular structures. In actual application process as energy absorbers, there may be...

During a side impact accident of an automobile, the automobile threshold plays an important role in maintaining the living space of passengers, and thus the crashworthiness design of thresholds may...

Aiming at reducing the energy absorption of the hydrogen cylinder for fuel cell vehicles in collision, which may lead to fierce explosion, this paper introduces an energy-absorbing protective shell combining with negative Poisson’s ratio (NPR) structure to the hydrogen cylinder. It adopts three honeycomb structures of the same mass and three kinds of aluminum alloy to determine the optimal structure and material scheme of the protective shell. Besides, sensitivity analysis is selected to screen the design parameters of the optimal structure scheme. Based on this, the overall mass of the designed protective shell, the specific energy absorption of NPR structure, the maximum impact force of rigid wall, and the maximum stress of the liner are taken to establish the optimization mathematical model. Furthermore, adaptive mutation genetic algorithm (AMGA), non-dominated sorting genetic algorithm-ii (NSGA-II), and adaptive simulated annealing algorithm (ASA) are exerted as the optimization algorithms separately to conduct optimization design and a comparison is made between the optimization results. The results show that the optimized energy-absorbing protective shell has better crashworthiness and energy absorption effect, which can effectively improve the collision safety of the hydrogen cylinder. It provides a new idea for the protection design of hydrogen storage system in fuel cells in the future.

In this paper, the crashworthiness characteristics of tapered structures with the uniform cells in cross-section subjected to oblique impacts are theoretically and numerically investigated. Benefit...

This study focuses on the axial and oblique low-velocity impact response of thin-walled aluminium conical frusta with circular cutouts at two different locations through experimental and finite ele...

This work deals with the development of an improved numerical model, based on the explicit finite element method, aimed at investigating the energy absorption capabilities of a full-scale composite...

Recently, multi-cell structures have received increased attention for crashworthiness applications due to their superior energy absorption capability. However, such structures were featured with high peak collapsing force (PCL) forming a serious safety concern, and this limited their application for vehicle structures. Accordingly, this paper proposes windowed shaped cuttings as a mechanism to reduce the high PCL of the multi-cell hexagonal tubes and systemically investigates the axial crushing of different windowed multi-cell tubes and also seeks for their optimal crashworthiness design. Three different multi-cell configurations were constructed using wall-to-wall (WTW) and corner-to-corner (CTC) connection webs. Validated finite element models were generated using explicit finite element code, LS-DYNA, and were used to run crush simulations on the studied structures. The crashworthiness responses of the multi-cell standard tubes (STs), i.e., without windows, and multi-cell windowed tubes (WTs) were determined and compared. The WTW connection type was found to be more effective for STs and less favorable for WTs. Design of experiments (DoE), response surface methodology (RSM), and multiple objective particle swarm optimization (MOPSO) tools were employed to find the optimal designs of the different STs and WTs. Furthermore, parametric analysis was conducted to uncover the effects of key geometrical parameters on the main crashworthiness responses of all studied structures. The windowed cuttings were found to be able to slightly reduce the PCL of the multi-cell tubes, but this reduction was associated with a major negative implication on their energy absorption capability. This work provides useful insights on designing effective multi-cell structures suitable for vehicle crashworthiness applications.

The proportion of motor vehicle crash deaths involving a collision with fixed objects is not decreasing. To address this issue and consequently to decrease transportation hazards, a novel crash cushion comprised of load-bearing blocks was introduced. Its alpha version is easily and inexpensively obtainable; the beta version is suitable for use in harsh environments. In this contribution, the effect of the collision on imaginary vehicle passengers is examined. Besides, the effect of impact velocity on collision severity is discussed and both versions of crash cushions are compared in occupant injury potential. The effect of a combination of crash cushions with different crashworthiness measures is also studied. Inferences drawn from this study can be used by designers and contractors to assess the collision severity and optimize the use of the cushioning elements. The presented cushioning elements can replace stones and solid blocks in cross-drainage culverts, but hypothetically they could also be used in other structures which pose risks around traffic lanes or in underwater protection of bridge piers.

The results of the crashworthiness assessment under grounding scenarios are presented in the previous part of this two-part companion paper. This part presents results from numerical analyses with focus on structural performance accounting for seabed topology, and investigation of energy formulae for application in calculation of grounding damage. Study in this work is divided into three stages, i.e. finite element method (FEM) verification using laboratory experiment, numerical calculation of ship grounding using FEM, and comparison of the FEM results with empirical formulae of damage-energy calculation. Fundamental formula of Minorsky is considered with other improvement expression, such as Woisin and Zhang. Investigation suggested that the recent-developed expression produces the closest estimation to the verified FEM results. On the other hand, fundamental formulae of Minorsky is the farthest compared to the FEM, which indicates constant value in the expression needs to be more specific as improved in the Woisin formula.

Composite materials are being widely used in automobile industry in order to meet the ever increasing demand to achieve significant weight reduction by maintaining the performance levels. Additiona...

In crash event, aerospace structures are designed to collapse progressively, dissipating high kinetic energy and protecting the passengers against abrupt decelerations. To achieve this goal, a bett...

