scholarly journals Effect of Internal Microstructure Distribution on Quasi-Static Compression Behavior and Energy Absorption of Hollow Truss Structures

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5094
Author(s):  
Huilan Ren ◽  
Haiting Shen ◽  
Jianguo Ning
Keyword(s):  
Compressive Strength ◽  
Energy Absorption ◽  
Experimental Tests ◽  
Truss Structure ◽  
Truss Structures ◽  
Microstructure Design ◽  
Static Compression ◽  
Compression Behavior ◽  
Melting Technique ◽  
Quasi Static Compression

In this work, hollow truss structures with different internal microstructure distributions, i.e., basic hollow truss structure (specimen HT), hollow truss structure with internal microstructure at joints (specimen HTSJ), and hollow truss structure with internal microstructure on tube walls (specimen HTSW), were designed and manufactured using a selective laser melting technique. The effect of internal microstructure distribution on quasi-static compressive behavior and energy absorption was investigated by experimental tests and numerical simulations. The experimental results show that compressive strength and specific compressive strength of specimen HTSW increase by nearly 50% and 14% compared to specimen HT, and its energy absorption per volume and mass also increase by 52% and 15% at a strain of 0.5, respectively. However, the parameters of specimen HTSJ exhibit limited improvement or even a decrease in different degrees in comparison to specimen HT. The numerical simulation indicates that internal microstructures change the bearing capacity and structural weaknesses of the cells, resulting in the different mechanical properties and energy absorptions of the specimens. Based on the internal microstructure design in this study, adding microstructures into the internal weaknesses of the cells parallel to the loading direction is an effective way to improve the compressive properties, energy absorption and compressive stability of hollow truss structures.

scholarly journals Static Mechanical Properties of Expanded Polypropylene Crushable Foam

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 249
Author(s):  
Przemysław Rumianek ◽  
Tomasz Dobosz ◽  
Radosław Nowak ◽  
Piotr Dziewit ◽  
Andrzej Aromiński
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Strain Rate ◽  
Energy Absorption ◽  
Experimental Tests ◽  
Absorption Capacity ◽  
Strain Rates ◽  
Foam Density ◽  
Energy Absorption Capacity ◽  
Closed Cell

Closed-cell expanded polypropylene (EPP) foam is commonly used in car bumpers for the purpose of absorbing energy impacts. Characterization of the foam’s mechanical properties at varying strain rates is essential for selecting the proper material used as a protective structure in dynamic loading application. The aim of the study was to investigate the influence of loading strain rate, material density, and microstructure on compressive strength and energy absorption capacity for closed-cell polymeric foams. We performed quasi-static compressive strength tests with strain rates in the range of 0.2 to 25 mm/s, using a hydraulically controlled material testing system (MTS) for different foam densities in the range 20 g/dm3 to 220 g/dm3. The above tests were carried out as numerical simulation using ABAQUS software. The verification of the properties was carried out on the basis of experimental tests and simulations performed using the finite element method. The method of modelling the structure of the tested sample has an impact on the stress values. Experimental tests were performed for various loads and at various initial temperatures of the tested sample. We found that increasing both the strain rate of loading and foam density raised the compressive strength and energy absorption capacity. Increasing the ambient and tested sample temperature caused a decrease in compressive strength and energy absorption capacity. For the same foam density, differences in foam microstructures were causing differences in strength and energy absorption capacity when testing at the same loading strain rate. To sum up, tuning the microstructure of foams could be used to acquire desired global materials properties. Precise material description extends the possibility of using EPP foams in various applications.

scholarly journals Compressive Property of an Auxetic-Knitted Composite Tube Under Quasi-Static Loading

2020 ◽  
Vol 20 (2) ◽  
pp. 101-109 ◽  
Author(s):  
Andrews Boakye ◽  
Rafui King Raji ◽  
Pibo Ma ◽  
Honglian Cong
Keyword(s):  
Energy Absorption ◽  
Compression Test ◽  
Impact Loading ◽  
Static Loading ◽  
Fiber Content ◽  
Compressive Property ◽  
Static Compression ◽  
Arrow Head ◽  
Composite Tube ◽  
Quasi Static Compression

AbstractThis research investigates the compressive property of a novel composite based on a weft-knitted auxetic tube subjected to a quasi-static compression test. In order to maximize the influence of the fiber content on the compression test, a Kevlar yarn was used in knitting the tubular samples using three different auxetic arrow-head structures (i.e. 4 × 4, 6 × 6 and 8 × 8 structure). A quasi-static compression test was conducted under two different impact loading speeds (i.e. 5 mm/min and 15 mm/min loading speed). The results indicate that the energy absorption (EA) property of the auxetic composite is highly influenced by the auxeticity of the knitted tubular fabric.

Quasi-static compression behavior and microstructure changes in low-cost AA6061 composites

2021 ◽  
pp. 095440622110553
Author(s):  
Hariharasakthisudhan P ◽  
Hariharasudhan T ◽  
Karthik S ◽  
Sathickbasha K ◽  
Surya Rajan B
Keyword(s):  
Aspect Ratio ◽  
Strain Hardening ◽  
Axial Strain ◽  
Low Cost ◽  
Research Work ◽  
Strain Hardening Exponent ◽  
Static Compression ◽  
Compression Behavior ◽  
Maximum Value ◽  
Quasi Static Compression

The workability study of the composites enhances the understanding of the degree of plastic deformation that can be employed on it. The current research work highlights the response of the low-cost aluminum composites reinforced with exhausted alkaline battery powders under quasi-static compression. The effect of reinforcements and aspect ratio against the strain hardening exponent and strength coefficients were investigated. The microstructural changes after quasi-static compression were studied and related to the changes in the property of the composites. The composite with 6 wt.% of reinforcement showed the least amount of porosity as 1.2%. In most of the cases, the maximum value of average strain hardening exponent with respect to axial strain was noted in the composites with 6 wt. % of reinforcement. The lowest aspect ratio of 0.5 showed the maximum workability in the composites. The average strength coefficient was found to be maximum (308.58 MPa) in the composite with 2 wt.% reinforcement. The elongated grains and slip bands were observed in the microstructure of the compressed specimens.

scholarly journals Energy Absorption of Different Cell Structures for Closed-Cell Foam-Filled Tubes Subject to Uniaxial Compression

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1579 ◽  
Author(s):  
Yang Yu ◽  
Zhuokun Cao ◽  
Ganfeng Tu ◽  
Yongliang Mu
Keyword(s):  
Energy Absorption ◽  
Absorption Efficiency ◽  
Foam Core ◽  
Aluminum Foams ◽  
Static Compression ◽  
Cell Structures ◽  
Closed Cell ◽  
Energy Absorption Efficiency ◽  
Foam Filled ◽  
Quasi Static Compression

The energy absorption of different cell structures for closed-cell aluminum foam-filled Al tubes are investigated through quasi-static compression testing. Aluminum foams are fabricated under different pressures, obtaining aluminum foams with different cell sizes. It is found that the deformation of the foam core is close to the overall deformation, and the deformation band is seriously expanded when the cell size is fined, which leads to the increase of interaction. Results confirm that the foam-filled tubes absorb more energy due to the increase of interaction between the foam core and tube wall when the foaming pressure increases. The energy absorption efficiency of foam-filled tubes can reach a maximum value of 90% when the foam core is fabricated under 0.30 MPa, which demonstrates that aluminum foams fabricated under increased pressure give a new way for the applications of foam-filled tubes in the automotive industry.

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