Energy Absorption Properties Research Articles

Tunable mechanical performance of nanoporous energy absorption composite material

Abstract Nanofluidic energy absorption materials (NEAs) represent smart and efficient energy absorption composite materials in the ever-growing application of advanced protective structures. In this paper, an integrated experimental and molecular dynamics simulation study is conducted on the NEAs (ZSM-5/water) to investigate the tunable strategy of mechanical performance and energy absorption by considering the microstructural, mechanical, and thermal factors. The results demonstrate that the NEAs is an efficient and tunable liquid spring-like volume memory material. The typical NEAs show superior energy absorption capacity, achieving a specific energy absorption of 5.17 J/cm³ and an energy absorption ratio of 1.14 J/cm³ per cycle. Compared with insensitivity of the loading rate, the solid-fluid mass ratio is confirmed to significantly affect energy absorption performance, with an optimal ratio of approximate 1. Temperature is validated as an effective in-situ tunable parameter for NEAs in terms of both infiltration and energy absorption properties, with only slight effect on exfiltration. The critical infiltration pressure and specific energy absorption decrease by 23% and 40% as temperature increase from 25°C to 80°C. The gas-fluid interaction based energy absorption mechanism under high temperatures is proposed according to the comparison between experimental results and molecular dynamics simulations. The findings in this work will provide novel materials solutions for the intelligent energy absorption protective structures.

A lattice-mechanical metamaterial with tunable two-step deformation, tunable stiffness, tunable energy absorption and programmable properties

Abstract Mechanical metamaterials have attracted much attention in recent years because of excellent properties. However, most mechanical metamaterials have only a relatively fixed and single deformation mode. Although some multi-step deformation metamaterials have been proposed, their rich static and dynamic mechanical properties have yet to be studied in depth. Therefore, a lattice-mechanical metamaterial is introduced in this study. Under vertical compression, different unit cells under the same architecture can achieve two or three steps of deformation, respectively. Metamaterials built from these unit cells can also achieve the same properties. These properties can exist in multiple directions and are not affected by the number of unit cells. In addition, this metamaterial not only has adjustable two-step deformation, adjustable stiffness, and adjustable energy absorption properties but it can also be spatially programmed by changing geometric parameters and tessellation. Finally, a 3D design version of the metamaterial is provided, and its conceptual application is briefly demonstrated. The developed metamaterial can achieve more static and dynamic mechanical properties while taking into account two-step deformation. This can provide richer content for the development of mechanical metamaterials and also provide new perspectives for the application of energy absorbers, aerospace, and industrial products.

Materials and Structures Used in Aeronautics: Present and Future Perspectives

In recent years, significant advancements have been made in the development of novel materials for aeronautic applications. This effort aims to reduce costs by extending the operational life of structural and engine components, improving fuel economy, load capacity, and flight range. This paper investigates metallic materials such as aluminum alloys, titanium alloys, magnesium alloys, steels, nickel superalloys, and metal matrix composites (MMCs), providing an overview of recent advancements and highlighting current challenges and future perspectives in aeronautic metals. Several crucial factors are considered when selecting materials for aviation applications. These materials must withstand various environmental conditions, including humidity and temperature, as well as mechanical stresses such as tension, compression, bending, cyclic loads, creep, and torsion. The selection process is complicated by the wide range of available materials and the numerous variables involved, with cost being a critical factor in making an informed decision. In aviation, the most significant material characteristics are strength combined with lightness and stability in the operating environment. Trial and error can be costly in this context, necessitating well-planned design and engineering to ensure resistance to aerodynamic forces during flight. This approach has drawn the interest of aircraft designers since the inception of the Boeing 747, which utilized 1.3% composite materials. Modern aircraft, such as the Airbus A380 and Boeing 787, now incorporate 25% and 50% composite structures, respectively. Research has increasingly focused on enhancing the efficiency of structural engineering and material development through the use of sandwich structures. These structures are valued for their excellent stiffness-to-weight ratios and impact energy absorption properties. A typical sandwich structure consists of two thin, rigid face layers bonded to a core material. While various core materials like balsa and foam have been used in aviation, the honeycomb structure is the most prevalent. Honeycomb core configurations, including hexagon, reinforced hexagon, rectangle, flex-core, and square cell, primarily serve to support normal loads in the longitudinal direction and shear loads along the transverse axis.

