Novel Design and Comparison of Structural and Modal Analyses of Auxetic Geometry versus Honeycomb Geometry

2021 ◽  
Vol 36 (4) ◽  
pp. 398-402
Author(s):  
U. Kemiklioğlu
Keyword(s):  
Tensile Strength ◽  
Modal Analysis ◽  
Impact Energy ◽  
Ansys Software ◽  
Energy Increase ◽  
Auxetic Structures ◽  
Lateral Displacements ◽  
The Impact ◽  
Novel Design ◽  
Auxetic Structure

Abstract Auxetic structures are popular, since they have many applications in defense, textile and sport industries. The advantages of providing comfort and protection to people for the impact energy increase the usability of auxetic structures in these areas. Within the scope of this study, two structures were designed as honeycomb and auxtetic structures with lateral displacements in opposite directions. The auxetic and honeycomb structures were modeled in Ansys software by keeping the boundaries of these two structures close to each other. Structural and modal analysis were applied to these structures and the auxetic structure gave better results in terms of the tensile strength.

scholarly journals 4D Printing of NiTi Auxetic Structure with Improved Ballistic Performance

Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 745
Author(s):  
Hany Hassanin ◽  
Alessandro Abena ◽  
Mahmoud Ahmed Elsayed ◽  
Khamis Essa
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Analytical Model ◽  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
4D Printing ◽  
Auxetic Structures ◽  
Negative Poisson's Ratio ◽  
The Impact ◽  
Auxetic Structure

Auxetic structures have attracted attention in energy absorption applications owing to their improved shear modulus and enhanced resistance to indentation. On the other hand, four-dimensional (4D) printing is an emerging technology that is capable of 3D printing smart materials with additional functionality. This paper introduces the development of a NiTi negative-Poisson’s-ratio structure with superelasticity/shape memory capabilities for improved ballistic applications. An analytical model was initially used to optimize the geometrical parameters of a re-entrant auxetic structure. It was found that the re-entrant auxetic structure with a cell angle of −30° produced the highest Poisson’s ratio of −2.089. The 4D printing process using a powder bed fusion system was used to fabricate the optimized NiTi auxetic structure. The measured negative Poisson’s ratio of the fabricated auxetic structure was found in agreement with both the analytical model and the finite element simulation. A finite element model was developed to simulate the dynamic response of the optimized auxetic NiTi structure subjected to different projectile speeds. Three stages of the impact process describing the penetration of the top plate, auxetic structure, and bottom plate have been identified. The results show that the optimized auxetic structures affect the dynamic response of the projectile by getting denser toward the impact location. This helped to improve the energy absorbed per unit mass of the NiTi auxetic structure to about two times higher than that of the solid NiTi plate and five times higher than that of the solid conventional steel plate.

scholarly journals Effect of Aluminum on Microstructure and Mechanical Properties of Weld Metal of Q960 Steel

Crystals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 26
Author(s):  
Zongxuan Zou ◽  
Zhengjun Liu ◽  
Xingyu Ai ◽  
Dan Wu
Keyword(s):  
Tensile Strength ◽  
Weld Metal ◽  
Impact Energy ◽  
Hsla Steel ◽  
Low Carbon Steel ◽  
High Strength ◽  
Low Carbon ◽  
Cored Wire ◽  
Al Content ◽  
The Impact

High-strength low-alloy (HSLA) steel is used in important steel structural members because of its strength and plastic toughness. Q960 steel is HSLA steel obtained by adding an appropriate amount of alloy elements and quenching and tempering treatment on the basis of ordinary low-carbon steel. This kind of steel has strong hardenability due to the alloy elements added. Cold cracks, embrittlement and softening of the heat-affected zone easily occur after welding. In particular, the low-temperature impact toughness cannot meet the requirements and limits its use. In this paper, self-shielded welding is used to adjust the content of aluminum in flux-cored wire. The relationship between weld metal (WM) microstructure and strength and properties was studied by tensile test and impact test, and the influence mechanism of Al content on weld metal microstructure and properties was analyzed. The results show that when the content of Al is 0.21%, the impact energy at 0 °C~−60 °C is the best, the tensile strength can reach 1035 MPA and the number of pores is small. The size of inclusions in WM is mostly less than 1.0 μm Al2O3 spherical oxide. It can become the center of acicular ferrite (AF) and increase the nucleation probability. However, with the increase of Al content, large irregular AlN inclusions are produced, which reduces the tensile strength and impact energy of the welded joint.