With the development of aircraft industry, there is an urgent demand for pursuing higher crashworthiness design standard of fuselage. However, there is a challenge for improving the crush performan...

A constitutive damage model is proposed in order to investigate the crushing response of crossply and 0 ° plies composite laminates, using a VUMAT subroutine implemented in ABAQUS/Explicit. This da...

This paper evaluates the crashworthiness performance of concentric structures with different numbers of tubes (i.e. one to five) and cross-sectional shapes (i.e. hexagon, octagon, decagon and circle) under the multiple loadings of θ = 0, 10, 20 and 30°. An experimentally validated finite element model generated in LS-DYNA is employed to calculate the crashworthiness parameters including the specific energy absorption, maximum crush force and crush force efficiency. A total of 20 concentric structures are analyzed to explore the effects of number of tubes and cross-sectional shapes on the crushing performance. A multi-criteria decision-making method known as TOPSIS is also used to compare and rank the concentric structures in terms of crushing performance. Based on the results, the hexagonal structure including two tubes and octagonal, decagonal and circular structures including three tubes demonstrate the best results among their corresponding cross-sectional shapes. These structures show 9, 39, 38 and 39% higher specific energy absorption compared to their corresponding single tubal cases, respectively. However, in comparison to single tubal cases, they generate 4, 57, 57 and 58% higher maximum crush force, respectively. As such, the values for the improvement of the crush force efficiency are 3, 26, 25 and 21%, respectively. Furthermore, the decagonal structure including three tubes provides the highest energy absorbing characteristics as compared with all the other structures studied in this research. Meanwhile, taking into account all the multiple loading conditions, this structure shows 50% higher specific energy absorption than the hexagonal structure including single tube (as the weakest structure).

A commonly assumed ship-to-ship collision scenario is a rigid ship bow hitting the side of a ship perpendicularly. A bulbous bow has a slender shape overall but a rounded end, while a stem has a sh...

This paper proposes a novel collision post structure designed to improve the crashworthiness of subway cab cars. The structure provides two innovative features: 1) a simpler connection between the post and the car roof, which gives a more reasonable load transfer path to reduce the stress concentration at the joint; and 2) a stiffness induction design that provides an ideal deformation model to protect the safe space of the cab cars. The novel collision post structure was evaluated with finite element analysis, and a prototype cab car was mechanically tested. The results demonstrate that the deformation response was stable and agreed well with the expected ideal mode. The maximum load was 874.17 kN and the responses remained well above the elastic design load of 334 kN as required by the design specification. In addition, there was no significant tearing failure during the whole test process. Therefore, the novel collision post structure proposed has met the requirements specified in new standard to improve the crashworthiness of subway cab cars. Finally, the energy absorption efficiency and light weight design highlights were also summarized and discussed.

Lithium-ion batteries (LIBs) are widely employed in electric vehicles owing to their high power density, long cycle life, and environmental friendliness. However, LIBs are hazardous in the event of a crash, leading to thermal runaway. In this study, the basic structure of a battery module is analyzed to improve the crashworthiness of LIBs. A simplified finite element model of the battery module structure, which is a battery unit composed of two pouch cells and a cooling fin, is set up and verified by conducting module-level simulations. The simulation results reveal that the cooling fin in the battery module has the potential to absorb energy. Six sandwich configurations are introduced to modify the cooling fin. With a unidirectionally stiffened double hull USDH structure serving as an example, a parametric analysis is conducted, demonstrating that the sandwich height does not influence the areal density; a small height of 3 mm can make the material work sufficiently while avoiding early buckling of the structure. Further, the crashworthiness of different sandwich configurations with the same areal density and height is compared, leading to three deformation modes. USDH and circular core structures are found to be able to effectively reduce the peak force and improve the energy absorption ability.

Steel fenders are frequently employed in bridge pier shields to engross collision energy due to vessel impact. However, vulnerability to corrosion is a major drawback in existing steel fenders. To end this, an innovative composite fender structure consisting of corrugated steel and Preplaced Aggregate Fibre Reinforced Concrete (PAFRC) is introduced. Corrugated plates of steel are intended to absorb energy and stiff guard outer panels made with PAFRC exhibit enhanced resistance to impact and ductility. Six steel-PAFRC fenders were prepared with the steel plates of two different thicknesses, where the four top panels of the PAFRC are reinforced with short and long hooked end steel fibres while bottom panels are made with non-fibrous preplaced aggregate concrete (PAC). All steel-PAFRC fenders were tested through a drop weight impact testing device to investigate their impact behaviour and failure mechanism. Collision energy at crack initiation and the ultimate crack of PAFRC panels, crushing deformation of corrugated plates and failure configuration were also examined. Additionally, a numerical model of composite fenders was developed and verified through experimental evidence. Research revealed the crashworthiness of PAFRC panel was higher when compared to the PAC panel. The relative resistance of corrugated plates of steel and the PAFRC panels had a dramatic effect on the composite fender’s impact response.

