Design of Sandwich Panels With Prismatic Cores

2005 ◽  
Vol 128 (2) ◽  
pp. 186-192 ◽  
Author(s):  
Z. Wei ◽  
F. W. Zok ◽  
A. G. Evans

The paper focuses on optimization of lightweight sandwich panels with prismatic cores subject to bending loads in the two principal in-plane directions. Comparisons are made with optimal designs of panels with corrugated cores: a limiting case. When optimized for loading transverse to the prism axis, prismatic panels outperform those with corrugated cores, especially at lower loads. In contrast, when optimized for longitudinal loading, the corrugated core panel is always superior. Both panels exhibit significant anisotropy: a deficiency mediated by optimizing jointly for both orientations. The designs emerging from joint optimizations have only slightly lower load capacity than those optimized singly, but with the benefit of equal strengths in the two principal directions. Moreover, jointly optimized corrugated and prismatic panels perform equally well. Both are competitive with honeycomb core panels, especially at high load capacities. With the additional potential for multifunctionality (notably active cooling), the corrugated panels appear to be particularly promising thermostructural elements.

Author(s):  
Shah Alam ◽  
Damodar Khanal

Abstract The goal of this paper is to analyze the impact behavior among geometrically different sandwich panels shown upon impact velocities. Initially, composite model with aluminum honeycomb core and Kevlar (K29) face sheets is developed in ABAQUS/Explicit and different impact velocities are applied. Keeping other parameters constant, model is simulated with T800S/epoxy face sheets. Residual velocities, energy absorption (%), and maximum deformation depth is calculated for sandwich panel for both models at five different velocities by executing finite element analysis. Once the better material is found for face sheets, process is extended by varying the ratio of front face sheet thickness to back face sheet thickness keeping other geometrical parameters constant to find the better geometry. Also, comparison of impact responses of sandwich composite panel on different ratio of front face sheet thickness to back face sheet thickness is done and validated with other results available in literature.


Author(s):  
Sam E. Calisch ◽  
Neil A. Gershenfeld

Honeycomb sandwich panels are widely used for high performance parts subject to bending loads, but their manufacturing costs remain high. In particular, for parts with non-flat, non-uniform geometry, honeycombs must be machined or thermoformed with great care and expense. The ability to produce shaped honeycombs would allow sandwich panels to replace monolithic parts in a number of high performance, space-constrained applications, while also providing new areas of research for structural optimization, distributed sensing and actuation, and on-site production of infrastructure. Previous work has shown methods of directly producing shaped honeycombs by cutting and folding flat sheets of material. This research extends these methods by demonstrating work towards a continuous process for the cutting and folding steps of this process. An algorithm for producing a manufacturable cut-and-fold pattern from a three-dimensional volume is designed, and a machine for automatically performing the required cutting and parallel folding is proposed and prototyped. The accuracy of the creases placed by this machine is characterized and the impact of creasing order is demonstrated. Finally, a prototype part is produced and future work is sketched towards full process automation.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yong Xiao ◽  
Yefa Hu ◽  
Jinguang Zhang ◽  
Chunsheng Song ◽  
Xiangyang Huang ◽  
...  

The aim of this paper was to investigate bending responses of sandwich panels with aluminium honeycomb core and carbon fibre-reinforced plastic (CFRP) skins used in electric vehicle body subjected to quasistatic bending. The typical load-displacement curves, failure modes, and energy absorption are studied. The effects of fibre direction, stacking sequence, layer thickness, and loading velocity on the crashworthiness characteristics are discussed. The finite element analysis (FEA) results are compared with experimental measurements. It is observed that there are good agreements between the FEA and experimental results. Numerical simulations and experiment predict that the honeycomb sandwich panels with ±30° and ±45° fibre direction, asymmetrical stacking sequence (45°/−45°/45°/−45°), thicker panels (0.2 mm∼0.4 mm), and smaller loading velocity (5 mm/min∼30 mm/min) have better crashworthiness performance. The FEA prediction is also helpful in understanding the initiation and propagation of cracks within the honeycomb sandwich panels.


2014 ◽  
Vol 590 ◽  
pp. 58-62 ◽  
Author(s):  
Hugo Miguel Silva ◽  
José Filipe Bizarro de Meireles

Sandwich geometries, mainly panels and beams are widely used in several transportation industries, namely aerospace, aeronautic and automotive. Sandwich geometries are known for their advantages in structural applications: high specific stiffness, low weight, and possibility of design optimization prior to manufacturing. This study aims to know the influence of the number of reinforcements (ribs), and of the thickness on the mechanical behavior of sandwich panels subjected to bending and torsion loads separately. In this study, 3 geometries are compared: simple web-core beam, corrugated core, and honeycomb core. The last 2 are asymmetric, due to the use of odd number of ribs. The influence of the geometry on the results is discussed, by means of a parameter that establishes a relation between the stiffness behavior and the mass of the object. It is shown that the all relations are non-linear, despite the elastic nature of the analysis, by means of the application of loads with low intensity.


2013 ◽  
Vol 2013 ◽  
pp. 1-20 ◽  
Author(s):  
Chang Qi ◽  
Shu Yang ◽  
Dong Wang ◽  
Li-Jun Yang

The dynamic responses of honeycomb sandwich panels (HSPs) subjected to in-plane projectile impact were studied by means of explicit nonlinear finite element simulations using LS-DYNA. The HSPs consisted of two identical aluminum alloy face-sheets and an aluminum honeycomb core featuring three types of unit cell configurations (regular, rectangular-shaped, and reentrant hexagons). The ballistic resistances of HSPs with the three core configurations were first analyzed. It was found that the HSP with the reentrant auxetic honeycomb core has the best ballistic resistance, due to the negative Poisson’s ratio effect of the core. Parametric studies were then carried out to clarify the influences of both macroscopic (face-sheet and core thicknesses, core relative density) and mesoscopic (unit cell angle and size) parameters on the ballistic responses of the auxetic HSPs. Numerical results show that the perforation resistant capabilities of the auxetic HSPs increase as the values of the macroscopic parameters increase. However, the mesoscopic parameters show nonmonotonic effects on the panels' ballistic capacities. The empirical equations for projectile residual velocities were formulated in terms of impact velocity and the structural parameters. It was also found that the blunter projectiles result in higher ballistic limits of the auxetic HSPs.


2011 ◽  
Vol 261-263 ◽  
pp. 770-774
Author(s):  
Dong Ruan ◽  
Mohd Azman Yahaya ◽  
James Hicks ◽  
Jayson Lloyd ◽  
Feng Zhu

Sandwich panels consisting of two aluminium two face-sheets and a core made of aluminium honeycomb were studied in this paper. These sandwich panels are good candidates for cladding systems employed to protect other structures again blast loadings. In this paper, the mechanical response and deformation of these sandwich panels subjected to simulated blast loadings are investigated experimentally. The effects of impact pulse, foil thickness and cell size of aluminium honeycombs have been discussed.


2008 ◽  
Vol 42 (4) ◽  
pp. 385-412 ◽  
Author(s):  
K.S. Raju ◽  
B.L. Smith ◽  
J.S. Tomblin ◽  
K.H. Liew ◽  
J.C. Guarddon

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