scholarly journals Determination of energy absorption in different cellular auxetic structures

2019 ◽  
Vol 20 (3) ◽  
pp. 302 ◽  
Author(s):  
M. Shokri Rad ◽  
Hossein Hatami ◽  
R. Alipouri ◽  
A. Farokhi Nejad ◽  
F. Omidinasab
Keyword(s):  
Energy Absorption ◽  
Experimental Testing ◽  
Impact Resistance ◽  
Geometrical Parameters ◽  
Compression Tests ◽  
Fundamental Properties ◽  
Simulation Techniques ◽  
Auxetic Materials ◽  
Auxetic Structures ◽  
Energy Absorbers

This paper deals with the effect of unit cell configuration on the energy absorption response of different cellular auxetic structures subjected to quasi-static and dynamic loadings through the experimental and numerical methods. Among the various structures, a re-entrant structure was selected due to its fundamental properties underlying the main characteristics of an auxetic material. Computer simulation techniques using ABAQUS software validated by experimental testing were used to conduct the evaluation of such devices. Several re-entrant structures with different geometrical parameters were modeled and compared with the conventional ones. Standard compression tests were carried out on the different structures produced by the 3D printing machine to evaluate the influence of auxeticity phenomenon in the energy absorption capability. It is discovered that the auxetic structures are superior to non-auxetic structures in terms of all studied impact resistance and energy absorption indicators due to their ability to withstand quasi-static axial impact loads. The primary outcome of this research is to extract design information for the use of auxetic materials as energy absorbers where quasi-static loading is expected.

Bi-tubular corrugated composite conical–cylindrical tube for energy absorption in axial and oblique loading: Analysis and optimization

2020 ◽  
Vol 54 (18) ◽  
pp. 2399-2432 ◽  
Author(s):  
Amirreza Sadighi ◽  
Mahshid Mahbod ◽  
Masoud Asgari
Keyword(s):  
Finite Element ◽  
Energy Absorption ◽  
Cylindrical Tube ◽  
Element Model ◽  
Geometrical Parameters ◽  
Compression Tests ◽  
Static Compression ◽  
Optimization Study ◽  
Crushing Force ◽  
Optimum Model

In this paper, a new bi-tubular corrugated composite tube, consisting of inner and outer cylindrical and conical tubes is proposed. Different models with various geometrical parameters including the radius of curvatures and their numbers are considered and studied numerically in axial and oblique crushing in order to achieve favorable crashworthiness parameters. Moreover, quasi-static compression tests have been conducted to obtain results in order to validate the finite element model. There has been a sensible agreement between the numerical results and experimental data. Finite element models are also validated using the analytical solutions for both straight and corrugated composite tubes. Regardless of the number and radius of curvatures, as the crashworthiness of bi-tubular corrugated structures both in axial and oblique crushing is investigated and compared with their single-wall and bi-tubular straight peers, a considerable improvement is achieved in all crashworthiness parameters, including desirable increase in specific energy absorption, favorable reduction in peak force, and consequently a beneficial rise in crushing force efficiency. In addition, an optimization study using a suitable multi-objective function is done to choose the best model among the existing models, in addition to finding an optimum model via genetic algorithm. In the next step, a parametric study is conducted on the best model to inspect how well it undergoes oblique crushing at different angles. Finally, this best model and two other candidates have been chosen to investigate the effect of using foams and then the energy absorption capability of the empty and foam-filled tubes has been compared.

scholarly journals Energy Absorption Enhancement by Unit Cell Angle Grading or Sandwich Panels with Auxetic Core

2022 ◽  
Vol 58 (4) ◽  
pp. 94-101
Author(s):  
Oana Alexandra Mocian ◽  
Dan Mihai Constantinescu ◽  
Florin Baciu ◽  
Andrei Indres
Keyword(s):  
Energy Absorption ◽  
Sandwich Panels ◽  
Structural Response ◽  
Absorption Enhancement ◽  
Auxetic Materials ◽  
Unit Cells ◽  
Auxetic Structures ◽  
3D Printed ◽  
Manufacturing Techniques ◽  
Energy Absorbing

Architectured structures, particularly auxetic materials, have demonstrated encouraging applications in energy absorption as they facilitate the customization of their structural response. Specific geometries of unit cells can thus be tailored for particular needs due to recent progress in additive manufacturing techniques. This paper experimentally studies how the grading of the cell unit angle of an auxetic core in a sandwich panel affects its energy absorbing capability and structural response. 3D printed sandwich panels with uniform and graded auxetic cellular core were tested under quasistatic compression. The results show that sandwich panels with graded core exhibit much better energy absorption capabilities with higher plateau stress and densification strain. This indicates that, by appropriately controlling its geometry, auxetic structures can show further potential as core in sandwich panels for energy absorption applications.

scholarly journals Study in circular auxetic structures for efficiency enhancement in piezoelectric vibration energy harvesting

