Real Crash Test Research Articles

Effect of Chain-Link Fence Attachment on the Crash Performance of an H1 Containment Level Safety Barrier

Longitudinal barriers are among the road safety equipment used to prevent vehicles from leaving the roadway. These systems are designed to be lightweight for economic reasons without compromising their structural adequacy. In this study, the effect of chain-link fence on impact severity and structural performance of a longitudinal barrier was investigated through finite element (FE) analyses. An H1 containment level longitudinal barrier FE model was validated using real crash test results. After modifying the validated system to reduce its weight, crash test simulations (TB11 and TB42) were conducted on the modified system, both with and without chain-link fence attachment. The chain-link fence was placed below the rail and in traffic side of post, in a manner that had not been applied before. FE analyses found that the chain-link fence minimally altered TB11 test performance. In TB42 simulations without a chain-link fence, the vehicle climbed over the rail, resulting in test failure. However, when chain-link fence is used, same barrier contained and redirected the vehicle, leading to a successful test. It was concluded that using chain-link fences can enhance the crash performance of longitudinal barriers by limiting the barrier lateral deformation. Further detailed studies, supported by real crash tests, on the placement of fences in barriers are recommended.

Finite Element Analysis and Investigation of Critical Impact Point of Steel Guardrails Affecting Safety and Structural Performance

After the guardrails are designed, the structural adequacy and safety criteria are determined by the relevant standards and full-scale crash tests. One of the widely used standards is European Norm 1317 (EN1317). Guardrail systems generally consist of rails and posts. The guardrails are more rigid around the posts, which are mounted on the ground or embedded in soil at certain intervals. Therefore, it is important for driver/passenger and roadside safety to determine the most critical point in terms of structural and safety performance and design according to the most unfavourable situation. With this motivation, in this study, the effect of different impact points on the structural and safety performance of the H1W4 guardrail was investigated by finite element (FE) analysis. For this purpose, first of all, the finite element models of the H1W4-A system were calibrated and validated with real crash test data. Then, with the help of the validated models, analyses were completed for different impact points as 0.5, 1.0, 1.5 and 2.0 meters with a half-meter difference for the standard 2-meter post spacing. In the light of the measured safety parameters such as Acceleration Severity Index (ASI), Theoretical Head Impact Velocity (THIV) and structural performance criteria such as working width (W) and exit angle (α), the critical impact point for the guardrail was determined. Contrary to what is generally known, crashing vehicles into flexible points (0.5 and 1.0 m) rather than impacting rigid points (1.5 and 2.0 m) creates a more negative situation in crash tests.

Comparison of Volunteers' Head Displacement with Computer Simulation-Crash Test with Low Speed of 20 km/h.

Recently, the automotive industry has used simulation programs much more often than experimental research. Computer simulations are more and more often used due to the repeatability of simulation conditions and the possibility of making modifications in simulation objects. Experimental and simulation studies carried out are aimed at developing a model of a simulation dummy adapted to both frontal and rear crash tests, taking into account changes in the moment of resistance in individual joints. The main purpose of the article is to reproduce a real crash test at a low speed of 20 km/h in a simulation program. For this purpose, a series of experimental crash tests with the participation of volunteers was carried out, and then a crash test with a dummy was simulated in the MSC ADAMS program. The experimental studies involved 100 volunteers who were divided into three percentile groups (C5, C50, C95). With the help of force sensors and a high-speed camera, crash tests of volunteers were recorded. The collected data from the force sensors made it possible to map the force in the seat belts. For low-speed crash tests, the displacement and acceleration of individual body parts of the dummy and volunteers can be measured using vision systems. The article identified head displacements of volunteers in the TEMA program based on a video analysis of a crash test film with a frequency of up to 2500 frames per second. The displacement of the simulation dummy's head in the MSC ADAMS program in the considered crash time interval from 0.0 to 0.4 s for all three percentile groups coincided with the head displacement of the volunteers during the experimental crash test.

