scholarly journals Dynamic Compressive Behaviors of Two-Layer Graded Aluminum Foams under Blast Loading

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1445 ◽  
Author(s):  
Minzu Liang ◽  
Xiangyu Li ◽  
Yuliang Lin ◽  
Kefan Zhang ◽  
Fangyun Lu
Keyword(s):  
Energy Absorption ◽  
Aluminum Foam ◽  
Blast Resistance ◽  
Blast Loading ◽  
Deformation Energy ◽  
Aluminum Foams ◽  
Conflicting Objectives ◽  
Energy Dissipated ◽  
Transmitted Impulse ◽  
Energy Absorbing

Experimental and numerical analyses were carried out to reveal the behaviors of two-layer graded aluminum foam materials for their dynamic compaction under blast loading. Blast experiments were conducted to investigate the deformation and densification wave formation of two-layer graded foams with positive and negative gradients. The shape of the stress waveform changed during the propagation process, and the time of edge rising was extended. Finite element models of two-layer graded aluminum foam were developed using the periodic Voronoi technique. Numerical analysis was performed to simulate deformation, energy absorption, and transmitted impulse of the two-layer graded aluminum foams by the software ABAQUS/Explicit. The deformation patterns were presented to provide insights into the influences of the foam gradient on compaction wave mechanisms. Results showed that the densification wave occurred at the blast end and then gradually propagated to the distal end for the positive gradient; however, compaction waves simultaneously formed in both layers and propagated to the distal end in the same direction for the negative gradient. The energy absorption and impulse transfer were examined to capture the effect of the blast pressure and the material gradient. The greater the foam gradient, the more energy dissipated and the more impulse transmitted. The absorbed energy and transferred impulse are conflicting objectives for the blast resistance capability of aluminum foam materials with different gradient distributions. The results could help in understanding the performance and mechanisms of two-layer graded aluminum foam materials under blast loading and provide a guideline for effective design of energy-absorbing materials and structures.

The Dynamic Response of Sandwich Structures with Cellular Metallic Core under Blast Loading

2018 ◽  
Vol 933 ◽  
pp. 188-195 ◽  
Author(s):  
Yu Chen Guo ◽  
Gui Ping Zhao
Keyword(s):  
Energy Absorption ◽  
Sandwich Structures ◽  
Blast Resistance ◽  
Hollow Spheres ◽  
Blast Loading ◽  
Dynamic Responses ◽  
Face Sheet ◽  
Outer Face ◽  
Aluminum Foams ◽  
Finite Element Software

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.

scholarly journals Quasi-Static Compression Deformation and Energy Absorption Characteristics of Basalt Fiber-Containing Closed-Cell Aluminum Foam

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 921 ◽  
Author(s):  
Donghui Yang ◽  
Zichen Zhang ◽  
Xueguang Chen ◽  
Xing Han ◽  
Tao Xu ◽  
...  
Keyword(s):  
Pore Size ◽  
Energy Absorption ◽  
Cell Walls ◽  
Aluminum Foam ◽  
Pure Aluminum ◽  
Present Condition ◽  
Aluminum Foams ◽  
Commercially Pure ◽  
Closed Cell ◽  
Absorption Characteristics

In this work, closed-cell aluminum foams with 4 wt.% contents of short-cut basalt fibers (BFs) were successful prepared by using the modified melt-foaming method. The pore size of BF-containing aluminum foam and commercially pure aluminum foam was counted. The distribution of BF and its effect on the compressive properties of closed-cell aluminum foams were investigated. The results showed that the pore size of BF-containing aluminum foams was more uniform and smaller. BF mainly existed in three different forms: Some were totally embedded in the cell walls, some protruded from the cell walls, and others penetrated through the cells. Meanwhile, under the present condition, BF-containing aluminum foams possessed higher compressive strength and energy absorption characteristics than commercially pure aluminum foams, and the reasons were discussed.

scholarly journals Anisotropic Compressive Behavior of Functionally Density Graded Aluminum Foam Prepared by Controlled Melt Foaming Process

