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Powered Two-Wheeler riders are over-represented in crash statistics worldwide, and currently available safety solutions have not triggered a decreasing trend. A new device concept, comprised of a wearable vest with belt stripes sewn on the back and fastened to the motorcycle frame through a metal cable, was developed to save riders' lives. The objective of this paper is the evaluation of its protective effectiveness in a set of representative crash configurations selected from the ISO 13232 database. The configurations were reproduced in a multibody environment, and each of them was characterised through the following parameters: the impact speeds, contact points, relative heading angle, and the Boolean presence of the safety device. The preliminary evaluation revealed encouraging outcomes as several body regions reported reduced injury indices. However, the benefits depended on the speed range and impact configuration. Overall, the benefits outweighed the additional risks in the selected accident database. [ABSTRACT FROM AUTHOR]

The derailment of a high-speed train in a tunnel will cause a very serious accident, but there are few research articles on anti-collision facilities in tunnels. In order to promote the sustainable development of high-speed trains and reduce the severity of accidents caused by derailment in tunnels of high-speed trains, this paper puts forward a crash barrier scheme in tunnels through the method of numerical simulation; the coupling finite element model of train–crash barrier–tunnel is established by using ABAQUS. The changes in lateral velocity and lateral displacement after the train hits the crash barrier without embedding steel bars are explored. We also explore the influence of different reinforcement amounts on the changes in the lateral speed and lateral displacement of trains under the condition of embedding steel bars. The results show that with the increase in stirrups and vertical reinforcement, the anti-impact and sustainable operation capability of the crash barrier are greater. It can also be seen from the lateral displacement of the train that the train shows the reverse movement trend, and the crash barrier plays a good role in intercepting the train. These research results can provide a reference for the sustainable development of transportation infrastructure construction. [ABSTRACT FROM AUTHOR]

This work investigates linear and non-linear parametric reduced order models (ROM) capable of replacing computationally expensive high-fidelity simulations of human body models (HBM) through a non-intrusive approach. Conventional crash simulation methods pose a computational barrier that restricts profound analyses such as uncertainty quantification, sensitivity analysis, or optimization studies. The non-intrusive framework couples dimensionality reduction techniques with machine learning-based surrogate models that yield a fast responding data-driven black-box model. A comparative study is made between linear and non-linear dimensionality reduction techniques. Both techniques report speed-ups of a few orders of magnitude with an accurate generalization of the design space. These accelerations make ROMs a valuable tool for engineers. [ABSTRACT FROM AUTHOR]

Nowadays, the importance of energy conservation and environmental sustainability issues has led to developments of environmentally friendly products like electric vehicles (EVs). The EVs are not already as widespread as internal combustion engine vehicles (ICEVs) and also the complicated inherent crash behaviour put their crashworthiness at the first development steps. However, besides the battery safety, other major issues such as corresponding vehicle crashworthiness as a consequence of engine and sub-related components elimination and also battery packaging should be addressed. Although before reaching a more specific crash limits for EVs safety evaluation test cases, one could use the ICEV's conventional crash scenarios for the structural crashworthiness evaluations. In this article, the side pole impact as the severe load case according to ENCAP was introduced and protection of the battery pack is improved by implementing a novel energy absorber element into the body sill side. The analyses have performed based on validated computational simulations. The finite element model of the structure is prepared by ANSA and the simulations carried out via ABAQUS and the non-linear explicit finite element software of PAM-CARSH. The various assessment criteria such as pole intrusion, internal energy, section loads before and after the conversion are analysed in order to find an optimum configuration of the structure for battery protection. Obtained results show a significant enhancement in vehicle crashworthiness performance. [ABSTRACT FROM AUTHOR]

In this study, the boundary conditions of crash simulation are derived by analyzing the LTAP/OD (left turn across path/opposite direction) crash conditions when driving at an intersection. Head and neck injury are analyze using crash simulation. Using traffic accident databases released national highway traffic safety administration, the crash speed and angle of the LTAP/OD accident at the intersection are derived. Using data of driving path and car-to-car contact section, driving simulation is performed to derive crash points in case of an intersection LTAP/OD crash. After composing a car-to-car crash simulation model with the crash points, crash speeds, angles, six crash analysis is conducted. Based on the simulation results, more dangerous cases are selected and additional crash simulations are calculated with a driver and a passenger dummy. By analyzing the simulation result data on the neck of the dummies, the risk in this boundary condition is evaluated. [ABSTRACT FROM AUTHOR]

This work contributes to the understanding of damage of adhesive layers generated during the manufacturing process and its effect on the subsequent load carrying capacity of the joint. A temperature dependent cohesive zone model is used to predict damage during the manufacturing process. Therefore, parameters for a temperature-dependent as well as a strain rate-dependent model were determined on various specimens. It is shown, that it is possible to predict the manufacturing induced damage within the adhesive layer with sufficient accuracy using a cohesive zone model. Furthermore, a continuous process chain for numerical simulations is developed, which allows to determine the adhesive layer damage by means of a process simulation and to consider the changed mechanical properties in a subsequent crash simulation. To simplify the procedure, a software tool is presented that automatically performs the described steps. The developed method is applied to a car body simulation to investigate the effects caused by the manufacturing process. [ABSTRACT FROM AUTHOR]

