Artificial neural network metamodeling-based design optimization of a continuous motorcyclists protection barrier system

Proceedings of the Institution of Mechanical Engineers, Part D:

Ozcan

2022

Self Cite

Road restraint systems-RRS are passive safety designs installed on roadsides to ensure the safety of errant vehicle passengers as well as pedestrians. The adequacy of these systems is assessed through full-scale vehicle crash testing for which evaluation criteria are determined by standards such as EN1317. Recently the same RRS is crash tested two times with two different 900 kg passenger cars and test results varied significantly. After a failed crash test instead of modifying the barrier test vehicle was replaced and the same test was repeated. It was surprising to see that the failed RRS this time satisfied the EN1317 evaluation criteria. Despite the use of the same mass vehicle in the crash tests, the different results obtained were a source of motivation for investigating the inadequacy of EN1317. In this study, the adequacy of the 900 kg vehicle criteria used in the determination of the safety parameters in the EN1317-TB11 test was investigated by creating validated finite element-FE models. After the FE analysis it was concluded that test vehicle properties, such as vehicle mass and velocity provided in EN1317 are deemed to be insufficient and more explicit vehicle selection parameters, given in the study, are needed to provide safer and more uniform crash testing results.

Section: Numerical Results and Discussionmentioning

confidence: 97%

Section: Vehicles Typementioning

confidence: 99%

Criteria inadequacy of the vehicles used for the calculation of safety parameters in the EN1317-TB11 test

Proceedings of the Institution of Mechanical Engineers, Part D:

Ozcan

2022

Self Cite

“…In the study for the development of bollard systems used to protect the infrastructure facilities used in the city [10], the weaknesses of the existing bollard systems were identified and suggestions were made for their improvement. In the study conducted by Yilmaz et al [11], the motorcyclist protection barrier system was optimized, as a result safer and more economical sections were obtained. Moreover, such as, improving crash cushion systems that provide road safety [12], ASI value of cable barrier for different speeds [13], determining the danger levels of obstacles such as traffic lights, trees, lighting poles, rocks, ditches, etc.…”

Section: Figure 1 -(A) Concrete Barriers (Rigid) (B) Steel Guardrails...mentioning

confidence: 99%

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

Turkish Journal of Civil Engineering

2023

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 unfavorable 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.

“…Based on prior successful research, the ideal mesh size for the post and base was determined to be 10 mm. 2,[34][35][36] For soil model, the critical area around posts was meshed at 4 mm, with mesh sizes growing to 10 mm toward the outer edge of the soil model. And outer shell meshed at 20 mm since there will no deformation calculation on it.…”

Section: Guardrail Post Types and Fe Modelsmentioning

confidence: 99%

Head-on and angular impact-based investigation of mechanical behavior of guardrail post types with finite element analysis

Proceedings of the Institution of Mechanical Engineers, Part C:

2023

The geometric sections of guardrail systems that provide roadside safety are important in terms of their safety and structural performance. Guardrail systems generally consist of posts and beam. One of the critical components that affect the performance of steel guardrail systems is the post. Many different types of posts are used in practice. In this sense, the mechanical performance of the most commonly used S-C-I-Z-rectangular-circular post types in this study was investigated and compared on the basis of their failure performances. For this, the finite element (FE) model of the pendulum system, which was previously validated with empirical data, was used. In the FE analysis, the mechanical performance of posts embedded in soil and fixed on top of the ground was investigated by the pendulum system in head-on and angular impact situations. As a result of the FE analyses; the mechanical performances were different for head-on and angular impact situations. However, since circular and rectangular posts show the best performance in case of angular impact, and considering in terms of guardrail systems, angular impact situations are a matter of concern, it has been understood that the use of closed-section posts as circular and rectangular in guardrail systems will provide safety and economic advantages.