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Showing papers in "International Journal of Crashworthiness in 2010"


Journal ArticleDOI
TL;DR: In this paper, the authors systematically determined the crush behavior of thin-walled straight and conical shell structures and investigated comparatively under axial impact loading for various absorber designs and investigated the energy absorption characteristics and crush forces.
Abstract: In this study, the crush behaviour of thin-walled straight and conical shell structures was systematically determined for various absorber designs and investigated comparatively under axial impact loading. The main parameters in the design of these structures are cross-section geometry, wall thickness and semi-apical angle. Several cross sections have been studied: circular, square and hexagonal. In the finite element simulations, these designs were fixed at one end and impacted by a rigid wall from the other with specified mass and velocity giving the required impact energy according to the European regulation ECE R29 by using explicit finite element code LS-Dyna. After crash simulations, energy absorption characteristics and crush forces were obtained for each crush element having different cross sections, wall thicknesses and semi-apical angles. Peak crush force, mean crush force, crush force efficiency and specific energy absorption (SEA) were calculated for a deformation length of 100 mm. In all case...

131 citations


Journal ArticleDOI
TL;DR: In this article, the assessment of several methods using Lagrangians and Arbitrary Lagrangian Eulerian (ALE) formulations in Radioss to model bird impacts onto rigid panels is presented.
Abstract: The first part of the paper deals with the assessment of several methods using Lagrangian and Arbitrary Lagrangian Eulerian (ALE) formulations in Radioss to model bird impacts onto rigid panels. FE results are compared with experiments in terms of local pressure, including Hugoniot and Stagnation ones, and global load. Two methodologies are chosen: one using a Lagrangian method and an hydrodynamic viscous model for the bird, and another using ALE method and an hydrodynamic bi-phase liquid/gas medium for the air and bird model. With the Lagrangian method, results are in a good agreement compared with available experimental results but the computing cost is expensive. With the ALE method, the calculation cost is lower. The second part of the paper deals with bird impact modelling onto metallic riveted panels using both FE methods. Results are in a good agreement with experiment when the metallic panel IS dented only. For bird penetration cases. results highlight the problem of the modelling of the ...

78 citations


Journal ArticleDOI
TL;DR: In this article, a multi-objective optimisation approach is proposed to consider the robustness issue of those objective functions in the presence of parameter uncertainties, and two polynomial meta-models based on the evolved group method of data handling (GMDH) neural networks are then obtained to simply represent both the absorbed energy (E) and the peak crushing force (F max) with respect to geometrical and material design variables using the training and testing data obtained from the finite-element study.
Abstract: In order to maximise the impact automotive energy-absorbing capacity considering uncertainties in the parameters of the design, it is desired to perform a robust optimum design process. Moreover, the optimum design of such absorption system is inherently a multi-objective optimisation problem. In this paper, a multi-objective optimisation approach is thus proposed to consider the robustness issue of those objective functions in the presence of parameter uncertainties. First, the axial impact crushing behaviour of the S-shaped box beams, as a highly simplified model of the front member of a vehicle body, is studied by the finite-element method using the software ABAQUS. Two polynomial meta-models based on the evolved group method of data handling (GMDH) neural networks are then obtained to simply represent both the absorbed energy (E) and the peak crushing force (F max) with respect to geometrical and material design variables using the training and testing data obtained from the finite-element study. Usin...

47 citations


Journal ArticleDOI
TL;DR: In this paper, the authors focused on the crashworthiness of a civil aircraft with different strut configurations and found that there is a contradiction between the acceleration characteristics and the cubic capacity of cargo holds during the structural design, and the four key factors could not arrive at optima under the same strut configuration.
Abstract: To meet aviation safety and crashworthiness requirement, the crashworthiness of civil aircraft has been extensively investigated. In our case, we focused on the crashworthiness of a civil aircraft with different strut configurations. The finite element model of civil aircraft with sound simplifications was undertaken to simulate the vertical drop test subject to the velocity of 7 mps. Two angles were defined to represent the configuration of strut, and the variation of the failure behaviour, energy absorption capability, acceleration characteristics and the cubic capacity of cargo holds with the two angles were given. The results showed that there is a contradiction between the acceleration characteristics and the cubic capacity of cargo holds during the structural design, and the four key factors could not arrive at optima under the same strut configuration. They should be balanced to obtain better structure, and the strut with moderate angles for civil aircraft was advisable based on the results of our research.