Impact resistance of polyvinyl alcohol-polypropylene fiber toughened foamed concrete under low-velocity impact: experiments and 3D meso-scale modelling

Foamed concrete exhibits good energy absorption and shock absorption properties due to its microporous structure. Compared with conventional concrete, foamed concrete can more readily enter the plastic stage and more effectively reflect and absorb impact energy. However, a scientific deficit of knowledge about the impact resistance of foamed concrete with various hardeners and there is a lack of accurate verified models of such a process. In this study, the impact resistance of polyvinyl alcohol-polypropylene fiber toughened foamed concrete under different impact speeds and different amounts of polyvinyl alcohol has been investigated using the cube drop weight impact test. The toughening mechanism of polyvinyl alcohol is revealed through XRD analysis. In addition, 3D meso-scale modelling of a composite material composed of foam, mortar, an interface transition zone and fiber was conducted using the Python-based secondary development of Abaqus to simulate impact resistance. The results have demonstrated that the impact resistance (ultimate bearing capacity, total absorbed energy and dynamic increase factor) of the toughened foamed concrete samples initially increased and subsequently decreased with the addition of polypropylene fiber and polyvinyl alcohol. At the impact speed of 1.6m/s, compared with ordinary foamed concrete, the ultimate bearing capacity of polyvinyl alcohol polypropylene fiber toughened foamed concrete is increased by 107.8%, the total absorbed energy is increased by 119.7%, and the dynamic increase coefficient is increased by 31.6%; At the impact speed of 2.0m/s, compared with ordinary foamed concrete, the ultimate bearing capacity of polyvinyl alcohol polypropylene fiber toughened foamed concrete is increased by 134.2%, the total absorbed energy is increased by 87.9%, and the dynamic increase coefficient is increased by 50%. The simulation results are in good agreement with the test results, establishing that 3D meso-scale modelling modeling can accurately describe the impact resistance test of foamed concrete. It is further confirmed that 3D meso-scale modelling is reliable for predicting the impact resistance of polymer-fiber toughened foamed concrete.

The Impact of the Geometry of Cellular Structure Made of Glass-Filled Polyamide on the Energy-Absorbing Properties of Design Elements

The Impact of the Geometry of Cellular Structure Made of Glass-Filled Polyamide on the Energy-Absorbing Properties of Design Elements

Analyzing vibration transmission through cantilever systems using biomechanical and impact-responsive metamaterial structures

Vibration control in cantilever systems is a critical challenge in various engineering applications, where unwanted vibrations can lead to structural fatigue, reduced performance, and potential failure. This study investigates the effects of integrating biomechanical and impact-responsive metamaterials into cantilever systems to mitigate vibration transmission. The metamaterials, characterized by their adaptive stiffness and energy-absorbing properties, are strategically embedded in key structural components such as the arms, joints, and base. Through experimental analysis, this work assesses the reduction in vibration amplitude, shifts in natural frequency, enhanced damping capacity, energy absorption during impact, and strain reduction at critical points. The results show that the metamaterial-enhanced system achieves significant reductions in vibration amplitude, up to 40%, and increases in natural frequency by over 30%, minimizing the risk of resonance. Additionally, the damping ratio is improved by as much as 53%, while the energy absorption during impact is increased by up to 26%. Strain reduction at critical points reaches 24%, contributing to improved mechanical resilience. These findings demonstrate the potential of biomechanical and impact-responsive metamaterials in enhancing the dynamic performance of cantilever systems, offering a new approach to vibration mitigation in engineering applications.

