scholarly journals Application of Foldcore Sandwich Structures in Helicopter Subfloor Energy Absorption Structure

2017 ◽  
Vol 248 ◽  
pp. 012033 ◽  
Author(s):  
H Z Zhou ◽  
Z J Wang
Keyword(s):  
Energy Absorption ◽  
Sandwich Structures

scholarly journals The energy absorption behavior of novel composite sandwich structures reinforced with trapezoidal latticed webs

2021 ◽  
Vol 60 (1) ◽  
pp. 503-518
Author(s):  
Juan Han ◽  
Lu Zhu ◽  
Hai Fang ◽  
Jian Wang ◽  
Peng Wu
Keyword(s):  
Bearing Capacity ◽  
Energy Absorption ◽  
Sandwich Structure ◽  
Ultimate Load ◽  
Sandwich Structures ◽  
Elastic Displacement ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Composite Sandwich ◽  
Composite Sandwich Structures

Abstract This article proposed an innovative composite sandwich structure reinforced with trapezoidal latticed webs with angles of 45°, 60° and 75°. Four specimens were conducted according to quasi-static compression methods to investigate the compressive behavior of the novel composite structures. The experimental results indicated that the specimen with 45° trapezoidal latticed webs showed the most excellent energy absorption ability, which was about 2.5 times of the structures with vertical latticed webs. Compared to the traditional composite sandwich structure, the elastic displacement and ultimate load-bearing capacity of the specimen with 45° trapezoidal latticed webs were increased by 624.1 and 439.8%, respectively. Numerical analysis of the composite sandwich structures was carried out by using a nonlinear explicit finite element (FE) software ANSYS/LS-DYNA. The influence of the thickness of face sheets, lattice webs and foam density on the elastic ultimate load-bearing capacity, the elastic displacement and initial stiffness was analyzed. This innovative composite bumper device for bridge pier protection against ship collision was simulated to verify its performance. The results showed that the peak impact force of the composite anti-collision device with 45° trapezoidal latticed webs would be reduced by 17.3%, and the time duration will be prolonged by about 31.1%.

Numerical and experimental investigation for enhancing the energy absorption capacity of the novel three-dimensional printed sandwich structures

2021 ◽  
pp. 146442072199749
Author(s):  
H Geramizadeh ◽  
S Dariushi ◽  
S Jedari Salami
Keyword(s):  
Energy Absorption ◽  
Sandwich Structures ◽  
Three Dimensional ◽  
Absorption Capacity ◽  
The Novel ◽  
Energy Absorption Capacity ◽  
Fused Deposition ◽  
Honeycomb Sandwich ◽  
Out Of Plane ◽  
Vertical Walls

The current study focuses on designing the optimal three-dimensional printed sandwich structures. The main goal is to improve the energy absorption capacity of the out-of-plane honeycomb sandwich beam. The novel Beta VI and Alpha VI were designed in order to achieve this aim. In the Beta VI, the connecting curves (splines) were used instead of the four diagonal walls, while the two vertical walls remained unchanged. The Alpha VI is a step forward on the Beta VI, which was promoted by filleting all angles among the vertical walls, created arcs, and face sheets. The two offered sandwich structures have not hitherto been provided in the literature. All models were designed and simulated by the CATIA and ABAQUS, respectively. The three-dimensional printer fabricated the samples by fused deposition modeling technique. The material properties were determined under tensile, compression, and three-point bending tests. The results are carried out by two methods based on experimental tests and finite element analyses that confirmed each other. The achievements provide novel insights into the determination of the adequate number of unit cells and demonstrate the energy absorption capacity of the Beta VI and Alpha VI are 23.7% and 53.9%, respectively, higher than the out-of-plane honeycomb sandwich structures.

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.

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.

The compressive properties and strengthening mechanism of the middle-trabecular beetle elytron plate

2018 ◽  
Vol 22 (4) ◽  
pp. 948-961 ◽  
Author(s):  
Jinxiang Chen ◽  
Xindi Yu ◽  
Mengye Xu ◽  
Yoji Okabe ◽  
Xiaoming Zhang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Energy Absorption ◽  
Sandwich Structures ◽  
Strengthening Mechanism ◽  
Absorption Capacity ◽  
Compressive Properties ◽  
Energy Absorption Capacity ◽  
Standard Energy

For the development of new types of lightweight sandwich structures, the compressive properties and strengthening mechanism of the middle-trabecular beetle elytron plate were investigated for various values of η (the ratio of the trabecular radius to the honeycomb wall length). The results are as follows: (1) When η = 0.1, the increases in the compressive strength and standard energy absorption capacity of the middle-trabecular beetle elytron plate compared with the honeycomb plate exceed those of the end-trabecular beetle elytron plate; with an increase to η = 0.15, the compressive strength remains nearly the same, the energy absorption capacity undergoes a significant further increase, and the trabeculae exhibit Φ-type failure. (2) The strengthening mechanism that gives rise to the compressive properties of the middle-trabecular beetle elytron plate is proposed as follows: the trabeculae are located at the center of the honeycomb walls, where the maximum deformations would otherwise occur; they constrain the deformation of the honeycomb walls; and the number of trabeculae in the middle-trabecular beetle elytron plate also exceeds that in the end-trabecular beetle elytron plate. (3) Middle-trabecular beetle elytron plates have the advantage of facile manufacturing, which will establish a basis for promoting the application of beetle elytron plates.

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.

Experimental study of ballistic resistance of sandwich targets with aluminum face-sheet and graded foam core

2018 ◽  
Vol 22 (2) ◽  
pp. 461-479 ◽  
Author(s):  
A Alavi Nia ◽  
M Kazemi
Keyword(s):  
Energy Absorption ◽  
Sandwich Structures ◽  
Single Layer ◽  
Average Density ◽  
Face Sheet ◽  
Foam Core ◽  
Ballistic Limit ◽  
Ballistic Resistance ◽  
Damaged Zone ◽  
The Impact

In this research, we have investigated the ballistic resistance of sandwich structures with aluminum face-sheet and graded polyurethane foam core with different densities. The effects of graded changes of core foam density and the effect of the sequence of foam layers with different densities on energy absorption and ballistic limit of sandwich structures under the impact of hemispherical nose projectiles at high speeds (160 to 300 m/s) are studied. The results of this study showed that increasing the density and thickness of the foam core leads to increase in the ballistic limit and energy absorption; also, the ballistic limit of sandwich structures with the same mass with graded foam core for three- and five-layer panels is, respectively, 10.37 and 5.57% more than single-layer foam core with the average density in case the foam layer with less density is placed in the impact side. By using the graded foam core (laminate), the core resistance is increased and the damaged zone shape is changed, and the energy absorption of back face-sheet is increased.

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