41 citations


Journal ArticleDOI
TL;DR: In this article, numerical and experimental techniques were used to investigate the effect of bird strike on different types of aircraft bubble windows with different geometries and materials, and the results from all techniques were found to be almost similar and in good agreement with the test data.
Abstract: This paper uses numerical and experimental techniques to investigate the effect of bird strike on different types of aircraft bubble windows with different geometries and materials. Three different methods, namely Lagrangian, Arbitrary Lagrangian Eulerian (ALE) and Smooth Particle Hydrodynamics (SPH) are used to simulate bird strike effects on different types of bubble windows during the impact phase. Simple tension tests are carried out on some samples to determine the behaviour of window material during impact while models reported in the literature are used for modelling the bird. First, a simple bubble window is studied numerically using the Lagrangian, ALE and SPH techniques and the results are compared with experimental data. The results from all techniques are found to be almost similar and in good agreement with the test data. This will give way to only ALE to be used for other case studies. Next, bird impacts on a two-layer bubble window with a Poly Vinyl Butyral (PVB) interlayer and a multi-wall...

36 citations


Journal ArticleDOI
TL;DR: In this article, a new crush trigger, called crown trigger, is introduced at one end of carbon-fibre-reinforced polymer circular tubes, which can effectively control the position of crushing initiation and increase the crushing stability.
Abstract: A new crush trigger, called crown trigger, is introduced at one end of carbon-fibre-reinforced polymer circular tubes. Quasi-static compression tests are performed on the tubes to investigate their energy absorption characteristics. It is observed that all tubes are crushed in a brittle fracturing mode. Both crown trigger and bevel trigger can effectively control the position of crushing initiation, reduce the peak load and increase the crushing stability. It is also found that the tube wall of each specimen is delaminated mainly into three layers. The relatively intact exterior layer may constrain the axial splits of the middle layer, make the lamina bundles break off near the base, slow down the central wall crack propagation and thus eliminate a low-performance failure mode. As compared with the bevel trigger, the crown trigger provides nearly the same specific energy absorption but 18.4% lower specific triggering stress and 21.2% higher crushing load efficiency.

34 citations


Journal ArticleDOI
TL;DR: In this paper, a subject specific finite element (FE) model of femur is developed and the parameters of two material models of cortical bone (isotropic elastic-plastic and elastic transversally isotropic) are identified based on three-point bending test data using optimisation techniques.
Abstract: Bone fractures occur frequently at mid-shaft femoral site of the front seat vehicle occupants during frontal and offset automotive crashes. A numerical investigation of femoral shaft tolerance under axial and bending loading corresponding to traffic accidents is presented in the current study. A subject specific finite element (FE) model of a femur is developed and the parameters of two material models of cortical bone (isotropic elastic–plastic and elastic transversally isotropic) are identified based on three-point bending test data using optimisation techniques. A Monte Carlo analysis is performed on a surface approximation of the optimised models over a domain of +/− 20% of the optimised parameter values and showed that the elastic moduli of femur are the most influential parameters on the bone stiffness curve prior to bone fracture. The mid-shaft femoral tolerance curves demonstrate sensitivity with respect to the impact direction of transversal load due to the initial curvature of the femur, but ins...

