Material oriented crash-box design – Combining structural and material design to improve specific energy absorption

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.

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Expansion based composite tubes as energy absorbers for improved specific energy absorption: FEA based study

Materials Today Proceedings ◽

10.1016/j.matpr.2020.12.786 ◽

2021 ◽

Author(s):

Venkateswarlu Gattineni ◽

Venukumar Nathi

Keyword(s):

Energy Absorption ◽

Specific Energy ◽

Composite Tubes ◽

Specific Energy Absorption ◽

Energy Absorbers

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Ballistic Performance Evaluation of Kevlar-Glass Fibre Hybrid Composite Laminate against Medium Velocity Impact

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1165.47 ◽

2021 ◽

Vol 1165 ◽

pp. 47-64

Author(s):

Saurabh S. Kumar ◽

Rajesh G. Babu ◽

U. Magarajan

Keyword(s):

Energy Absorption ◽

Specific Energy ◽

Glass Fibre ◽

Hybrid Composite ◽

Composite Laminates ◽

Areal Density ◽

Ballistic Performance ◽

Performance Requirement ◽

Specific Energy Absorption ◽

Fabric Composite

In this paper, the post ballistic impact behaviour of kevlar-glass fibre hybrid composite laminates was investigated against 9×19 mm projectile. Eight different types of composite laminates with different ratios of kevlar woven fibre to glass fibre were fabricated using hand lay-up with epoxy matrix. Ballistic behaviour like ballistic Limit (V50), energy absorption, specific energy absorption and Back Face Signature (BFS) were studied after bullet impact. The results indicated that as the Percentage of glass fibre is increased there was a linear increment in the ballistic behaviour. Addition of 16% kevlar fabric, composite sample meets the performance requirement of NIJ0101.06 Level III-A. Since the maximum specific energy absorption was observed in Pure Kevlar samples and the adding of glass fibre increases the weight and Areal Density of the sample, further investigations need to be carried out to utilize the potential of glass fibre for ballistic applications.

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Enhancement in specific energy absorption of invertubes

International Journal of Mechanical Sciences ◽

10.1016/j.ijmecsci.2019.06.016 ◽

2019 ◽

Vol 159 ◽

pp. 424-440 ◽

Cited By ~ 3

Author(s):

T.J. Reddy ◽

V. Narayanamurthy ◽

Y.V.D. Rao

Keyword(s):

Energy Absorption ◽

Specific Energy ◽

Specific Energy Absorption

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

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1177/0954407020961885 ◽

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).

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

The Journal of Strain Analysis for Engineering Design ◽

10.1177/0309324719847069 ◽

2019 ◽

Vol 54 (3) ◽

pp. 176-191 ◽

Cited By ~ 2

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.

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

Materials Science Forum ◽

10.4028/www.scientific.net/msf.991.62 ◽

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.

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Architected functionally graded porous lattice structures for optimized elastic-plastic behavior

Proceedings of the Institution of Mechanical Engineers Part L Journal of Materials Design and Applications ◽

10.1177/1464420720923004 ◽

2020 ◽

Vol 234 (8) ◽

pp. 1099-1116 ◽

Cited By ~ 2

Author(s):

Mahshid Mahbod ◽

Masoud Asgari ◽

Christian Mittelstedt

Keyword(s):

Mechanical Properties ◽

Energy Absorption ◽

Specific Energy ◽

Elastic Moduli ◽

Maximum Stress ◽

Functionally Graded ◽

Plastic Behavior ◽

Lattice Structures ◽

Porous Structures ◽

Specific Energy Absorption

In this paper, the elastic–plastic mechanical properties of regular and functionally graded additively manufactured porous structures made by a double pyramid dodecahedron unit cell are investigated. The elastic moduli and also energy absorption are evaluated via finite element analysis. Experimental compression tests are performed which demonstrated the accuracy of numerical simulations. Next, single and multi-objective optimizations are performed in order to propose optimized structural designs. Surrogated models are developed for both elastic and plastic mechanical properties. The results show that elastic moduli and the plastic behavior of the lattice structures are considerably affected by the cell geometry and relative density of layers. Consequently, the optimization leads to a significantly better performance of both regular and functionally graded porous structures. The optimization of regular lattice structures leads to great improvement in both elastic and plastic properties. Specific energy absorption, maximum stress, and the elastic moduli in x- and y-directions are improved by 24%, 79%, 56%, and 9%, respectively, compared to the base model. In addition, in the functionally graded optimized models, specific energy absorption and normalized maximum stress are improved by 64% and 56%, respectively, in comparison with the base models.

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