scholarly journals Investigation of the Specific Energy Absorption of Triply Periodic Minimal Surfaces Subjected to Impact Loading

2021 ◽  
Vol 250 ◽  
pp. 01022
Author(s):  
Sara AlMahri ◽  
Rafael Santiago ◽  
Dong-wook Lee ◽  
Henrique Ramos ◽  
Haleimah Alabdouli ◽  
...  
Keyword(s):  
Strain Rate ◽  
Energy Absorption ◽  
Specific Energy ◽  
Minimal Surfaces ◽  
Direct Impact ◽  
Loading Conditions ◽  
Impact Compression ◽  
Specific Energy Absorption ◽  
Triply Periodic Minimal Surfaces ◽  
Triply Periodic

Triply periodic minimal surfaces (TPMS) have attracted tremendous research interest due to their lightweight and superior mechanical properties. In this study, two TPMS sheet-based structures (FRD and Neovius) are designed, fabricated, and tested under dynamic and quasistatic loading conditions. Selective laser melting (SLM) is employed to facilitate the fabrication of such complex structures out of stainless steel (SS316L). Scanning electron microscopy (SEM) is utilized to assess the quality of the printed structures. The dynamic compressive behaviour is investigated through performing a direct impact compression test via a Direct Impact Hopkinson Bar (DIHB) at a strain rate of 2000 s-1. Quasi-static tests are also performed at a strain rate of 0.005 s-1. The specific energy absorption (SEA) is compared under both loading conditions to investigate the performance of such structures under dynamic loading. Results show that both structures exhibit higher SEA values under high deformation rates. In fact, Neovius structures outperform FRD structures in terms of specific energy absorption as it exhibits a SEA value of 22.11 J/g and 24.8 J/g SEA in quasi-static and dynamic conditions, respectively.

Crashworthiness performance of concentric structures with different cross-sectional shapes under multiple loading conditions

2020 ◽  
pp. 095440702096188
Author(s):  
Sadjad Pirmohammad
Keyword(s):  
Energy Absorption ◽  
Specific Energy ◽  
Absorption Maximum ◽  
Element Model ◽  
Hexagonal Structure ◽  
Loading Conditions ◽  
Cross Sectional ◽  
Specific Energy Absorption ◽  
Multiple Loading ◽  
Energy Absorbing

This paper evaluates the crashworthiness performance of concentric structures with different numbers of tubes (i.e. one to five) and cross-sectional shapes (i.e. hexagon, octagon, decagon and circle) under the multiple loadings of θ = 0, 10, 20 and 30°. An experimentally validated finite element model generated in LS-DYNA is employed to calculate the crashworthiness parameters including the specific energy absorption, maximum crush force and crush force efficiency. A total of 20 concentric structures are analyzed to explore the effects of number of tubes and cross-sectional shapes on the crushing performance. A multi-criteria decision-making method known as TOPSIS is also used to compare and rank the concentric structures in terms of crushing performance. Based on the results, the hexagonal structure including two tubes and octagonal, decagonal and circular structures including three tubes demonstrate the best results among their corresponding cross-sectional shapes. These structures show 9, 39, 38 and 39% higher specific energy absorption compared to their corresponding single tubal cases, respectively. However, in comparison to single tubal cases, they generate 4, 57, 57 and 58% higher maximum crush force, respectively. As such, the values for the improvement of the crush force efficiency are 3, 26, 25 and 21%, respectively. Furthermore, the decagonal structure including three tubes provides the highest energy absorbing characteristics as compared with all the other structures studied in this research. Meanwhile, taking into account all the multiple loading conditions, this structure shows 50% higher specific energy absorption than the hexagonal structure including single tube (as the weakest structure).