31 citations


Journal ArticleDOI
TL;DR: In this paper, a systematic study has been conducted to examine possible strategies in order to design crashworthy external and internal structures for a high-speed train nose, and the effects of foam usage in different spaces between internal and external layers of the nose are shown.
Abstract: The external shape of a high-speed train nose is usually designed according to the aerodynamic considerations and to minimise the drag forces and noises. Crashworthiness of the nose is another aspect that is important from the passive-safety point of view. To improve the crashworthiness characteristics, usually there are not many options for changing the external shape of a high-speed train nose; therefore, a systematic study has been conducted to examine possible strategies in order to design crashworthy external and internal structures for a high-speed train nose. It is observed that the longer and slender noses show better crashworthiness characteristics. In addition, various multi-layer noses are studied, and the best internal-layer geometry is proposed. At the last step the effects of foam usage in different spaces between internal and external layers of the nose are shown.

30 citations


Journal ArticleDOI
TL;DR: Wang et al. as mentioned in this paper built a survey group to randomly collect vehicle-pedestrian accidents and analyse these accidents from the vehicle-Pedestrian crash characteristics and the relationships between the pedestrian injury outcome and the impact speed.
Abstract: In China, pedestrians were the most common and the most vulnerable of road users, meaning pedestrians were involved in vehicle-pedestrian accidents more frequently. Little attention has been paid to the investigation of such accidents. One surveying group was built to randomly collect vehicle-pedestrian accidents and analyse these accidents from the vehicle–pedestrian crash characteristics and the relationships between the pedestrian injury outcome and the impact speed. 184 pedestrians were injured and killed in these investigated passenger-car-pedestrian accidents. Among the 184 pedestrians involved in these accidents, 151 were crossing road arbitrarily (82.1%). There were only 17 accidents where the pavement and guardrail satisfied the safety standard. The males were the majority of the casualties (64.7%). Pedestrian injury localisations in head, extremities, chest and torso accounted for 68.5%, 68.5%, 24.5% and 15.8%, respectively. Of the fatalities, 71.4% resulted from brain injury. The injury outcome...

27 citations


Journal ArticleDOI
TL;DR: In this article, the design of pedestrian bucks, intended to represent the basic vehicle front-end structures, consisting of five components: lower stiffener, bumper, hood leading edge and grille, hood and windshield.
Abstract: Previous vehicle-to-pedestrian impact simulations and experiments using pedestrian dummies and cadavers have shown that factors such as vehicle shape, pedestrian anthropometry and pre-impact conditions influence pedestrian kinematics and injury mechanisms. Generic pedestrian bucks, which approximate the geometrical and stiffness properties of current vehicles, would be useful in studying the influence of vehicle front-end structures on pedestrian kinematics and loading. This study explores the design of pedestrian bucks, intended to represent the basic vehicle front-end structures, consisting of five components: lower stiffener, bumper, hood leading edge and grille, hood and windshield. The deformable parts of the bucks were designed using types of currently manufactured materials, which allow fabricating the bucks in the future. The geometry of pedestrian bucks was approximated according to the contour cross-sections of two sedan vehicles used in previous pedestrian dummy and cadaver impact tests. Other ...

26 citations


Journal ArticleDOI
TL;DR: The Jordan rollover system (JRS) as mentioned in this paper is a self-contained device that occupies a small footprint to perform controlled tests within industry-accepted laboratory crash test tolerances at a far more reasonable cost than other test devices.
Abstract: A review of most of the existing rollover dynamic devices was conducted in view of assessing their flexibility, reliability, repeatability and crash reconstruction potential. The outcomes indicate the Jordan Rollover System (JRS) to offer the better potential with respect to a repeatable dynamic test procedure in all aspects than the Inverted Drop Test, the Dolly Test Procedure SAE J2114 or FMVSS 208, the Controlled Rollover Impact System, the Corkscrew Rollover System, and above all the newly updated FMVSS 216 Roof Crush Resistance Test. The positive attributes of the JRS are that the device as a research tool is flexible and accurate enough to accommodate most prescribed input conditions; it measures dynamic near and far side impact roof crush loads, not possible with other test devices; it has excellent repeatability en par with the National Highway Traffic Safety Administration and the Insurance Institute for Highway Safety dynamic frontal, side and rear impact tests; it is scientifically acceptable and indeed represents an improvement over other dynamic test devices used by the industry; it provides reliable roof crush and roof crush speed comparisons between vehicles; and it measures cumulative roof crush data believed by many experts in rollover to be a function of head–neck system injury severity. In addition, the JRS is a self-contained device that occupies a small footprint to perform controlled tests within industry-accepted laboratory crash test tolerances at a far more reasonable cost than other test devices. It is the best available dynamic test device in terms of assessing the interaction between roof deformation, occupant kinematics and restraint systems. Original equipment manufacturers and associated researchers can use the device to supplement the new FMVSS 216 in this regard. This is particularly so considering that the next phase of the FMVSS 216 is the development of a dynamic procedure. Moreover, the device can be readily used to star rate rollover crashworthiness of vehicles.