Microstructures and Mechanical Properties of High Strength Low Carbon Bainitic Steel

2015 ◽  
Vol 817 ◽  
pp. 257-262 ◽  
Author(s):  
Xiao Long Yang ◽  
Yun Bo Xu ◽  
Xiao Dong Tan ◽  
Yong Mei Yu ◽  
Di Wu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Impact Energy ◽  
Bainitic Steel ◽  
Cooling Temperature ◽  
Fast Cooling ◽  
Microstructures And Mechanical Properties ◽  
The Impact ◽  
Strength And Toughness

Based on TMCP and UFC technology, the microstructures and mechanical properties of 0.05% C bainitic steel were studied in this paper. The bainite morphology and precipitation within bainite lath were observed by SEM and TEM, and the mechanical properties of bainitic steel were measured by tensile and impact test. The results showed that the yield and tensile strengths of steel were 713 MPa and 891 MPa respectively, and the elongation was 15.8% with impact energy of 95J at the temperature of-20°C as the final cooling temperature in hot rolling of 550°C. For comparison, the steel obtained the yield strength of 725 MPa, tensile strength of 930 MPa and elongation of 18% as the final cooling temperature of 450°C. However, the impact energy of steel was 195J at the temperature of-20°C. While at the same final cooling temperature of 450°C, the fast cooling-holding temperature-fast cooling was applied to experimental steel with a faster cooling rate of 50°C/s, hence the steel acquired the yield strength of 845 MPa, tensile strength of 1037 MPa, and elongation of 15.5% with impact energy of 168J at the temperature of-20°C. The strength and toughness of 0.05%C bainitic steel is related to the bainite morphology and precipitation distribution. Hence, the strength and toughness can be improved by control the different cooling processes for adjusting the content of lath bainite, distribution of granular bainite and precipitation.

Tribological Behavior, Machinability, and Optimization of EDM of AA-2014 Hybrid Composite Reinforced With SiC and Glass Particulates

2020 ◽  
pp. 228-269
Author(s):  
Mohan Kumar Pradhan
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Impact Energy ◽  
Tribological Behavior ◽  
Stir Casting ◽  
Electro Discharge Machining ◽  
Pca Method ◽  
Influencing Parameters ◽  
Moora Method ◽  
The Impact

In the present work, the mechanical, tribological behavior of the machinability using electro discharge machining on a hybrid reinforced with different compositions of SiC and glass particulates are fabricated through a stir casting route. The effect of composition with machine parameters on the responses was observed. The Taguchi L9 orthogonal array was used for conducting the experiments, and the optimal EDM machining condition was obtained by performing MULTI-MOORA method integrated with PCA method. However, the effect of load, speed, and composition was investigated for tribological properties. It has been observed that SiC and glass particulates, significantly affect the compressive strength and hardness. However, the impact energy reduces an increase in the brittle nature of the composite. The glass particles do not contribute to the tensile strength but significantly improve the tribological property. The composition and pulse current found to be the most influencing parameters, the composition (Al- 2014+2wt% glass+3 wt% SiC) has led to the best combination for machinability.

scholarly journals Impact Analysis of Auxetic Structures for Military Applications

2021 ◽  
Vol 9 (9) ◽  
pp. 2238-2249
Author(s):  
Rohit De
Keyword(s):  
3D Printing ◽  
Polyvinyl Chloride ◽  
Poisson’S Ratio ◽  
Impact Analysis ◽  
Poisson's Ratio ◽  
Suitable Material ◽  
Auxetic Structures ◽  
Explicit Dynamic ◽  
The Impact ◽  
Auxetic Structure

Abstract: Auxetic structures are special structures which tend to become wider when subjected to longitudinal tension instead of getting compressed, which implies structures having a negative poisson’s ratio. These structures are used in impact pads due to this unique property. In this comparative study were done on different types of materials and structures which are recognized for 3D printing the auxetic structures. The three stages of explicit dynamic analysis involves firstly selecting the most appropriate structures from chiral truss, re-entrant hexagon, arrow head and one non- auxetic structure which is hexagon structure. From this the structure having the least deformation at the impact point is selected which is re-entrant hexagon. Following this, keeping re-entrant hexagon as the structure, the next set of analysis is performed by varying the structure materials. Polycarbonate, polystyrene, polyvinyl chloride and high density polyethylene were studied and the analysis results showed, polyvinyl chloride as the suitable material. Lastly the limiting velocity for the impact is calculated by varying the impact velocity from 800m/s, 1000m/s and 1200m/s beyond which the structure experienced fracture. This study proposes the selection of suitable auxetic structure and material for manufacturing impact pads. Keywords: Auxetic structures, impact pads, indentation resistance, explicit dynamics, 3D printing, FDM, Poisson’s ratio

scholarly journals Conceptual Design of a Roller Obstacle Deflector

2020 ◽  
Vol 9 (11) ◽  
pp. 217-224
Keyword(s):  
Conceptual Design ◽  
Impact Energy ◽  
Impact Force ◽  
Ansys Software ◽  
Software Simulation ◽  
Reaction Forces ◽  
Living Organisms ◽  
The Impact ◽  
Animal Category ◽  
Absorb Impact Energy

