Papers by Keyword: Blast Loading

Abstract: The collapse of buildings during explosions or other extreme events is often linked to the failure of key structural elements such as columns. As vertical load-bearing members, reinforced concrete (RC) columns are essential for maintaining the stability of structures, but are also among the most vulnerable components when exposed to blast loads. This study focuses on the numerical prediction of the dynamic behavior of RC columns subjected to explosive-driven shock tube (EDST) loading. The analysis is based on an experimental campaign using a laboratory-scale RC column specimen with a height of 1500 mm and a circular cross-section of 100 mm, tested under blast loading generated by a 30 g C4 charge. To simulate the structural response and optimize computational performance, three finite element techniques are evaluated and compared: Multi-Material Arbitrary Lagrangian-Eulerian (MM-ALE), Load Blast Enhanced (LBE), and the Idealized Triangular Loading (ITL) method. All three models are validated against experimental data. In terms of mid-span out-of-plane displacement, MM-ALE showed the best accuracy with a 2.1% discrepancy, followed by LBE at 8.8%, and ITL at 10.6%. Regarding computation time, MM-ALE required 12 hours, while LBE was three times faster and ITL was six times faster than MM-ALE. The LBE method presents a balance between speed and accuracy but relies on precise input values for reflected pressure and impulse, which are typically derived from MM-ALE simulations or analytical expressions. The ITL method, while computationally efficient, tends to overestimate peak displacements due to its simplified and uniform pressure application. Among the three approaches, MM-ALE remains the most accurate.

Abstract: Dedicated metal armor protection for land transport vehicles is an effective solution against blast threats. However, the added weight of these solutions can reduce the vehicle's maneuverability and, indirectly, its maximum payload capacity. To overcome this weight problem, the use of composite materials as additional armor for the vehicle can be an innovative and lightweight solution. In previous studies, different configurations have been subjected to the blast effect in order to analyze and understand their dynamic behavior. The first fiber reinforcements used for composite materials, based on stacked layers of E-glass fabric, were able to withstand dynamic blast loads. However, these reinforcements tend to have the same performance as the all-steel solution for the same areal weight. Therefore, the objective of this study is to investigate the use of 3D woven fiber reinforcements based on E-glass yarn in composite materials for better dynamic performance under blast loading. The fabricated targets were tested against the same blast threat in a free field configuration. The distance between the charge and the targets was kept constant (except for the full thickness 3D woven composite). During the blast, the dynamic deformation in the thickness direction was recorded and different targets were compared. According to the resulting dynamic deformation under the impact of the blast, a better performance of the full thickness 3D woven composite material matched with the protective steel plate was revealed.

Abstract: The constraint of frame column has a significant effect on its dynamic response under blast loading. To study the influence factors of column end constraint, the effect of adjacent members and distributed mass of floors is studied using numerical analysis. The results show that the members that are directly connected to the column end are the main contributors to its end constraint. And these adjacent members may be simplified as being fixed at the far ends. It has also been found that the displacement at the column end decreases with the increase of the column end floors mass. The results in this paper is useful for the further derivation of column end constraint model.

Abstract: The dynamic responses of sandwich structures with MHS(metal hollow sphere)and closed cell aluminum foams under blast loading were simulated numerically by employing the finite element software ANSYS/LS-DYNA. Both sandwich panels and sandwich spheres were modeled. Some factors that determine the blast resistance of the sandwich structures were investigated. According to the parametric studies, the sandwich structures with thin inner face sheet and thick outer face sheet have stronger blast resistance than others. Also the results show that sandwich structures with interlaced hollow spheres have a better performance than those with paratactic hollow spheres. Moreover, it's inferred that the density graded core with the biggest density as the first impact layer and the least density as the last layer has more benefits in energy absorption. The comparison between sandwich structures with metal hollow spheres and those with aluminum foams was studied experimentally and numerically and the results demonstrate that structures with aluminum foam have advantage in energy absorption but structures with MHS are stronger and can undertake more TNT.

