Ultralight X-type lattice sandwich structure (I): Concept, fabrication and experimental characterization

Abstract

A new type of ultra-lightweight metallic lattice structure (named as the X-type structure) is reported. This periodic structure was formed by two groups of staggered struts in the traditional pyramid structure, and fabricated by folding expanded metal sheet along rows of offset nodes and then brazing the folded structure (as the core) with top and bottom facesheets to form sandwich panels. The out-ofplane compressive and shear properties of the X-type lattice sandwich structure were investigated experimentally and compared to those of the sandwich having a pyramidal truss core. It is found that the formation of the 2-dimensional staggered nodes can effectively make the X-type structure more resistant to inelastic and plastic buckling under both compression and shear loading than the pyramidal lattice truss. Obtained results show that the compressive and shear peak strengths of the X-type lattice structure are about 30% higher than those of the pyramidal lattice truss having the same relative density. sandwich panel, lattice structure, X-type structure, brazing, plastic yielding

Development of multifunctional lightweight cellular metals through interdisciplinary efforts

“…The base materials that have been considered include pure aluminum and its alloys, stainless steel, pure copper and its alloys, FeCrAlY, etc. The types of cellular metal reported in Science in China E include aluminum foams with closed cells [2] , sintered FeCrAlY foams with open cells [3,4] , phononic crystals [5] , pin-reinforced foams [6] , and lattice metals [7,8] . The development of these materials is not only to master the relevant fabrication technologies, but also to further address fundamental issues related to their processing, properties and practical applications using a combination of experimental, theoretical and numerical approaches.…”

“…We also proposed a new type of metallic lattice truss structure (i.e., the X-type structure) as the core for constructing sandwich panels [7] , which was fabricated by folding expanded metal sheets along rows of offset nodes and then brazing to facesheets. Both the compressive and shear peak strengths of the X-structure were found to be about 30% higher than those of the pyramidal structure.…”

An X-type lattice cored ventilated brake disc with enhanced cooling performance

“…These two lattices can be fabricated by folding an identical metal sheet with the same set of moulds. However, the X-type lattice is mechanically superior, providing approximately 30% higher peak compressive and shear strengths for a given relative density (or porosity) [50,51].…”

Novel strengthening methods for ultralightweight sandwich structures with periodic lattice cores

“…Recently, considerably more attention has been paid to solving the mass production and cost issues, which has, therefore, led to an interest in the development of alternative approaches such as the triaxially woven helical wires [9] and the expanded metal sheet folding methods [10,11]. Besides, in terms of mechanical performance, the further strengthening of lattice materials fabricated with existing technologies is also considered important.…”

“…For example, it has been established both experimentally [12] and theoretically [13] that the mechanical performance of a Kagome lattice structure is superior to that of a tetragonal lattice structure having the same relative density. Also, we recently proposed [11] a new type of topology for constructing flat or curved lattice-cored sandwich structures, namely, the X-type structure, which is formed by two groups of staggered struts in the traditional pyramidal lattice structure, and fabricated by folding expanded metal sheets along rows of offset nodes and then brazing the folded structure (as the core) with top and bottom facesheets. Both the out-of-plane compressive and shear properties of the X-type lattice structure were found experimentally as well as theoretically to outperform those of the pyramidal lattice structure [11,14].…”