Dynamics of frontal crash in/without the presence of passive safety systems

The paper aims to debate on experimental retrieved accelerations from real crash tests, based on different scenarios, to enable assessment on driver potential injury. Scenarios included the presence of passive safety systems (e.g., airbag, seat belt) and test data are being processed to estimate the head injury criteria (HIC) followed by its correlation with abbreviated injury scale values (AIS). A dummy, average male resemblance, was developed in-situ and used in the experimental configuration. Signals were being acquired by few accelerometers disposed on the dummy’s head and thorax using a Pic DAQ system (DSD, Linz, Austria). Data processing and values of injury criteria underline the importance of passive safety systems proven HIC experienced a consistent decrease in the presence of both air-bag and seatbelt.

Vehicle occupant safety development with finite element method

AbstractCrash tests of vehicles are specified by government programs. This laws are includes only minimum requirements for individual components. Therefore additional consumer protection load cases have been developed by independent private institutes. Finite element method simulations can reduce development periods and the number of cost-intensive real crash tests. The goals of the calculations are that the early detection of component failure, the protection of occupants or pedestrians. The biggest challenge of the future, in the field of vehicle occupant safety is the interaction of the airbags and belt system with dummy by the electric vehicles, which have the concept of autonomous driving function. The aim of the research is to investigate this area using a simulation model.

An innovative approach on the renewable hybrid barrier: combined use of wood and sand

ABSTRACT Background: Wooden materials have been among the basic materials used in many different areas due to some advantages throughout the history. Roadside barriers, which are called passive safety structures, can be produced with different materials such as wood, steel, concrete, and plastic. In this study, Renewable Hybrid Barriers (RHB), a new type of barrier that is used wood in terms of aesthetics, renewability, high shock resistance, and used sand in terms of impact absorption capacity and low cost, produced by taking into account some of the disadvantages of other barrier types. These barriers are planned to be used especially in historical/touristic areas, scenic roads, and in urban areas as urban furniture. Real-time crash tests in accordance with EN 1317 (Road Restraint Systems) standard require high cost and long time. Therefore, the pendulum crash test mechanism frequently used in the literature was manufactured at which the experiments were carried out. Results: The results revealed that the RHBs which has 2 cm thick timber and sand used together, were sufficient and suitable in terms of both cost and necessary safety criteria. It was observed that impregnation and heat treatment applications did not have a considerable negative effect on the performance of RHBs which provide an opportunity to use RHBs for outdoor conditions.. Conclusion: In the light of the results of the study, the optimum wood timber thickness was determined as 2 cm regarding TB 31 test criteria. It is proposed that the crash tests for different wood species, timber thickness, and/or barrier dimensions should carry out in future studies. This study can serve as the basis for the next step, real-time real crash tests. Since the study includes an interdisciplinary subject, it is thought that it will inspire different studies.

Assessment of lumbar spinal disc injury in frontal crashes

Frontal vehicle crashes have been a leading cause of spinal injuries in recent years. Reconstruction of frontal crashes using computational models and spinal load analysis helps us understand the patterns of injury and load propagation during frontal crashes. By reconstructing a real crash test and using a viscoelastic crash dummy model, spinal injury patterns were analyzed. The results indicated that a moderate crash with an impact speed of 56 km/h leads to injuries in L1-L2 and L5-S1 levels (L for lumbar and S for sacral vertebrae). The largest spinal loads and injuries were mainly observed immediately after the airbag deployment when the peak of the crash acceleration transpires. Also, the effects of impulse magnitude on the spinal loads and head injury criterion (HIC) showed that HIC is more sensitive than compressive forces to the magnitude of impulse. Moreover, the effects of disc preconditioning as a major factor in the risk of injury was evaluated. The results demonstrate that as the lumbar spine is subjected to a longer preloading, it will be more vulnerable to injury; preconditioning of the discs more adversely affected the risk of injury than a 10% increase in the crash impulse. Overall the results highlight the importance of spinal injury prevention in frontal crashes.