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Pejman Eghbali ◽  
Davood Younesian ◽  
Armin Moayedizadeh ◽  
Mostafa Ranjbar
Keyword(s):  
Energy Harvesting ◽  
Large Scale ◽  
Experimental Testing ◽  
Electrical Power ◽  
Vibration Energy ◽  
Geometrical Parameters ◽  
Efficiency Enhancement ◽  
Vibration Energy Harvesting ◽  
Power Extraction ◽  
Auxetic Structures

Abstract Piezoelectric (PZT) components are one of the most popular elements in vibration sensing and also energy harvesting. They are very well established, cost effective and available in different geometries however there are still several challenges in their application particularly in vibration energy harvesting. They are normally narrow-band elements and work in high-frequency range. Their efficiency and power extraction density are also generally low compared with different electromagnetic techniques. Auxetic structures are proposed here to enhance efficiency of the piezoelectric circular patches in vibration energy harvesting. These kinds of patches namely PZT buzzers are inexpensive (less than 10 USD) elements and easily available. Two novel circular auxetic substrates are proposed to improve power extraction capacity of the conventional piezoelectric buzzers. Negative Poison’s ratio of the proposed meta-structure helps in efficiency enhancement. The concept is introduced, analyzed and verified through the finite element modeling and experimental testing. The idea is proved to work by comparing the harvested electrical power in the auxetic design against the conventional plain system. A parametric study is then carried out and effects of important electrical and geometrical parameters as well as the material property on the power extraction efficiency are assessed to arrive at optimum parameters. It is shown that by employing the auxetic design, a remarkable improvement in the harvested power is achievable. It is shown that for the two proposed auxetic designs, at the resonance frequency, we could reach to 10.2 and 13.3 magnification factor with respect to the plain energy harvester. Another important feature is that the resonant frequency in these new designs is very much lower than the conventional resonators. Results of this study can open a new path to application of inexpensive PZT buzzers in large-scale vibration energy harvesting.

scholarly journals Experimental and Numerical Analysis of 3D Printed Polymer Tetra-Petal Auxetic Structures under Compression

2021 ◽  
Vol 11 (21) ◽  
pp. 10362
Author(s):  
Demetris Photiou ◽  
Stelios Avraam ◽  
Francesco Sillani ◽  
Fabrizio Verga ◽  
Olivier Jay ◽  
...  
Keyword(s):  
Finite Element ◽  
3D Printing ◽  
Mechanical Response ◽  
Mechanical Performance ◽  
Poisson Ratio ◽  
Impact Resistance ◽  
Experimental Tests ◽  
Polymer Materials ◽  
Compression Tests ◽  
Auxetic Structures

Auxetic structures possess a negative Poisson ratio (ν < 0) as a result of their geometrical configuration, which exhibits enhanced indentation resistance, fracture toughness, and impact resistance, as well as exceptional mechanical response advantages for applications in defense, biomedical, automotive, aerospace, sports, consumer goods, and personal protective equipment sectors. With the advent of additive manufacturing, it has become possible to produce complex shapes with auxetic properties, which could not have been possible with traditional manufacturing. Three-dimensional printing enables easy and precise control of the geometry and material composition of the creation of desirable shapes, providing the opportunity to explore different geometric aspects of auxetic structures with a variety of different materials. This study investigated the geometrical and material combinations that can be jointly tailored to optimize the auxetic effects of 2D and 3D complex structures by integrating design, modelling approaches, 3D printing, and mechanical testing. The simulation-driven design methodology allowed for the identification and creation of optimum auxetic prototype samples manufactured by 3D printing with different polymer materials. Compression tests were performed to characterize the auxetic behavior of the different system configurations. The experimental investigation demonstrated a Poisson’s ration reaching a value of ν = −0.6 for certain shape and material combinations, thus providing support for preliminary finite element studies on unit cells. Finally, based on the experimental tests, 3D finite element models with elastic material formulations were generated to replicate the mechanical performance of the auxetic structures by means of simulations. The findings showed a coherent deformation behavior with experimental measurements and image analysis.

scholarly journals The Influences of Projectile Material and Environmental Temperature on the High Velocity Impact Behavior of Triaxial Braided Composites

2021 ◽  
Vol 11 (8) ◽  
pp. 3466
Author(s):  
Lulu Liu ◽  
Shikai Yin ◽  
Gang Luo ◽  
Zhenhua Zhao ◽  
Wei Chen
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Energy Absorption ◽  
Cryogenic Temperature ◽  
Environmental Temperature ◽  
Impact Resistance ◽  
Matrix Cracking ◽  
Braided Composites ◽  
Damage Pattern ◽  
Braided Composite

Two-dimensional (2D) triaxial braided composites with braiding angle (± 60°/0°) have been used as aero-engine containing casing material. In the current paper, three types of projectile with the same mass and equivalent diameter, including cylinder gelatin projectile, carbon fiber-reinforced plastics (CFRP), and titanium alloy blade-like projectile, were employed to impact on triaxial braided composites panels with thickness of 4.3 mm at room temperature (20 °C) to figure out the influences of projectile materials on the damage pattern and energy absorption behavior. Furthermore, the influences of environmental temperature were also discussed considering the aviation service condition by conducting ballistic impact tests using CFRP projectile at cryogenic temperature (−50 °C) and high temperature (150 °C). The triaxial braided target panel were pre-heated or cooled in a low-temperature chamber before mounted. It is found that soft gelatin project mainly causes global deformation of the target and therefore absorb much more energy. The triaxial braided composite absorb 77.59% more energy when impacted with CFRP projectile than that with titanium alloy projectile, which mainly results in shear fracture. The environmental temperature has influences on the damage pattern and energy absorption of triaxial braided composites. The cryogenic temperature deteriorates the impact resistance of the triaxial braided composite material with matrix cracking damage pattern, while high temperature condition improves its impact resistance with shearing fracture damage pattern.