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2470 ◽  
Author(s):  
Bingbing Zhang ◽  
Shuangqi Hu ◽  
Zhiqiang Fan
Keyword(s):  
Energy Absorption ◽  
Aluminum Foam ◽  
Image Correlation ◽  
Lateral Strain ◽  
Transverse Compression ◽  
Deformation Bands ◽  
Aluminum Foams ◽  
Static Compression ◽  
Plateau Stress ◽  
Foaming Process

Aluminum foams with a functionally graded density have exhibited better impact resistance and a better energy absorbing performance than aluminum foams with a uniform density. Nevertheless, the anisotropic compression behavior caused by the graded density has scarcely been studied. In this paper, a density graded aluminum foam (FG) was prepared by a controlled foaming process. The effect of density anisotropy on the mechanical behavior of FGs was investigated under quasi-static compression and a low-velocity impact. Digital image correlation (DIC) and numerical simulation techniques were used to identify deformation mechanisms at both macro and cell levels. Results show that transverse compression on FGs lead to a higher collapse strength but also to a lower energy absorption, due to the significant decrease in densification strain and plateau stress. The deformation behavior of FGs under longitudinal compression was dominated by the progressive extension of the deformation bands. For FGs under transverse compression, the failure mode of specimens was characterized by multiple randomly distributed deformation bands. Moreover, the transverse compression caused more deformation on cells, through tearing and lateral stretching, because of the high lateral strain level in the specimens. It was concluded that the transverse compression of FGs lead to a lower plateau stress and a lower cell usage, thus resulting in a poorer energy absorption efficient; this constitutes a key factor which should be taken into consideration in structural design.

scholarly journals Dynamic Response and Optimal Design of Curved Metallic Sandwich Panels under Blast Loading

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Chang Qi ◽  
Shu Yang ◽  
Li-Jun Yang ◽  
Shou-Hong Han ◽  
Zhen-Hua Lu
Keyword(s):  
Dynamic Response ◽  
Energy Absorption ◽  
Sandwich Panel ◽  
Blast Resistance ◽  
Blast Loading ◽  
Outer Face ◽  
Air Blast ◽  
Blast Response ◽  
Artificial Neural Network Ann ◽  
Air Blast Loading

It is important to understand the effect of curvature on the blast response of curved structures so as to seek the optimal configurations of such structures with improved blast resistance. In this study, the dynamic response and protective performance of a type of curved metallic sandwich panel subjected to air blast loading were examined using LS-DYNA. The numerical methods were validated using experimental data in the literature. The curved panel consisted of an aluminum alloy outer face and a rolled homogeneous armour (RHA) steel inner face in addition to a closed-cell aluminum foam core. The results showed that the configuration of a “soft” outer face and a “hard” inner face worked well for the curved sandwich panel against air blast loading in terms of maximum deflection (MaxD) and energy absorption. The panel curvature was found to have a monotonic effect on the specific energy absorption (SEA) and a nonmonotonic effect on the MaxD of the panel. Based on artificial neural network (ANN) metamodels, multiobjective optimization designs of the panel were carried out. The optimization results revealed the trade-off relationships between the blast-resistant and the lightweight objectives and showed the great use of Pareto front in such design circumstances.

Dissolution Method of Aluminum Foams Containing Mg Using Carbamide Space Holder

2017 ◽  
Vol 888 ◽  
pp. 373-376
Author(s):  
Amirah Ahmad Hamdi ◽  
Nurul Akmal Mohd Sharif ◽  
Anasyida Abu Seman
Keyword(s):  
Energy Absorption ◽  
Aluminum Foam ◽  
Aluminium Foam ◽  
Aluminum Foams ◽  
Dissolution Method ◽  
Space Holder

This study investigated the properties of aluminium foam containing Mg with various amount of space holder. Aluminum foam was fabricated using dissolution method with various amount of carbamide (20, 40 and 60 wt. %). Aluminum foam with 60 wt. % carbamide has the lowest density (0.68 g/cm3) and exhibited the highest porosity (74.97%). However, the results indicates that aluminum foam with 40 wt. % of carbamide have good compressive and energy absorption with acceptable density and porosity value.