Monitoring the effects of vehicle components’ size on optimum structural crashworthiness

To determine the effects of vehicle components’ size on the optimum structural crashworthiness of a vehicle, sufficient data on the expected crash behaviour are required. Considering the high fiscal cost of obtaining the real crash test data, and extreme computational difficulty associated with relying on high-order numerical models, this work explores the adequacy of a generic two-degree-of-freedom lumped mass–spring model in handling this research problem. The generic model was first validated using appropriate experimental data and further utilized in evaluating crashworthiness performance under various design conditions. Statistical analysis of the system response reveals the necessary design considerations required to achieve improved crashworthiness. A multi-criteria optimization study was conducted using the resulting statistical models and suitable optimization algorithms. The optimization study suggests a set of feasible Pareto-optimal trade-off solutions that guarantee optimal crashworthiness.

A validation sensor based on carbon-fiber-reinforced plastic for early activation of automotive occupant restraint systems

Abstract. In the automotive industry, sensors and sensor systems are one of the most important components in upcoming challenges like highly automated and autonomous driving. Forward-looking sensors (radar, lidar and cameras) have the technical capability to already provide important (pre-)crash information, such as the position of contact, relative crash velocity and overlap (width of contact) before the crash occurs. Future safety systems can improve crash mitigation with sophisticated vehicle safety strategies based on this information. One such strategy is an early activation of restraint systems compared with conventional passive safety systems. These integrated safety systems consist of a combination of predictive forward-looking sensors and occupant restraint systems (airbags, belt tensioners, etc.) to provide the best occupant safety in inevitable crash situations. The activation of the restraint systems is the most critical decision process and requires a very robust validation system to avoid false activation. Hence, the information provided by the forward-looking sensor needs to be highly reliable. A validation sensor is required to check the plausibility of crucial information from forward-looking sensors used in integrated safety systems for safe automated and autonomous driving. This work presents a CFRP-based (carbon-fiber-reinforced plastic) validation sensor working on the principle of change in electrical resistance when a contact occurs. This sensor detects the first contact, gives information on impact position (where the contact occurs) and provides information on the overlap. The aim is to activate the vehicle restraint systems at near T0 (time of first contact). Prototypes of the sensor were manufactured in house and manually and were evaluated. At first, the sensor and its working principle were tested with a pendulum apparatus. In the next stage, the sensor was tested in a real crash test. The comparison of the signals from the CFRP-based sensor with presently used crash sensors in the vehicle highlights its advantages. The crash event can be identified at 0.1 ms after the initial contact. The sensor also provides information on impact position at 1.2 ms and enables a validation of the overlap development. Finally, a possible algorithm for the vehicle safety system using forward-looking sensors with a validation sensor is described.

Instantaneous Incident Detection System Based on Analysis of Acoustic Signal from Crash and Skid in Tunnel

Introduction:An acoustic signal-based tunnel accident detection system was developed in this study. In a tunnel environment, the sound diffusion effect is minimized and thanks to that, discrimination of accident sounds (crash and skid) from other noises can apparently be accomplished.Discussion:The system is composed of three parts: algorithm, field device, and center system. To distinguish accident-related acoustic signals such as a crash or skid among various other sounds in a tunnel, a delicate algorithm that can discriminate those signals from other normal signals generated from moving vehicles was created.Conclusion:The developed algorithm processes acoustic signals to filter out noises and to identify accident-related signals. The field device, installed in a tunnel, collects analog sounds, transforms them into digital signals, and transmits the digital signals to the server in the tunnel traffic management center. Lastly, in the tunnel traffic management center, the acoustic signal processing algorithm described above, installed in a server system, can instantaneously detect accidents. Once confirmed by the system operators, the information on the detected accidents is intended to be provided to drivers following behind as well as relevant agencies to prevent secondary accidents and to respond promptly. The developed system was evaluated in a real tunnel environment using traffic accident sounds acquired from real crash tests. The detection rates were 95, 91, and 80% at distances of 10, 30, and 50 m, respectively with a detection duration less than 1.4 s. Compared to conventional detection systems using loop detectors or video images that have a long detection time of around 1 min, the developed system can be regarded as superior in that it has an extremely short detection time, which, of course, is one of the most important factors for automatic incident detection systems.

