Crash Test Research Articles

Frontal A-pillar impact study based on commercial vehicle cabs

To examine whether the passive safety of the cab of a certain commercial vehicle meets the regulatory requirements in a 90° rollover traffic accident, a frontal A-pillar impact simulation test platform is built according to the regulation JT/T1178.1-2018 and the crash simulation is analyzed in LS-DYNA. The driver’s passive safety is comprehensively considered by taking the deformation of the cab structure and the driver’s survival space as the indexes. Aiming at the A-pillar crash test data that does not meet the requirements of the crash regulations, a joint optimization method of welding and strengthening the structure in the inner cavity of the A-pillar and replacing the original material with high-strength steel is proposed. The optimized cab is again subjected to an A-pillar collision simulation test and the optimized results are obtained. The plastic strain of the cab is reduced from the original 0.21 to 0.175 and the minimum living space is increased. The maximum increase in the vertical distance between the driver’s legs and the steering wheel is 52 mm, which improves the passive safety of the cab to a certain extent and provides a reference for enterprises.

“We want to carry out up to 500 crash tests a year”

“We want to carry out up to 500 crash tests a year”

Characterization of Motorcycle Encroachments in the U.S

In 2020, there were 5,579 motorcyclist fatalities in the U.S., which is the highest on record. Despite accounting for only 3% of registered vehicles, motorcycles are involved in 42% of fatal guardrail impacts. Roadside safety hardware testing guidelines are outlined in the Manual for Assessing Safety Hardware (MASH) for passenger vehicles and large trucks but these procedures do not include any motorcycle impacts. Although international test procedures for roadside hardware prescribe motorcycle crash tests, it is not known if the prescribed test conditions reflect the conditions at which motorcycles depart the roadway in the U.S. A better understanding of the characteristics of motorcycles departing the roadway in the U.S. is needed before the development of motorcycle crash tests. This study used the National Cooperative Highway Research Program (NCHRP) 17-88 database to compare the encroachment and impact characteristics of motorcycles, passenger vehicles, single-unit trucks, and tractor-trailer trucks. Motorcycles were found to have a similar distribution of impact angles to passenger vehicles, with an 85th percentile of 24 degrees. The median and 85th percentile impact angle was found to be shallower for tractor-trailer trucks compared with motorcycles and passenger vehicles. Additionally, large trucks and motorcycles were found to roll over at a higher frequency than passenger vehicles. During the first event, almost 80% of motorcycles were upright. By the second event, almost 50% of motorcyclists were separated from the motorcycle. This indicates that a large percentage of riders lose contact with the motorcycle during the first event and are separated during any subsequent events. Based on these results, future motorcycle-barrier tests should consider an upright configuration and an impact angle of 24 degrees.

Evaluation of AIS3+ car occupant injuries using deterministic and probabilistic methods in frontal crashes

Computational modelling was used to assess the capability of a deterministic and a probabilistic method to predict the incidence of AIS3+ injuries in passenger car occupants by comparing the predictions of the methods to the actual injuries observed in real-world crashes. The likelihood of sustaining an injury was first calculated using a computer model for a selected set of injury criteria in different impact conditions based on real-world crashes; AIS3+ injuries were then predicted using each method separately. Regardless of the method, the number of serious injuries was over-predicted. It was also noted that the used injury criteria suggested the occurrence of specific injuries that were not observed in the real world. Although both methods are susceptible to be adapted to improve their predictions, the question of the suitability of using some of the most commonly accepted injury criteria used with crash test dummies for injury assessment with human body models deserves further research.

Analysis of Head Displacement during a Frontal Collision at a Speed of 20 km/h—Experimental Studies

The aim of the research is to compare the head displacements of volunteers with the head displacements of the KPSIT C50 dummy, taking into account the change of vehicle seat belts. Unfortunately, sudden braking or collisions between vehicles is becoming more and more common, especially during traffic jams. There is considerable ignorance in the literature on the behavior of the human body during a low-speed collision, which motivates the development of low-speed crash test procedures in order to reduce the risk of cervical spine injuries. The tests were carried out at a teaching station designed to measure the forces in seat belts and the displacements of individual body elements (dummy or volunteer) during a low-speed crash test. The article is part of extensive research on crash tests using volunteers and KPSIT physical dummies. The study involved 150 volunteers who were divided into specific percentile groups. The article compares the head displacements of the constructed KPSIT C50 dummy with the head displacements of volunteers representing the 50th percentile group of the male population. The study conducted with volunteers was under control and was completely safe for people participating in the study. The research shows that the use of a bucket sports seat equipped with four-point or five-point seat belts significantly reduces the movement of the head during a low-speed collision. This type of vehicle seat is safer and provides a reduced risk of injury from hitting the head on the steering column in a low-speed collision when the airbag has not deployed. Moreover, research shows that standard seat belts placed in passenger vehicles allow the head to move freely forward in the event of an accident or low-speed collision. Therefore, if the speed is too low to deploy the airbag, there is a high probability that the driver and passengers will hit their heads against the cockpit of the passenger vehicle during a collision at a speed of 20 km/h.

