scholarly journals Effects of cell aspect ratio and relative density on deformation response and failure of honeycomb core structure

2020 ◽  
Vol 7 (1) ◽  
pp. 015332 ◽  
Author(s):  
Muhammad Salman Khan ◽  
Seyed Saeid Rahimian Koloor ◽  
Mohd Nasir Tamin
Keyword(s):  
Aspect Ratio ◽  
Relative Density ◽  
Core Structure ◽  
Honeycomb Core ◽  
Deformation Response

Design and modelling of auxetic double arrowhead honeycomb core sandwich panels for performance improvement under air blast loading

2020 ◽  
pp. 109963622093556 ◽  
Author(s):  
Ganchao Chen ◽  
Yuansheng Cheng ◽  
Pan Zhang ◽  
Jun Liu ◽  
Changhai Chen ◽  
...  
Keyword(s):  
Relative Density ◽  
Performance Improvement ◽  
Energy Absorption ◽  
Large Scale ◽  
Front Face ◽  
Horizontal Distance ◽  
Honeycomb Core ◽  
Deformation Response ◽  
Back Face ◽  
Global Deformation

In the present study, a 2D-based large-scale metallic auxetic double arrowhead honeycomb core sandwich panel (DAHSP) was proposed and its deformation response, energy dissipation characteristics and associated mechanisms under air blasts were investigated using a validated numerical model. It aims at the performance improvement of DAHSPs through the design of core relative density with respect to different strategies. The DAHSPs considered mainly experienced a local dome superimposed upon global deformation of front face and global deformation of back face, while the core webs were heavily buckled and progressively collapsed. The results confirmed the material concentration effect of DAH cores induced by the negative Poisson’s ratio (NPR). It was found that the panel deformation response was highly related to their deformation/failure mechanisms. Relative to core web thickness, the increase of number of core layers led to a more remarkable decrease in permanent deflections. However, the decline of inclined angles not always reduced the back face deflection due to the competition between enhanced bending stiffness and deteriorated local contact force. An ideal means to decrease the panel deformation is to enlarge the inclined angles at low relative density but to decrease the horizontal distance when the relative density increases to a high level. The panel with thinner core webs at low relative density and the panel with narrowed inclined angles at high relative density is more beneficial to plastic energy absorption. In addition, a core configuration with a thinner tendon but a thicker stuffer promoted the exploitation of NPR and further improved the panel energy absorption.

Mathematical modeling and parametric study of magnetic negative stiffness dampers

2020 ◽  
Vol 23 (8) ◽  
pp. 1702-1714
Author(s):  
Wenxiu Liu ◽  
Eric M Lui
Keyword(s):  
Mathematical Modeling ◽  
Aspect Ratio ◽  
Parametric Study ◽  
Pushover Analysis ◽  
Negative Stiffness ◽  
Base Shear ◽  
Residual Drift ◽  
Deformation Response ◽  
Electromagnetic Damping ◽  
Inverse Force

This article presents mathematical modeling and parametric study of a type of magnetic negative stiffness dampers. A magnetic negative stiffness damper uses the interaction forces and movement of magnets inside a conductive pipe to achieve inverse force–deformation response and create frequency dependent damping. One advantage of magnetic negative stiffness dampers over other conventional dampers is that they do not add stiffness to the system and hence will not increase the force in the structural members to which the magnetic negative stiffness damper is attached. Using nonlinear regression analysis, simple formulas to describe the magnetic force and electromagnetic damping of a specific type of magnetic negative stiffness dampers are derived. A parametric study is then performed to show that maximum negative stiffness is obtained when the height-to-diameter (aspect) ratio of the magnets is in the range of 0.3–0.4, and for design applications upper bound values for the clear spacing-to-radius ratio and aspect ratio of the magnets are determined to be 3 and 2, respectively. The highest value of damping coefficient is found to correspond to a magnet aspect ratio of 1.6, and for design purpose the pipe wall thickness should be set equal to the height of the magnet. Based on a pushover analysis of three frames modeled as single-degree-of-freedom systems, it is found that the frame with the magnetic negative stiffness damper experiences lower base shear at the expense of a slightly higher residual drift. The effect of base shear reduction is more pronounced when the target displacement is small.

Beetle elytron plate and the synergistic mechanism of a trabecular-honeycomb core structure

2018 ◽  
Vol 62 (1) ◽  
pp. 87-93 ◽  
Author(s):  
JinXiang Chen ◽  
XiaoMing Zhang ◽  
Yoji Okabe ◽  
Juan Xie ◽  
MengYe Xu
Keyword(s):  
Core Structure ◽  
Honeycomb Core ◽  
Synergistic Mechanism

Energy Absorption Characteristics of Crash Box of New Honeycomb Core Structure with Foam-Filled

2021 ◽  
Vol 22 (1) ◽  
pp. 221-230
Author(s):  
Xiang Li ◽  
Yanmiao Wang ◽  
Xingxing Xu ◽  
Xiangbin Cao ◽  
Rui Li
Keyword(s):  
Energy Absorption ◽  
Core Structure ◽  
Honeycomb Core ◽  
Foam Filled ◽  
Absorption Characteristics

Effects of Ti(C,N) Nanoparticles on Mechanical Properties of the Si3N4 Ceramics

2011 ◽  
Vol 80-81 ◽  
pp. 119-122
Author(s):  
Qian Li ◽  
Fu Sheng Zhu ◽  
Zhi Meng Xiu ◽  
Xu Dong Sun
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Aspect Ratio ◽  
Relative Density ◽  
Hot Pressing ◽  
Bending Strength ◽  
Lateral Growth ◽  
Toughening Mechanism ◽  
Vacuum Sintering ◽  
Crack Bridging

Si3N4-Ti(C,N) nanocomposites fabricated by vacuum hot pressing with Al2O3 and Y2O3 as additives were investigated. The results showed that the α-Si3N4 phase converted completely into whisker-shaped β-Si3N4 grains after vacuum sintering at 1700°C. Suitable addition and well dispersion of the Ti(C,N) particles can restrained the lateral growth of the β-Si3N4 grains, increasing aspect ratio of the β-Si3N4 grains and improving bending strength of the composites. Fracture toughness of the composites is higher than that of the β-Si3N4 ceramics, and the main toughening mechanism is crack bridging due to the higher aspect ratio of the β-Si3N4 grains.With the addition of 1vol% of Ti(C,N), the composite has a relative density of 99.31%, Vicker’s hardness of 15.9 GPa, bending strength of 993 MPa, and fracture toughness of 9.9 MPa·m1/2.

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