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.

Experimental and numerical study on the crashworthiness evaluation of an intercity coach under frontal impact conditions

2020 ◽  
Vol 234 (13) ◽  
pp. 3026-3041 ◽  
Author(s):  
Mehmet Ali Güler ◽  
Muhammed Emin Cerit ◽  
Sinem Kocaoglan Mert ◽  
Erdem Acar
Keyword(s):  
Finite Element ◽  
Energy Absorption ◽  
Numerical Study ◽  
Absorption Capacity ◽  
The Body ◽  
Steering Wheel ◽  
Energy Absorption Capacity ◽  
Bus Structure ◽  
Bus Body ◽  
Absorption Characteristics

In this study, the energy absorption capacity of a front body of a bus during a frontal crash was investigated. The strength of the bus structure was examined by considering the ECE-R29 European regulation requirements. The nonlinear explicit finite element code LS-DYNA was used for the crash analyses. First, the baseline bus structures without any improvements were analyzed and the weak parts of the front end structure of the bus body were examined. Experimental tests are conducted to validate the finite element model. In the second stage, the bus structure was redesigned in order to strengthen the frontal body. Finally, the redesigned bus structure was compared with the baseline model to meet the requirements for ECE-R29. In addition to the redesign performed on the body, energy absorption capacity was increased by additional energy absorbers employed in the front of bus structure. This study experimentally and numerically investigated the energy absorption characteristics of a steering wheel armature in contact with a deformable mannequin during a crash. Variations in the location of impact on the armature, armature orientation, and mannequin were investigated to determine the effects of the energy absorption characteristics of the two contacting entities.

Energy-Based Crashworthiness Optimization for Multiple Vehicle Impacts

2004 ◽  
Author(s):  
H. Fang ◽  
K. Solanki ◽  
M. F. Horstemeyer
Keyword(s):  
Finite Element ◽  
Energy Absorption ◽  
Absorption Capacity ◽  
Full Scale ◽  
Side Impact ◽  
Frontal Impact ◽  
Vehicle Model ◽  
Energy Absorption Capacity ◽  
Side Impacts ◽  
Design Variables

In this paper, we use a full-scale finite element vehicle model of a 1996 Dodge Neon in simulating two types of vehicle crashes, offset-frontal and side impacts. Based on an analysis of the vehicle’s histories of internal energy absorption under both impacts, we select twenty components as design variables in the optimization of the vehicle’s weight without decreasing the vehicle’s energy absorption capacity and energy absorption rate. We use the second-order polynomials in creating the metamodels for the response functions of energy absorption under both impacts. The optimization result shows a significant reduction on the total weight of the selected components. The LS-DYNA MPP v970 and a full-scale finite element vehicle model of 320,872 nodes and 577,524 elements are used in the simulations. A simulation of 100 ms offset-frontal impact takes approximately 17 hours with 36 processors on the IBM Linux SuperCluster, which has a total of 1038 Intel Pentium III 1.266 GHz processors and 607.5 GB RAM. A simulation of 100 ms side impact takes approximately 29 hours with the same condition as the offset-frontal simulation.

scholarly journals An experimental study on the bending response of multi-layered fibre-metal-laminates

2019 ◽  
Vol 53 (18) ◽  
pp. 2579-2591 ◽  
Author(s):  
M Kuhtz ◽  
N Buschner ◽  
T Henseler ◽  
A Hornig ◽  
M Klaerner ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Structural Response ◽  
High Energy ◽  
Light Metal ◽  
Absorption Capacity ◽  
Structural Behaviour ◽  
Energy Absorption Capacity ◽  
Fibre Metal Laminates ◽  
Test Parameters ◽  
Fibre Metal

The combination of thin light metal sheets with fibre-reinforced thermoplastic layers in multi-layered fibre-metal-laminates advantageously combines the properties of both material classes. In this way, components can be developed which have both significantly increased specific properties (strength and stiffness with respect to density) and high energy absorption capacity compared with conventional design with mono materials. However, the structural behaviour of crash structures is decisively determined by material behaviour of the thermoplastic and metal constituents as well as the interface properties between both constituents and the corresponding delamination behaviour. To evaluate the structural response of multi-layered fibre-metal-laminates under highly dynamic loading conditions, Charpy tests were performed, where the test parameters, light metal material configuration, support length and laminate thickness, were varied. Moreover, the metal sheet surfaces were pre-treated by embossing to achieve different surface topologies. The influence of the different test parameters on the specific energy absorption capacity was characterised by the analysis of force–displacement curves.

Energy Absorption Capacity of Expanding Tube with Fiber-Reinforcement

2014 ◽  
Vol 626 ◽  
pp. 57-61
Author(s):  
Gin Boay Chai ◽  
Guo Xing Lu
Keyword(s):  
Finite Element ◽  
Energy Absorption ◽  
Reaction Force ◽  
Three Dimensional ◽  
Absorption Capacity ◽  
Finite Element Analyses ◽  
Absorption Mechanism ◽  
Energy Absorption Capacity ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Abstract. This contribution presents the investigation of energy absorption mechanism of metal tubes and composite-wrapped metal tubes subjected to a diametric deformation via an expansion process. In the experiments, the expansion of the tubes was performed under quasi-static loading using a conical-cylindrical expansion die. The experimental results are repeatable and thus reliable. An extensive finite element analyses and experimental investigation were carried out in parallel. Both two-dimensional and three-dimensional finite element models were created based on the actual experimental geometrical and material parameters. Results from the finite element analyses correlate rather well with the experimental data. Glass fibre-wrapped metal tubes showed an increased steady-state reaction force which in turn reflects better specific energy absorption capacity for every layer of composite wrapped as compared to bare metal tubes.

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 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.

Crashworthiness optimization of hierarchical hexagonal honeycombs under out-of-plane impact

2020 ◽  
pp. 095440622093910
Author(s):  
M Altin ◽  
E Acar ◽  
MA Güler
Keyword(s):  
Finite Element ◽  
Energy Absorption ◽  
Specific Energy ◽  
Numerical Study ◽  
Absorption Capacity ◽  
Optimization Approach ◽  
Energy Absorption Capacity ◽  
Specific Energy Absorption ◽  
Honeycomb Structures ◽  
Out Of Plane

This paper presents a numerical study of regular and hierarchical honeycomb structures subjected to out-of-plane impact loading. The specific energy absorption capacity of honeycomb structures via nonlinear explicit finite element analysis is investigated. The constructed finite element models are validated using experimental data available in the literature. The honeycomb structures are optimized by using a surrogate-based optimization approach to achieve maximum specific energy absorption capacity. Three surrogate models polynomial response surface approximations, radial basis functions, and Kriging models are used; Kriging models are found to be the most accurate. The optimum specific energy absorption value obtained for hierarchical honeycomb structures is found to be 148% greater than that of regular honeycomb structures.

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