Journal ArticleDOI
TL;DR: In this paper, the collapse characteristics and energy-absorption capability of three kinds of hybrid composite tubes, G827-G803/3234, G 827- G803/5224, and G8 27-759/ 5224, are studied.
Abstract: The collapse characteristics and energy-absorption capability of three kinds of hybrid composite tubes, G827-G803/3234, G827-G803/5224 and G827-759/5224, are studied in the present article. Each of the specimens containing two kinds of brittle fibre has been examined by both axial quasi-static and impact crushing test. The effects of fibre type, fibre content and loading conditions on the crushing-failure characteristics, peak load and energy-absorption capability are discussed. The test results show that for G827-G803/3234 tubes, the crushing failure mode is changed from the splaying mode to the fragmentation mode when quasi-static loading is changed to impact loading, while for others there is no such characteristic. The fibre type and fibre content have significant influences on peak load. It is observed that the tubes containing only one kind of brittle fibre have lower peak load than the ones containing two kinds of fibres with approximately equal hybridisation contents. The energy-absorption capabil...

Journal ArticleDOI
K. T. Gursel1, S. N. Nane1
TL;DR: In this article, the deformation mechanism of vehicles was analyzed in full frontal, offset frontal and side impact scenarios using an explicit analysis algorithm within the ‘ANSYS/LS-DYNA’ program, using data models for various vehicles.
Abstract: During the last decade, automobile manufacturers have used computer simulations and are developing computer technology widely and more effectively to improve the crashworthiness of vehicles. Car manufacturers analyse the crashworthiness of vehicle designs in various crash scenarios, by means of advanced vehicle models, using finite element methods. This considerably reduces the number of costly crash tests performed with the designed vehicles in test labs. In this study, the deformation mechanism of vehicles was analysed in full frontal, offset frontal and side impact scenarios. The analyses used an explicit analysis algorithm within the ‘ANSYS/LS-DYNA’ program, using data models for various vehicles. The simulation results were compared with actual crash test data of the corresponding vehicles. The comparisons indicate that the obtained results are reliable and the algorithm used in these analyses can be useful in crash simulations, thereby considerably reducing the number of crash tests required during ...

Journal ArticleDOI
TL;DR: In this paper, the failure properties of knee ligaments under dynamic loadings like those undergoing during pedestrian impacts were studied. And the results showed that knee ligament failure properties can be classified into two groups corresponding to the cruciate and the lateral ligaments.
Abstract: A new experimental device was designed to study the failure properties of knee ligaments under dynamic loadings like those undergoing during pedestrian impacts. This device consists of a hydraulic actuator in order to impose various loading conditions on isolated knee ligaments. The originality of this device leads in the ligaments locking system obtained with spherical joint. Each sample is obtained with an isolated bone-ligament-bone complex embedded in resin. The sample can then be tested for various orientations of ligaments during loading. Results were obtained on twenty human ligaments subjected to tensile traction tests in their fibre axes at 2m/s velocity. These results show that knee ligaments failure properties can be classified into two groups corresponding to the cruciate and the lateral ligaments. For each group it was also possible to identify specific damage pattern (with peeling failure and bone avulsion), failure mode (ductile and brittle for lateral and cruciate ligaments), dama...

