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

2021 ◽  
pp. 146442072110533
Author(s):  
Hassan Mansoori ◽  
Ramin Hamzehei ◽  
Soheil Dariushi
Keyword(s):  
Energy Absorption ◽  
Poisson’S Ratio ◽  
Absorption Capacity ◽  
Negative Stiffness ◽  
Poisson's Ratio ◽  
Energy Absorption Capacity ◽  
Element Analysis ◽  
Assembly Method ◽  
Cylindrical Tubes ◽  
Force Displacement

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 Bio-inspired Zero Poisson’s Ratio Graded Metamaterials with High Energy Absorption Performance

2022 ◽  
Author(s):  
Ramin Hamzehei ◽  
Ali Zolfagharian ◽  
Soheil Dariushi ◽  
Mahdi Bodaghi
Keyword(s):  
Cell Wall ◽  
Energy Absorption ◽  
Poisson’S Ratio ◽  
High Energy ◽  
Absorption Capacity ◽  
Poisson's Ratio ◽  
Base Pairs ◽  
Energy Absorption Capacity ◽  
Static Compression ◽  
Unit Cells

Abstract This study aims at introducing a number of two-dimensional (2D) re-entrant based zero Poisson’s ratio (ZPR) graded metamaterials for energy absorption applications. The metamaterials’ designs are inspired by the 2D image of a DNA molecule. This inspiration indicates how a re-entrant unit cell must be patterned along with the two orthogonal directions to obtain a ZPR behavior. Also, how much metamaterials’ energy absorption capacity can be enhanced by taking slots and horizontal beams into account with the inspiration of the DNA molecule’s base pairs. The ZPR metamaterials comprise multi-stiffness unit cells, so-called soft and stiff re-entrant unit cells. The variability in unit cells’ stiffness is caused by the specific design of the unit cells. A finite element analysis (FEA) is employed to simulate the deformation patterns of the ZPRs. Following that, meta-structures are fabricated with 3D printing of TPU as hyperelastic materials to validate the FEA results. A good correlation is observed between FEA and experimental results. The experimental and numerical results show that due to the presence of multi-stiffness re-entrant unit cells, the deformation mechanisms and the unit cells’ densifications are adjustable under quasi-static compression. Also, the structure designed based on the DNA molecule’s base pairs, so-called structure F''', exhibits the highest energy absorption capacity. Apart from the diversity in metamaterial unit cells’ designs, the effect of multi-thickness cell walls is also evaluated. The results show that the diversity in cell wall thicknesses leads to boosting the energy absorption capacity. In this regard, the energy absorption capacity of structure ‘E’ enhances by up to 33% than that of its counterpart with constant cell wall thicknesses. Finally, a comparison in terms of energy absorption capacity and stability between the newly designed ZPRs, traditional ZPRs, and auxetic metamaterial is performed, approving the superiority of the newly designed ZPR metamaterials over both traditional ZPRs and auxetic metamaterials.

scholarly journals In-plane Dynamic Crushing of a Novel Bio-inspired Re-entrant Honeycomb With Negative Poisson's Ratio 

2021 ◽  
Author(s):  
Yonghui Wang ◽  
Qiang He ◽  
Yu Chen ◽  
Hang Gu ◽  
Honggen Zhou
Keyword(s):  
Energy Absorption ◽  
Impact Velocity ◽  
Poisson’S Ratio ◽  
Dynamic Compression ◽  
Absorption Capacity ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Energy Absorption Capacity ◽  
Plateau Stress ◽  
Negative Poisson's Ratio

Abstract In order to seek higher crashworthiness and energy absorption capacity, based on biological inspiration, a novel bio-inspired re-entrant honeycomb (BRH) structure with negative Poisson's ratio is designed by selecting lotus leaf vein as biological prototype. The numerical simulation model is established by the nonlinear dynamics software ABAQUS and further compared with the available reference results to verify the feasibility. The dynamic compression behavior and energy absorption capacity of two types of BRH (BRH-Ⅰ and BRH-Ⅱ) are firstly compared with conventional re-entrant honeycomb (RH). The simulation results show that BRH have better mechanical properties and energy absorption characteristics. Then, the crushing behavior of BRH-Ⅱ under different impact velocities are systematically studied. Three typical deformation modes of BRH-Ⅱ are observed through the analysis of deformation profile. The quasi-static plateau stress is closely related to the cellular structure. Based on one-dimensional shock theory, the empirical equations of dynamic plateau stress for BRH-Ⅱ with different relative densities are given by using least-square fitting. In addition, the effects of impact velocity and relative density on plateau stress and energy absorption behavior are also studied. The results show that the energy absorption capacity of BRH-Ⅱ is increased nearly six times compared with RH at the same impact velocity.

scholarly journals FEA and Quasi-static Test on Energy Absorption Characteristic of Space Orthogonal Concave Honeycomb Structure with Negative Poisson’s Ratio

2022 ◽  
Vol 2160 (1) ◽  
pp. 012064
Author(s):  
Nan Sun ◽  
Shuai Wang ◽  
Kaifa Zhou ◽  
Wenyi Ma ◽  
Bohao Xu
Keyword(s):  
Energy Absorption ◽  
Poisson’S Ratio ◽  
Honeycomb Structure ◽  
Absorption Capacity ◽  
Poisson's Ratio ◽  
Absorption Characteristic ◽  
Negative Poisson’S Ratio ◽  
Energy Absorption Capacity ◽  
Static Compression ◽  
Negative Poisson's Ratio