Safety roller barrier (SRB) is an innovative road safety device that utilises foam rollers to absorb and convert shock energy into rotational energy, showcasing its remarkable ability to minimise the risk and severity of casualties in road accidents. In this study, a simulation-based optimisation approach was employed to obtain the optimal design for the SRB. Quasi-static and dynamic mechanical properties of the construction materials were experimentally obtained. SRB finite element (FE) models were then created based on installed systems in multiple Australian cities. The model was validated using full-scale TL4 crash tests according to the specifications outlined in the Manual for Assessment of Safety Hardware (MASH). Subsequently, a parametric study was conducted to explore the influence of design parameters such as post spacing, rail height, and roller number. Finally, a parallel Bayesian optimisation algorithm was applied to re-design the SRB system with enhanced performance and reduced cost. This optimisation process yielded several sets of optimal parameters, paving the way for a more effective and economically viable SRB design. • Numerical model of safety roller barrier (SRB) crash was built and validated. • Parametric studies were conducted to reveal optimal designs of SRB. • The geometry of SRB was optimised using parallel Bayesian optimisaiton method. [ABSTRACT FROM AUTHOR]

For the successful introduction of buses fueled by hydrogen, the safety of hydrogen buses is being discussed and investigated by governments and research institutes. This study is focused on evaluation approaches for hydrogen bus crashworthiness with hydrogen fuel systems located on the roof structure. Based on rollover safety regulations, the primary countermeasures are not only to ensure that there is no contact between the hydrogen fuel system and other parts of the vehicle or the ground, but also to confirm adequate occupant residual space for occupant protection during rollover accidents. Thus, the experimental concept to check safety countermeasures along with computational approaches and procedures are discussed with regards to the rollover test loading conditions in this study. A rollover test setup process was investigated and a hydrogen bus rollover test was performed. Furthermore, a hydrogen bus FE model has been developed and the structural response was verified. The results and conclusion provide the conceptual framework to evaluate hydrogen bus crashworthiness. [ABSTRACT FROM AUTHOR]

Due to the reduction of vehicle development time and cost constraints, increasing volumes of vehicle development work are being transferred from automotive manufacturers to suppliers. In the area of vehicle structure development, one of the major challenges for suppliers is to deliver a good structural solution in a short time with very limited vehicle data. For those crash-relevant components or modules, such as the A- and B-pillar and the door module, considerable inaccuracies can be expected in the results when using partial vehicle data, as opposed to complete data, with the traditional component validation methods. In this work, a new component development method has been developed, and its implementable crash test bench for small vehicles has been virtually realised. This method focuses on the side impact tests at this phase, such as side impact with a mobile deformable barrier and a side pole impact. Reducing the number of required surrounding components and finding proper boundary conditions that can be implemented in the real test bench are the principle objectives of this work. The results of the crash simulations show a good correlation between the component sub-model and the full vehicle (FV) model using this method. [ABSTRACT FROM AUTHOR]

Woven fabric thermoplastic composites possess high specific strength and stiffness along with thermoformability. To utilize the full potential of these materials to achieve better crash-safe designs in automotive structural parts, their crash behavior must be predicted accurately. For reliable crash simulations, strain rate-dependent material data and equally capable material modeling are required. In this study, quasi-static and high-speed tests are carried out to measure tensile and in-plane shear properties. A strain rate-dependent continuum damage mechanics model is formulated to describe the deformation and damage behavior of woven glass fabric composites. Tensile and in-plane shear tests on a lab scale are used to calibrate the material parameters of the model. The model was implemented as a user-defined material subroutine (VUMAT) for Abaqus. Experimental results from coupon tests were used to verify the results of a single-element simulation. Finally, a structural level dynamic crash test of a u-profile on a drop tower was used to validate the predictions of the user material model. [ABSTRACT FROM AUTHOR]

The undesirable stresses and deformations during a high-speed crash can cause a short circuit or sudden fire in the battery packs, which represents a significant safety concern for vehicles. In this paper, computer-aided simulations are conducted to provide a supplemental and economic approach to evaluate the crashworthiness of a battery-pack enclosure. First, a nonlinear dynamic finite element model of a battery-pack enclosure is established and validated using the modal test. The crush and crash simulations, based on the governing equations and explicit FE code, LS-DYNA, are performed according to the test standard. Second, three high-strength steel materials are used in the validated finite-element model to perform a crashworthiness simulation with respect to robustness and lightweight design. The results show how both materials and thickness affect the crashworthiness of an automotive battery-pack enclosure. Finally, the weight of the battery-pack enclosure is reduced, while the crashworthiness is improved as well. [ABSTRACT FROM AUTHOR]

Event Data Recorders (EDRs) have been used for the purpose of investigating traffic accidents for more than 20 years. Some countries have regulated their application by law, and they are a valid evidence during investigations and reconstructions. However, recording devices are used as a source of information, not as a database from which it is possible to reconstruct the event. Investigations using only recording devices are still not possible due to the some phenomena that exist, and due to the constructional features of the devices. Scientists from Japan and Poland tested the accuracy of the data from the devices and performed reconstructions of accidents. Both teams have established that it is possible to perform reconstruction only in simple situations, such as a straight-line crash of one vehicle into another. When there are several participants in a crash, or a crash was preceded by a maneuver, it is not possible to determine what really happened. Further development of data recording devices is necessary, in order to increase their efficiency during the reconstruction of traffic accidents.

