Effect of Wall Thickness Variation on the Energy Absorption Efficiency of Cylindrical Tubes Under Axial Loading

2021 ◽  
pp. 589-598
Author(s):  
M. Nalla Mohamed
Keyword(s):  
Energy Absorption ◽  
Wall Thickness ◽  
Axial Loading ◽  
Absorption Efficiency ◽  
Thickness Variation ◽  
Energy Absorption Efficiency ◽  
Cylindrical Tubes ◽  
Wall Thickness Variation

Fabrication and Properties of Syntactic Magnesium Foams

1998 ◽  
Vol 521 ◽  
Author(s):  
M. Hartmann ◽  
K. Reindel ◽  
R. F. Singer
Keyword(s):  
Compressive Strength ◽  
Energy Absorption ◽  
Wall Thickness ◽  
Volume Fraction ◽  
Hollow Spheres ◽  
Three Dimensional ◽  
Syntactic Foam ◽  
Absorption Efficiency ◽  
Casting Technique ◽  
Energy Absorption Efficiency

ABSTRACTSyntactic magnesium foams which consist of thin-walled hollow alumina spheres embedded in a magnesium matrix were fabricated by infiltrating a three-dimensional array of hollow spheres with a magnesium melt by using a gas pressure-assisted casting technique.The resulting composite contains closed cells of homogeneous and isotropic morphology. The densities of the syntactic magnesium foams were between 1.0 and 1.4 g/cm3. The densities were controlled by variations in the bulk density of the hollow spheres with the volume fraction of spheres kept constant at approximately 63 %.Compressive deformation characteristics of the composites were evaluated with respect to the influence of matrix strength and sphere wall thickness on characteristic variables such as compressive strength, plateau stress and energy absorption efficiency. Differences in the strength of the magnesium-based matrix materials investigated (cp-Mg, AM20, AM50, AZ91) had little influence on the compressive strength of the syntactic foam. However, an increasing relative wall thickness of the hollow ceramic spheres led to a significant strength enhancement. In all cases the ratio between compressive and plateau strength rose with increasing composite strength resulting in decreasing energy absorption efficiency.

Energy Absorption of Origami Crash Box: Numerical Simulation and Theoretical Analysis

2018 ◽  
Author(s):  
Mengyan Shi ◽  
Jiayao Ma ◽  
Yan Chen ◽  
Zhong You
Keyword(s):  
Energy Absorption ◽  
Theoretical Study ◽  
Low Cost ◽  
Deformation Mode ◽  
Absorption Efficiency ◽  
Great Promise ◽  
Good Match ◽  
Energy Absorption Efficiency ◽  
Thin Walled ◽  
Initial Peak

Thin-walled tubes as energy absorption devices are widely in use for their low cost and high manufacturability. Employing origami technique on a tube enables induction of a predetermined failure mode so as to improve its energy absorption efficiency. Here we study the energy absorption of a hexagonal tubular device named the origami crash box numerically and theoretically. Numerical simulations of the quasi-static axial crushing show that the pattern triggers a diamond-shaped mode, leading to a substantial increase in energy absorption and reduction in initial peak force. The effects of geometric parameters on the performance of the origami crash box are also investigated through a parametric study. Furthermore, a theoretical study on the deformation mode and energy absorption of the origami crash box is carried out, and a good match with numerical results is obtained. The origami crash box shows great promise in the design of energy absorption devices.

Bending Behavior of Simply-Supported Sandwich Beams Subjected to Large Deflection

2018 ◽  
Vol 777 ◽  
pp. 569-574
Author(s):  
Zhong You Xie
Keyword(s):  
Energy Absorption ◽  
Large Deflection ◽  
Absorption Efficiency ◽  
Sandwich Beams ◽  
Element Simulation ◽  
Energy Absorption Efficiency ◽  
Load Carrying ◽  
Absorption Performance ◽  
Bending Behavior ◽  
The Moment

Due to thin skins and soft core, it is apt to local indentation inducing the concurrence of geometrical and material nonlinearity in sandwich structures. In the paper, finite element simulation is used to investigate the bending behavior of lightweight sandwich beams under large deflection. A modified formulation for the moment at mid-span section of sandwich beams under large deflection is presented, and energy absorption performance is assessed based on energy absorption efficiency. In addition, it is found that no local indentation arises initially, while later that increases gradually with loading displacement increasing. The height of the mid-span section as well as load-carrying capacity decreases significantly with local indentation depth increasing.

