Radial basis function surrogate model-based optimization of guardrail post embedment depth in different soil conditions

Abstract

For guardrail designers, it is essential to achieve a crashworthy and optimal system design. One of the most critical parameters for an optimal road restraint system is the post embedment depth or the post-to-soil interaction. This study aims to assess the optimum post embedment depth values of three different guardrail posts embedded in soil with varying density. Posts were subjected to dynamic impact loads in the field while a detailed finite element study was performed to construct accurate models for the post–soil interaction. It is well-known that experimental tests and simulations are costly and time-consuming. Therefore, to reduce the computational cost of optimization, radial basis function–based metamodeling methodology was employed to create surrogate models that were used to replace the expensive three-dimensional finite element models. In order to establish the radial basis function model, samples were derived using the full factorial design. Afterward, radial basis function–based metamodels were generated from the derived data and objective functions performed using finite element analysis. The accuracy of the metamodels were validated by k-fold cross-validation, then optimized using multi-objective genetic algorithm. After optimum embedment depths were obtained, finite element simulations of the results were compared with full-scale crash test results. In comparison with the actual post embedment depths, optimal post embedment depths provided significant economic advantages without compromising safety and crashworthiness. It is concluded that the optimum post embedment depths provide an economic advantage of up to 17.89%, 36.75%, and 43.09% for C, S, and H types of post, respectively, when compared to actual post embedment depths.

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

“…In the LS-DYNA model, the rail and post section are “Shell” modeled, and the “MAT24” is used as the material for both. Bolt connections between rail and post are defined as “Beam.” Materials and models validated from previous studies 10,31,32 were used in this research.…”

“…Bolt connections between rail and post are defined as ''Beam.'' Materials and models validated from previous studies 10,31,32 were used in this research. Figure 3 shows the meanings of the symbols which are forming the name of the guardrail system that is classified according to EN 1317 standards.…”

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

“…Bolt connections between rail and post are defined as 'Beam'. Materials and models validated from previous studies [8], [26], [29] were used in this research.…”

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

“…There are many different types and geometries of posts in practice. [2][3][4][5] The mechanical behavior of the material can change depending on the geometric shapes. In future guardrail designs, which geometry provides the best performance for the posts, considering their mechanical behavior?…”

“…For the study, the FE pendulum system, which was previously validated with empirical data, was used because empirical studies would take time and cost. 2 In this sense, FE analysis provides advantages in terms of time and cost. It also allows different variations to be tested.…”