Crashworthiness analysis of cylindrical tubes with coupling effects under quasi-static axial loading: An experimental and numerical study

Abstract

In most cylindrical tubes, the occurrence of negative stiffness under compression is unavoidable. This downward trend in the force–displacement relationship means a decrease in the energy-absorption capacity. To this end, this paper introduces a new assembly method comprising two concentric cylindrical tubes. The inner cylinder possesses positive Poisson's ratio behavior, whereas the outer cylinder exhibits negative Poisson's ratio behavior. When compressed, the outer and inner cylinders shrink and expand, respectively, creating surface contacts between the two cylinders, called coupling effects. This property not only avoids the occurrence of negative stiffness in outer cylindrical tube, but also increases the energy-absorption capacity in an upward trend in the force–displacement relationship. To confirm this claim, three different types of cylindrical tubes, possessing positive Poisson’s ratio, zero Poisson's ratio, and negative Poisson’s ratio behaviors, are considered. A finite-element analysis is implemented to simulate deformation patterns of cylindrical tubes. Then, to verify the results of finite-element analysis, a laser-cutting method is applied to fabricate cylindrical tubes from stainless steel tubes. The results show that the proposed assembly method increases the energy-absorption capacity by up to 95% compared to the well-known auxetic tube. Next, a parametric study is performed, in which the gap space between the two cylinders is considered as a design variable. The results reveal the smaller the gap space, the higher the energy-absorption capacity. The absorbed energy in the assembled cylinders without gap space is 17.6 J, which is 36% greater than that of cylinders with 13 mm gap space. The effects of relative density and crushing speed are also evaluated. When compared to the crushing speed, the energy-absorption capacity is highly dependent on relative density.

3D-Printed Programmable Mechanical Metamaterials for Vibration Isolation and Buckling Control

“…According to the re-entrant unit cells, some different designs for graded ZPR cylinders [12,13] are proposed for the consideration of QZS properties as depicted in Figure 2. Since ZPR cylinders were investigated earlier, the QZS characteristic of the ZPR cylinders is the main contribution of this study, achieved via buckling control and "soft and stiff unit cells".…”

“…Mechanical properties can be programmed to a wide variety of conventional designs via the use of 3D printing technology. Mechanical metamaterials are divided into several main groups, including positive Poisson's ratio (PPR) structures such as honeycombs [3][4][5][6], zero Poisson's ratio (ZPR) structures [7][8][9], and negative Poisson's ratio (NPR) structures, socalled auxetics [10][11][12][13]. Metamaterials have been used for various applications, including electromagnetic fields for achieving negative permeability, acoustics, and vibration isolation [14][15][16].…”

Parrot Beak‐Inspired Metamaterials with Friction and Interlocking Mechanisms 3D/4D Printed in Micro and Macro Scales for Supreme Energy Absorption/Dissipation

“…[ 9 ] In general, metamaterials can be divided into several main groups, including positive Poisson's ratio (PPR) structures such as honeycombs, [ 10–12 ] zero Poisson's ratio (ZPR), [ 13,14 ] buckling metamaterials, [ 15,16 ] and negative indices mechanical metamaterials. [ 17–23 ]…”

“…[9] In general, metamaterials can be divided into several main groups, including positive Poisson's ratio (PPR) structures such as honeycombs, [10][11][12] zero Poisson's ratio (ZPR), [13,14] buckling metamaterials, [15,16] and negative indices mechanical metamaterials. [17][18][19][20][21][22][23] More related to our work, energy-absorbing structures are often designed using repeatable nonlinear buckling effects to achieve recoverable structures. [24] Most traditional dampers have cylindrical shapes, [25] and this study will also focus on cylindrical metamaterials designed by repeating the unit cells along the radial and axial directions.…”

4D Metamaterials with Zero Poisson's Ratio, Shape Recovery, and Energy Absorption Features

“…The most prevalent applications can be found in the automotive, railway, and aerospace industries. [2,3] It is important to reduce the mortality rate caused by car crashes in the automotive industry. When it comes to passengers' safety, some critical crashworthy elements must be considered to design proper energy absorbers.…”