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Mechanical Behaviour of Sandwich Composites in Automotive Applications
Published in Mohamed Thariq Hameed Sultan, Murugan Rajesh, Kandasamy Jayakrishna, Repair of Advanced Composites for Aerospace Applications, 2022
Amol Bhanage, Saurabh Bait, Ramesh Sakhare
The sandwich composite structure consists of a core of low strength and two thin skin or face sheets of high strength. The thin face sheets or skins are made from metal alloys, or polymer sheet or fibre reinforced composites. The core is thick, made of materials such as polymer or metal foam, honeycomb, balsa wood, web core, etc. This core and face sheets are bonded together to facilitate the load transfer mechanism. The most common core materials are thermoset polymer foams to accomplish high temperature tolerances, although thermoplastic foams are used in all applications. The most common are polyurethane (PUR), polyvinyl chloride (PVC), polymethacryl-imide (PMI), polyetherimide (PEI), polyphenols (PF) and polystyrenes (PS). From these, PMI and PEI are high performance cores used in aerospace applications. Honeycomb structures are known for low weight and high bending stiffness and are widely used under tensile and bending loads. These structures are used in place of conventional materials under high loading. Honeycomb cores clearly dominate over alternative materials. These honeycomb cores are based on aluminum alloys, i.e., Al 3003, Al 2024, Al 5052, etc., and phenolic resin bathed aramid fibre paper, the latter under the trade name Nomex (K. F. Karlsson and Tomas Astrom 1997).
Hypersonic Aircraft
Published in G. Daniel Brewer, Hydrogen Aircraft Technology, 2017
The second structural concept, shown at the bottom of Figure 5–26, is an integral thermal insulation/tank structure which is made of a honeycomb sandwich with the core evacuated to provide the necessary insulative properties. Several different materials are candidates to be used for the honeycomb structure: titanium alloys, advanced powder metallurgy aluminum alloys, aluminides, and metal-matrix composites. Facesheets can be attached to the core by low temperature brazing or by adhesive bonding. Panels made of the resulting honeycomb structure would be welded together to form a structurally efficient, cryogenic fuel containment vessel.
Out-of-plane impact analysis for a bioinspired sinusoidal honeycomb
Published in Mechanics of Advanced Materials and Structures, 2022
Xiaolin Deng, Shangan Qin, Jiale Huang
Honeycomb structures are widely used in the fields of energy absorption and protection [1]. Honeycomb structures are lightweight, have a long effective crushing distance, and absorb a large amount of kinetic energy during impact while maintaining a stable stress level. Varieties of different shapes of honeycombs have been designed, mainly including hexagonal [2], reentrant hexagonal [3], reentrant star-shaped [4], reentrant star-arrowhead [5], multicell [6], chiral [7], series-connected parallograms auxetic [8], square [9], circular [10], tetrachiral [11], horseshoe [12], star [13], hierarchical honeycombs [14–16] and the comparison of the crashworthiness for different honeycomb structures also has been carried out [17, 18]. Its structural form mainly includes the honeycomb sandwich structure [19, 20], and filled honeycomb structures are obtained by filling thin-walled structures [21, 22]. In recent years, some novel three-dimensional honeycomb structures have also been designed and studied. For example, Andrew et al. [23, 24] proposed three different types of three-dimensional honeycomb structures and manufactured the corresponding samples using additive manufacturing technology. The crushing behaviors and energy absorption characteristics under low-velocity impact have also been systematically studied.
Research on out-of-plane impact characteristics of self-similar gradient hierarchical quasi-honeycomb structure
Published in International Journal of Crashworthiness, 2022
Xiang Li, Mingjie Cai, Ruibo He, Xingxing Xu
With the increasing attention to the passive safety protection of structures in the engineering field, the collision problem has become an important topic in engineering field. The research on the dynamic behavior of structures during collisions and design energy absorbing buffer structures with higher impact resistance has great significance in engineering. Honeycomb structure has many characteristics, such as lightweight, high specific strength, high specific stiffness and excellent energy absorption, widely applied in aerospace, automobile and ship, armor protection and other important fields. Therefore, it is very urgent to study honeycomb impact characteristics. At present, hexagonal honeycomb structures [1], square honeycomb structures [2] and triangular honeycomb structures [3] are the most common honeycomb structures in the engineering field, which usually consist of a single type of cellular elements arranged periodically.
Experimental and numerical analysis of flexural and impact behaviour of glass/pp sandwich panel for automotive structural applications
Published in Advanced Composite Materials, 2018
M.A. Khan, A.K. Syed, H. Ijaz, R.M.B.R. Shah
Advanced composite materials such as honeycomb sandwich structures attracted automotive industry to produce lightweight structures. Honeycomb structures allow producing lightweight, high strength, high stiffness structures with relative high out-of-plane compression and shearing properties. Consequently, application of these materials in automotive structural applications results in decrease in weight without compromising structural safety and increase in fuel efficiency and reduction in CO2 emissions. A composite sandwich panel is typically consists of a core made of honeycomb-shaped polymeric material and two thin face sheets of high-performance fibre-reinforced composite are bonded or fused together to form an efficient load-carrying assembly. The laminated skins carry tensile and compression loading, while the core provides the transverse shear resistance and increases the second moment of area of the whole structure [1]. A sandwich panel subjected to bending or transverse load creates compressive and tensile stresses on the top and bottom skins, respectively, and shear stresses in the core. Therefore, for sandwich panels, it is critical to consider such complex stresses within the structure and resulting damage mechanisms for intended applications.