Combining Micro and Macro Relative Density: An Experimental and Computational Study on Hierarchical Porous 3D‐Printed Polylactic Acid Structures

Polymer foams and cellular solids have gained significant interest due to their enhanced properties. This study introduces a novel approach by employing foamed fused filament fabrication printing of cellular solids. A composite polylactic acid filament containing chemical blowing agents is used to create structures with varying micro relative density, which is examined through scanning electron microscopy and tensile testing, with comparisons made to a Mori Tanaka analytical model and representative volume elements investigation. Two different types of cellular solid structures, specifically body‐centered cubic and Gyroid triple periodic minimal surface structures, have been created with different thicknesses and printed at various temperatures. This is done to attain a range of micro‐ and macroporosity, leading to samples with equal total relative densities. Compression tests, coupled with finite element analysis, provide insights into the influence of each type of porosity. The fabricated specimens exhibit compressive strengths ranging from 1.07 to 79.14 MPa and elastic moduli ranging from 0.064 to 3.35 GPa. The findings suggest that porous structures relying on macroporosity exhibit higher compressive strength, while those relying on microporosity demonstrate more appealing energy absorption properties, particularly under stresses approaching the plateau region.

Shape recovery effect and energy absorption of reusable honeycomb structures

When using auxetic honeycomb structures to create repeatable energy-absorbing components, a key challenge is selecting the appropriate unit configuration for effective functional integration. In this work, four typical honeycomb structures were prepared, and the mechanical behaviors, shape recovery effects, and energy absorption properties of three types of auxetic honeycomb structures re-entrant honeycomb (RH), arrow honeycomb (AH), and star honeycomb (SH) were compared with those of hexagonal honeycomb (HH) through quasi-static loading–unloading tests. The findings indicate that the 3D printed polyurethane (TPU) honeycomb structures demonstrate robust shape recovery, stable energy absorption, notable stress softening characteristics. The recovery behaviors can be characterized by three distinct phases, namely hyperelastic, transitional, and viscoelastic. The unit configuration significantly influences the shape recovery capability, with apparent elastic modulus and stability of the energy absorption efficiency determining the overall shape recovery capability. The loading method also affects the energy absorption and dissipation patterns in different honeycomb structures. In terms of specific energy absorption (SEA), AH has the highest rating, with RH and SH at 86 % and 50 % of the SEA of AH respectively. The number of reusable cycles is primarily dictated by the specific configuration of the unit type. In scenarios involving reusability, the energy absorption capacity of the TPU honeycomb can only reach 70 % of its original energy absorption capacity. This study may inform the application of auxetic materials in reusable energy absorbers.

Additive manufactured 3D re-entrant auxetic structures for enhanced impact resistance

Abstract This study presents a novel exploration of the geometric parameters within a 3D re-entrant auxetic lattice structure, specifically focusing on their unique impact energy absorption properties, which were systematically evaluated through drop weight impactor testing. Each lattice configuration was additively manufactured using stereolithography, allowing for precise control over strut thickness (t), re-entrant angle (θ), and the aspect ratio (h/l) of unit cells during both low and high energy impact scenarios. This study found that the overall auxetic behavior is predominantly controlled by the aspect ratio of the cell ribs, while the modulus is governed by rib thickness. A finite element model was subsequently developed to simulate the experimental impact loading conditions and was used to examine a wider range of parameters that were not experimentally tested. The simulated dynamic test results displayed the deformation trends and changes to the Poisson's ratio. Among the studied parameters, experimental results highlighted that a lattice structure with t = 1.6 mm, θ = 65°, and a h/l ratio = 1.8 exhibited the highest specific energy absorption (SEA) under uniaxial impact deformation with 5 Joules of impact energy. Conversely, when employing 20 Joules of impact energy revealed the greatest SEA at t = 1.0 mm, θ = 65°, and an h/l ratio of 2.2. The results demonstrate unique deformation mechanism of auxetic structures under impact loading and the capacity to adapt the 3D re-entrant lattice structure for applications requiring tailored impact energy absorption.