Mechanics of Conventional Spinning

1963 ◽  
Vol 85 (4) ◽  
pp. 346-350 ◽  
Author(s):  
H. C. Sortais ◽  
S. Kobayashi ◽  
E. G. Thomsen
Keyword(s):  
Wall Thickness ◽  
Pure Aluminum ◽  
Tangential Force ◽  
Deformation Energy ◽  
Thickness Variation ◽  
Force Component ◽  
Commercially Pure ◽  
Conventional Spinning ◽  
Wall Thickness Variation ◽  
Experimental Values

In conventional spinning of cones, the cone-wall thickness variation was studied using blanks of 1100-0 commercially pure aluminum sheet of 0.050-in. thickness. The results revealed that the radial stress induced in the unspun flange is the major cause of nonuniform wall thickness of spun cones. The theoretical tangential force component was derived by use of the deformation energy method. Qualitative agreement was found between the theoretical and the experimental values of tangential force component in the underspinning conditions.

Compressive Properties of Electroless Ni-P Coating Reinforced Magnesium Alloy Foams

2021 ◽  
Vol 889 ◽  
pp. 123-128
Author(s):  
Sheng Jun Liu ◽  
Zhi Qiang Dong ◽  
Ren Zhong Cao ◽  
Da Song ◽  
Jia An Liu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Energy Absorption ◽  
Absorption Efficiency ◽  
Absorption Capacity ◽  
Compressive Properties ◽  
Compressive Test ◽  
Energy Absorption Capacity ◽  
Energy Absorption Efficiency ◽  
Hybrid Foams ◽  
Electroless Ni

In this study, the open-cell Mg-2Zn-0.4Y foams were prepared by infiltration casting method. The Ni/Mg hybrid foams were prepared by electroless Ni-P coating on the foam struts to improve the compressive strength and energy absorption capacity. The compressive properties of the Mg alloy foams and Ni/Mg hybrid foams were studied by quasi-static compressive test. The experimental results show that the Ni-P coating is composed of crystallites. The Ni-P coating can significantly enhance the compressive strength, energy absorption capacity and energy absorption efficiency of the foams.

scholarly journals Energy Absorption of Different Cell Structures for Closed-Cell Foam-Filled Tubes Subject to Uniaxial Compression

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1579 ◽  
Author(s):  
Yang Yu ◽  
Zhuokun Cao ◽  
Ganfeng Tu ◽  
Yongliang Mu
Keyword(s):  
Energy Absorption ◽  
Absorption Efficiency ◽  
Foam Core ◽  
Aluminum Foams ◽  
Static Compression ◽  
Cell Structures ◽  
Closed Cell ◽  
Energy Absorption Efficiency ◽  
Foam Filled ◽  
Quasi Static Compression

The energy absorption of different cell structures for closed-cell aluminum foam-filled Al tubes are investigated through quasi-static compression testing. Aluminum foams are fabricated under different pressures, obtaining aluminum foams with different cell sizes. It is found that the deformation of the foam core is close to the overall deformation, and the deformation band is seriously expanded when the cell size is fined, which leads to the increase of interaction. Results confirm that the foam-filled tubes absorb more energy due to the increase of interaction between the foam core and tube wall when the foaming pressure increases. The energy absorption efficiency of foam-filled tubes can reach a maximum value of 90% when the foam core is fabricated under 0.30 MPa, which demonstrates that aluminum foams fabricated under increased pressure give a new way for the applications of foam-filled tubes in the automotive industry.

Crash Analysis of UAV Hybrid Composite Fuselage Structure under Different Impact Conditions

2019 ◽  
Vol 953 ◽  
pp. 88-94
Author(s):  
Mohamed Zahran ◽  
Mostafa Abdelwahab
Keyword(s):  
Energy Absorption ◽  
Hybrid Composite ◽  
Absorption Efficiency ◽  
Crash Analysis ◽  
Critical System ◽  
Maximum Acceleration ◽  
Finite Element Software ◽  
Energy Absorption Efficiency ◽  
Hybrid Composite Material ◽  
Technological Developments

Due to the rapid scientific and technological developments in the aerospace industry, the requirement for safety and energy absorption efficiency is increasing, and in order to achieve that target, the analyzing of the sudden crash is required to know how to reduce it. Therefore, the main objective of the present work is to analyze the crashing response of the hybrid composite fuselage structure during different impact landing conditions. Moreover, extract the maximum acceleration at the most important locations in the UAV fuselage where most of the critical system is installed. The explicit non-linear finite element software LS-DYNA/WORKBENCH ANSYS is chosen to simulate the crushing of the referenced and the proposed UAV fuselage and investigate the maximum crushing accelerations responses on the payload under different landing conditions. The numerical results show that strengthen the fuselage structure using hybrid composite material has a notable effect on the energy absorption, and transferred acceleration on the payload. Moreover, the hybrid composite fuselage structure can reduce the transferred acceleration on the payload up to 39.65% in comparison with the metal fuselage. In addition, to study the crash analysis during sudden accidents is very important, in order to find the way to reduce it, but can’t avoid it. Hence, the UAV payload should be arranged to avoid the maximum acceleration.

