Numerical Simulation on Response of Foam Core Sandwich Panels Subjected to Underwater Explosion

2016 ◽  
Author(s):  
Dongjie Ai ◽  
Yuansheng Cheng ◽  
Jun Liu ◽  
Jianhu Liu ◽  
Haikun Wang ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Sandwich Structures ◽  
Near Field ◽  
Sandwich Panels ◽  
Underwater Explosion ◽  
Core Material ◽  
Design Parameters ◽  
Equal Weight ◽  
Core Height ◽  
Panel Thickness

Sandwich panel structures, which consist of two thin faces and low relative density cores, can significantly mitigate the possibilities of panel fractures. In the present paper, numerical simulations are conducted to study the deformation and fracture modes of sandwich structures under near-field underwater blasts and contact underwater blasts. Two different core materials are employed, namely aluminum foam and PVC foam. Main focus of this paper was placed to (i) study the failure mechanisms and energy absorption characteristics of sandwich structures in typical conditions, (ii) to demonstrate the benefits of such structures compared with solid plates of equal weight, and (iii) to obtain the properties of withstanding underwater explosion for single core material sandwich panels. In addition, the effects of panel thickness configuration and core height on deformation and energy absorption of the plates were explored. Results indicated that sandwich structures showed an effective reduction in the maximum panel deflection compared with a monolithic plate of same mass. The design parameters have great impacts on the results.

Low Velocity Impact Response of Composite/Sandwich Structures

2016 ◽  
Vol 725 ◽  
pp. 127-131 ◽  
Author(s):  
Kumar V. Akshaj ◽  
P. Surya ◽  
M.K. Pandit
Keyword(s):  
Sandwich Structures ◽  
Weight Ratio ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Core Material ◽  
Design Parameters ◽  
Low Velocity ◽  
Velocity Impact ◽  
Composite Sandwich ◽  
Set Up

Dent resistance of structures is one of the important design parameters to consider in automotive, aerospace, packaging and transportation of fragile goods, civil engineering and marine industries. It is important to study the dynamic impact response of various combinations of skin and core materials which can provide desired fracture toughness and highest strength to weight ratio for such applications. This paper discusses the low velocity impact response of sandwich structures having unique combination of mild steel as skin material bonded to thermoplastics/PU foam as core material. HDPE, LDPE and polypropylene were the choice of thermoplastics and an optimum combination of materials for the sandwich structure was evaluated using drop-weight experimental set up. It is observed that LDPE is the best choice of core material for the sandwich structures considered.

Ballistic resistance and energy absorption of honeycomb structures filled with reactive powder concrete prisms

2017 ◽  
Vol 19 (5) ◽  
pp. 544-571 ◽  
Author(s):  
Xiaochao Jin ◽  
Tao Jin ◽  
Buyun Su ◽  
Zhihua Wang ◽  
Jianguo Ning ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Sandwich Structures ◽  
Design Parameters ◽  
Reactive Powder Concrete ◽  
Velocity Range ◽  
Hexagonal Cell ◽  
Ballistic Resistance ◽  
Honeycomb Sandwich ◽  
Reactive Powder ◽  
The Impact

Two kinds of innovative re-entrant and hexagonal cell honeycomb sandwich structures filled with reactive powder concrete were proposed, and the ballistic resistance and energy absorption of the sandwich structures were investigated by numerical simulations. The deformation and failure modes of the different structures were analyzed and evaluated in detail. The honeycomb sandwich structures filled with reactive powder concrete prisms improved the capacity of ballistic resistance and energy absorption significantly, compared to the normal reactive powder concrete plates and sandwich structures without reactive powder concrete prisms. The analysis shows that the auxetic re-entrant cell honeycomb sandwich structures have a better ballistic performance than the hexagonal cell honeycomb sandwich structures. The sandwich structures were subjected to impact by three kinds of projectiles: flat, hemispherical and conical nosed. The ballistic limit of the flat nosed projectile is the highest, while the impact performance of the conical and hemispherical nosed projectiles is obviously different from the flat nosed projectile, especially in a relative high velocity range. The sharper nose leads to a higher value of exit velocity and mass loss. In addition, effects of different design parameters on ballistic resistance were also studied by changing the thickness of honeycomb cell and face plates. Results indicate that the thickness of honeycomb walls and face plates have significant effect on the ballistic resistance and energy absorption in a relative low velocity range, while there are no big differences when the initial impact velocity exceeds 400 m/s.

scholarly journals The Fluid-Solid Interaction Dynamics between Underwater Explosion Bubble and Corrugated Sandwich Plate