Viscoelastic negative stiffness metamaterial with multistage load bearing and programmable energy absorption ability

ABSTRACT The mechanical properties of negative stiffness (NS) metamaterial could be customized and tuned in a wide range for various requirements, achieving programmable performances by the design from the aspect of structure and material. This work investigates the viscoelastic NS metamaterial based on double curved beams using a combined approach of experiments, simulations, and analytical modeling with an emphasis on multistage loading bearing and programmable energy absorption ability. Numerical simulations are first implemented based on the finite element models of three types of metamaterial cells, which provide comparisons of load bearing and energy absorption properties. Further, the effects of geometric parameters of multistage metamaterial element and the mechanisms are analyzed. An analytical discrete model is then innovatively developed to provide straightforward understandings of the geometric effects and reveal the role of viscoelasticity by examining the instantaneous loading responses and rate-dependent behaviors. Experimentally, we fabricate the metamaterial samples using 3D-printing technique and perform compression tests to validate the properties based on different boundary conditions, loading rates and cyclic loading and unloading. Results of this work show the potential of wide programmable room for mechanical properties through structure and functional material design, such as multistage load bearing capacity and energy absorption ability.

3D-printable Kresling-embedded honeycomb metamaterials with optimized energy absorption capability

Abstract Kresling origami structure has attracted significant interest for achieving extraordinary mechanical properties. In this study, we proposed a new strategy to develop 3D-printable Kresling-embedded honeycombs (KEHs) based mechanical metamaterials and achieve optimized mechanical energy absorption capability. By exploiting the twisted deformation modes and boundary constraints, various KEH reinforced metamaterials were designed, where their deformation behaviors and energy absorption properties were investigated using finite element analysis and quasi-static compression tests. Effects of orientation twisting angle, boundary constraint and crease tilting angle on the deformation behaviors of these KEH reinforced metamaterials were studied to optimize their energy absorption properties. Finally, deformation behaviors and energy absorption properties of KEH reinforced metamaterials incorporated of KEH arrays in both 2D structure and 3D structures were studied. Both experimental and simulation results showed that the proposed KEH reinforced metamaterials achieved much more stable compression behaviors and higher energy absorption capabilities than those of the traditional honeycomb structures. This study provides a novel KEH reinforcement strategy for 3D printed metamaterials with optimized energy absorption capabilities to dramatically expand their practical applications.

Investigation of dynamic impact behavior of bighorn sheep horn

The horn of the bighorn sheep is composed of keratin-based biological material that has a tubule-lamella structure, which gives it anisotropic hardening properties under impact loading. This paper aims to investigate the energy dissipation mechanisms inherent in bighorn sheep horns by developing a numerical material model that accounts for the horn’s anisotropic features and strain-rate effects. To this end, a transversely isotropic constitutive model, which includes both anisotropic hardening and strain-rate effects, was formulated to accurately predict the mechanical behavior of bighorn sheep horns. Material characterization was conducted through uniaxial compression tests that were conducted under quasi-static and dynamic conditions. The developed constitutive model was implemented into LS-Dyna via a user-defined material subroutine and was validated against empirical data. The validated numerical model was used to investigate the horn’s mechanical responses under dynamic loading conditions. The paper focused on impact energy dissipation mechanisms, including energy absorption and transition, stress distribution, and displacement wave propagation. The insights gained from this paper are expected to significantly contribute to the development of novel artificial materials with enhanced energy absorption and impact mitigation properties.