Resistance Rivet Spot Welding (RRSW) is a joining technique with high flexibility and cost efficiency for connecting steel and aluminum sheet metal parts in an automotive body in white (BIW). Using this method, both pure steel and steel–aluminum mixed BIW can be produced in the same assembly line. The prediction of the load-bearing capacity and failure behavior in crashworthiness calculation by the OEMs requires a stable finite element (FE) simulation model for both static and dynamic load cases. In this paper, an experimental and numerical study on the behavior of RRSW connections is presented. After the analysis of different material models with varying FE codes, the material model MAT 100DA of LS-DYNA was chosen as the starting point for crash simulation. For the determination of the model parameters as well as the entire FE model, material tests with different strain rates and KS-II-tests with three different velocities were performed. The FEM parameters were determined via iterative parameter calibration. Lap shear, peeling, and component tests were conducted for parameter validation along with the FE calculations. In the experiment, the loading rate-dependent behavior of the RRSW joining was observed in terms of force-displacement curves and the failure phenomenon. The simulation's results show that the performance of vehicle components joined by RRSW are predicable by using the material model MAT_100DA. The prediction of failure behavior can be further improved by using a detailed meso-scale model. [ABSTRACT FROM AUTHOR]

Simulating the vehicle collision has gained importance in the automotive sector due to its accuracy, cost effectiveness and enhanced reliability. It aids in improving the safety of driver and passenger and also examine the cause of crash or collision. This numerical analysis investigates the materials capability to enhance safety. A three-dimensional vehicle model was developed along with its roll cage using solid work tool. Hypermesh work bench was employed to discretise the sensitive parts of the body and roll cage using beam 189 element having six degree of freedom at each node. The existing structural steel members were replaced with reinforced carbon fibre in all the sensitive part of the body and roll cage and its structural stability was assessed using the frontal, side and roll over crash simulation using LS Dyna. This investigation also reveals the change in internal energy, kinetic energy absorption and momentum transfer for both structural steel and carbon fiber under all the crash scenarios. The outcomes of this numerical investigation proved that the reinforced carbon fiber can be effectively replaced with the structural steel to enhance safety. [ABSTRACT FROM AUTHOR]

This study investigates the use of hemp/glass fiber reinforced epoxy composites for designing automotive front bumper beams, focusing on crashworthiness and pedestrian safety. The composite bumper beam model is evaluated through low- and high-velocity crash simulations and pedestrian leg form impact tests using LS-DYNA software. Optimal stacking sequences are analyzed, with high-strength glass fibers positioned on the outer layers to bear impact loads and low-density hemp fibers in the middle. The hybrid hemp (H)/glass (G) fiber composite laminate can absorb up to 90 % of the impact energy absorbed by a glass fiber composite, with a ± 45° fiber orientation, showing exceptional energy absorption capabilities. The [G(±45°) 4 , H(±45°) 4 ] S composite bumper beam offers superior impact performance, safety, and a weight reduction of 49.2 % compared to a commercial steel bumper beam. This study highlights the potential of natural fiber composites as sustainable alternatives in automotive design. [ABSTRACT FROM AUTHOR]

Woven fabric thermoplastic composites possess high specific strength and stiffness along with thermoformability. To utilize the full potential of these materials to achieve better crash-safe designs in automotive structural parts, the measurement of non-linear shear behavior and its material modeling for FEM simulations is required. The standard testing method was used to measure the pure shear behavior of woven fabric composites. These results were compared with the shear behavior of material in the presence of normal stresses along the fiber direction. Tensile and compression cyclic testing of ± 45° laminate were carried out to measure the stiffness degradation and hardening of the material in the presence of tensile normal and compression normal stress. A methodology is proposed for taking into account the differences in shear behavior under different loading directions in an FEM simulation. Based on the experimental evidence, improvements in the mathematical description of plasticity and damage in continuum damage mechanics models are proposed. The model was implemented as a user-defined material subroutine (VUMAT) for Abaqus. The experimental results from coupon tests were used to verify the results of a single element simulation. Finally, a three-point bending test was used to validate the predictions of the user material model. [ABSTRACT FROM AUTHOR]

Multi material mix is a promising approach to reduce weight and the carbon footprint in automotive engineering at competitive costs. As a result, automotive industry is getting more venturous, exploring and applying other materials than metals and plastics – e.g. fibre reinforced plastics (FRPs). In this context, engineered wood products (EWPs) and wood composites should be considered: Wood composites provide high stiffness, strength, excellent damping, high resistance against fatigue and a very low density at low material costs. It is hypothesized that modern wood composites are competitive to metals and artificial fibre-reinforced materials when designed and applied properly. The application of wood and wood composites in automotive engineering calls for precise and reliable material data, required for initial material selection and later in numerical simulation. In this study, a material model normally used for modelling FRPs was adopted. A material database was generated for three hardwood species, to establish the required material parameters and validate material model. Results prove that wooden components can be simulated in crash situations and the selected material model is applicable, even in full vehicle simulation. [ABSTRACT FROM AUTHOR]

A new technique to accelerate the positioning of human body models (HBMs) by means of a dimensionality reduction of a database of precomputed simulations is presented. First, a set of important subspace deformation modes which are used to approximate the model's movements observed in the training simulations are computed. In the second step, a convex optimization problem is solved in order to obtain an optimal position of the human body model as described by the user. We apply the proposed method to a new reclined seating position of the Total Human Model for Safety (THUMS, v5). [ABSTRACT FROM AUTHOR]

A reliability analysis approach was studied for the assessment of roadside barriers under vehicular crashes. It was achieved using computational mechanics and a simulation-based reliability analysis method. Traditionally, the evaluation of roadside barriers has been conducted based on limited crash tests. With the development of high-performance computer hardware and software, numerical crash simulations can be performed using high-fidelity finite element (FE) methods. Based on the crash simulation results, various barrier systems can be assessed. Due to the high nonlinearity and implicit nature of crash responses, approximate models such as metamodels become useful to replace numerical crash analyses. In this work, augmented radial basis functions (RBFs) were used to generate approximate models of limit state functions, which represented crash responses exceeding certain limit values. With explicit limit state functions, failure probabilities or probabilities of exceedance were calculated using Monte Carlo simulations (MCS). The combination of crash simulations and a metamodeling technique allows an efficient reliability analysis, when expensive numerical analyses are required. A New Jersey concrete barrier example was analyzed and various crash responses and their limits were considered. The probability-based analysis method provides a useful tool to improve transportation safety. It can potentially replace the prescriptive pass/fail approach traditionally employed in barrier evaluation and design. [ABSTRACT FROM AUTHOR]