2016 ◽  
Vol 2016 ◽  
pp. 1-21
Author(s):  
Hao Wang ◽  
Yuan Sheng Cheng ◽  
Jun Liu ◽  
Lin Gan
Keyword(s):  
Shock Wave ◽  
Failure Modes ◽  
Sandwich Structures ◽  
Numerical Models ◽  
Near Field ◽  
Three Dimensional ◽  
Underwater Explosion ◽  
Bubble Collapse ◽  
Fe Model ◽  
Wave Load

Lightweight sandwich structures with highly porous 2D cores or 3D (three-dimensional) periodic cores can effectively withstand underwater explosion load. In most of the previous studies of sandwich structure antiblast dynamics, the underwater explosion (UNDEX) bubble phase was neglected. As the UNDEX bubble load is one of the severest damage sources that may lead to structure large plastic deformation and crevasses failure, the failure mechanisms of sandwich structures might not be accurate if only shock wave is considered. In this paper, detailed 3D finite element (FE) numerical models of UNDEX bubble-LCSP (lightweight corrugated sandwich plates) interaction are developed by using MSC.Dytran. Upon the validated FE model, the bubble shape, impact pressure, and fluid field velocities for different stand-off distances are studied. Based on numerical results, the failure modes of LCSP and the whole damage process are obtained. It is demonstrated that the UNDEX bubble collapse jet local load plays a more significant role than the UNDEX shock wave load especially in near-field underwater explosion.

scholarly journals Mechanical response of aluminum foam sandwich structure under impact load

2022 ◽  
Author(s):  
Wenke Lu ◽  
Junyan Zhang
Keyword(s):  
Energy Absorption ◽  
Mechanical Response ◽  
Impact Load ◽  
Layer Structure ◽  
Sandwich Panels ◽  
Absorption Efficiency ◽  
Shallow Shells ◽  
Double Layer Structure ◽  
Energy Absorption Efficiency ◽  
Panel Thickness

Abstract This study investigates the mechanical response of aluminum foam sandwich panels, sandwich cylindrical shells, and sandwich shallow shells under impact loads. First, a finite element model of the sandwich panel was established, and an impact load was applied. The numerical results were compared with theoretical and experimental results to verify the model's effectiveness. Second, the energy absorption efficiency and overall deformation of sandwich panels, sandwich cylindrical shells, and sandwich shallow shells under the same impact load were studied. The research shows that the energy absorption performance of the sandwich shells is better than that of the sandwich panels, and the overall deformation is less than that of the sandwich panels. The effect of increasing panel thickness on the two types of sandwich shell studies is based on this basis. The conclusions describe that increasing the panel thickness will significantly reduce the structure's energy absorption efficiency and deformation. Finally, the effect of single-and double-layer structure on the impact resistance of sandwich shells was studied when the total thickness of the sandwich structure was unchanged. The results show that compared with the single-layer structure, the energy absorption efficiency, overall deformation, and contact force between the projectile and structure of the double-layer structure will be reduced.

Lightweight Sandwich Structures in Innovative Vehicle Design under Crash Load Cases

2016 ◽  
Vol 879 ◽  
pp. 2419-2427 ◽  
Author(s):  
Simon M. Brückmann ◽  
Horst E. Friedrich ◽  
Michael Kriescher ◽  
Gundolf Kopp ◽  
Roman Gätzi
Keyword(s):  
Energy Absorption ◽  
Sandwich Structures ◽  
Core Material ◽  
Analytical Determination ◽  
Energetic Efficiency ◽  
Failure Behavior ◽  
Vehicle Concept ◽  
Lightweight Construction ◽  
Structural Applications ◽  
Core Materials

On modern vehicles, the demand is made to be in every respect as efficient as possible. A technical method to increase energetic efficiency is to reduce the vehicle mass through the implementation of lightweight construction measures. The energy consumption decreases by that and the vehicle dynamics behavior of conventionally and alternatively respectively electrically powered vehicles increases. In the department Lightweight and Hybrid Design Methods of the Institute of Vehicle Concepts in Stuttgart in collaboration with 3A Composite Core Materials, a method which allows to realize sandwich structures for automotive structural applications analytically and conceptually, is developed. The development method based on material and component testing and material values would be determined at different loads, for example in pressure and in-plane tests. These values are transmitted into the analytical determination of so called failure mode maps to derive appropriate sandwich structures. With novel sandwich structures the objectives of high structural stiffness and strength are tracked, as well as a high level of energy absorption potential. By function integrating the potential of lightweight construction, depending on the energy absorption per structural weight, can be further increased. Accompanying tests on generic structures are made to validate the failure behavior. Also the influence of core material on the deformation behavior is examined. The results from the tests are transferred to a vehicle front structure of a planned lightweight vehicle of class L7E called "Safe Light Regional Vehicle" (SLRV). The behavior of the structure is examined in static and dynamic tests. The energy absorbing capacity can be further increased by geometric optimization and the use of different core materials. The research on sandwich materials is part of the research project Next Generation Car (NGC) of the DLR and represents in terms of the new vehicle concept SLRV in sandwich design a novel vehicle concept of this joint project.