Quasi-Static Crushing of Aluminum Foam-Filled Thin-Walled Aluminum Tubes

2018 ◽  
Vol 933 ◽  
pp. 209-214
Author(s):  
Yang Yu ◽  
Zhuo Kun Cao ◽  
Min Li ◽  
Hong Jie Luo
Keyword(s):  
Cell Size ◽  
Energy Absorption ◽  
Aluminum Foam ◽  
Cell Structure ◽  
Peak Load ◽  
Aluminum Foams ◽  
Static Compression ◽  
Aluminum Tubes ◽  
Foam Filling ◽  
Foam Filled

The effect of aluminum foams with different cell structure on the quasi-static compression behavior and energy absorption of aluminum tubular structures was investigated. For comparison, empty tubes and aluminum foams with different cell structure were also tested, respectively. The results indicated that the value of crushing peak load of aluminum foam-filled tubes increases from 57.88% (1.94mm cell size) to 89.33% (1.22mm cell size) respectively compared with 2.83mm cell size. Splitting deformation of foam filling was found to effect in increasing the extra contact between the foam filling and the tube during progressive crushing, which increases the lateral compressive forces on the tubes. The energy absorption of aluminum foams filled aluminum tubes was also improved significantly due to the change of cell structure.

Fabrication and characterization of hypoeutectic open-cell Al-Si foams using gravity die casting and squeeze casting

2018 ◽  
Vol 115 (5) ◽  
pp. 509 ◽  
Author(s):  
Samsudin Fitri Aida ◽  
Mirsad Nur Hijrah ◽  
Amirah Ahmad Hamdi ◽  
Hussain Zuhailawati ◽  
Abu Seman Anasyida
Keyword(s):  
Energy Absorption ◽  
Aluminum Foam ◽  
Squeeze Casting ◽  
Die Casting ◽  
Compression Tests ◽  
Open Cell ◽  
Space Holder ◽  
Absorption Energy ◽  
Energy Absorbing

Gravity die casting and squeeze casting are the techniques used for the fabrication of hypoeutectic open-cell Al-Si foams which are characterized and studied for their energy absorbing quality in compression tests. The effect of different amounts of sodium chloride (NaCl) (up to 56 vol.%) as a space holder in the casting of aluminum foam on the morphology, density, porosity, compressive and energy absorption properties of aluminum foam was studied. The hypoeutectic Al-Si alloy with NaCl particles as a space holder was used to fabricate the aluminum foam using gravity die casting and squeeze casting. The hypoeutectic open-cell Al-Si foams produced by squeeze casting showed smaller pore size, better pore distribution, higher porosity, good compressive strength and greater energy absorption energy compared to that of gravity die casting. The hypoeutectic open-cell Al-Si foams with 44 vol.% NaCl using squeeze casting showed the best properties among all foams due to its moderate and well-distributed porosity.

scholarly journals An analytical model of linear density foam–protected structure under blast loading

2017 ◽  
Vol 8 (3) ◽  
pp. 454-472 ◽  
Author(s):  
Ye Xia ◽  
Chengqing Wu ◽  
Terry Bennett
Keyword(s):  
Energy Absorption ◽  
Analytical Model ◽  
Linear Density ◽  
Blast Resistance ◽  
Blast Loading ◽  
Maximum Energy ◽  
Absorption Capacity ◽  
Aluminium Foam ◽  
Structural Deformation ◽  
Reinforced Concrete Structure

Aluminium foam is widely known as an energy absorptive material which can be used as a protective cladding on structures to enhance blast resistance of the protected structures. Previous studies show that higher density provides larger energy absorption capacity of aluminium foam, but results in a larger transmitted pressure to the protected structure. To lower the transmitted pressure without sacrificing the maximum energy absorption, graded density foam has been examined in this study. An analytical model is developed in this article to investigate the protective effect of linear density foam on response of a structure under blast loading. The model is able to simulate structural deformation with reasonable accuracy compared with experimental data. The sensitivity of density gradient of foam cladding on reinforced concrete structure is tested in the article.