This study describes the numerical simulation results of aluminum/carbon-fiber-reinforced plastic (CFRP) hybrid joint parts using the explicit finite-element solver LS-DYNA, with a focus on capturing the failure behavior of composite laminates as well as the adhesive capacity of the aluminum–composite interface. In this study, two types of adhesive modeling techniques were investigated: a tiebreak contact condition and a cohesive zone model. Adhesive modeling techniques have been adopted as a widely commercialized model of structural adhesives to simulate adhesive failure based on fracture mechanics. CFRP was studied with numerical simulations utilizing LS-DYNA MAT54 to analyze the crash capability of aluminum/CFRP. To evaluate the simulation model, the results were compared with the force–displacement curve from numerical analysis and experimental results. A parametric study was conducted to evaluate the effect of different fracture toughness values used by designers to predict crash capability and adhesive failure of aluminum/CFRP parts.

This paper deals with a FEA simulation of the vehicle crash with steel safety barriers in ANSYS LS-DYNA® 15.0. Two types of safety barriers are used: JSNH4/H2 and JSAM-2/H2. A geometrical model of the barrier in the Modeler ANSYS® Workbench™ 15.0 was created and after that it was transformed into LS-DYNA® 15.0 to complete the crash test simulation. After computation in solver ANSYS LS-DYNA® 15.0 the results of the simulation such as impact forces, a body displacement and an integral energy were analyzed.

In this investigation, metal foam was produced by casting aluminum around intersecting ceramic cylinders. Through this study, an attempt was made to propose the use of homogeneous metal foams in impact attenuation. The metal foam in this investigation was made using a novel casting method. The testing was done on a UTM and subsequent simulations on an explicit dynamic solver in an ABAQUS environment. The crash simulation is initiated after a certain level of similarity between results of the UTM compression test and FEM compression analysis. The results demonstrate that a compact and cheap impact energy absorption unit can be made using the described method. The simulation compares a solid block to the obtained foam in terms of "Energy absorption per unit volume" and total kinetic energy of the impact test set-up. [ABSTRACT FROM AUTHOR]

• Simulation of human errors and vehicle crashes on existing microsimulation packages. • Simulation of potential conflicts with road side barriers and obstacles. • New conflict indicators based on human errors consider severity of potential crash. • Safety evaluations considering heavy vehicles and non-conflicting trajectories. This paper presents a methodology that could support researchers and engineers in the important and original issue of the simulation of crashes and the evaluation of consequences on existing microsimulation packages. The proposed approach, by introducing potential driver errors, specifically allows consideration of the potential conflicts with road side barriers and obstacles and between vehicles that are moving on trajectories (close in space) that do not intersect. The severity of resulting crashes can, then, be evaluated in terms of accurate crash dynamic variables. Moreover, the methodology presented in the paper allows researchers to develop new conflict indicators that overcome many limitations of traditional traffic safety conflict indicators which, unfortunately, do not consider: the types of vehicle that are involved in a conflict, roadside obstacles or barriers, vehicles which are travelling on non-conflicting trajectories and the severity of a potential resulting crash. The paper applies a specific family of new simple and reproducible conflict indicators and provides the information necessary to develop new algorithms and simulation methodologies which, introducing human error in traffic simulation, may revolutionize the way traffic microsimulation can be used to establish a traffic safety for different scenarios. Feasibility tests on simple networks are presented and the results show the feasibility of making safety evaluations for different traffic scenarios by introducing driver errors. [ABSTRACT FROM AUTHOR]

• Sensitivity Analysis helps to identify the key factors concerning the robustness. • SA of Vehicle Restraint Systems is a way enhance the robustness of the design. • Certification of VRS based on very few crash tests is quite unsatisfactory. • The two most influential parameters are the post thickness and post yield strength. • Combining numerical studies and SA is a way to improve regulations. Restricted by high calculation cost of single engineering model run and large number of model runs for sampling-based Sensitivity Analysis (SA), qualitative SA are used for parameter study of the Vehicle Restraint System (VRS) and quantitative SA of such models has always been a challenge. Sequential approaches are proposed for SA of complex systems and the SA of a VRS is realized: sampling-based SA methods are discussed; SA of a simple three points dynamic bending test model is realized, the aims are to compare different two-level screening methods and put into practice the sequential SA; crash test FE model of a VRS is created and used for SA; influential uncertain parameters of the VRS are identified qualitatively through screening analyses (SA with Two-level screening and Morris Analysis), and Sobol' indices are used to quantify the influence of influential parameters with Kriging metamodeling. The uncertain parameters which contribute the most to robustness of the VRS are identified and their influences are quantified by combining screening analyses and Sobol' Indices. [ABSTRACT FROM AUTHOR]