Journal ArticleDOI
TL;DR: In this article, a response surface approach to modelling car-pedestrian impact events and a multi-objective optimisation technique aimed at finding a front-end car geometry that minimises the injury outcome is presented.
Abstract: The paper presents a response surface approach to modelling car–pedestrian impact events and a multi-objective optimisation technique aimed at finding a front-end car geometry that minimises the injury outcome. The results of the study, involving a parametric front car model and four anthropometric-group pedestrian models, demonstrate the ability of RBF-based response surface models to adequately describe car–pedestrian impacts despite the high nonlinearity of such events. Moreover, the response surface models have been successfully used to find front-end car geometry that minimises injury levels across all four anthropometric groups.

Journal ArticleDOI
TL;DR: In this paper, the results of eight tests conducted on three post-mortem human subjects were presented as part of an ongoing effort to characterise human thoracic response to belt loading in a well controlled and repeatable laboratory environment.
Abstract: This research was completed as part of an ongoing effort to characterise human thoracic response to belt loading in a well controlled and repeatable laboratory environment. This paper presents the results of eight tests conducted on three post-mortem human subjects. The sled test environment provides realistic occupant kinematics and restraint interaction in the inertial environment of a vehicle collision, but is too complex for detailed analysis of thoracic deformation under belt loading. To study in more detail the kinematics of the chest when loaded anteriorly by a seat belt, three male post-mortem human surrogates (31-62 years of age) were mounted on a stationary apparatus that supported the spine and shoulder in a configuration comparable to that achieved in a 48 km/h sled test at the time of maximum chest deformation. The belt was positioned across the anterior torso with attachments at D-ring and buckle locations based on the geometry of a mid-sized sedan. The belt was attached to a trolley driven ...

Journal ArticleDOI
TL;DR: The objective of the present work was to study the dynamic responses and head–brain injuries in car-to-pedestrian collisions via accident reconstructions via mathematical models of the pedestrians and passenger vehicles through in-depth analysis of accident data collected through on-the-spot and retrospective investigations.
Abstract: The objective of the present work was to study the dynamic responses and head brain injuries in car-to-pedestrian collisions via accident reconstructions. Six pedestrian accident cases were used in the reconstructions using mathematical models of the pedestrians and passenger vehicles. The cases were selected from an in-depth analysis of accident data collected through on-the-spot and retrospective investigations and documented in a database in China. The six selected cases provided sufficient data for reconstructions, including details on pedestrian injuries, accident cars, road fixtures and the environment. The reconstruction results were compared with observations and measurements in accident investigations. The correlation of calculated dynamic parameters with registered severity of head brain injury was analysed and realised. The results provided background knowledge for the prediction of head brain injury and the development of pedestrian protection countermeasures.

Journal ArticleDOI
TL;DR: In this paper, an alternative approach based on an array of thin-walled circular tubes attached to the front bulkhead of the car was considered, and experiments were conducted at the University of Leeds to study the behaviour of empty and honeycomb-filled tubes subjected to quasi-static and dynamic loading.
Abstract: An important feature of the Formula SAE (Society of Automotive Engineers) race car design competition is that the car must withstand a certain level of frontal impact without intrusion into the driver foot-well area or damaging levels of deceleration to the driver himself. For the car to be competitive, any impact-absorbing structure must be lightweight and hence many teams use aluminium honeycomb inside the car's frontal nose cone. This paper considers an alternative approach based on an array of thin-walled circular tubes attached to the front bulkhead of the car. Experiments have been conducted at the University of Leeds to study the behaviour of empty and honeycomb-filled tubes subjected to quasi-static and dynamic loading. Aluminium (6063 T6 alloy) tubes filled with Nomex® HRH-10 honeycomb were employed in the current study. The experimental programme included five quasi-static tests and four dynamic tests. It was found that the honeycomb-filled tubes absorbed around 10% more energy than the empty tu...

