Adaptive coupling of FEM and SPH method for simulating dynamic post-soil interaction under impact loading

Soil-embedded vehicle barrier systems are frequently placed along high-speed highways to safely redirect errant motorists away from roadside hazards. Improved knowledge and understanding of the dynamic interactions between posts and soil are essential for advancing and optimizing these protective systems. Although the Finite Element Method (FEM) is a standard tool in the design, analysis, and evaluation of such systems, its conventional application faces challenges in accurately simulating the large soil deformations encountered by post-soil systems under impact loading. In this study, we introduce an innovative computational framework designed to simulate dynamic post-soil interactions through an adaptive coupling of the FEM and Smoothed Particle Hydrodynamics (SPH). The adaptive FEM-SPH approachʼs accuracy was validated through quantitative and qualitative analyses, benchmarked against empirical data from a unique series of physical impact tests. The results from the adaptive FEM-SPH model demonstrated remarkable agreement with observed force vs. displacement and energy vs. displacement responses, emphasizing its potential as a viable tool for assessing the performance and behavior of post-soil systems under vehicular impacts. Comparative analysis with existing simulation techniques for addressing the post-soil impact problem highlighted the adaptive FEM-SPH model's adaptability, robustness, and accuracy, thereby enriching the understanding of dynamic soil-structure interactions under impact loading. Moreover, this approach facilitated the derivation of a unique relationship between the post's center of rotation and its embedment depth, offering valuable insights for designing and optimizing barrier systems. The implications of our findings are poised to augment the design, analysis, and overall effectiveness of barrier systems, contributing to enhanced motorist safety.