• A novel experimental method, dubbed the "Mode I Caiman test", is introduced. • Characterize spot weld failure and propagation within spot weld groups. • Experiments show complex interaction of weld material and parent metal strengths. • Numerical simulations of the experiments were performed using spot weld models. • Mode I Caiman test can validate the calibrated spot weld model and demonstrate deficiencies to help improve accuracy. A novel experimental method, dubbed the "Mode I Caiman test", is introduced to characterize spot weld failure and propagation within spot weld groups. The test configuration comprises a partially welded pair of channel sections subjected to Mode I tensile loading through an opening mode loading applied at the un-welded end of the channels. Experiments were performed considering hot stamped USIBOR® 1500-AS in a fully hardened condition (fully quenched) or in a tailored condition in which the strength of the welded flanged regions was altered using in-die heating (IDH). Both static and dynamic loading conditions are considered. The static loading utilized a conventional tensile frame while the dynamic experiments were performed on an instrumented crash sled at velocities of 7.5 m/s. A high speed thermal imaging camera was utilized to detect the temperature rise associated with plastic work during individual weld failure. This proved to be a rather novel and effective technique to detect weld failure and enabled tracking of weld failure propagation through the weld group for the different parent metal (flange) conditions. The experiments served to demonstrate the complex interaction between weld nugget, heat affected zone (HAZ) and parent metal strengths. For high parent metal strengths (fully quenched, martensitic condition), the welds exhibited interfacial and weld pull-out failure modes with rapid unzipping of the weld group resulting in relatively low energy absorption. In contrast, the lower strength tailored flanges exhibited a more stable (slower) failure propagation through the weld group and considerably higher energy absorption which is largely attributed to greater dissipation through deformation of the flange itself. Numerical simulations of the experiments were performed using spot weld models calibrated from single weld lap shear, cross tension, and coach peel experiments. The models captured the peak loads rather well, but predictions of rate of failure propagation within the weld line exceeded that seen in the experiments, pointing to the need for improved post-failure models for spot weld simulation. In automotive structures in which numerous welds are present, the amount of energy absorbed in weld failure can significantly affect the impact response of the structure. The Mode I Caiman test presents a new opportunity to calibrate the energy release rate of spot weld damage models to improve their accuracy when modelling spot welded connections involving multiple spot welds. [ABSTRACT FROM AUTHOR]

Industrials have an intensive use of numerical simulations in order to avoid physical testing and to speed up the design stages of their products. The numerical testing is indeed quicker to set-up, less expensive, and supplies a lot of information about the system under study. Moreover, it can be much closer to the physical tests as the computation power increases. Despite the rise of this power, time consuming simulations remain challenging to be used in design process, especially in an optimization study. Crash simulations belong to this category. These rapid dynamic computations are used by RENAULT during the sizing of the vehicle structure in order to ensure that it meets specifications set up to reach safety criteria in case of accidents. They are completed using finite element software such as VPS (Virtual Performance Solver) developed by ESI group that will be used in this study. For car manufacturers, the goal of the optimization study is to minimize the mass of the vehicle (and thus its consumption) by modifying the thicknesses of some parts (from 20 to 100 variables). Industrials such as RENAULT currently perform optimization studies based on numerical design of experiments. The number of computations required by this technique is from 3 to 10 times the number of variables. This is too much in order to be intensively used in a design process. In order to decrease the time-to-market and to explore alternative technical solutions, we explore the potential of using a parametrized reduced order model in the optimization studies. The parametrized reduced order model gives an estimation of the high-fidelity result for a new set of parameters without using the solver, by analysing the existing results of previous computations with various sets of parameters. The developed reduced order model is called ReCUR. It is partly based on a CUR approach embedded in a regression analysis. The regression statistical model uses the data of a few calculations made with the solver. Other tools such as clustering and linear programming are used to get the regression analysis more efficient. It is hoped to drastically reduce the number of required simulations of a standard optimization study. In this paper, the construction of the reduced order model will be presented. Then, the relevancy of using the reduced order model into a design process will be exhibited through the treatment of two industrial test-cases. Some improvements of the method as well as several potential uses will then be outlined. The applications will highlight the promising power of the method to shorten design process using optimization and long-run simulations. [ABSTRACT FROM AUTHOR]

The article presents a new solution of child-resistant systems to improve the safety of children transported in motor vehicles subjected to a side impact during a vehicle crash. The proposed concept works by means of implementation of an energy dissipation mechanism acting between a child restraint system anchorage and a restraint system seat. The effectiveness of the proposed system is evaluated using numerical analyses of a simplified basic model as well as more complex mechanical design of the mechanism. The latter is analyzed as a part of the child restraint system (CRS) together with a deformable model of an anthropomorphic test device of Q3 series. Tests outcomes clearly show a positive effect of application of the proposed energy dissipation system resulting in reduction of head and thorax acceleration and influencing a lower factor (index) of the head injury criteria. The presented solution shows that there is still a room for improvement of young passengers safety. [ABSTRACT FROM AUTHOR]

Objective: This article discusses differences between a side impact procedure described in United Nations/Economic Commission for Europe (UN/ECE) Regulation 129 and scenarios observed in real-world cases.Methods: Numerical simulations of side impact tests utilizing different boundary conditions are used to compare the severity of the Regulation 129 test and the other tests with different kinematics of child restraint systems (CRSs). In the simulations, the authors use a validated finite element (FE) model of real-world CRSs together with a fully deformable numerical model of the Q3 anthropomorphic test device (ATD) by Humanetics Innovative Solution, Inc.Results: The comparison of 5 selected cases is based on the head injury criterion (HIC) index. Numerical investigations reveal that the presence of oblique velocity components or the way in which the CRS is mounted to the test bench seat fixture is among the significant factors influencing ATD kinematics. The results of analyses show that the side impact test procedure is very sensitive to these parameters. A side impact setup defined in Regulation 129 may minimize the effects of the impact.Conclusions: It is demonstrated that an artificial anchorage in the Regulation 129 test does not account for a rotation of the CRS, which should appear in the case of a realistic anchorage. Therefore, the adopted procedure generates the smallest HIC value, which is at the level of the far-side impact scenario where there are no obstacles. It is also shown that the presence of nonlateral acceleration components challenges the quality of a CRS and its headrest much more than a pure lateral setup. [ABSTRACT FROM AUTHOR]