Journal ArticleDOI
TL;DR: In this article, the authors presented a crashworthiness design of thin-walled curved steel beams with box and channel cross section, and three parameters were chosen as design variables and optimised to acquire the maximisation of the beam's energy absorption capacity during crashes.
Abstract: This paper presents a crashworthiness design of thin-walled curved steel beams with box and channel cross section. Three parameters are chosen as design variables and optimised to acquire the maximisation of the beam's energy absorption capacity during crashes. In this study, the thin-walled curved beam's energy absorption capacity is expressed in terms of the specific energy absorption (SEA), and the response surface method is employed to formulate the SEA as a function of the three design variables. Finite element (FE) models for such beams are created and used for crashworthiness analyses for the objective of deriving such functions. After having the optimal designs, the effects of the design variables on the curved beam's crash performance are investigated through parametric studies. Finally, simplified FE models are created for the thin-walled curved beams again and used for the same optimisation problem. The optimal designs obtained from the simplified FE models are compared to the previous ones to ...

Journal ArticleDOI
TL;DR: In this article, an optimal design of hexagonal cross-sectional profile of such curved beams is obtained based on the observations of typical crash responses of a series of thin-walled curved hexagonal beam samples.
Abstract: This paper focuses on the crashworthiness analysis and crash responses of thin-walled curved beams with hexagonal cross sections. An optimal design of hexagonal cross-sectional profile of such curved beams are obtained based on the observations of typical crash responses of a series of thin-walled curved hexagonal beam samples. The optimised curved beam achieves maximum energy-absorption capability. Detailed finite element (FE) models and finite element analysis (FEA) method are employed to investigate the crash behaviour of the curved hexagonal beams and provide the observations for the optimum design. In this design optimisation problem, the specific energy absorption is set as the objective, and the cross-sectional side length and wall thickness are selected as two design variables. The design samples are selected from design space using factorial design method, and the design problem is formulated based on the FEA results of the design samples, by the use of design of experiments method. Afterwards, s...

Journal ArticleDOI
TL;DR: In this article, a frontal sled test was conducted to evaluate the bio-fidelity of the THOR dummy in comparison with the Hybrid III dummy and the post-mortem human surrogates (PMHS).
Abstract: Ten 48 km/h frontal sled tests were conducted to evaluate the biofidelity of the THOR dummy. Three replicate tests were conducted with THOR, three with a 50 th percentile male Hybrid III dummy, and four with post-mortem human surrogates (PMHS). The tests, conducted in a buck representing a mid-size US sedan, included a force-limited three-point belt system with buckle-side pretensioner and a driver side airbag. Following the tests, select parameters were used to compare THOR's responses with those of the Hybrid III dummy and the PMHS. The tesults were mass scaled in order to account for size differences between the subjects. Based on cadaveric response corridors, the sled test results provided evidence that THOR is more biofidelic than the Hybrid III dummy. THOR lap belt loads, head acceleration, and movement of the anterior chest wall were more similar to those of the PMHS than were those of the Hybrid III. However, THOR recorded less head forward movement and pelvic acceleration than did the PMHS.

Journal ArticleDOI
TL;DR: In this article, the authors used finite element analysis (FEA) of a deformable helmet with a realistic shape to estimate the peak head-form acceleration in oblique helmet impact tests.
Abstract: The Department for Transport introduced a safety helmet assessment and rating program (SHARP) for motorcycle helmets sold in the United Kingdom. The mechanics behind the part of the scheme that uses a rigid sphere head-plus-helmet model to estimate the peak headform acceleration in oblique helmet impact tests is assessed and the approximations exposed. When finite element analysis (FEA) of a deformable helmet with a realistic shape was used, the predicted levels of oblique peak acceleration were much smaller than those estimated by the SHARP scheme. The statistical data of motorcyclists’ impact velocities, sites and impact type, used to weight the SHARP impact results, were shown to overemphasise impacts at the sides of the helmet. It was concluded that the derived oblique impact test results, based on an inappropriate mechanics model, are meaningless. Consequently, the helmet star ratings are not related to head protection levels.