Abstract As a representative of metamaterials, negative Poisson’s ratio (NPR) material possesses special mechanical properties such as expansion, negative compression ratio and so forth. As a result, it is widely used in the fields of vehicles, aerospace, et al. In this paper, a novel space orthogonal concave honeycomb structure (OC) is designed based on traditional concave honeycomb structure (CHS). In order to explore the influence rule of OC structure on the deformation and energy absorption capacity of crash box under low-speed collision, mechanical analysis and parameter research on OC structure are conducted through quasi-static compression test and numerical simulation. The results suggest that the finite element results of OC structure fit well with the experimental results, and the FEM is highly credible. In addition, the novel OC sandwich structure can effectively enhance the deformation capacity and improve the energy absorption performance of the crash box. When the wall thickness ? of OC structure is 1mm and angle ? is 50°, the deformation and energy absorption capacity of the crash box increased by 25.6% and 19.3% respectively.

scholarly journals Post Tensioned CFRP tubes for improved energy absorption

2021 ◽  
Author(s):  
Venkateswarlu Gattineni ◽  
◽  
Venukumar Nathi ◽  
Keyword(s):  
Energy Absorption ◽  
Impact Energy ◽  
Absorption Capacity ◽  
Energy Absorption Capacity ◽  
Element Analysis ◽  
Simulation Techniques ◽  
Thin Tube ◽  
Post Tensioning ◽  
Cfrp Tubes ◽  
Post Tensioned

Thin-walled tubes made of CFRP (Carbon fiber reinforced Polymer) are being increasingly used as CC (Crush Cans) due to their higher specific energy absorption capacity in the automotive domain for absorbing impact energy during a frontal crash. Finite element analysis (FEA) based computational methods have matured over the years with increased accuracy and acceptable correlation with experimental results. FEA-based computational studies when used appropriately can reduce the number of physical tests and prototypes required besides accelerating the overall cycle design time. The present work proposes an FEA based design validation approach for the evaluation of post-tensioned crush can design that can absorb more impact energy compared to a normal CFRP thin tube. The FEM based method uses a combination of multiple simulation techniques to predict the behavior of a post-tensioned tube. The post-tensioning in the present work has been proposed in the form of internal pressure for the thin tube. It was found that a safe value of pressure, when applied as a post-tensioning load, can improve the energy absorption capacity without increasing the weight of the tube.

ENERGY ABSORPTION OF EXPANSION TUBE CONSIDERING LOCAL BUCKLING CHARACTERISTICS

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5993-5999 ◽  
Author(s):  
KWANG-HYUN AHN ◽  
JIN-SUNG KIM ◽  
HOON HUH
Keyword(s):  
Energy Absorption ◽  
Local Buckling ◽  
Expansion Ratio ◽  
Absorption Capacity ◽  
Buckling Load ◽  
Expansion Tube ◽  
Absorbed Energy ◽  
Energy Absorption Capacity ◽  
Element Analysis ◽  
Numerical Result

This paper deals with the crash energy absorption and the local buckling characteristics of the expansion tube during the tube expanding processes. In order to improve energy absorption capacity of expansion tubes, local buckling characteristics of an expansion tube must be considered. The local buckling load and the absorbed energy during the expanding process were calculated for various types of tubes and punch shapes with finite element analysis. The energy absorption capacity of the expansion tube is influenced by the tube and the punch shape. The material properties of tubes are also important parameter for energy absorption. During the expanding process, local buckling occurs in some cases, which causes significant decreasing the absorbed energy of the expansion tube. Therefore, it is important to predict the local buckling load accurately to improve the energy absorption capacity of the expansion tube. Local buckling takes place relatively easily at the large punch angle and expansion ratio. Local buckling load is also influenced by both the tube radius and the thickness. In prediction of the local buckling load, modified Plantema equation was used for strain hardening and strain rate hardening. The modified Plantema equation shows a good agreement with the numerical result.

Stab-resistance of auxetic weft-knitted fabric with Kevlar fibers at quasi-static loading

2019 ◽  
pp. 152808371986504 ◽  
Author(s):  
Yaxin Sun ◽  
Wanli Xu ◽  
Wenfang Wei ◽  
Pibo Ma ◽  
Fenglin Xia
Keyword(s):  
Static Loading ◽  
Poisson’S Ratio ◽  
Peak Load ◽  
Absorption Capacity ◽  
Raw Material ◽  
Poisson's Ratio ◽  
Knitted Fabric ◽  
Energy Absorption Capacity ◽  
Weft Knitted Fabric ◽  
Stab Resistance

In this paper, a novel auxetic weft-knitted fabric was firstly designed, which was based on the rhombus-shaped grid re-entrant structure. Then the fabric was fabricated using Kevlar filament yarn with 200D fineness on a computerized flat knitting machine. And the Poisson’s ratio values in weft, warp, and diagonal directions of this weft-knitted fabric were measured. The results showed that it exhibits the negative Poisson’s ratio effect in all three directions. Then the quasi-static stab resistance tests at five different puncture speeds were carried out on this auxetic weft-knitted fabric and the plain weft-knitted fabric with same raw material and similar loop length. The experimental results show that the auxetic weft-knitted fabric has higher peak load and energy absorption capacity at quasi-static loading. The results also show that the quasi-static stab resistance of the auxetic weft-knitted fabric strengthens with the increase of the puncture speed, but changes little after the puncture speed reaches a certain value (50 mm/min).

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