Study regarding the influence of airbag deployment time on the occupant injury level during a frontal vehicle collision

The aim of this paper was to analyse the influence of airbag deployment delay upon the head of the occupant in the case of frontal collision using simulations in PC Crash and MADYMO dummy as the occupant. The study will also take into account the pretension delay of the seat-belt which is activated along with the airbag. Frontal airbags on both the passenger and the driver were analysed including the occupant kinematics during the collision. Also, to validate the simulation, a comparison was done with a real crash test. We predict that by increasing the delay of deployment, the head acceleration will increase due to the fact the head travels close to the instrument panel/steering wheel, and the force of the airbag will generate a significant acceleration upon the head. To better assess the potential injury of the occupant, the head injury criteria (HIC) will be calculated and correlated with the Abbreviated injury scale (AIS) code.

The influence of position of the post or its absence on the performance of the cable barrier system

Road safety barriers are used to increase safety in potentially dangerous places on the roads. They are designed and installed on the roads to prevent any vehicle from getting outside the travelled way or from entering the opposite lane of the road. Barriers, which are used on European roads, have to undergo full scale crash tests according to the EN 1317 standards. Nowadays as a supplement to real crash tests, numerical simulations are commonly used. The work concerns the influence of position of the post or its absence on the crashworthiness of the cable barrier based on numerical study results.

Study regarding seat’s rigidity during rear end collisions using a MADYMO occupant model

The aim of this paper is to study the effects of different front occupant backseat’s rigidities in the case of a rear end collision using a multibody virtual model of an occupant. Simulation will be conducted in PC Crash, the most common accident reconstruction software using a MADYMO multibody occupant to simulate kinematics and dynamic of the passenger. Different backseat torques will be used to see how this will influence the acceleration in the head and torso of the occupant. Also, a real crash test is made to analyze the kinematics of the occupant. We believe that the softer seat’s rigidity will reduce not only the head’s acceleration but also reduces the effect of „whiplash” upon the neck due to the fact that the backseat will rotate backwards increasing its displacement and absorb some of the energy generated by the collision. Although a softer seat could reduce the head’s acceleration, a broken seat will increase it due to the fact that the impact of the backseat with the vehicle’s rear seats will generate a second collision. So, in order to achieve a lower acceleration, a controlled torque is recommended and a controlled angular displacement of the backseat is to be used.

Application of Genetic Algorithm on Parameter Optimization of Three Vehicle Crash Scenarios

This paper focuses on the development of mathematical models for vehicle frontal crashes. The models under consideration are threefold: a vehicle into barrier, vehicle-occupant and vehicle to vehicle frontal crashes. The first model is represented as a simple spring-mass-damper and the second case consists of a double-spring-mass-damper system, whereby the front mass and the rear mass represent the vehicle chassis and the occupant, respectively. The third model consists of a collision of two vehicles represented by two masses moving in opposite directions. The springs and dampers in the models are nonlinear piecewise functions of displacements and velocities respectively. More specifically, a genetic algorithm (GA) approach is proposed for estimating the parameters of vehicles front structure and restraint system for vehicle-occupant model. Finally, using the existing test-data, it is shown that the obtained models can accurately reproduce the real crash test data.