The ability to accurately predict the crashworthiness performance is crucial to the use of composites in the primary energy absorbing structures in vehicles. Such predictions require material models that consider not only the initial failure but also the responses of severely damaged composites. The latter requirement exceeds the boundary of any existing physics based models. To address this problem, an enhanced continuum damage mechanics (ECDM) model has been developed. ECDM employs two sub-models, i.e. a pre-failure model and a post-failure model, to describe the stress–strain behavior in the pre-peak and post-peak regions. This setup allows one to consider the growth of damage and irreversible strains in the two regions under different evolution laws corresponding to different damage/deformation mechanisms. The ECDM model was evaluated in quasi-static and dynamic tube crash simulations of triaxial braided composites. The results show that the irreversible strains and residual stiffness are critical to the energy absorption prediction of composites. The ECDM model provides much improved correlations with the experimental results than the existing models. [ABSTRACT FROM AUTHOR]

• Reviewed recent literature on crash analysis and simulation of mixed traffic when CAVs and human-driven vehicles co-exist. • Three main aspects are reviewed: data source, simulation methods, and human factors. • The state of the art in these three related aspects and research gap in integrating them were identified. • Future research is recommended to contribute to road safety by developing an all-in-one-step crash analysis system. • Guide future research to push for a safer transportation infrastructure in the mixed traffic with CAVs. Traffic accidents are one main cause of human fatalities in modern society. With the fast development of connected and autonomous vehicles (CAVs), there comes both challenges and opportunities in improving traffic safety on the roads. While on-road tests are limited due to their high cost and hardware requirements, simulation has been widely used to study traffic safety. To make the simulation as realistic as possible, real-world crash data such as crash reports could be leveraged in the creation of the simulation. In addition, to enable such simulations to capture the complexity of traffic, especially when both CAVs and human-driven vehicles co-exist on the road, careful consideration needs to be given to the depiction of human behaviors and control algorithms of CAVs and their interactions. In this paper, the authors reviewed literature that is closely related to crash analysis based on crash reports and to simulation of mixed traffic when CAVs and human-driven vehicles co-exist, for studying traffic safety. Three main aspects are examined based on our literature review: data source, simulation methods, and human factors. It was found that there is an abundance of research in the respective areas, namely, crash report analysis, crash simulation studies (including vehicle simulation, traffic simulation, and driving simulation), and human factors. However, there is a lack of integration between them. Future research is recommended to integrate and leverage different state-of-the-art transportation-related technologies to contribute to road safety by developing an all-in-one-step crash analysis system. [ABSTRACT FROM AUTHOR]

A finite element impact simulation study was performed to gain an insight about the crash test details considering construction tolerance effects of the reinforcement of posts in an open-type guardrail system. Accuracy of the simulation was verified using qualitative and quantitative comparisons with a full-scale crash experiment of trucks and cars. Subsequent simulation results present that the improved model performs much better in containing and redirecting the impacting vehicle in a stable manner. The numerical results for various parameters are verified by comparing different models with dynamic responses and passenger safety evaluations determined in the barrier from the crash simulation. [ABSTRACT FROM AUTHOR]

An enhanced non-local failure criterion for laminated safety glass under low velocity impact for explicit finite element simulations with element erosion is presented. Hereby, the fracture strength of the glass depends on the stress rate and is approximated by a power law for the crack velocity resulting from the sub–critical crack growth. In dependence of the size of the finite elements, the singularity of the stress field in the vicinity of the crack tip is underestimated by the element erosion technique. In contrast to classical linear elastic fracture mechanics, the model uses a non-local approach for a decrease of strength in the direction of a crack perpendicular to the maximum in–plane stresses, instead of an increase of the stress field in the vicinity of the crack tip. The failure criterion is implemented in the explicit solver LS–DYNA as an user defined material model. In order to investigate the accuracy of the model, the results are compared to head impact tests on windscreens used in the context of crash simulations. [ABSTRACT FROM AUTHOR]

A common problem in the numerical simulation of complex real-world systems is the fact that the parameters of the models usually exhibit some degree of uncertainty and exact values for their quantification can hardly be provided. This non-determinism in numerical models may arise as a consequence of different sources: on the one hand, natural variability or scatter, on the other hand, uncertainties that arise from an absence of information, vagueness in parameter definition, subjectivity in numerical implementation, or simplification and idealization as it usually appears in every modeling procedure. As one possible approach to solve this limitation, an interdisciplinary methodology to an advanced modeling and analysis of systems is presented, which allows for the inclusion of uncertainties from the very beginning of the modeling procedure. This approach is based on fuzzy arithmetic, a special field of fuzzy set theory, where the uncertain values of the model parameters are represented by so-called fuzzy numbers, reflecting in a rather intuitive and plausible way the blurred range of possible parameter values. As a result of this special modeling technique, more comprehensive system models can be derived which outperform the conventional, crisp-parameterized models by providing simulation results which reflect both the system dynamics and the effect of the uncertainties. The methodology is exemplarily illustrated by an application from the field of automotive crash simulation which demonstrates that advanced modeling and simulation of dynamical systems, based on fuzzy arithmetical techniques for including the presumably limiting uncertainties, can provide significant additional benefit. A variety of further applications from other fields of the engineering sciences is given in the references, highlighting the charm of fuzzy predictions. [ABSTRACT FROM AUTHOR]

