Influence of pore shape on impact dynamics characteristics of functionally graded brittle materials

2021 ◽  
pp. 030932472110297
Author(s):  
Yongqiang Li ◽  
Nianzhu Wang ◽  
Wenkai Yao ◽  
Tao Wang ◽  
Mao Zhou
Keyword(s):  
Energy Dissipation ◽  
Impact Energy ◽  
Elastic Limit ◽  
Brittle Materials ◽  
Functionally Graded ◽  
Deformation Wave ◽  
Hugoniot Elastic Limit ◽  
Piston Velocity ◽  
Energy Dissipation Capacity ◽  
The Impact

Improving the impact energy dissipation capacity of functionally graded brittle materials through pore design will help avoid or delay failure. In order to improve the impact energy dissipation capacity of functionally graded brittle materials, pores with specific shapes can be implanted inside them. The effect of pore shape on the impact properties of functionally graded brittle materials was investigated using a lattice-spring model that can quantitatively represent the mechanical properties of functionally graded brittle materials. The calculated results show that the pores with negative Poisson’s ratio such as inner-concave triangle, fourth-order star, and inner-concave hexagon are easy to collapse under the impact, while the square and square-hexagon pores have the strongest resistance to deformation. For all seven pore shapes, the Hugoniot elastic limit of the samples decreased gradually with increasing porosity, and the Hugoniot elastic limit did not change with the change of piston velocity. The propagation velocity of the deformation wave increases with the piston velocity and the velocity of the particle corresponding to the Hugoniot state behind the deformation wave increases accordingly. The principle that pores can enhance the macroscopic impact energy dissipation capacity of functionally graded brittle material samples revealed in this paper will contribute to the prevention of sample impact failure and provide guidance for the optimal design of impact kinetic properties of samples.

Analysis of Non-Classical Models which Have been Subjected to Percussive Loads Using Equations of Energy and Power

2014 ◽  
Vol 1036 ◽  
pp. 608-613 ◽  
Author(s):  
Krzysztof Jamroziak ◽  
Miroslaw Bocian
Keyword(s):  
Energy Dissipation ◽  
Impact Energy ◽  
Dynamic Models ◽  
Specific Impulse ◽  
Pulse Excitation ◽  
Classical Dynamic ◽  
Simple Description ◽  
Classical Models ◽  
The One ◽  
The Impact

The article presents an analysis of impact energy dissipation process with selected non-classical dynamic models. Identification of impact energy dissipation phenomena in layered mechanical systems (for example: composite ballistic shields) is a great challenge, because on the one hand a model with parameters responsible for the energy dissipation is being sought on the one hand and on the other it is necessary to optimise the number of parameters. The sought model should be reduced to a simple description of the phenomenon and should contain a complex reproduction of the whole mechanical system. In this case the impact energy dissipation was described using selected degenerate systems. Models were treated by extortion surge having a specific impulse of force. The mathematical description of the pulse excitation was carried out using the energy and potency balance equations. The verification of mathematical identification equations was conducted using a computer simulation technique for the selected model’s parameters.

Low-Velocity Flexural Impact Analyses of Functionally Graded Sandwich Beams Using Finite Element Modeling

2018 ◽  
Vol 10 (10) ◽  
pp. 1850113 ◽  
Author(s):  
Kemal Arslan ◽  
Recep Gunes
Keyword(s):  
Finite Element ◽  
Contact Force ◽  
Impact Energy ◽  
Considerable Effect ◽  
Functionally Graded ◽  
Low Velocity ◽  
Compositional Gradient ◽  
Number Of Layers ◽  
Impact Side ◽  
The Impact

A comparative numerical investigation on low-velocity impact response of a metal/ ceramic functionally graded sandwich beam (FGSB) is performed by the commercial finite element (FE) software, LS-DYNA[Formula: see text]. The mechanical properties of the FG core are represented by a power-law depending on the volume fractions of the constituents. The effective elastic properties and elastoplastic behavior of the FG core are defined by Mori–Tanaka method and TTO (Tamura–Tomota–Ozawa) model, respectively. The effects of number of layers, compositional gradient, impact energy, and impact side are investigated. The simulation results indicated that both number of layers and compositional gradient have almost no effect on the kinetic energy history. In other respects, the compositional gradient exhibits a considerable effect, and the number of layers has a minor effect on the contact force history. Increasing impact energy does not have a considerable effect in terms of number of layers whereas it exhibits a significant effect in terms of compositional gradient on the percentage difference between the peak contact forces. Finally, the impact side does not influence the contact force history for all number of layers and compositional gradients.