Pedestrian Safety in Frontal Tram Collision, Part 2: Laminated Glass as a Crucial Part of the Absorption and Deformation Zone-Its Impact Test and Analysis.

As was shown in the previous part of the study, windshields are an important part of the passive safety means of modern low-floor trams with an extraordinary effect on pedestrian safety in a pedestrian-tram collisions. Therefore, maximum attention must be paid to the definition of tram windshield characteristics. This article describes a windshield crash test, from which data are obtained to verify the feasibility of the applied computational approaches. A developed analytical model is utilised for a simple description of the energy balance during collision with an illustrative definition of the important parameters of laminated glass as well as their clear physical interpretations. The finite element analysis (FEA) performed in Ansys software using two versions of material definition, namely a simpler (*MAT_ELASTIC with nonlocal failure criterion) and a more complex (*MAT_GLASS with brittle stress-state-dependent failure) material model, which are presented as suitable for obtaining a detailed description of the shattering process of laminated glass, which can also be used effectively in windshield engineering.

Numerical Modelling and Investigation of the Impact Behaviour of Single Guardrail Posts

Vehicle restraint systems are vital hardware elements in road safety engineering. The certification process of a vehicle restraint system includes full-scale crash tests, component testing and numerical simulation of these tests. To achieve reliable crash test simulation results, the soil–post interaction must be modelled to capture the behaviour realistically. There is no standardised approach for modelling the soil–post interaction in the praxis. In this study, the finite element method is utilised to investigate the soil–post response under quasi-static and dynamic impact loading. Two different modelling techniques are applied for this purpose. The first technique is the finite element continuum method, with the soil modelled using the advanced hypoplastic constitutive relation and calibrated using laboratory test data. The second technique is a lumped-parameter model, for which a systematic parameters calibration routine using basic soil properties is introduced. The numerical models are validated using a series of full-scale field tests performed by the authors on single posts in standard road shoulder materials. The performance comparison of the investigated modelling techniques shows that the hypoplastic constitutive relation can capture the post behaviour realistically under different loading conditions using the same parameter set. The introduced lumped-parameter model adequately simulates the post behaviour with high computational efficiency, which is very important when simulating several posts. The conducted parametric study elucidates that the soil’s relative density, the post’s embedment length, and the post-section modulus govern the single post’s lateral load-bearing behaviour and energy dissipation capacity.

Study of Vehicle-Based Metrics for Assessing the Severity of Side Impacts

<div>A research program has been launched in Iran to develop an evaluation method for comparing the safety performance of vehicles in real-world collisions with crash test results. The goal of this research program is to flag vehicle models whose safety performance in real-world accidents does not match their crash test results. As part of this research program, a metric is needed to evaluate the severity of side impacts in crash tests and real-world accidents. In this work, several vehicle-based metrics were analyzed and calculated for a dataset of more than 500 side impact tests from the NHTSA crash test database. The correlation between the metric values and the dummy injury criteria was studied to find the most appropriate metric with the strongest correlation coefficient values with the dummy injury criteria. Delta-V and a newly created metric <span> <math> <mrow> <mi>T</mi> <msubsup> <mi>K</mi> <mrow> <mn>2</mn> <mn>0</mn> <mn>0</mn> </mrow> <mi>Y</mi> </msubsup> </mrow> </math> </span>, which is an indicator of the kinetic energy transferred to occupants in a 200 ms time interval and in the lateral direction, were found to be the most appropriate metric for assessing the crash severity of side impacts with strong correlation coefficients with head injury criteria such as HIC<sub>36</sub> and HIC<sub>15</sub>, resultant spinal acceleration, and moderate correlation coefficients with average rib deflection and abdominal forces. Due to the need to calculate the metric based on EDR measurements, <span> <math> <mrow> <mi>T</mi> <msubsup> <mi>K</mi> <mrow> <mn>2</mn> <mn>0</mn> <mn>0</mn> </mrow> <mi>Y</mi> </msubsup> </mrow> </math> </span> was chosen as the side impact severity metric for the research program.</div>

Pedestrian Safety in Frontal Tram Collision, Part 1: Historical Overview and Experimental-Data-Based Biomechanical Study of Head Clashing in Frontal and Side Impacts.