Cushioning energy absorption of composite layered structures including paper corrugation, paper honeycomb and expandable polyethylene

2019 ◽  
Vol 54 (3) ◽  
pp. 176-191 ◽  
Author(s):  
Yanfeng Guo ◽  
Meijuan Ji ◽  
Yungang Fu ◽  
Dan Pan ◽  
Xingning Wang ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Specific Energy ◽  
Peak Stress ◽  
Layered Structures ◽  
Absorption Efficiency ◽  
Compression Stress ◽  
Static Compression ◽  
Specific Energy Absorption ◽  
Energy Absorption Efficiency ◽  
Paper Honeycomb

The composite layered structures including paper corrugation, paper honeycomb and expandable polyethylene are innovative structures of cushioning energy absorption, and the compression and impact resistances of the expandable polyethylene can be enhanced by laminating the corrugated paperboard or honeycomb paperboard. This article evaluated the compression performance and cushioning energy absorption of the composite layered structures by the static compression and drop impact compression tests. On one hand, the static compression properties showed that the total energy absorption, energy absorption per unit volume and stroke efficiency of the composite layered structures were all higher than those of expandable polyethylene. The specific energy absorption was enhanced with the increase in compression strain but almost not affected by the compression rate. The specific energy absorption of the composite layered structures including the expandable polyethylene and honeycomb paperboard was greater than those of the expandable polyethylene and corrugated paperboard. The energy absorption efficiency of the composite layered structures including the expandable polyethylene and corrugated paperboard was large for the low compression stress level, yet that of the composite layered structures including the expandable polyethylene and honeycomb paperboard was large for the high compression stress level. On the other hand, the dynamic compression characteristics showed that the peak stress, energy absorption per unit area, energy absorption per unit volume and specific energy absorption of the composite layered structures embodying paper sandwich cores and expandable polyethylene had linear increasing trends with the increase of drop shock energy. At the same drop impact condition, the composite layered structures including the honeycomb paperboard and expandable polyethylene had better cushioning energy absorption, the peak stress decreased by 23.6% on average, the energy absorption efficiency raised by 8.85% on average and the specific energy absorption increased by 18.1% on average than those including the corrugated paperboard and expandable polyethylene. Therefore, the corrugated paperboard and honeycomb paperboard can helpfully improve the cushioning energy absorption of the expandable polyethylene, and the composite layered structures embodying the expandable polyethylene, corrugated paperboard and honeycomb paperboard may hold excellent packaging protection.

A Novel Omnidirectional Self-Locked Energy Absorption System Inspired by Windmill

2020 ◽  
Vol 87 (8) ◽  
Author(s):  
Yizhe Liu ◽  
Feng Xiong ◽  
Kuijian Yang ◽  
Yuli Chen
Keyword(s):  
Energy Absorption ◽  
Absorption Efficiency ◽  
Absorption System ◽  
Tube System ◽  
Round Tube ◽  
Action Mode ◽  
Energy Absorption Efficiency ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Shed Light

Abstract Impact accidents cause great damage to lives and properties because the destructiveness, direction, and action mode of impact loadings can hardly be predicted. Ordinary thin-walled tube systems for energy absorption require outside constraints or inside fasteners to avoid tube splashing, which affects the modifiability of the systems and limits their application in emergencies. In an effort to break through this limitation, inspired by windmill, a novel omnidirectional self-locked energy absorption system has been proposed. The proposed system is made up of thin-walled tubes with windmill-liked cross section, which are specially designed to interlock with adjacent tubes and thus provide constraints among individual tubes to resist impact loadings in spatial arbitrary directions. The spatial omnidirectional self-locking capability of the windmill-inspired system is demonstrated under distributed and concentrated impact loadings. Moreover, the windmill-inspired system shows higher energy absorption efficiency than that of the widely used round tube system and previous self-locked system under loadings in various directions, and their energy absorption properties can be further improved by combining with the round tube system, adjusting the geometric parameter of each tube and designing the arrangement of tubes with different properties in the system. This work may shed light on the energy absorption system design and expand the application of self-locked energy absorption systems.

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