Damage investigation of blast loaded UHPFRC panels with optimized mixture design using advanced material models

Abstract

The increasing use of innovative materials in blast- and impact-resistant structures underscores the demand for robust simulation and design methods. Concrete, especially Ultra High Performance Fiber Reinforced Concrete (UHPFRC), has emerged as a key player in this domain. The present study delves into the damage investigation and dynamic response assessment of blast loaded UHPFRC panels with optimized mixture design (microsilica content, water curing conditions, and fibre proportions). The so-assembled UHPFRC material is calibrated and validated, adjusting parameters from experimental results addressing the tensile and compressive behaviours of material based on standard experimental methods. The investigation navigates through experimental and numerical challenges, emphasizing the limitations of applying available models to UHPFRC, and necessitates recalibration for optimal alignment with experimental results. An in-depth numerical analysis using LS-DYNA software is also carried out, aiming to understand the dynamic behaviour of UHPFRC panels under blast loading and performing a comparative analysis between UHPFRC and normal strength concrete (NSC) panels with and without reinforcement, emphasizing the superior performance of UHPFRC. Furthermore, the study addresses the importance of determining the minimum thickness for UHPFRC panels as protective barriers. This involves a specific strategy based on regulations and considering minimal damage to the panel, leading to the proposal of an empirical formulation. Additionally, a sensitivity analysis has been conducted to identify the influential parameters on the response of the panel. The findings of this study revealed that modelling the UHPFRC material using finite element analysis and employing advanced material models yield promising outcomes. Moreover, the proposed empirical formulation demonstrates a good level of accuracy and efficiency in predicting the minimum thickness for UHPFRC panels under blast conditions. The results of the sensitivity analysis also indicate that explosive charge weight, standoff distance, and panel thickness are the most critical parameters. These insights contribute to a comprehensive understanding of UHPFRC dynamic behaviour in blast conditions, offering valuable considerations for future applications and design implementations in this evolving field.

Keywords

• Ultra high performance fiber reinforced concrete (UHPFRC)
• Blast load
• Optimized mixture design
• Minimum required thickness
• Finite element (FE) modelling