Large deformation of corrugated sandwich panels under three-point bending

2020 ◽  
pp. 109963622092765 ◽  
Author(s):  
Fukun Xia ◽  
Yvonne Durandet ◽  
T X Yu ◽  
Dong Ruan
Keyword(s):  
Energy Absorption ◽  
Specific Energy ◽  
Mechanical Response ◽  
Sandwich Panels ◽  
Deformation Mode ◽  
Theoretical Models ◽  
Peak Force ◽  
Specific Energy Absorption ◽  
Three Point Bending ◽  
Core Height

Corrugated sandwich panels are widely used in engineering applications for their excellent energy absorption and lightweight. In this research, the mechanical response of aluminum corrugated sandwich panels subjected to three-point bending is investigated experimentally, numerically, and theoretically. In the experiments, the sandwich panels were loaded under two conditions, namely base indentation and node indentation. A parametric study is conducted by ABAQUS/explicit to investigate the effects of geometric configurations (corrugation angle, core height, and core thickness) on the deformation mode, peak force, and energy absorption. Both peak force and specific energy absorption vary with the geometric parameters. Theoretical models are further developed to predict the force–displacement curves of the panels under the two loading conditions. The theoretically predicted crushing force is in good agreement with both the experimental and simulated results. Finally, the non-dominated sorting genetic algorithm II is adopted to optimize the geometric configuration to improve the specific energy absorption and reduce the weight of corrugated sandwich panels.

Wrinkling of Functionally Graded Sandwich Structures Subject to Biaxial and In-Plane Shear Loads

2017 ◽  
Vol 84 (12) ◽  
Author(s):  
Victor Birman ◽  
Harold Costa
Keyword(s):  
Uniaxial Compression ◽  
Sandwich Structures ◽  
Sandwich Panels ◽  
Shear Loading ◽  
Functionally Graded ◽  
Biaxial Compression ◽  
Equal Weight ◽  
Plane Shear ◽  
The Core ◽  
Shear Loads

Benefits of a functionally graded core increasing wrinkling stability of sandwich panels have been demonstrated in a recent paper (Birman, V., and Vo, N., 2017, “Wrinkling in Sandwich Structures With a Functionally Graded Core,” ASME J. Appl. Mech., 84(2), p. 021002), where a several-fold increase in the wrinkling stress was achieved, without a significant weight penalty, using a stiffer core adjacent to the facings. In this paper, wrinkling is analyzed in case where the facings are subject to biaxial compression and/or in-plane shear loading, and the core is arbitrary graded through the thickness. Two issues addressed are the effect of biaxial or in-plane shear loads on wrinkling stability of panels with both graded and ungraded core, and the verification that functional grading of the core remains an effective tool increasing wrinkling stability under such two-dimensional (2D) loads. As follows from the study, biaxial compression and in-plane shear cause a reduction in the wrinkling stress compared to the case of a uniaxial compression in all grading scenarios. Accordingly, even sandwich panels whose mode of failure under uniaxial compression was global buckling, the loss of strength in the facings or core crimpling may become vulnerable to wrinkling under 2D in-plane loading. It is demonstrated that a functionally graded core with the material distributed to increase the local stiffness in the interface region with the facings is effective in preventing wrinkling under arbitrary in-plane loads compared to the equal weight homogeneous core.

scholarly journals Experimental and modeling investigations of the behaviors of syntactic foam sandwich panels with lattice webs under crushing loads

2021 ◽  
Vol 60 (1) ◽  
pp. 450-465
Author(s):  
Zhilin Chen ◽  
Yu Zhang ◽  
Jun Wang ◽  
Hota GangaRao ◽  
Ruifeng Liang ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Energy Absorption ◽  
Sandwich Structures ◽  
Syntactic Foam ◽  
Sandwich Panels ◽  
Numerical Results ◽  
Fiber Reinforced Polymer ◽  
Fe Model ◽  
Fiber Reinforced ◽  
Reinforced Polymer