The equivalent static loads method for nonlinear dynamic response structural optimization may be failed in large deformation crash conditions, due to topology optimization with the equivalent static loads mostly beyond the linear range and causing numerical defects such as high compliance of elements. To overcome the above disadvantage, an advanced structural topology optimization method for crashworthiness considering crash-reduced large deformation and plastic buckling is proposed using newly defined equivalent linear static loads. The equivalent linear static loads can adaptively scale to guarantee that the topology optimization is performed within linear range. At each cycle, the crash simulation is performed and the nonlinear nodal displacement vector at the time step with the maximum strain energy is scaled by an adaptive displacement-scaling factor. The equivalent linear static loads that are generated by multiplying the linear stiffness matrix and the scaled nodal displacement vector will be incorporated into topology optimization, which can guarantee the topology optimization to remain in linear range and further solve the numerical instability problems. The process is repeated until the convergence criteria are satisfied. The effectiveness of the proposed method is evaluated by solving a crashworthiness topology optimization of a crash box considering crash-induced plastic buckling to determine the location and profile of crash triggers. The results show that the proposed method can effectively solve the large deformation crashworthiness topology optimization of thin-walled structures and provides a feasible strategy for crash triggers design in crash box.

This paper is a sequel to the authors’ earlier article (Paik et al. 2020a, Full-scale collapse testing of a steel stiffened plate structure under cyclic axial-compressive loading, Structures, https://doi.org/10.1016/j.istruc.2020.05.026). The aim of the paper was to present a test data on the ultimate compressive strength characteristics of a full-scale steel stiffened plate structure at cryogenic condition which may be due to unwanted release of liquefied gases. Steel plate panels of an as-built containership carrying 1,900 TEU were referenced for this purpose. The test structure was fabricated in a shipyard using exactly the same welding technology as used in today’s shipbuilding industry. It is observed that the test structure reaches the ultimate limit states triggered by brittle fracture, which is totally different from typical collapse modes at room temperature. Details of the test database are documented as they can be used to validate computational models for the structural crashworthiness analysis involving brittle fracture at cryogenic condition.

To improve vehicle side crashworthiness, this paper first introduces the negative Poisson’s ratio structure to the traditional B-pillar and proposes a negative Poisson’s ratio B-pillar. Then, the performance of the negative Poisson’s ratio B-pillar is studied in detail by comparison with a traditional B-pillar and honeycomb B-pillar. Aiming at the problem that the side crashworthiness is also significantly affected by the side structure parameters of vehicle body, the factorial analysis theory is adopted to screen out the side structure parameters with significant effect. Based on this, by combining the optimal Latin hypercube design and response surface model, a multi-objective optimization design is conducted for those structure parameters based on non-dominated sorting genetic algorithm II. Finally, the normal boundary intersection method is adopted to seek the Pareto optimal solution, and the simulation results show that compared with the traditional B-pillar, the negative Poisson’s ratio B-pillar optimized by non-dominated sorting genetic algorithm II has better comprehensive crashworthiness. The results of this paper can provide some basis for the design and optimization of vehicle side crashworthiness.

Lightweight design of bus body can improve energy consumption and operating cost. Nonetheless, design for strength and crashworthiness of bus superstructure is vital to occupant safety during accidents. This work proposes a methodology to design an effective lightweight frame layout and member sections of bus superstructure under requirements of bending stiffness, torsion stiffness, and rollover safety conforming to ECE-R66 based on optimization techniques. The bus configuration is firstly resolved by iterative topology optimizations with the objective function based on the structural weight and compliance subjected to the maximum displacement constraints for each load case. Topology optimization offers a preliminary design possessing the required stiffness while its structural weight is decreased by 2.5 % from the baseline model. Gauge optimization is then applied to adapt the thicknesses of the frame cross-sections. Due to high computational cost of dynamic rollover test, the correlation between nonlinear rollover test and linear quasi-static test with an adjusted deformation limit is proposed to accelerate the process. The most significant design parameter to rollover safety is shown to be the roof structure. Weight distribution and energy absorption of structural components for different models are examined and discussed as the basis to good practice in design for safety.

The rollover safety of Three-Wheel Vehicles (TWVs) is critical because of its instability in severe steering, side collisions and flip-over compared to Four-Wheel Vehicles (FWVs). In order to evaluate the rollover safety, the roof crash conditions in various types of accidents are investigated to provide a reliable roof structure. In order to prepare for roof crash conditions for TWVs, investigation has been carried out in aids of multibody dynamic simulations and motion simulations. According to the simulation, the rear region of a TWV’s roof crashes onto the pavement in case of the rollover. To design an optimal roof structure of TWVs, topology optimization is utilized based on the roof crash conditions. The preliminary design of the roof structure from topology optimization is modified into eight different designs by changing the shape of a roof structure. In this paper, both a static crash test and a dynamic crash test are simulated to obtain the best design of the roof structure of TWVs. The dynamic crash test of a roof structure is essential because of the rate dependency of materials and evaluation of real crashworthiness. From the preliminary designs, an optimal shape of a roof structure is determined considering possible cases of actual rollover. The optimal shape shows that the front members of the cross-bar reinforcement and window screen member need to be straight and the rear member needs to be arch-shaped.