Recent Advances in Additive Manufacturing of Fibre-Reinforced Materials: A Comprehensive Review

Additive manufacturing (AM) plays a significant role in the 4th Industrial Revolution due to its flexibility, allowing AM equipment to be connected, monitored, and controlled in real time. In advance, the minimum waste of material, the agility of manufacturing complex geometries, and the ability to use recycled materials can provide an advantage to this manufacturing method. On the other hand, the poor strength and durability of the thermoplastics used in the manufacturing process are the major drawback that keeps AM behind common production methods such as casting and machining. Fibre-reinforced polymers can enhance mechanical properties, advance AM from the commonly used polymers, and make AM competitive against conventional production methods. The main focus of the current review is to examine the work conducted in the field of reinforced additively manufactured technologies in the literature of recent years. More specifically, this review discusses the conducted research in the composite fibre coextrusion (CFC) additive manufacturing techniques developed over the past years and the materials that can be used. In addition, this study includes an up-to-date comprehensive review of the evaluation of fibre-reinforced 3D printing along with its benefits in terms of mechanical response, namely tensile, flexural, compression and energy absorption, anisotropy, and dynamic properties. Finally, this review highlights possible research gaps regarding fibre-reinforced AM and proposes future directions, such as deeper investigations into energy absorption and anisotropy, to position fibre-reinforced AM as a preferred fabrication method for ready-to-use parts in cutting-edge industries, including automotive, aerospace, and biomedical sectors.

Optimized design of energy absorption of aluminum foam filled CFRP thin-walled square tube based on agent model

PurposeAluminum foam-filled thin-walled unit structures have received much attention for their excellent energy absorption properties. To improve the energy absorption effect of car energy absorption box under axial compression, this paper optimizes the fiber lay-up sequence, fiber angle and aluminum foam density of aluminum foam filled carbon fiber reinforced plastic (CFRP) thin-walled square tubes.Design/methodology/approachDesign of sample points required to construct the proxy model using design of experiments (DOE) method, and the data sample points of different models are obtained through Abaqus simulation and test. A double high-precision proxy model with the maximum specific energy absorption (SEA) and the minimum initial peak crash force (PCF) as the evaluation index is constructed based on the response surface function method. The NSGA-II multi-objective genetic algorithm was used to optimize the design parameters and obtain the optimal solution for the Pareto front, and the results were verified by using the multi-objective optimization toolbox in design-expert.FindingsThe results show that the optimal solution to the multi-objective optimization problem with the inclusion of the lay-up sequence is ρ = 0.5g/cm3 for a fiber lay-up angle varying in the range ±15–90° and an aluminum foam density varying in the range 0.2g/cm3-0.5g/cm3, with a lay-up method of [±87°/±16°/±15°/±89°]. The two optimization methods correspond to SEA and PCF errors of 2.109% and 4.1828%, respectively. The optimized SEA value is 18.2 J/g and the PCF value is 18,230 N. The optimized design reduces the peak impact force and increases the specific energy absorption, which improves the energy absorption effect of thin-walled energy-absorbing boxes for automobiles.Originality/valueIn this paper, the impact resistance of CFRP thin-walled square tubes filled with aluminum foam is optimized. Based on numerical simulations and experiments to obtain the sample point data for constructing the dual-agent model, we investigate the effect of filling with different densities of aluminum foam under the simultaneous change of fiber lay-up angle and order on its mechanical properties in this process, and carry out the multi-objective optimization design with NSGA-II algorithm.

Study on the energy absorption characteristics of multi-spherical point-contact cushioning components

Abstract Under the impact load, the weak parts in the structure are prone to damage, leading to the failure of the whole equipment to work properly. Selecting appropriate cushioning materials to resist impact is a commonly used technical method. Generally, the cushioning efficiency of cushioning materials is proportional to their thickness. For structures with unlimited space, the impact resistance can be improved by increasing the thickness of cushioning materials. However, for structures with limited space, ductile metals are generally selected as cushioning materials to absorb energy through plastic deformation. In this paper, a cushioning component with a multi-spherical point contact structure is designed and processed with ductile metal. Energy absorption properties of the structure under the same impact load with different spherical diameters and numbers are studied based on the Split Hopkinson Pressure Bar (SHPB) test. The test results show that under the same impact load, the larger the spherical diameter is, the smaller the impact deformation is. Energy absorption efficiency is proportional to the number and diameter of the spheres. The maximum energy absorption of the 4×Sϕ6 spherical structure is 26.6J, with an energy absorption rate of 37.3%. The research results provide guidance for the design of cushioning components under impact load.