Optimal deceleration of surrogate models in a generic side impact set-up

ABSTRACTOptimal deceleration being defined as the fastest deceleration possible, without breaching any injury criteria, is the ultimate goal for automotive safety systems. Here, the optimal deceleration in a generic side impact set-up will be presented for three different models of the human body, commonly used in vehicle safety. Various forms of surrogate models for the human body are used in the development of automotive safety systems. Traditional crash test dummies developed for real crash tests also exist as simulation models. Modern human body models, digital surrogate models directly derived from the human body, offer more insight and higher biofidelity. A finite element model and a multibody model of a second generation European Side Impact dummy (ES-2re) will be compared to the Total Human Model for Safety (THUMS) through the method of optimal deceleration. This method can also be used to facilitate the design of safety systems for next generation dummy models.

Comparison of optimisation strategies for the determination of precise dummy head trajectories based on the fusion of electrical and optical measured data in frontal crash scenarios

When determining the trajectory of the dummy head during a vehicle crash test, the head is not visible for all cameras during the whole movement, since it, e.g., dips into the airbag. Another possibility is to calculate the trajectory with acceleration and gyro sensor data. When using low-cost inertial measurement units, the calculated trajectory differs from the video analysis by 0.15 metres. The idea is to model possible electrical sensor errors and inaccurate known initial conditions and determine them in an optimisation process in which the video trajectory is taken as the target function. This paper deals with the optimisation process to determine if the optimisation function has a unique minimum. Based on that, several optimisation algorithms are compared and three of them are selected for a detailed comparison. The best of them is selected to show the calculation of a trajectory for a real world crash test.

Occupant Risk Analysis for Guardrail Roadside Safety Barrier Systems: Analysis and Evaluation of Full Scale Crash Tests

Collision with roadside objects such as trees, utilities and guardrail are a major road-safety problem and reported the highest rate of side-impact accidents on roadways in which about 225,000 people have been involved. In this study the common methods to evaluate occupant risk factors involving in crash to roadside barrier systems are reviewed. The collected previous real crash test on guardrail system with regards to occupant impact risk factors are prepared based on different system performance. Higher average for longitudinal impact velocity for Thrie-beam system is found. On the other hand, Weak-post system is provided less severe system in terms of longitudinal impact velocity.

The Safety Assessment Research on Front Body Structural of Commercial Motor-Vehicles of Passenger Transport

A Load-type Commercial Motor-vehicle of Passenger Transport was studied as the research subject in researching front crash safety evaluation technology of front structure by the real car crash test methods, which is to explore the front crash safety evaluation technology suitable for china's National conditions. The results show that the Testing procedure and Evaluation will not only conducive to the carrying out of Commercial Motor-vehicles of Passenger Transport access about structural safety detection, but also played an important role in promoting the safety of the domestic bus, road transport safety, and social harmony.

Rapid Algorithm of High Risky Position on Car Hood for Pedestrian Crash Based-Computer Simulation

ntroduction This paper has proved that the HIC of local Car hood crash area is relative to the distance between the crash point and potential secondary crash point, and with the rigidity of the second crash point, in the process of protection for pedestrians. The pertinence formula was built and the high risky spot of each local crash areas was doped out quickly, and the accuracy of the formula is validated by the subsequent real car crash test. When the vehicles and the pedestrian have the crash accident, the pedestrian casualty rate is very high, develops the pedestrian to protect the research positively, particularly the forehead crash trouble-free service, regarding the guardian vehicle crashs in weak one the pedestrian, has the very vital significance.

Parameters Optimization Method for Hot Forming Panels Based on the Crashworthiness and Lightweight

This paper studies the parameters optimization of the hot forming panels based on the crashworthiness and lightweight. Combined with hot forming technology, it takes the key structural parameters as the design variables, the positive / bias crashworthiness as the constraint condition, the lightweight body as the design objective, studies the vehicle frontal crash safety. According to the final optimized design, a real car crash tests had been completed and the excellent results shown that the parametric method based on the vehicle crashworthiness is an important guarantee methods to achieve the body structure optimized design.