Effect of the Fine Recycled Aggregates on the Dynamic Compressive Behavior of Recycled Mortar

2020 ◽  
Vol 991 ◽  
pp. 62-69
Author(s):  
Sallehan Ismail ◽  
Mohamad Asri Abd Hamid ◽  
Zaiton Yaacob
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Energy Absorption ◽  
Specific Energy ◽  
Split Hopkinson Pressure Bar ◽  
Recycled Aggregates ◽  
Fine Aggregate ◽  
Peak Strain ◽  
Specific Energy Absorption ◽  
The Impact

This study aims to investigate the dynamic behavior of recycled mortar under impact loading using a split Hopkinson pressure bar (SHPB). Several mortar mixtures were produced by adding various fine recycled aggregates (FRA) to the mixture in replacement percentages of 0%, 25%, 50%, 75%, and 100% of the natural fine aggregate (NFA). The effects of strain rate on compressive strength and specific energy absorption were obtained. Results show that the dynamic compressive strength and specific energy absorption of recycled mortar are highly strain rate dependent; specifically, they increase nearly linearly with the increase in peak strain rate. However, the compressive strength and specific energy absorption of recycled mortar are generally lower than those of NFA mortar (reference samples) under similar high strain rates. The findings of this research can help researchers and construction practitioners to ascertain the appropriate mix design procedure to optimize the impact strength properties of recycled mortar for protective structural application.

Static and Dynamic Crush Behavior of Circular Aluminum Extrusions With Rigid PU Foam Filler

2002 ◽  
Author(s):  
Salamah Y. Maaita ◽  
Golam M. Newaz
Keyword(s):  
Energy Absorption ◽  
Axial Compression ◽  
Specific Energy ◽  
Pure Aluminum ◽  
Loading Conditions ◽  
Specific Energy Absorption ◽  
Aluminum Tube ◽  
Compression Loading ◽  
Foam Filled ◽  
A New Technique

This paper introduces a new technique to increase the specific energy absorption (SEA) for foam-filled circular aluminum tube significantly. The idea is to first utilize initiators to deform the foam inside an aluminum tube under the effects of constraints of the tube wall. Then the aluminum tube and foam are crushed together. In this study, the foam with 190mm length has been filled inside a 200mm aluminum tube and attached to two 50 mm length initiators (one initiator in each side of the tube). Initially, the foam-filled tube has been compressed a total of 90mm by entering and sliding the two initiators inside the aluminum tube. Then the foam, two initiators and the aluminum tube have been compressed together for another 30 mm (The total crushing distance is 120mm). The technique was utilized under quasi-static and dynamic axial compression loading conditions and is found to increase the specific energy absorption (SEA) for the foam-filled circular aluminum tube up to 30% more compared to pure aluminum tubes for quasi-static and dynamic axial compression loading conditions. Both experimental and analytical/computational results are presented.

The effect of loading rate on the compression properties of carbon fibre-reinforced epoxy honeycomb structures

2020 ◽  
Vol 54 (19) ◽  
pp. 2565-2576 ◽  
Author(s):  
RA Alia ◽  
J Zhou ◽  
ZW Guan ◽  
Q Qin ◽  
Y Duan ◽  
...  
Keyword(s):  
Carbon Fibre ◽  
Strain Rate ◽  
Energy Absorption ◽  
Specific Energy ◽  
Compression Strength ◽  
Loading Rate ◽  
Specific Energy Absorption ◽  
Honeycomb Cores ◽  
Energy Absorbing ◽  
Absorption Characteristics

The effect of varying strain rate on the compression strength and energy absorption characteristics of a carbon fibre-reinforced plastic honeycomb core has been investigated over a wide range of loading rates. The honeycombs were manufactured by infusing an epoxy resin through a carbon fibre fabric positioned in a dismountable honeycomb mould. The vacuum-assisted resin transfer moulding technique yielded honeycomb cores of a high quality with few defects. Compression tests were undertaken on single and multiple cells and representative volumes removed from the cores in order to assess how the compression strength and specific energy absorption vary with test rate. Crushing tests over the range of strain rates considered highlighted the impressive strength and energy-absorbing response of the honeycomb cores. At quasi-static rates of loading, the compression strength and specific energy absorption characteristics of the unidirectional samples exceeded those of the multidirectional cores. Here, extensive longitudinal splitting and fibre fracture were the predominant failure mechanisms in the cores. For all three stacking sequences, the single-cell samples offer higher compression strength than their five-cell counterparts. In contrast, the specific energy absorption values were found to be slightly higher in the five-cell cores. The experiments highlighted a trend of increased compression strength with loading rate in the multidirectional samples, whereas the strength of the [0°]4 samples was relatively insensitive to strain rate. Finally, the energy absorbing capacity of all structures studied was found to be reasonably constant at increasing rates of strain.