Part of the work of AircraftFire, a project investigating the effects of fire and crash on aircraft survivability, is presented. This work compares the effect of changing the material model from metallic to composite on the impact damage and floor acceleration characteristics. First, the metallic two- and six-frame sections of an A320 are analysed, with drop test data to compare for reference and validation. The six-frame metallic and composite sections for a larger, A350-like aircraft are examined to compare the relative safety of newer composite fuselages. The composite model includes both a quasi-isotropic analysis with damage based on maximum allowable strain, and a ply-by-ply laminate model with Hashin damage. Energy dissipation and acceleration analyses follow, which show the potentially dangerous acceleration pulses for passengers seated in the cabin. [ABSTRACT FROM PUBLISHER]

A new constitutive model for metallic foams is developed to overcome the deficiency of existing models in commercial finite element codes. The proposed constitutive model accounts for volume changes under hydrostatic compression and combines the hydrostatic pressure and von Mises stress into one yield function. The change of the compressibility of the metallic foam is handled in the constitutive model by allowing for shape changes of the yield surface in the hydrostatic pressure-von Mises stress space. The backward Euler method is adopted to integrate the constitutive equations to achieve numerical accuracy and stability. The model is implemented into LS-DYNA as a user-defined subroutine, verified with existing solutions, and validated with foam testing data. The verified and validated model is then utilized in the crushing simulations of foam-filled columns with square and hexagonal cross-sections. Two constitutive models are studied: the first using an exponential function to describe the relationship of plastic Poisson's ratio with respect to true strain and the second using linear interpolation function as an alternative approximation. The new foam model provides satisfactory prediction of crushing forces and deformed shapes compared to experimental results. Additionally, the new foam model was shown to have better numerical stability and accuracy than existing LS-DYNA built-in material models. [ABSTRACT FROM AUTHOR]

In recent years, vehicle demographics have changed to include a relatively large proportion of light trucks, such as pickups, vans and sport-utility vehicles. It is found that several types of guardrail systems, including the G4(2W) guardrail system, are unable to redirect the pickup trucks to roadway safely. Therefore, in this study, several options are considered; they include improving the splice connections and adjusting the guardrail height and the post spacing to improve the performance of this system. The G4(2W) guardrail system is modelled in LS-DYNA and validated with a previous full-scale crash test conducted by the Texas A&M Transportation Institute. A parametric study based on the results of the LS-DYNA crash simulation according to Length of Need test 3-11 and 3-10 is conducted to investigate key factors of guardrail systems, including the splice configuration, the post spacing and the guardrail height. The purpose of this study is to find a model that satisfies the requirements of Test Level 3 outlined in Manual for Assessing Safety Hardware (MASH)'s criteria. [ABSTRACT FROM PUBLISHER]

To overcome the instability encountered in axial crash simulations of composite tubes with shell elements, a new modeling technique: the shell-beam (SB) element method, has been developed. This method creates an element which is capable of deforming in the through thickness direction while retaining the efficiency of the shell elements. The SB element was evaluated with virtual one-element, cantilever beam and in-plane compression tests. The results showed that the SB element is effective in terms of overcoming the instability and convergence issues of traditional 2D and 3D discretized elements under in-plane compression. The SB element was further evaluated together with an in-house material model, called the enhanced continuum damage mechanics (ECDM) model, in crash simulations of triaxial braided composite tubes with five configurations and seven test conditions. The simulations captured both the failure morphologies and force-displacement responses obtained in experiments. [ABSTRACT FROM AUTHOR]

There are many severe and fatal crashes that result from vehicles colliding with street columns such as lighting columns. These cause extremely high impact forces and deformation on the frontal area of the car. The objective of the study is to demonstrate the frontal crash simulation of vehicle against lighting columns to examine injury risk and potential of safety. In particular, various FE models are used to perform contact–impact nonlinear dynamic analysis of lighting columns with vehicle. In this paper Abaqus explicit code is used to numerically simulate the crash of the vehicle with present columns and other lighting columns fabricated from a new suggested material. The acceleration, contact force and deformed energy at the frontal region of the vehicle are traced. It is found that the lighting columns with new suggested material have impact properties to decelerate the vehicle and absorb higher energy during impact.

A crash test is a form of destructive testing in order to ensure safe design in case of an impact or collision. These impact tests are carried out to understand a components structural behaviour and its response under different collision conditions. But it is not always economical to destroy a specimen to ensure its safety, especially in case of small scale production. Moreover actual crash testing in different conditions requires high resources and time. Crash simulation is very popular now a days because it is a virtual representation of a destructive crash test of a vehicle using a computer simulation in order to examine the level of safety of the vehicle and its occupants in different conditions like collision velocity, collision direction, colliding object, material and number of component of colliding object etc and hence saves the time and cost. Data obtained from a crash simulation indicate the capability of the vehicle body to protect the vehicle occupants during a collision against injury. In this study a FE crash analysis of commercial truck cabin in two different cases (Bare cabin and loaded cabin) using Finite Element Approach (FEA) is focused. Crash analysis of truck cab is performed using FEA in order to predict the design parameters for minimization harm to the occupants of the vehicle. A bare truck cabin and a rigid wall were used to simulate crash conditions with different crashing velocity and impact angles. CATIA V5R20 CAD software is used for the modeling of the selected cabin components followed by FE meshing through Hypermesh and then analysis is done using LS-DYNA by setting the boundary conditions, material properties etc. appropriately. [ABSTRACT FROM AUTHOR]