Design method for individualised 3D printed lattice shoe midsoles

Additive manufacturing has enabled the production of individualised 3D printed shoe soles with improved properties. A promising approach is to use lattice structures that have high energy absorption properties and low weight. A design method of a cellular shoe midsole with optimised strut diameters of lattice structures is proposed. The shoe sole model is obtained by re-modelling a 3D scan of a foot to ensure a customised fit. The optimisation of strut thicknesses is based on a simplified stress distribution acting on the shoe sole during walking or running, using finite element simulations. Therefore, the optimal strut thickness for each region of the sole can be determined and adjusted. Two types of lattice structures with different topology and thus significant variations in stiffness are chosen, resulting in a wide range of required strut thicknesses. The developed design process allowed for the creation of a 3D printed shoe sole with improved strut thicknesses and a customised fit. The resulting cellular shoe soles are additively manufactured and experimental compressive tests are conducted to investigate the mechanical behaviour and differences between the shoe soles with the corresponding lattice types. The results show that both shoe soles have a similar behaviour under compression. The design tool developed has the potential to improve foot health and comfort, especially for people with foot problems, as all parameters affecting the performance of a shoe sole can be adjusted. However, more research is needed to fully understand the durability and performance of these shoe soles in real-world conditions.

Enhanced energy absorption and mechanical properties of porous Ti-6Al-4 V alloys with gradient disordered cells fabricated by laser powder bed fusion

Additive manufacturing (AM) has revolutionized the production of porous metals, greatly improving control over their structural properties and offering unprecedented advantages in lightweight applications and energy absorption. Balancing energy absorption and compressive strength in ordered and disordered porous structures is challenging due to shear deformation and deformation mechanisms. This study investigates the mechanical and energy absorption properties of porous Ti-6Al-4 V alloys with gradient disordered cells fabricated using laser powder bed fusion (LPBF). The compressive response of samples with different regularities (R) and varying layers of disordered cells was analyzed through quasi-static compression experiments and finite element simulations. The results indicate that introducing a disordered cell gradient significantly enhances energy absorption by preventing the formation of shear bands observed in porous structures with ordered cell structures. When the regularity (R) is 0.8, 0.4, and 0.2 with one or two layers of disordered cells, mechanical properties are optimized and characterized by a balance between compressive strength and energy absorption. It is significant that, while preserving or enhancing compressive strength, the energy absorption of the material can be augmented substantially. Specifically, porous Ti-6Al-4 V (R = 0.8, L4) achieves an energy absorption increase of up to 154.9kJ/m³, which represents a dramatic enhancement of approximately 245.0 % over the regular porous structure (R = 0 or L0), which absorbs only 44.9 kJ/m³. Compared to ordered and disordered porous structures, the disordered cell gradient demonstrates significant potential in tuning the mechanical properties of porous metals, thereby advancing their applications in aerospace, biomedical, and protective fields.

Optimizing energy absorption and peak force in metal/glass fiber sandwich panels with trapezoidal cores

Sandwich panels with trapezoidal metal/glass fiber cores are increasingly popular due to their lightweight and energy-absorption properties. This study employs response surface methodology (RSM) and Box-Behnken design to investigate the effects of core angle, fiber orientation, and MCM-48 nanoparticles on the panels’ energy absorption and peak force, developing regression models with high R2 values of 0.9027 and 0.9228, respectively. Experimental tests were conducted to validate these models, showing minimal deviation from predicted values. Results indicate that increasing the fiber orientation angle from 30° to 90° enhances energy absorption and peak force by 72.18 and 46.9%, respectively, and adding MCM-48 nanoparticles up to 0.25% weight improves energy absorption by 60.8%. A core angle of 52° balances energy absorption and peak force, while integrating a metal wire mesh within the panels significantly enhances energy absorption and reduces core brittleness. The optimal parameters for maximum energy absorption and minimum peak force include a core angle of 58°, fiber orientation of 73.5°, and no nanoparticles. These findings provide valuable insights into the design and optimization of sandwich panels for various applications.