Abstract The composite sandwich structures with foam core and fiber-reinforced polymer skin are prone to damage under local impact. The mechanical behavior of sandwich panels (glass fiber-reinforced polymer [GFRP] skin reinforced with lattice webs and syntactic foams core) is studied under crushing load. The crushing behavior, failure modes, and energy absorption are correlated with the number of GFRP layers in facesheets and webs, fiber volume fractions of facesheets in both longitudinal and transverse directions, and density and thickness of syntactic foam. The test results revealed that increasing the number of FRP layers of lattice webs was an effective way to enhance the energy absorption of sandwich panels without remarkable increase in the peak load. Moreover, a three-dimensional finite-element (FE) model was developed to simulate the mechanical behavior of the syntactic foam sandwich panels, and the numerical results were compared with the experimental results. Then, the verified FE model was applied to conduct extensive parametric studies. Finally, based on experimental and numerical results, the optimal design of syntactic foam sandwich structures as energy absorption members was obtained. This study provides theoretical basis and design reference of a novel syntactic foam sandwich structure for applications in bridge decks, ship decks, carriages, airframes, wall panels, anticollision guard rails and bumpers, and railway sleepers.

Evaluation of the effect of core lattice topology on the properties of sandwich panels produced by additive manufacturing

2020 ◽  
pp. 146442072095801
Author(s):  
JG Monteiro ◽  
M Sardinha ◽  
F Alves ◽  
AR Ribeiro ◽  
L Reis ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Relative Density ◽  
Energy Absorption ◽  
Sandwich Structures ◽  
Sandwich Panels ◽  
Single Layer ◽  
Thin Plates ◽  
Two Dimensional ◽  
Finite Element Software ◽  
Manufacturing Technologies

Sandwich structures are frequently used in automotive, aerospace and marine industries, as they provide adequate functional properties. The two-dimensional regular hexagonal cell shape, i.e. honeycomb is the most used core structure in sandwich panels. Recently, a new type of cellular structures composed of lattice struts has been proposed, as they combine high stiffness, strength and energy absorption with low weight. The main purpose of this research is to investigate the effect of the lattice topology on the flexural behaviour of sandwich panels. Five lattice geometries inspired in crystalline structures were designed, namely, body-centred parallelepiped, body-centred parallelepiped with struts in z-axis, body- and face-centred parallelepiped with struts in z-axis, face-centred parallelepiped with struts in z-axis and parallelepiped simple. The relative density of all the lattices was kept constant as 0.3. Both numerical and experimental approaches were used to evaluate the flexural properties and failure behaviour of the sandwich structures under three-point bending tests. The numerical analysis was undertaken with the finite element software NX Nastran. Taking advantage of additive manufacturing technologies, material extrusion was used to produce polylactic acid samples with the configurations aforementioned. The sandwich panels are composed by a single layer formed by the lattice core and two thin plates, at the bottom and top. The three parts of the panel were manufactured all together. The simulation results indicate that, among the lattices studied, topologies body-centred parallelepiped with struts in z-axis and body- and face-centred parallelepiped with struts in z-axis exhibit higher strength, while body- and face-centred parallelepiped with struts in z-axis shows higher stiffness and higher energy absorption, attaining values that do not differ much from the ones obtained with a two-dimensional hexagonal cellular structure, with the same relative density. As a consequence, some of the geometries studied may have the potential to be considered as alternatives to conventional structures in the design of sandwich structures.

Dynamic Response of Sandwich Panels With Functionally Graded Aluminum Foam Cores Subjected to Underwater Explosion

2016 ◽  
Author(s):  
Changzai Zhang ◽  
Pan Zhang ◽  
Jun Liu ◽  
Jianqiang Pan ◽  
Yanjie Zhao ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Energy Absorption ◽  
High Efficiency ◽  
Sandwich Panels ◽  
Underwater Explosion ◽  
Functionally Graded ◽  
Face Sheet ◽  
Permanent Displacement ◽  
Bottom Face ◽  
Stretching Deformation

Numerical investigations were conducted using the MSC.Dytran software on the dynamic response of functionally graded sandwich panels when subjected to underwater explosion. The effects of the number of layers and density distribution of graded cores on the blast performance were analyzed in several aspects under the constraint of equivalent mass. The simulation results have demonstrated that sandwich panels experience both bending and large plastic stretching deformation. Compared to single layered sandwich panel, those panels with graded cores overall possess smaller central permanent displacement and better energy absorption capability. Central deflection of bottom face sheet decreases as the density of cores descends from top to bottom face. A large proportion of the energy dissipates in the plastic deformation of top face sheet by the end of response, followed by the bottom face sheet, and core compression absorbers the minimum. Utilizing the high efficiency of energy absorption by adjusting those cores with greater density near to the top face sheet can further mitigate the damage from explosion.

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