In 1981, the International Civil Aviation Organization (ICAO) instigated the ‘Frangible Aids Study Group’ (FASG), with the aim to define design requirements and crash test procedures addressing the frangibility of airport navigation aids and their support masts. The FASG group soon stated that a specific wing section model should be used as a standard test impactor. This paper describes an attempt to model and verify a virtual model of a wing impactor based on static and dynamic compression test sensitivity analyses. The motivation is to define a standard FE model that will ultimately reduce the need for physical testing, while providing improved opportunities for understanding mechanisms and design parameters related to frangibility. The sensitivity to finite element (FE) model assumptions is studied to ensure a representative deflection-force characteristic for crash tests. The study shows that strain at a fracture value of 15% combined with a bi-linear hardening model gives the most reliable simulation results. This material combination also seems to give the most correct wing impactor behaviour in high-speed crash simulations. The simulations also prove that 1 kHz low pass filtering of reaction forces efficiently eliminates artificial peak forces not contributing to wing damage. [ABSTRACT FROM PUBLISHER]

Background:: Car crash simulations need a lot of computation time. Model reduction can be applied in order to gain time-savings. Due to the highly nonlinear nature of a crash, an automatic separation in parts behaving linearly and nonlinearly is valuable for the subsequent model reduction. Methods:: We analyze existing preprocessing and clustering methods like k-means and spectral clustering for their suitability in identifying nonlinear behavior. Based on these results, we improve existing and develop new algorithms which are especially suited for crash simulations. They are objectively rated with measures and compared with engineering experience. In future work, this analysis can be used to choose appropriate model reduction techniques for specific parts of a car. A crossmember of a 2001 Ford Taurus finite element model serves as an industrial-sized example. Results:: Since a non-intrusive black box approach is assumed, only heuristic approaches are possible. We show that our methods are superior in terms of simplicity, quality and speed. They also free the user from arbitrarily setting parameters in clustering algorithms. Conclusion:: Though we improved existing methods by an order of magnitude, preparing them for the use with a full car model, they still remain heuristic approaches that need to supervised by experienced engineers. [ABSTRACT FROM AUTHOR]

Concrete barriers are one of the most widely used safety features for preventing errant vehicles from entering opposing travel lanes on highways. As a safety device, a concrete barrier is also required to safely redirect a striking vehicle such that it is not bounced into travel lanes and collide with other vehicles. Given its rigidity compared to most vehicular structures, the performance of a concrete barrier is mainly influenced by its shape or the cross-sectional geometry. Over the years, concrete barriers have been continuously improved using roadway crash data and crash tests. Although the current in-service concrete barriers satisfy the requirements of safety standards, the empirical approach is not cost-effective for designing new barrier systems. In this study, a simulation-based optimization approach was adopted to obtain the optimum design of a concrete barrier by combining nonlinear finite element (FE) simulations, metamodeling with radial basis functions (RBFs), and a genetic algorithm (GA). The performance of the concrete barrier was determined by evaluating vehicular responses specified in the current safety standard, Manual for Assessing Safety Hardware (MASH). Nonlinear FE simulations were first carried out on sample designs to obtain the vehicular responses for creating the RBF metamodels, which were then used in the optimization process to replace the expensive FE simulations. An optimal design of the concrete barrier was obtained by the GA and was shown to have improved safety performance over the original design. [ABSTRACT FROM AUTHOR]

The influences of geometrical parameters like adhesive layer thickness and gap-filling on the mechanical properties of adhesively bonded joints are investigated by means of experimental studies with controlled parameter variations. In addition, corresponding simulation models are used to analyse these effects. As a result, the behaviour of joints under variation of manufacturing parameters can be reproduced with high accuracy. Furthermore, the validated simulation models are used to perform sensitivity analysis on a component-like specimen. Based on these studies, tolerance ranges can be specified and robust design optimisation can be carried out. [ABSTRACT FROM AUTHOR]

The accuracy of crash simulation is critical to evaluating the design of a vehicle, especially for energy-absorption capacity and crash mode. Hence, it is necessary to integrate the forming effect into crash model as a key input. In this study, the front rail, a typical thin-walled beam structure which was assembled in a passenger vehicle, was observed for its important role of absorbing kinetic energy in the vehicle frontal impact. Comparison between front rail crash simulation model (1) with no forming effect, (2) considering forming effect, and the result of sled impact test shows that the hardening effect from the forming history strengthens the component, and thus significantly influences the crash mode of the front rail. [ABSTRACT FROM PUBLISHER]

Occupant responses and injuries are important considerations in the design and assessment of roadside safety devices such as barriers. Although incorporating occupant responses and injuries into the design of safety devices is highly recommended by the current safety regulations, there are limited studies that directly consider occupant responses and injuries. Crash test dummies are seldom equipped in the state-of-the-art crash testing of roadside barriers and thus occupant responses and injury risks are evaluated primarily based on vehicle responses. In the present work, occupant responses and injuries in automotive crash events were investigated by incorporating crash test dummies into the vehicle model that was used in the finite element (FE) simulations of roadside crashes. The FE models of a Ford F250 pickup truck and a Hybrid III 50th percentile crash test dummy were employed and a passive restraint system was developed in the FE model. The FE model was validated using existing experiments including a sled test and a full-frontal impact test. Simulations of the Ford F250 impacting a concrete barrier and a W-beam guardrail were conducted and the occupant responses were analyzed. Furthermore, occupant injuries were quantitatively estimated using occupant injury criteria based directly on dummy responses and compared to those based solely on vehicle responses. The correlations between vehicle responses and occupant injuries were studied. [ABSTRACT FROM AUTHOR]