Enhancing sports mouthguards with PLA + and PC: stress reduction, energy absorption, and topology optimization.

The objective of this paper was to compare the effectiveness of different materials for mouthguards in preventing oral and maxillofacial injuries during sports activities. The present study compares the stress-reduction and energy absorption capabilities of two other fused filament materials - poly(lactic-acid plus) (PLA+) and polycarbonate (PC), with Ethylene-vinyl acetate (EVA), which is the most commonly used material for mouthguard fabrication. Two human skulls were modelled, and a boxing glove simulated punches along the x, y, and z-axes with 5mm displacement with 1 kN force. Firstly, the maximum principal stress curve in the skull was compared for forces along the three perpendicular directions. Furthermore, the present study examines materials energy absorption properties, including their specific energy absorption characteristics and initial peak von Mises stresses. Additionally, a topology optimization approach is used to create an alternative design for a mouthguard to improve specific energy absorption. The model without a mouthguard showed the highest stress concentration of 32.298MPa in the teeth, followed by the EVA material, which resulted in a maximum principal stress of 28.525MPa. Fused filament 3D materials, such as PLA + and PC, on the other hand, showed better mechanical effectiveness in both lower jaw dislocation and lower maximum principal stress by 30.82% and 51.25% in the mandibular and maxillary teeth. Though EVA comparatively shows better specific energy absorption capability at 2.24kJ/kg post-optimization than PLA + and PC, the peak principal stress experienced in the mandibular region was comparatively higher. The topology optimization, however, improved the energy-absorbing capabilities of PLA + by 4.5 times, reaching 1.37kJ/kg and PC from 0.165kJ/kg to 0.38kJ/kg. This study demonstrates that PLA + and PC have better stress reduction capabilities than EVA and could be promising materials for the fabrication of mouthguards in sports activities. This study highlights the importance of topology optimization in dental materials science and engineering to develop safer and more effective mouthguard designs.

Experimental and Numerical Evaluation of Calcium-Silicate-Based Mineral Foam for Blast Mitigation

Cellular materials such as aluminum and polyurethane foams are recognized for their effectiveness in energy absorption. They commonly serve as crushable cores in sacrificial cladding for blast mitigation purposes. This study delves into the effectiveness of autoclaved aerated concrete (AAC), a lightweight, porous material known for its energy-absorbing properties as a crushable core in sacrificial cladding. The experimental set-up features a rigid frame made of steel measuring 1000 × 1000 × 15 mm3 with a central square opening (300 × 300 mm2) holding a 2 mm thick aluminum plate representing the structure. The dynamic response of the aluminum plate is captured using two high-speed cameras arranged in a stereoscopic configuration. Three-dimensional digital image correlation is used to compute the transient deformation fields. Blast loading is achieved by detonating 20 g of C4 explosive set at 250 mm from the plate’s center. The study assesses the mineral foam’s absorption capacity by comparing out-of-plane displacement and mean permanent deformation of the aluminum plate with and without the protective solution. Six foam configurations (A to F) are tested experimentally and numerically, varying in the foam’s free space for expansion relative to its total volume. Results show positive protective effects, with configuration F reducing maximum deflection by at least 30% and configuration C by up to 70%. Foam configuration influences energy dissipation, with an optimal lateral surface-to-volume ratio (ζ) enhancing protective effects, although excessive ζ leads to non-uniform foam crushing. To address the influence of front skin deformability, a non-deformable front skin has been adopted. The latter demonstrates an increased effectiveness of the sacrificial cladding, particularly for ζ values above the optimal value obtained when using a deformable front skin. Notably, using a non-deformable front skin increases maximum deflection reduction and foam energy absorption by up to approximately 30%.