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This paper investigates the impact dynamics of pile-soil interactions, focusing on the mechanisms of kinetic energy dissipation within these systems during vehicular impacts. The study aimed to quantitatively evaluate the force-displacement and energy-displacement responses of piles embedded in crushed limestone material through dynamic bogie testing. A three-dimensional, large-deformation, nonlinear finite element model was developed to enhance the analysis. The computational model integrated a damage-based, elastoviscoplastic soil model with an elastoplastic steel pile model, incorporating strain rate effects. A continuum, damage-based element-erosion algorithm is also employed to accurately simulate large soil deformations, representing a significant advancement in simulation capabilities. The proposed model was validated against physical impact test data, demonstrating a strong correlation with measured force-displacement and energy-displacement results. This model was subsequently utilized to investigate the effects of impact velocity and soil strength on the energy dissipation capacity of pile-soil systems during lateral vehicular impacts. Additionally, this study critically examined the limitations of conventional simulation methods, such as the Updated Lagrangian Finite Element Method (UL-FEM), in capturing the dynamic pile-soil interactions and large soil deformations involved in laterally-impacted pile-soil systems. The research provided fundamental insights into the mechanics of dynamic soil-structure interactions under impact loading, contributing significantly to the geotechnical design and analysis of soil-embedded vehicle barrier systems. [ABSTRACT FROM AUTHOR]

The use of nonlinear, large-deformation, dynamic finite element analysis (FEA) has become a cornerstone in crash test simulations, playing a pivotal role in evaluating the safety performance of critical civil infrastructures, including soil-embedded vehicle barrier systems. This review paper offers a detailed examination of numerical modeling methodologies employed for simulating dynamic soil–structure interactions in crash test simulations, with a particular focus on dynamic impact pile–soil interaction. This interaction is a critical determinant in assessing the effectiveness of soil-embedded barrier systems during vehicular impacts. Our extensive review methodically categorizes and critically evaluates four prevalent modeling methodologies: the lumped parameter method, the subgrade reaction method, the modified subgrade reaction approach, and the direct or mesh-based continuum method. We explore each methodology's underlying philosophy, strengths, and shortcomings in accurately simulating the dynamic interaction between soil and piles under impact loading. This technical review aims to provide a thorough understanding of the critical and distinctive aspects of modeling soil's dynamic responses under impact loading conditions. Moreover, this paper is envisioned to serve as a foundational reference for future research endeavors, steering the advancement of innovative simulation techniques for tackling the dynamic impact soil–structure interaction problem. [ABSTRACT FROM AUTHOR]

Roadside safety structures (i.e., barrier systems) with thin-walled, soil-embedded support piles are critical in reducing the consequences of run-off-road (ROR) crashes, contributing to numerous deaths and injuries, and significant societal costs. Enhanced knowledge and understanding of soil-embedded barrier systems, especially the dynamic pile-soil interaction under vehicular impact, can help to lessen the severity of such crashes and preserve human life. Although the design and analysis of soil-embedded barrier systems have advanced significantly, existing modeling techniques cannot accurately capture large soil deformations under impact loading. In order to bridge this gap, this study proposes a novel computational methodology by coupling the Finite Element Method (FEM) and Arbitrary Lagrangian-Eulerian (ALE) method. Validated against extensive physical impact test data covering a variety of pile shapes, embedment depths, material properties, and impact conditions, this methodology effectively captures the dynamic responses of steel tube pile-soil systems involving large soil deformations and fluid-like soil flow. The coupled FEM-ALE-based methodology provides a more realistic simulation of laterally impacted pile-soil systems, potentially reducing the number of, and even the need for, full-scale crash tests. This study also provided mechanistic insights into the dynamic pile-soil systems' response to impact loading. A comparison with the pure Lagrangian approach showed the coupled FEM-ALE model's robustness, adaptability, and accuracy, advancing the understanding of dynamic soil-structure interactions under impact loading. • A novel simulation tool–the coupled FEM-ALE method–has been developed to capture dynamic pile-soil interactions under vehicular impacts. • The new method addresses limitations in current simulation techniques that often fail to accurately capture large soil deformations. • The methodology is validated using impact tests featuring a variety of pile shapes, embedment depths, and impact conditions. • Dynamic responses predicted by models were within 5 % to 12 % of the impact test data, implying high fidelity in simulating real-world phenomena. • A direct comparison with the traditional pure Lagrangian approach highlights the method's improved adaptability, robustness, and accuracy. [ABSTRACT FROM AUTHOR]

• Adaptive coupling of FEM and SPH method offers a novel computational approach to dynamic impact soil-foundation interaction problems. • Demonstrated accuracy and robustness of the adaptive FEM-SPH method across various post-soil systems and impact conditions. • The new adaptive FEM-SPH technique surpasses conventional post-soil models, capturing failure dynamics for flexible and rigid posts under impact loading. • Coupling the adaptive FEM-SPH method with a damage-based, elasto-viscoplastic constitutive law yields accurate soil fracture predictions during impact events. • Examined the complex dynamics of soil responses during impact with embedded posts. 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. [ABSTRACT FROM AUTHOR]