Journal ArticleDOI
TL;DR: In this paper, a 1/20th scale model of an aircraft fuselage is used to evaluate the impact design requirement for a 30 ft/s vertical impact velocity onto a rigid surface.
Abstract: Scale modelling of an aircraft fuselage and its measure of accuracy was investigated and determined with 1/5th, 1/10th, 1/15th and 1/20th times scaled models of an aircraft fuselage. Non-linear Finite Element Method (FEM) solver LS DYNA 3-D has been employed to analyse the experimental 1/20th scale aircraft fuselage model. The results were validated with the experimental scaled drop test model. The focus of this paper is to evaluate the scaling concept and its possible incorporation into the crashworthiness evaluation of fuselage as a potential crashworthiness evaluation tool. The impact design requirement for the 1/20th scale model fuselage section is to maintain 500 g floor-level acceleration for a 30 ft/s vertical impact velocity onto a rigid surface. This impact requirement corresponds to 25 g floor-level acceleration for a geometrically and constitutively similar full-scale fuselage section. Sub-floor concepts were then evaluated by conducting dynamic tests and confirmed with analytical calculations ...

Journal ArticleDOI
TL;DR: In this article, the elastic modulus and thickness of the interior panels of the door and B-pillar are considered as design parameters to enhance car safety performance for occupant chest protection by optimizing the interior panel's properties and design parameters.
Abstract: In a car side crash, the interior panels of the door and B-pillar could have a direct contact with the occupant of a struck car, which is a risk for occupant chest injuries. Therefore, the objective of the study is to enhance car safety performance for occupant chest protection by optimising the interior panel's properties and design parameters. A production passenger car finite-element model was developed and used to analyse the interior panels design for occupant protection. Prescribed structural motion technology was employed to reduce the computation time. The elastic modulus and thickness of the interior panels of the door and B-pillar are considered as design parameters. An optimisation of the interior panels was carried out by using the response surface methodology with quadratic functions. The efficiency of the optimisation was identified by reducing the risk of thorax injury by 25%.

Journal ArticleDOI
TL;DR: In this article, the effect of morphological imperfections at the cellular scale on the global response of the cellular material was investigated, and the results revealed the influence of these imperfections on low-density foams.
Abstract: In this paper, we develop and implement high-resolution, computationally efficient multi-cell finite-element (FE) models of metallic foams in order to more accurately investigate the collapse behaviour of these emerging materials. The main objective is to investigate the effect of morphological imperfections at the cellular scale on the global response of the cellular material. Attention was therefore devoted to three related aspects of the work. The first is concerned with the development of FE models of metallic foams accounting for morphological imperfections at the cellular level. The second is concerned with conducting parametric studies of different model parameters and examining their effect on the instantaneous load-deformation history, peak collapse loads and energy absorption levels of the foam. The third is devoted to a thorough comparison of the numerical simulations with experimental results. Results revealed the influence of these imperfections on low-density foams, and to a much lesser exte...

Journal ArticleDOI
Meng Luo1, Qing Zhou1
TL;DR: In this article, a sliding mechanism of vehicle seat with crash energy-absorption (EA) function is proposed and analyzed to reduce whiplash injury risk in low-speed rear-impact accidents.
Abstract: To reduce whiplash injury risk in low-speed rear-impact accidents, a sliding mechanism of vehicle seat with crash energy-absorption (EA) function is proposed and analysed in this study. It can reduce relative motion between occupant head and torso under rear impact and lower values of neck injury related parameters such as neck injury criterion (NIC), neck displacement criterion (NDC) and neck forces and moment. A number of parameters of seat structure and countermeasures have great influence on occupant head–neck responses in rear impacts. They include head restraint position, seat recliner characteristic and seatback cushion stiffness, as well as the newly proposed seat sliding characteristic. A numerical model that includes a seat and a BIORID II dummy is used in a parametric study to evaluate effects of whiplash injury risk reduction. The analysis results show that proper combinations of the values of these parameters can mitigate the whiplash injuries and they form the basis of the existing counterme...