scholarly journals Compressive Behavior of Luffa Sponge Material at High Strain Rate

2013 ◽  
Vol 535-536 ◽  
pp. 465-468 ◽  
Author(s):  
Jian Hu Shen ◽  
Mike Xie ◽  
Xiao Dong Huang ◽  
Shi Wei Zhou ◽  
Dong Ruan
Keyword(s):  
Strain Rate ◽  
Energy Absorption ◽  
Specific Energy ◽  
Base Material ◽  
Acoustic Vibration ◽  
Strain Rates ◽  
Plateau Stress ◽  
Specific Energy Absorption ◽  
Section Area ◽  
Luffa Sponge

The strain rate effect of luffa sponge material is an indispensable property for it to be used for acoustic, vibration, and impact energy absorption. Compressive tests at different strain rates on cylindrical column specimens of luffa sponge material were conducted over a wide density ranging from 24 to 64 kg/m3. A photographic technique was applied to measure the section area of the specimen with irregular shape. The mechanical properties of luffa sponge material at various strain rates were obtained based on this measurement. The dynamic data were compared to those of quasi-static experiments. It was found that compressive strength, plateau stress and specific energy absorption of luffa sponge material were sensitive to the rate of loading. Empirical formulae were developed for strength, densification strain and specific energy absorption at various strain rates in the macroscopic level by considering the luffa fiber as base material.

Dynamic Axial Compression of Square CFRP/Aluminium Tubes

2019 ◽  
Vol 794 ◽  
pp. 202-207
Author(s):  
Rafea Dakhil Hussein ◽  
Dong Ruan ◽  
Guo Xing Lu ◽  
Jeong Whan Yoon ◽  
Zhan Yuan Gao
Keyword(s):  
Energy Absorption ◽  
Specific Energy ◽  
Fibre Composite ◽  
Dynamic Tests ◽  
Carbon Fibre Composite ◽  
Specific Energy Absorption ◽  
Static Tests ◽  
Crushing Force ◽  
Cfrp Tubes ◽  
The Impact

Carbon fibre composite tubes have high strength to weight ratios and outstanding performance under axial crushing. In this paper, square CFRP tubes and aluminium sheet-wrapped CFRP tubes were impacted by a drop mass to investigate the effect of loading velocity on the energy absorption of CFRP/aluminium tubes. A comparison of the quasi-static and dynamic crushing behaviours of tubes was made in terms of deformation mode, peak crushing force, mean crushing force, energy absorption and specific energy absorption. The influence of the number of aluminium layers that wrapped square CFRP tubes on the crushing performance of tubes under axial impact was also examined. Experimental results manifested similar deformation modes of tubes in both quasi-static and dynamic tests. The dynamic peak crushing force was higher than the quasi-static counterpart, while mean crushing force, energy absorption and specific energy absorption were lower in dynamic tests than those in quasi-static tests. The mean crushing force and energy absorption decreased with the crushing velocity and increased with the number of aluminium layers. The impact stroke (when the force starts to drop) decreased with the number of aluminium layers.

Description of a 3-periodic minimal surface family with trigonal symmetry

1994 ◽  
Vol 209 (1) ◽  
Author(s):  
A. Fogden
Keyword(s):  
Minimal Surface ◽  
Minimal Surfaces ◽  
Weierstrass Representation ◽  
Systematic Analysis ◽  
Trigonal Symmetry ◽  
Triply Periodic Minimal Surfaces ◽  
Periodic Minimal Surface ◽  
Triply Periodic ◽  
The Family

AbstractA systematic analysis of a family of triply periodic minimal surfaces of genus seven and trigonal symmetry is given. The family is found to contain five such surfaces free from self-intersections, three of which are previously unknown. Exact parametrisations of all surfaces are provided using the Weierstrass representation.

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