This article represents the first paper in a two-part series dealing with safety during tram-pedestrian collisions. This research is dedicated to the safety of trams for pedestrians during collisions and is motivated by the increased number of lethal cases. The first part of this paper includes an overview of tram face development from the earliest designs to the current ones in use and, at the same time, provides a synopsis and explanation of the technical context, including a link to current and forthcoming legislation. The historical design development can be characterised by three steps, from an almost vertical front face, to leaned and pointed shapes, to the current inclined low-edged windshield without a protruding coupler. However, since most major manufacturers now export their products worldwide and customisation is only of a technically insignificant nature, our conclusions are generalisable (supported by the example of Berlin). The most advantageous shape of the tram's front, minimising the effects on pedestrians in all collision phases, has evolved rather spontaneously and was unprompted, and it is now being built into the European Commission regulations. The goal of the second part of this paper is to conduct a series of tram-pedestrian collisions with a focus on the frontal and side impacts using a crash test dummy (anthropomorphic test device-ATD). Four tram types approaching the collision at four different impact speeds (5 km/h, 10 km/h, 15 km/h, and 20 km/h) were used. The primary outcome variable was the resultant head acceleration. The risk and severity of possible head injuries were assessed using the head injury criterion (HIC15) and its linkage to the injury level on the Abbreviated Injury Scale (AIS). The results showed increasing head impacts with an increasing speed for all tram types and collision scenarios. Higher values of head acceleration were reached during the frontal impact (17-124 g) compared to the side one (2-84 g). The HIC15 values did not exceed the value of 300 for any experimental setting, and the probability of AIS4+ injuries did not exceed 10%. The outcomes of tram-pedestrian collisions can be influenced by the ATD's position and orientation, the impact speed and front-end design of trams, and the site of initial contact.

Performance design, development and verification of honeycomb aluminium barrier for vehicle side impact

SUVs are taken as the research object to develop the side deformation barrier with Chinese characteristics. By extracting characteristic parameters of typical SUVs, honeycomb aluminium barrier and trolley development objectives are defined and theoretical analysis are applied to guide the selection of barrier materials. Based on the dynamic load-cell wall test of barrier trolley, the evaluation method of honeycomb aluminium calibration performance is proposed. Through car-to-car crash test, a new verification method based on the deformation of the body structure and the height distribution of the crash load force is formatted. The results show that the new moving deformation barrier’s mechanical properties meet the design specifications, the prototype is stable in deformation modes and it can characterise the appearance and stiffness characteristics of SUV.

Research on vehicle aggressiveness evaluation based on full frontal crash test

In the frontal accident, vehicles with strong aggressiveness are an important factor in causing death or injury to vulnerable vehicles. To effectively evaluate the aggressiveness of vehicle frontal crash, the dynamic load values and distribution of vehicle frontal structures are collected using the load-cell wall. On this basis, evaluation intervals in the horizontal and vertical directions are established, and the standard deviation and negative deviation of collision loads were analyzed. Normalization is carried out to establish evaluation indices for horizontal and vertical load effects. The effectiveness of the evaluation indexes is verified through analysis of frontal collision tests on several vehicle models. The results showed that the vertical and horizontal collision energy transfer at the front end of the vehicle still needs to be strengthened.

Study on evaluation indexes of the full width deformable barrier test

In order to evaluate the crash compatibility of vehicles, the full width deformable barrier is introduced into the vehicle crash test. Real car to car frontal collision is better simulated by installing deformable barrier on the load-cell wall . By the load-cell wall data, the values and distribution of vehicle frontal collision loads can be further obtained. Based on this, the full width deformable barrier tests are conducted for different structural sedans and SUV. The height index, homology index, horizontal structure interaction index(HSI), vertical structure interaction index(VSI), and minimum load-cell index are analyzed and compared. The results indicate that there is uncertainty when calculating the homology index RH and the evaluation indexes proposed by FIMCAR repeat the first step of VSI and HSI. Therefore, the height index, VSI, and HSI indexes are selected as effective indexes for evaluating the compatibility of the full width deformable barrier test.