Abstract: The dynamic strain distribution behavior of a mortar block blasting was experimentally investigated. A small-scale blasting experiment using a mortar block with well-defined property was conducted and the dynamic strain distribution on the mortal block surface was analyzed using a Digital Image Correlation (DIC) method to establish the effective method for investigating the relationship between blast design and fracture mechanism. The block was blasted by simultaneous detonation of Composition C4 explosive charges with an electric detonator in two boreholes. The behavior of the block surface was observed by two high-speed cameras for three-dimensional DIC analysis and it was also measured by a strain-gauge for comparison. The three-dimensional displacements of the free surface of the block were obtained and dynamic strain distributions were computed. A point strain profile extracted from the analyzed strain distribution data was compared with a directly observed strain profile by the strain gauge.

Abstract: A precise, simple and efficient blast response numerical analysis of Light Armoured Vehicles (LAVs) as well as other structures is of great importance in the early design stages of prototype development in order to reduce the final cost. One of the most commonly used modelling techniques for blast response analyses of structures is the Multi-Material Arbitrary-Language-Euler (MM-ALE) method. However, the method is quite demanding for use, especially when complicated geometries such as LAV designs are involved. This paper presents a review of the pros and cons of the MM-ALE modelling technique for blast response analysis of LAV according to the testing procedures required by the AEP-55 standard.

Abstract: A theoretical research is carried out to study the large deflection response of a fully clamped rectangular metal sandwich plates with functionally graded foam core subjected to blast loading. Using a new yield criterion for sandwich cross-section with graded foam core, we obtained the analytical solutions for the dynamic response of rectangular sandwich plates. Finite element simulations with gradient layers foam core model are performed to study the dynamic response of the sandwich plates with graded foam core subjected to blast loading. The results of the analyses seem to predict well the deflections that are given numerically.

Abstract: This paper investigates the behaviour of a bio-inspired finite element composite model (that mimics the structure of nacre, the inner layer of molluscan shells) under blast loading. Nacre, which has attracted the attention of researchers over the past few decades, comprises 95% aragonite, brittle voronoi-like polygonal tablets that are joined by an organic matrix and arranged in a brick and mortar type structure. In this work, the finite element model developed herein was constructed using voronoi diagrams and geometric algorithms capable of automatically generating staggered layers of voronoi-like aluminium tablets bonded together by a vinylester adhesive layer. Many studies have led to the belief that the magnificent toughness of nacre is mainly attributed to the inter-platelet adhesive bonds. Results obtained from the finite element analysis show that this is indeed true, and it is imperative that the adhesive bond exhibits adequate toughness in order to be able to spread damage across the entire composite, thereby delaying localised failure.

Abstract: In this study, a finite element model was developed to understand the deformation and failure mechanisms of a multi-layered composite panel under blast. Fibre (E-glass fiber) and matrix (vinylester resin) damage and degradation of individual unidirectional composite laminas were modelled using the Hashin failure model. The delamination between laminas was modelled by a traction-separation cohesive law. A Polyurea layer was placed at the rear of the panel to study its effects on the damage evolution in the composite laminas, and was modelled using a Mooney-Rivlin constitutive law. The model-predicted deformation histories, fiber/matrix damage patterns, and inter-lamina delamination were compared between monolithic and composite panels. The model revealed that the Polyurea plays an important role in improving the panel’s performance.

Abstract: Plate is one of the most common structural elements, which appears in a wide range of applications: steel bridges, blast-resistance door, and armored vehicles. In this paper, the behavior of steel plates under blast loading was studied through numerical approaches using LS DYNA and then the results were compared with the experiment results obtained from existing literatures. The study of a clamped square plate exposed to blast loading in three distinct stand-off distances. Three different methods of modeling blast loading were used, namely: empirical blast method, arbitrary Lagrangian Eulerian (ALE) method, and coupling of Lagrangian and Eulerian method. The empirical blast method was deployed by using key card *LOAD_BLAST in LS-DYNA. In ALE method, Langrangian and Eulerian solution were combined in the same model and the fluid-structure interaction (FSI) handled by coupling algorithm. In coupling method, the engineering load blast in LS-DYNA (*LOAD_BLAST_ENHANCED) was coupled with the ALE solver. In terms of central deflection and computational time, the coupling method appeared to be the best method which is very time-effective and showed a good correlation with the experiment data.