NUMERICAL STUDY OF BLAST-RESISTANT SANDWICH PANELS WITH ROTATIONAL FRICTION DAMPERS

2013 ◽  
Vol 13 (06) ◽  
pp. 1350014 ◽  
Author(s):  
WENSU CHEN ◽  
HONG HAO
Keyword(s):  
Energy Absorption ◽  
Sandwich Panel ◽  
Numerical Study ◽  
Blast Resistance ◽  
Sandwich Panels ◽  
Blast Loading ◽  
Blast Loads ◽  
Friction Damper ◽  
Energy Absorber ◽  
Blast Energy

Blast-resistant structures are traditionally designed with solid materials of huge weight to resist blast loads. This not only increases the construction costs, but also undermines the operational performance. To overcome these problems, many researchers develop new designs with either new materials or new structural forms, or both to resist the blast loads. Friction damper, as a passive energy absorber, has been used in earthquake-resistant design to absorb vibration energy from cyclic loading. The use of friction damper in blast-resistant design to absorb high-rate impact and blast energy, however, has not been well explored. This study introduces a new sandwich panel equipped with rotational friction hinge device with spring (RFHDS) between the outer and inner plates to resist the blast loading. This device RFHDS, as a special sandwich core and energy absorber, consists of rotational friction hinge device (RFHD) and spring. The RFHD is used to absorb blast energy while the spring is used to restore the original shape of the panel. This paper studies the mechanism of RFHD by using theoretical derivation and numerical simulations to derive its equivalent force–displacement relation and study its energy absorption capacity. In addition, the energy absorption and blast loading resistance capacities of the sandwich panel equipped with RFHDS are numerically investigated by using Ls-Dyna. It is found that the proposed sandwich panel can recover, at least partially its original configuration after the loading and thus maintain its operational and blast-resistance capability after a blasting event. In order to maximize the performance of the proposed sandwich panel, parametric calculations are carried out to study the performance of RFHDS and the sandwich panels with RFHDS. The best performing sandwich panel with RFHDS in resisting blast loadings is identified. This sandwich panel configuration might be employed to mitigate blast loading effects in structural sandwich panel design.

scholarly journals Theoretical Analysis of Blast Protection of Graded Metal Foam-Cored Sandwich Cylinders/Rings

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3903 ◽  
Author(s):  
Minzu Liang ◽  
Xiangyu Li ◽  
Yuliang Lin ◽  
Kefan Zhang ◽  
Fangyun Lu
Keyword(s):  
Finite Element ◽  
Energy Absorption ◽  
Metal Foam ◽  
Blast Resistance ◽  
Structural Response ◽  
Blast Loading ◽  
Absorption Capacity ◽  
Analytical Models ◽  
Face Sheet ◽  
Energy Absorption Capacity

The blast resistance of a sandwich-walled cylinder/ring comprising two metal face-sheets and a graded metal foam core, subjected to internal air blast loading, is investigated. Analytical models are developed for the deformation of the sandwich cylinder with positive and negative gradient cores under internal blast loading. The deformation process is divided into three distinct phases, namely the fluid–structure interaction phase, core-crushing phase, and outer face-sheet deformation phase. Finite element modeling is performed using the Voronoi material model. The proposed analytical models are verified through finite element analysis, and reasonable agreement is observed between the analytical predictions and finite element results. The sandwich structures with high energy absorption capacity or low maximum radial deflection are satisfied for the protecting purpose of impact/blast resistance requirements. Typical deformation processes are classified and analyzed; the effects of explosive charge, face-sheet thickness, and core gradient on the structural response are also examined. The results indicate that both the deformation modes and the structural response of the cylinders are sensitive to the blast charge and core configuration. It is concluded that energy absorption capacity and maximum radial deflection are two conflicting goals for achieving high impact/blast resistance capability. An in-depth understanding of the behavior in sandwich-walled cylinders under blast impulse and the influence of the core configuration helps realize the advantages and disadvantages of using graded foam materials in sandwich structures and can provide a guideline for structural design.

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