Analysis of Vehicle Energy Absorption Compared to Non‐Standard Tests

AbstractOccupant safety is one of the fundamental aspects to be considered in structural design, which is why the computer aided engineering (CAE) methodology has become essential when studying a vehicle. For the past 10 years, therefore, when designing a vehicle, it is necessary to simulate both standard crash tests, required for marketing, and evaluation tests, carried out by independent consumer bodies. Thanks to the strong European (also national) drive to improve road safety, economic and technological investments have increased. In addition to this, the analysis criteria, and protocols for carrying out crash tests have also evolved to properly verify the crashworthiness of vehicles. Standard crash tests (e.g., EuroNCAP tests) are not exhaustive of all possible crash conditions that can occur in real life. Therefore, this study aims to investigate the structural behavior of a European B‐segment vehicle by performing non‐standard crash tests, i.e., not dictated by any regulation, analyzing different initial conditions. In particular, a frontal impact against a rigid barrier and a side impact against a deformable moving barrier (MDB) are analyzed using standardized test protocols and are then compared with non‐standard tests, analyzed using finite element models that evaluate the amount of energy absorption.Chiefly, in the non‐standard tests rotated the angle of the barrier to 10°, 20°, and 30° for the frontal impact. For the side impact, only the position of the barrier (front and rear) is varied.

소량생산 로드스터의 스페이스 프레임 전산 충돌 모의해석

This study conducts computerized crash analysis and actual crash tests on small-production vehicles. Accordingly, the results are graphically compared to see whether they are coherent. The analysis methods were designed based on the 2016 Hyundai Ioniq Electric vehicle. The computer simulation considered a frame constructed using shell elements, bumper constructed using solid elements, and bumper connector, which were analyzed using the finite element method. Subsequently, a fixed wall frontal crash test was conducted with placing male dummies on both the driver's seat and left side. Similar trends were detected by comparing the computer simulated crash and actual crash test analysis results. Finally, we confirmed that graphs with similar trends were generated.

Analysis of the selection of a child seat

The selection of a child seat is not an easy task for future parents. Information about child seats, assembly methods, usability and prices affect the purchasing preferences of parents or legal guardians of children. The article contains information about the factors to pay attention to when buying a child seat. The main purpose of the article is to analyze and evaluate information on the selection of a vehicle seat for the right passenger vehicle and child. The article discusses information about the ADAC child seat crash test and the plus test, which are mainly performed for rear-facing child seats.The article presents information on groups of child seats and the method of their installation in a passenger vehicle. The purchasing predispositions of parents and legal guardians in terms of the selection of a child seat were also described. It should be noted that most respondents pay attention to the level of safety of child seats than to their price.

Predicting head injury metrics during low- to moderate-speed frontal collisions using computational simulations

ObjectivesSubjective reports of mild traumatic brain injury (mTBI) are common following low-energy motor-vehicle collisions. Biomechanical analyses are useful in providing a quantitative means for determining the likelihood of sustaining mTBI. While occupant dynamics in low-speed rear impacts have been extensively investigated, peer-reviewed studies on occupant dynamics during low-speed frontal collisions are sparse. The objective of this study is to present a validated computational method to quantify the biomechanical response of the head in low- and moderate-speed frontal collisions. Data and methodsThis study used data from a previously-published series of four instrumented in-line front-to-rear staged collisions using 2014 Honda Accord sedans at closing velocities of approximately 7.4 kph (test L1), 12.7 kph (test L2), 21.7 kph (test L3), and 33.6 kph (test L4) kph. A model of the test vehicle occupant compartment was created using the MAthematical DYnamic MOdeling (MADYMO) software using methods previously described. Crash pulse data from L4 were applied to the MADYMO model. Seat belt parameters were optimized to achieve reasonable agreement between simulation results and test data for relevant head injury metrics (linear head acceleration [LHA], angular head acceleration [AHA], and HIC15). Crash pulses from the other tests in the series (L1, L2, and L3) were then applied to the model and peak values for LHA, AHA, and HIC15 were compared to the physical test data to demonstrate validation. ResultsThe optimization of seat belt and seat parameters within the MADYMO model resulted in accurate prediction of ATD dynamics demonstrated in Test L4. The simulation-predicted peak LHA was within 0.2 g of the test value, peak AHA was within 64 rad/s2, and HIC15 was within 0.46. When applied to the remainder of the tests (L1, L2, and L3), the optimized model showed excellent accuracy in predicting peak LHA and HIC15. When compared to the physical test data, the simulation-predicted values for LHA were within 0.4 g or less and the HIC15 values were within 0.4 or less across all tests. The model generally over-predicted AHA, particularly for the lower-severity collisions (L1 and L2). ConclusionsWe have demonstrated a reliable methodology for developing a biomechanical computational model to predict head injury metrics in low- to moderate-speed frontal collisions. This approach can be particularly valuable in forensic investigations of real-world crashes. Pre-existing crash test data can be used in conjunction with exemplar vehicle information to validate a MADYMO model. Appropriate crash pulse data from classical accident reconstruction techniques, event data recorders, or simulations can then be applied to the model to accurately predict head dynamics for real-world vehicle occupants without the need for full-scale staged crash tests.