An Obstacle Deflector is a device mounted in front of the trains to sweep away the obstacle off the track or absorb impact energy to prevent derailment. On considering the same concept which sweeps the obstacle, I have designed a device that sweeps away living obstacles (animals, Humans) from the tracks with life expectancy. Many animals are killed over the tracks in regular train accidents. Based on this issue, here my project discusses with the conceptual design of a roller obstacles deflector that absorbs the impact energy on collision and sideways the obstacle using roller based polyethylene rollers applied in front of the train. The cushioning effect designed for the device helps to reduce the impact force when Train hits the living obstacles (Human, cow and elephant) at speed of 30km/hr. or 8111 mm/s., With a load of 50 Tonne. As per study, human pain can be measured in Del (Dolorimeter) which explains that the maximum limit of pain average human being can withstand is 45 Del. But, breaking of a bone is almost equals to 57 Del. Some studies say Del is equal to 1403.508 N forces. By this data and using the reaction forces resulted at the time of clash in Ansys software simulation, we can state the amt. of pain (in terms of DEL) to some living organisms and can conclude the functionality of the device to save the life. This design works for the limited animal category based upon size and weight of the animal. This design works under the limited speed and with limited load to safeguard the animals and humans on the track. This design does not impact on the existing safety conditions of the railways as it’s absorb the impact up to limited extend. The modeling is done using CATIA. The explicit dynamics of impact is done with ANSYS

Effect of Alloy Addition on Mechanical Properties and Decarburization Sensitivity of Spring Steel

2012 ◽  
Vol 476-478 ◽  
pp. 188-193
Author(s):  
Jun Tian ◽  
Shun Xue ◽  
Guo Guang Cheng ◽  
Kuo Chih Chou
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Energy ◽  
Induction Furnace ◽  
High Strength ◽  
Spring Steel ◽  
Vacuum Induction Furnace ◽  
High Toughness ◽  
Alloy Addition ◽  
The Impact

The mechanical properties and decarburization layer depths after heat treatment have been investigated for the experimental steels，which were melted by means of 10Kg vacuum induction furnace in the laboratory . It has been confirmed that additions of silicon and vanadium can improve strength of the steels and, the tensile strength of the steels increases with silicon content from 1.4% up to 2.0%. The reduction of carbon content and the addition of carbide forming elements decrease the decarburization sensitivity of the steels tested. The tensile strengths of the steels with carbon less than 0.5% are between 1016.88 to 1674.64 MPa, and the impact energy between 15.50 to 34.50 J, which are compared with the tensile strength of 1160.89MPa, the impact energy of 19.00 J for 55SiCrV. The steels with optimized compositions, which consists of 0.4~0.5% C, 1.6~2.0% Si, 0.8% Cr, 0.2% V, have a satisfactory property with high strength, high toughness and good anti-decarburization.

scholarly journals Effects of Rare Earth Elements (Ce, Y) on Microstructure and Mechanical Properties of P20 Die Steel

2021 ◽  
Vol 2101 (1) ◽  
pp. 012085
Author(s):  
Dan Wu ◽  
Qiang Hu ◽  
Wei Chen ◽  
Deping Lu ◽  
Jin Zou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Rare Earth ◽  
Impact Energy ◽  
Mechanical Tests ◽  
Strength Increase ◽  
Die Steels ◽  
Matrix Microstructure ◽  
Microstructure And Mechanical Properties ◽  
The Impact

Abstract Electroslag remelting P20 die steels with different amount of CeO2 or Y2O3 additions have been investigated by using mechanical tests and scanning electronic microscope with energy dispersive spectrometry. The microstructure of P20 die steels is tempered martensite, in which plenty of carbides precipitate along the martensite laths. With addition of rare earth Ce or Y, the matrix microstructure is refined, the quantity of carbides is decreased, and the distribution of carbides becomes more uniform. As a result of these microstructural changes, both the impact energy and tensile strength increase with increasing rare earth content. The samples obtain optimum microstructure and mechanical properties when the amount of CeO2 or Y2O3 additions reach 4 wt.%. However, over-added CeO2 or Y2O3 (>4 wt.%) results in the increase of carbides quantity and the aggregation of carbides, which reduces the impact energy and tensile strength of the samples. Present study indicates that the optimum addition of CeO2 and Y2O3 for the P20 die steels is 4 wt.%.

Effect of combined drink cans and steel fibers on the impact resistance and mechanical properties of concrete

2020 ◽  
Vol 14 (2) ◽  
pp. 6734-6742
Author(s):  
A. Syamsir ◽  
S. M. Mubin ◽  
N. M. Nor ◽  
V. Anggraini ◽  
S. Nagappan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Indirect Tensile ◽  
The Impact

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study.  The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.    

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