Journal ArticleDOI
TL;DR: In this article, the authors proposed a test procedure to evaluate road infrastructure in terms of motorcyclists' safety, based on a theoretical study, reconstruction of accidents and a computer simulation work.
Abstract: The problem of injuries to motorcyclists caused by impacts with roadside barriers is not a recent issue (S. Peldschus, E. Schuller, J. Koenig, M. Gaertner, D. Garcia, and A. Mansilla, Technical bases for the development of a test standard for impacts of powered two-wheelers on roadside barriers, Proceedings of the 20th Enhanced Safety of Vehicles Conference, 2007) but at present, few standards have been proposed in this field. In APROSYS SP4 ‘Motorcycle accidents’, one of the main objectives is to develop a proposal of test procedure to evaluate road infrastructure in terms of motorcyclists' safety. For that purpose, it is necessary to know which are the most representative scenarios describing real motorcyclists' impacts against the infrastructure. Conclusive results have been obtained neither from the database analysis nor from the literature review. A theoretical study, reconstruction of accidents and a computer simulation work have been performed in order to select the parameters to be used in the sta...

Journal ArticleDOI
TL;DR: In this article, a project team with members from seven countries was set up to devise appropriate variable lists to collect fatal crash data, using retrospective detailed police reports (n = 1300), under the following topic levels: accident, road environment, vehicle and road user.
Abstract: A lack of representative European accident data to aid the development of safety policy, regulation and technological advancement is a major obstacle in the European Union. Data are needed to assess the performance of road and vehicle safety and also to support the development of further actions by stakeholders. A recent analysis conducted by the European Transport Safety Council identified that there was no single system in place that could meet all of the needs and that there were major gaps including in-depth crash causation information. This paper describes the process of developing a data collection and analysis system designed to partly fill these gaps. A project team with members from seven countries was set up to devise appropriate variable lists to collect fatal crash data, using retrospective detailed police reports (n = 1300), under the following topic levels: accident, road environment, vehicle and road user. The typical level of detail recorded was a minimum of 150 variables for each accident. The project will enable multidisciplinary information on the circumstances of fatal crashes to be interpreted to provide information on a range of causal factors and events surrounding the collisions. This has major applications in the areas of active safety systems, infrastructure and road safety, as well as for tailoring behavioural interventions.

Journal ArticleDOI
TL;DR: In this paper, a new experimental set-up, with well-known boundary conditions, has been developed for numerical model validation, allowing for impacts with angles ranging from 20° to 90° by a step of 5°.
Abstract: Aircraft structures should endure tyre debris impacts. Therefore, numerical simulations which are able to predict such phenomena are highly appreciated for the aircraft structures design. However, these simulations had to be checked by means of experimental data. In this paper, a new experimental set-up, with well-known boundary conditions, has been developed for numerical model validation. This new set-up allows for impacts with angles ranging from 20° to 90° by a step of 5°. In this study, rubber balls, which are 42 mm in diameter, are launched against 500 × 500 mm2 aluminium alloy plates. The impact velocities are in the range of 130 m/s.

Journal ArticleDOI
TL;DR: This evaluation contains the representation of the injury situations of child and adult cyclists, accident severity and injury samples are represented in detail, and the possible effectiveness of a bicycle helmet is discussed.
Abstract: For years, information and motivation campaigns have been conducted in order to increase the frequency of use of helmets for bicyclists. Observation of two-wheeler traffic in 2005 involving more than 13,000 cyclists showed an incidence of helmet use in only 6% of the cases. This may be the reason for the fact that there are no comparative studies from Germany that prove the protective effect of the helmet by comparing victims of road accidents who wore a bicycle helmet and those who did not. For this purpose, data collected at the site of accidents (in the German In-Depth Accident Study) have been used for the first time in 10 years during which accidents with helmeted bicyclists could be documented; scientific researchers drove to the scenes of the accidents using specially equipped emergency vehicles and documented vehicle deformations and accident traces in addition to the injuries. A comprehensive accident reconstruction supplies the data concerning the speed and injury mechanisms. The data are proces...