Determination and Static Analysis of the Chassis Model for Electric Vehicles

Vehicle technology with an internal combustion engine emerged at the end of the 19th century. Although it is not very well known, the first prototype studies of the electric vehicle coincide with the same period. Today, factors such as global warming, pollution and the decrease in fossil fuel reserves accelerate the transition to electric vehicle technology. In this context, a new system structure is needed for electrically driven systems differently from traditional vehicle structures. In this study, a chassis design for an electric vehicle is carried out. While designing, the part where the battery pack will be placed has been modeled and simulated with the help of the ANSYS program to protect the battery and electronic components that are particularly sensitive to impacts. In order to be successful in abuse tests such as Crush and Crash tests specified in the regulations and standards, the material selection and design should be done correctly. In this context, the right materials are determined as a result of the researches and 3D simulations are made and crash tests are carried out in the simulation environment. As a result, tube type chassis was chosen among many chassis models and 7079 aluminum alloy was found suitable as raw material. According to the simulation results, it is seen that the design and the selected alloy are suitable.

Analysis of Kinetic Metrics in Submarining vs Non-Submarining Conditions for a 6YO Pediatric Human Body Model in Frontal Impacts

<div>Field data has shown that belt-positioning boosters help reduce the risk of injury to children in a crash. This study builds on prior submarining work (Slusher et al. 2022) and aims to analyze kinetic metrics (which can be easily recorded from anthropomorphic test devices in crash tests) in submarining and non-submarining conditions for a 6-year-old pediatric human occupant in frontal crashes.</div>

A Parametric Thoracic Spine Model Accounting for Geometric Variations by Age, Sex, Stature, and Body Mass Index

<div>In this study, a parametric thoracic spine (T-spine) model was developed to account for morphological variations among the adult population. A total of 84 CT scans were collected, and the subjects were evenly distributed among age groups and both sexes. CT segmentation, landmarking, and mesh morphing were performed to map a template mesh onto the T-spine vertebrae for each sampled subject. Generalized procrustes analysis (GPA), principal component analysis (PCA), and linear regression analysis were then performed to investigate the morphological variations and develop prediction models. A total of 13 statistical models, including 12 T-spine vertebrae and a spinal curvature model, were combined to predict a full T-spine 3D geometry with any combination of age, sex, stature, and body mass index (BMI). A leave-one-out root mean square error (RMSE) analysis was conducted for each node of the mesh predicted by the statistical model for every T-spine vertebra. Most of the RMSEs were less than 2 mm across the 12 vertebral levels, indicating good accuracy. The presented parametric T-spine model can serve as a geometry basis for parametric human modeling or future crash test dummy designs to better assess T-spine injuries accounting for human diversity.</div>

Comparison of Head, Neck, and Chest Injury Risks between Front and Rear-Seated Hybrid III 50th-Percentile Male ATDs in Matched Frontal NCAP Tests

<div>The objective of this study was to compare head, neck, and chest injury risks between front and rear-seated Hybrid III 50th-percentile male anthropomorphic test devices (ATDs) during matched frontal impacts. Seven vehicles were converted to rear seat test bucks (two sedans, three mid-size SUVs, one subcompact SUV, and one minivan) and then used to perform sled testing with vehicle-specific frontal NCAP acceleration pulses and a rear seated (i.e., second row) Hybrid III 50th male ATD. Matched front seat Hybrid III 50th male ATD data were obtained from the NHTSA Vehicle Crash Test Database for each vehicle. HIC15, Nij, maximum chest acceleration, and maximum chest deflection were compared between the front and rear seat tests, as well as between vehicles with conventional and advanced three-point belt restraint systems in the rear seat. Additionally, a modified version of the NCAP frontal star rating was calculated for the front and rear seat tests. All injury metrics, except for chest acceleration, were higher in the rear seat compared to the front. In addition, injury thresholds were exceeded or nearly exceeded in the rear seat for Nij in three vehicles, chest acceleration in one vehicle, and chest deflection in three vehicles, while no thresholds were exceeded in the front seat. When comparing advanced and conventional restraints in the rear seat, all injury metrics were higher in the vehicles with conventional restraints. All vehicles with conventional restraints in the rear had a star rating of 1, while those with advanced restraints in the rear ranged from 2 to 3. Conversely, all vehicles had 5 stars for the front seat, except one that had 4 stars. Overall, these data highlight the disparity between front and rear seat occupant protection and the benefits of advanced rear seat safety restraints, and the need for future testing.</div>