Simulation of a Dummy Crash Test in ADAMS

The article presents a model designed dummy for crash test in ADAMS. The simulated model dummy has dimensions, shapes and mass corresponding to a 50-percentile man. The simulation program allows modification of the dummy parameters. It allows to study the dynamics of motion, distribution of forces and loads of individual parts of the body of the simulated model. The article describes the design process and how to select the appropriate stiffness and damping joints for the simulated dummy. The article contains the results of simulation crash tests performed in the ADAMS program, which were compared to results of the Hybryd III dummy physical crash test. The simulation is designed to reflect the greatest compliance of the movements of individual parts of the human body during the low speed collision.

Experimental and Numerical Assessment of Supporting Road Signs Masts Family for Compliance with the Standard EN 12767

The analysis aimed to assess the passive safety of supporting masts for road signs in accordance with EN 12767. Experimental tests were carried out based on the requirements of the standard for the smallest and the largest constructions within the product family. Numerical models of crash tests were prepared for whole product family using the Finite Element Method in the LS-Dyna environment. Based on the comparison of the experimental tests and the numerical calculations, the usefulness of the numerical model for estimating the actual value of the Acceleration Severity Index (ASI) and the Theoretical Head Impact Velocity (THIV) was assessed. With the use of these relationships the values of ASI and THIV for masts not tested experimentally were estimated. It was confirmed that the analyzed masts met the requirements for the passive safety of structures set out in the standard EN 12767. It was possible since as a result of the impact, the mast column detached from the base, allowing the vehicle to continue moving. The behavior of the masts was primarily influenced by the destruction of the safety connectors. The paper presents the most important elements from the point of view of designing such solutions.

Method to Correct the Velocity Variation Information of an Automatic Crash Notification System in Vehicle-to-Rigid Barrier Frontal Collisions

Automatic crash notification systems (ACNSs) play a key role in post-accident safety. To improve the accuracy and efficiency of ACNSs, a method to correct the velocity variation information of ACNSs was established. First, after the acceleration data of sled crash tests were analysed, the factors affecting the accuracy of the velocity variation information were determined, and the influence of the discrimination threshold and acceleration curve shape on the velocity variation information was examined. Second, according to the acceleration data generated by the simulation model of a sled crash, the correlation between the accuracy of the velocity variation information and influencing factors was modelled. Third, an automatic crash notification algorithm involving a velocity variation correction function (VVCF) was proposed based on the correlation model. Finally, to verify its reliability, the improved algorithm was applied to an automatic crash notification system (ACNS) terminal. The validation results show that the ACNS terminal can accurately identify collisions and transmit accident information. Moreover, more accurate velocity variation information can be retrieved.

Development, Crash Testing, and Evaluation of Steel-Post Trailing-End Guardrail Anchorage System

Trailing-end guardrail anchorage systems are widely used by most state departments of transportation (DOTs) and generally consist of simple adaptations of crashworthy end terminals. The safety performance and structural capacity of these trailing-end anchorage systems, when reverse-direction impacts occur near the end, is imperative in crashworthiness of guardrail systems. In 2013, a non-proprietary trailing-end anchorage system with a modified breakaway cable terminal (BCT) was developed by the Midwest Roadside Safety Facility (MwRSF) for the Midwest Guardrail System (MGS). Although this trailing-end guardrail anchorage system adequately met the Manual for Assessing Safety Hardware (MASH) TL-3 safety requirements, the use of two breakaway wood posts was deemed by some users to have several drawbacks. Thus, there was a critical need to develop a non-wood option to anchor the downstream end of the W-beam guardrail system, which led to the need to develop a steel-post trailing-end guardrail anchorage system for use with the MGS. Following the design and component testing of such a system, two full-scale crash tests were performed according to the MASH 2016 test designation nos. 3-37a and 3-37b. In the first test, a 2270P pickup truck struck the guardrail system and was adequately contained and redirected. In the second test, an 1100C small car struck the barrier and safely gated through the barrier. Both tests were deemed acceptable according to TL-3 safety criteria in MASH 2016. Recommendations are provided for the installation of a steel-post trailing-end guardrail anchorage system when used in combination with MGS.

Investigation and MASH Full-Scale Crash Testing of the Buried-in-Backslope Terminal Compatible with Midwest Guardrail System

Buried-in-backslope (BIB) terminal designs for beam guardrails were developed under the National Cooperative Highway Research Program (NCHRP) Report 350 criteria for 27¾-in. high guardrail systems. The design terminates a W-beam guardrail installation by burying the end terminal in the backslope. When properly designed and located, this type of anchor eliminates the possibility of an end-on impact with the barrier terminal and minimizes the likelihood of vehicular intrusion behind the barrier. Considering the increase in guardrail height to 31 in. in recent years, there is a need to modify the BIB terminal design for a 27¾-in. high guardrail to satisfy current crashworthiness standard criteria for a 31-in. high guardrail. The crash tests reported in this paper were performed in accordance with the Manual for Assessing Safety Hardware (MASH) Tests 3-34 and 3-35 for non-gating terminals, which represent the tests considered necessary to demonstrate MASH compliance of the device. The TL-3 BIB terminal system met MASH requirements and is considered MASH compliant. It is considered suitable for implementation at V-ditch locations with a 4H:1V or flatter foreslope where a MASH TL-3 BIB terminal system is needed and/or desired.

Development of a Non-Gating Guardrail Terminal

Guardrail terminals have evolved to the point where they absorb energy while utilizing tension in the rail to countermand the compression. However, non-gating terminals have yet to be developed. In the present study, the possibility of a non-gating guardrail terminal was investigated. Specifically, the combination of lateral and longitudinal forces that produce non-gating performance were determined from computer simulation. Next, a prototype terminal was crash tested at the research team’s laboratory. A terminal head was designed to deform the guardrail, and its internal structure was adjustable to control the longitudinal force. Posts were designed to control lateral forces by modifying their section modulus. This controlled the force at which the posts buckled in response to a collision. A prototype was subjected to two 15° crash tests using an SUV and a small car. In both tests, the kinetic energy of the test vehicle was fully absorbed and the Manual for Assessing Safety Hardware (MASH) criteria would have been met. Neither vehicle passed beyond the terminal head, making these test results the first of their kind.

CrashNet: an encoder–decoder architecture to predict crash test outcomes

Destructive car crash tests are an elaborate, time-consuming, and expensive necessity of the automotive development process. Today, finite element method (FEM) simulations are used to reduce costs by simulating car crashes computationally. We propose CrashNet, an encoder–decoder deep neural network architecture that reduces costs further and models specific outcomes of car crashes very accurately. We achieve this by formulating car crash events as time series prediction enriched with a set of scalar features. Traditional sequence-to-sequence models are usually composed of convolutional neural network (CNN) and CNN transpose layers. We propose to concatenate those with an MLP capable of learning how to inject the given scalars into the output time series. In addition, we replace the CNN transpose with 2D CNN transpose layers in order to force the model to process the hidden state of the set of scalars as one time series. The proposed CrashNet model can be trained efficiently and is able to process scalars and time series as input in order to infer the results of crash tests. CrashNet produces results faster and at a lower cost compared to destructive tests and FEM simulations. Moreover, it represents a novel approach in the car safety management domain.