Energy Analysis for Energy Dissipation Shed-Tunnel’s Rockfall Impact Signal

2011 ◽  
Vol 261-263 ◽  
pp. 1054-1057 ◽  
Author(s):  
Lin Feng Wang ◽  
Hong Mei Tang ◽  
Hong Kai Chen
Keyword(s):  
Energy Dissipation ◽  
Impact Energy ◽  
High Frequency ◽  
Energy Analysis ◽  
Low Frequency ◽  
Prevention Measures ◽  
Impact Frequency ◽  
Wavelet Theory ◽  
Frequency Increase ◽  
The Impact

Shed-tunnel is one of common prevention measures along the highway. First, denoised the rockfall impact signal when the rock impact the ordinary shed-tunnel and the energy dissipation shed-tunnel by the wavelet theory. The calculation result indicated that the wavelet theory’s denoise effect is very good. Then, pick-up each frequency band’s the rockfall impact signal, and analysed the energy for each frequency band’s impact signal. The result indicated that the energy dissipation shed-tunnel’s impact energy concentrate in the low frequency part. There are only 0.4% impact energy in the high frequency part. Besides, the energy dissipation shed-tunnel’s impact energy in the low frequency part is higher than the the ordinary shed-tunnel, and the energy dissipation shed-tunnel’s impact energy depressed velocity when the impact frequency increase is fast than the ordinary shed-tunnel. So the energy dissipation shed-tunnel’s design must consider the low frequency impact,and could ignore the high frequency impact.

scholarly journals Hierarchical design of synthetic gel composites optimized to mimic the impact energy dissipation response of brain tissue

2016 ◽  
Vol 1 (3) ◽  
pp. 290-300 ◽  
Author(s):  
Bo Qing ◽  
Krystyn J. Van Vliet
Keyword(s):  
Energy Dissipation ◽  
Brain Tissue ◽  
Impact Energy ◽  
Hierarchical Design ◽  
Mechanical Tunability ◽  
The Impact

Bilayered polymer design significantly enhances mechanical tunability, allowing the composite to replicate the impact energy dissipation response of brain tissue.

Three-dimensional dynamic analysis of ancient buildings with novel high damping isolation trenches

2021 ◽  
pp. 107754632110109
Author(s):  
Jin-bao Li ◽  
Zhong-wei Hu ◽  
Zhao-dong Xu ◽  
Ying-qing Guo
Keyword(s):  
Energy Dissipation ◽  
Three Dimensional ◽  
High Energy ◽  
Plane Shape ◽  
Energy Dissipation Capacity ◽  
The Stability ◽  
High Energy Dissipation ◽  
Supporting Force ◽  
The Impact

To improve the efficiency of conventional isolation trench and lighten the impact of the excavation on neighbor buildings, a novel high damping isolation trench is proposed. The viscoelastic braces equipped in the high damping isolation trench can dissipate the energy of ground-borne vibration while providing supporting force to ensure the stability of the soil on both sides. According to two actual ancient buildings, two types of high damping isolation trenchs with the plane shape of U and L are designed to solve the potential damages caused by long-term train-induced vibration. First, three-dimensional finite/infinite models based on these two buildings are established, respectively. Then, the energy dissipation characteristics are obtained by experiments. Through calculation, the control effects of the high damping isolation trenchs for these two buildings are investigated. The results indicate that the viscoelastic braces possess high energy dissipation capacity. After setting the high damping isolation trenchs around the structures, even at a small excavation depth, the acceleration and velocity responses of the two buildings are reduced significantly. Furthermore, the selected U-shaped and L-shaped trenches also show superiority compared with the conventional linear-shaped trench in this project.

Response and failure modes of biaxial warp-knitted flexible composite subject to low-velocity impact

2021 ◽  
pp. 152808372110154
Author(s):  
Ziyu Zhao ◽  
Tianming Liu ◽  
Pibo Ma
Keyword(s):  
Impact Energy ◽  
Linear Density ◽  
Failure Modes ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Minor Effect ◽  
Low Velocity ◽  
Velocity Impact ◽  
Flexible Composites ◽  
The Impact

In this paper, biaxial warp-knitted fabrics were produced with different high tenacity polyester linear density and inserted yarns density. The low-velocity impact property of flexible composites made of polyurethane as matrix and biaxial warp-knitted fabric as reinforcement has been investigated. The effect of impactor shape and initial impact energy on the impact response of flexible composite is tested. The results show that the initial impact energy have minor effect on the impact response of the biaxial warp-knitted flexible composites. The impact resistance of flexible composite specimen increases with the increase of high tenacity polyester linear density and inserted yarns density. The damage morphology of flexible composite materials is completely different under different impactor shapes. The findings have theoretical and practical significance for the applications of biaxial warp-knitted flexible composite.

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