A novel design of thin-walled energy absorption structures with local surface nanocrystallization

Optimization Design of an Embedded Multi-Cell Thin-Walled Energy Absorption Structures with Local Surface Nanocrystallization

“…It is of great significance to characterize the energy absorbed by structure and how to establish a complete evaluation system is also the goal of scientific researchers [7]. To evaluate the structural energy absorption properties, several energy absorption criteria are defined: the energy absorption capacity of the structure (energy absorption, EA), the energy absorption capacity of the structure per unit mass (specific energy absorption, SEA), the mean impact force (f m ) in the whole energy absorption process, the maximum impact load (f max ) in the impact process, etc.…”

“…The crystal microstructure of the surface layer is changed after SSNC, which is conducive to the buckling of the energy absorbing structure in the region with weak yield limit and resulting in layered compression mode. Xu et al [7] applies surface nanocrystallization technology to single tube with thin-walled structure, which makes the structure relatively easy to realize without changing the appearance and quality. However, for multi-cell structures, it is difficult to realize the nanocrystallization process, which can not achieve the ideal energy absorption effect.…”

“…Chen et al [19] has proved through experiments that the twin spacing of the material is easy to be obtained by controlling the surface treatment time, which treatment is reflected in the yield limit. Xu et al [7] experimentally analyzed that the yield strength of 304 stainless steel treated by UIT on the metal surface is controllable and proposed a bilinear constitutive model of the macrostructure. Therefore, in the modeling of nanocrystalline materials, the embedded multi-cell thin-walled structure is numerically simulated by modifying the material parameters.…”

“…By changing the shape of the thin-walled tube structure, the designs of grooves (groove, half groove), holes (round hole, square hole, etc. ), stiffeners, functionally graded tubes, multi cell tubes, nanocrystallized tubes [7] and the pre-creased tubes were carried out; Daneshi et al [8] introduced the groove into the design of the circular thin-walled tubes, and controlled the displacementload curve by changing the width of the grooves and the spacing between the grooves, so as to improve the energy absorbed by the tubes. Li et al [9] studied the energy absorption capacity of functionally graded composite tube under oblique loading and indicated that the energy absorption efficiency is the highest when the power-law index is 2.…”

“…Some previous papers have revealed that UIT has been widely used in various metals and the yield stress of materials was significantly improved [24,25]. Xu et al [7] proposed a novel treatment method for thin-walled tubes without introducing defects into the material, changing the configuration or adding materials. The surface of the thin-walled tube was nanocrystallized by ultrasonic impact equipment, the symmetrical and antisymmetric distributions were designed, the numerical simulation were compared to experimental results and proved that the local surface nanocrystallization was effective to improve the crashworthiness of the structure.…”