Fabrication of Bulk Functionally-Graded Syntactic Foams for Impact Energy Absorption

2012 ◽  
Vol 706-709 ◽  
pp. 711-716 ◽  
Author(s):  
Tadaharu Adachi ◽  
Masahiro Higuchi
Keyword(s):  
Theoretical Analysis ◽  
Energy Absorption ◽  
Functionally Graded ◽  
Fabrication Process ◽  
Syntactic Foams ◽  
Compression Tests ◽  
Matrix Resin ◽  
Local Fracture ◽  
Density Distributions ◽  
The Matrix

Function of functionally-graded (FG) foams as energy absorption material for impact was discussed on the basis of theoretical analysis, and fabrication process of the foams was proposed in the paper. The FG foams were found to be useful as impact absorber due to progressively local fracture or cushion in the theoretical analysis. Next the fabrication process of the FG foams was suggested. The graded dispersion of the micro-balloons was conducted before curing the matrix resin in the process. The density distributions in the FG foams were confirmed to be predicted by the numerical analysis on the basis of floating the micro-balloons. Finally, compression tests were carried out to evaluate mechanical properties.

An experimental investigation on mechanical performances of 3D printed lightweight ABS pipes with different cellular wall thickness

2021 ◽  
Vol 15 (2) ◽  
pp. 8169-8177
Author(s):  
Berkay Ergene ◽  
İsmet ŞEKEROĞLU ◽  
Çağın Bolat ◽  
Bekir Yalçın
Keyword(s):  
Compressive Strength ◽  
Energy Absorption ◽  
Wall Thickness ◽  
Lattice Structure ◽  
Honeycomb Structure ◽  
Cellular Structures ◽  
Compression Tests ◽  
Absorbed Energy ◽  
Great Opportunity ◽  
3D Printed

In recent years, cellular structures have attracted great deal of attention of many researchers due to their unique properties like exhibiting high strength at low density and great energy absorption. Also, the applications of cellular structures (or lattice structures) such as wing airfoil, tire, fiber and implant, are mainly used in aerospace, automotive, textile and biomedical industries respectively. In this investigation, the idea of using cellular structures in pipes made of acrylonitrile butadiene styrene (ABS) material was focused on and four different pipe types were designed as honeycomb structure model, straight rib pattern model, hybrid version of the first two models and fully solid model. Subsequently, these models were 3D printed by using FDM method and these lightweight pipes were subjected to compression tests in order to obtain stress-strain curves of these structures. Mechanical properties of lightweight pipes like elasticity modulus, specific modulus, compressive strength, specific compressive strength, absorbed energy and specific absorbed energy were calculated and compared to each other. Moreover, deformation modes were recorded during all compression tests and reported as well. The results showed that pipe models including lattice wall thickness could be preferred for the applications which don’t require too high compressive strength and their specific energy absorption values were notably capable to compete with fully solid pipe structures. In particular, rib shape lattice structure had the highest elongation while the fully solid one possessed worst ductility. Lastly, it is pointed out that 3D printing method provides a great opportunity to have a foresight about production of uncommon parts by prototyping.

Impact resistance and energy absorption mechanisms in hybrid composites

1989 ◽  
Vol 34 (4) ◽  
pp. 305-335 ◽  
Author(s):  
B.Z. Jang ◽  
L.C. Chen ◽  
C.Z. Wang ◽  
H.T. Lin ◽  
R.H. Zee
Keyword(s):  
Energy Absorption ◽  
Hybrid Composites ◽  
Impact Resistance

Adaptive-Curvature Structures with Auxetic Materials

2018 ◽  
Vol 1149 ◽  
pp. 53-63
Author(s):  
Roberto Naboni ◽  
Stefano Sartori ◽  
Lorenzo Mirante
Keyword(s):  
Large Scale ◽  
Morphological Features ◽  
Geometrical Parameters ◽  
Computational Tools ◽  
Auxetic Materials ◽  
Initial Geometry ◽  
Tools And Methods

Advancements in computational tools are offering designers the possibility to change their relationship with materials and establishing new synergies between matter, form and behaviour. This work explores this paradigm by introducing the use of auxetic metamaterials, specifically engineered to obtain properties beyond those found in nature, to generate structures with adaptive curvature obtained from planar construction elements. It is discussed how through programming an initial geometry with the strategic negotiation of several geometrical parameters it is possible to control finely the structural and morphological features of a structure. The paper presents approach, tools and methods for designing auxetics for large scale applications, and use them to create heterogeneous active-bending structures.

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