scholarly journals Influence of the material microstructural properties on a 3-point bending test

2020 ◽  
Vol 21 (5) ◽  
pp. 518
Author(s):  
Ahmed Maati ◽  
Laurent Tabourot ◽  
Pascale Balland ◽  
Salim Belaid

The purpose of this study is to highlight the role played by some important factors on sprinback phenomenon. This latter affects significantly the geometry of the manufactured product. Large automotive or plane body parts are specifically affected by this phenomenon which complicates the tools design. The study focuses here on specific materials with high trend to develop heterogeneous strains during forming processes. Due to its hexagonal crystalline structure, titanium has initial heterogeneous microstructure that grows stronger when plastic strain occurs. Heterogeneous microstructures induce the coexistence in the material of volumes with different mechanical properties even, in some case, with different mechanical behaviours. Therefore, accommodation between these volumes generates distributed internal stresses and important elastic energy storage. The macroscopic behaviour can be provided either by average phenomenological constitutive equation identical for all locations in the material or by integrating a set of local constitutive relations taking into account the variability of the behaviour as a function of the position in the material. In this context, experimental and numerical studies of a 3-point bending test on titanium alloy are considered.

Author(s):  
William Wan ◽  
Rudolph L. Gleason

Recent studies have revealed that carotid arteries from fibulin-5 (fbln5) null mice exhibit altered biomechanical and microstructural properties [1–2]. While the previous studies outline quantitative differences in mechanical properties of arteries from fbln5 null and wildtype mice, physical microstructural differences have yet to be quantified. Measurement of microstructural parameters will provide a crucial link between previously quantified mechanical properties and biological effects of knocking out the fbln5 gene. Characterizing microstructural properties will also provide experimental data to validate structurally-motivated constitutive relations and growth and remodeling models [3–4]. In this study, we quantified collagen fiber orientation in carotid arteries from fbln5 null and wildtype mice; collagen in mouse carotid arteries were imaged using multiphoton microscopy and analyzed using a fast Fourier transform algorithm.


2015 ◽  
Vol 813-814 ◽  
pp. 62-66
Author(s):  
S. Maivizhi Selvi ◽  
A. Saravana Kumar ◽  
G. Isaac Daniel Raj ◽  
N. Keerthana ◽  
G.D. Madhanagopal ◽  
...  

In this investigation, the influence of MoS2 on the mechanical properties of Al6061-Al2O3hybrid composites was studied. The composites of Al6061 alloy, AA 6061-6% Al2O3 and Al6061-6% Al2O3-2% MoS2 were manufactured using Stir casting method. These samples were examinedusing optical microscope for the dispersion of reinforcement (Al2O3 ) and solid lubricant (MoS2).The micro structure revealed that there were even distribution of the additives in the Al6061 matrix.The presence of these particles improved the mechanical properties of the composites. For these compositions flexural strength was found using 3 point bending test and impact strength was found using Charpy test. It was observed that the hardness, toughness and flexural strength values increases with the addition of Al2O3 and decreases with the addition of MoS2 to the second composition.


2021 ◽  
Vol 63 (1) ◽  
pp. 97-101
Author(s):  
İsmail Açar ◽  
Behçet Gülenç

Abstract The quality of welded joints depends on the most optimal welding parameters and the selection of shielding gas type. The shielding gas was selected for joining stainless steels through gas metal arc welding methods by considering properties such as chemical-metallurgical interaction of shielding gas and the molten weld metal during the welding process, heat transmission capability of the gas and cost. In this study, the effect of different shielding gas combinations on the mechanical and microstructural properties of 316 austenitic stainless steel joined by the metal inert gas (MIG) welding method was investigated. In the welding process, pure argon (100 % Ar), 98.5 % Ar + 1.5 % H2 and 95 % Ar + 5 % H2 were used as shielding gases. Tensile, hardness, and bending tests were conducted to determine mechanical properties of the welded samples. In addition, metallographic examinations were carried out to detect the macrostructural and microstructural properties of weld zones. According to the results obtained from the study, the highest tensile strength was obtained from the joints welded using 100 % Ar shielding gas. When the addition of H2 into the Ar gas increased, the tensile strength of the welded samples decreased. As a result of the tensile test, fractures occurred in the base metal in all welded samples. In all welding parameters, the hardness of the weld metal was lower as compared to the heat affected zone (HAZ) and the base metal. As a result of the bending test, crack and tearing defects were found in the weld zone.


Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1656
Author(s):  
Carla Huerta-López ◽  
Jorge Alegre-Cebollada

Biomaterials are dynamic tools with many applications: from the primitive use of bone and wood in the replacement of lost limbs and body parts, to the refined involvement of smart and responsive biomaterials in modern medicine and biomedical sciences. Hydrogels constitute a subtype of biomaterials built from water-swollen polymer networks. Their large water content and soft mechanical properties are highly similar to most biological tissues, making them ideal for tissue engineering and biomedical applications. The mechanical properties of hydrogels and their modulation have attracted a lot of attention from the field of mechanobiology. Protein-based hydrogels are becoming increasingly attractive due to their endless design options and array of functionalities, as well as their responsiveness to stimuli. Furthermore, just like the extracellular matrix, they are inherently viscoelastic in part due to mechanical unfolding/refolding transitions of folded protein domains. This review summarizes different natural and engineered protein hydrogels focusing on different strategies followed to modulate their mechanical properties. Applications of mechanically tunable protein-based hydrogels in drug delivery, tissue engineering and mechanobiology are discussed.


2008 ◽  
Vol 591-593 ◽  
pp. 436-440
Author(s):  
João Marcos K. Assis ◽  
Francisco Piorino Neto ◽  
Francisco Cristóvão Lourenço de Melo ◽  
Maria do Carmo de Andrade Nono

A comparative study between alumina added niobia ceramics and two alumina zirconia composites from nanostructured TZP (7% and 14% weight) was made. On this composites the zirconia were yttria stabilized and the alumina were submicron structured. As sintering aid a mixture of magnesia, niobia and talc were used on all samples. The sintering was performed at 1450 oC during 60 minutes. The characteristic grain size and shape of an alumina and zirconia powders, aggregates and agglomerates were characterized. The sintering ceramics were evaluated through hardness, fracture toughness and 4 point bending test. Weibull statistic was applied on the flexural results. Although the fracture toughness result from ZTA were lower, and seems to be affected by the liquid fase, the hardness and Weibull modulus were higher than alumina niobia. The grains size and the homogeneity of its distributions on the microstructure of this ceramics was correlated to these higher values. The results from these alumina zirconia composites showed a potential to apply as a ballistic armor material.


2021 ◽  
Vol 13 (10) ◽  
pp. 5494
Author(s):  
Lucie Kucíková ◽  
Michal Šejnoha ◽  
Tomáš Janda ◽  
Jan Sýkora ◽  
Pavel Padevět ◽  
...  

Heating wood to high temperature changes either temporarily or permanently its physical properties. This issue is addressed in the present contribution by examining the effect of high temperature on residual mechanical properties of spruce wood, grounding on the results of full-scale fire tests performed on GLT beams. Given these tests, a computational model was developed to provide through-thickness temperature profiles allowing for the estimation of a charring depth on the one hand and on the other hand assigning a particular temperature to each specimen used subsequently in small-scale tensile tests. The measured Young’s moduli and tensile strengths were accompanied by the results from three-point bending test carried out on two groups of beams exposed to fire of a variable duration and differing in the width of the cross-section, b=100 mm (Group 1) and b=160 mm (Group 2). As expected, increasing the fire duration and reducing the initial beam cross-section reduces the residual bending strength. A negative impact of high temperature on residual strength has also been observed from simple tensile tests, although limited to a very narrow layer adjacent to the charring front not even exceeding a typically adopted value of the zero-strength layer d0=7 mm. On the contrary, the impact on stiffness is relatively mild supporting the thermal recovery property of wood.


2013 ◽  
Vol 486 ◽  
pp. 283-288
Author(s):  
Ladislav Fojtl ◽  
Soňa Rusnáková ◽  
Milan Žaludek

This research paper deals with an investigation of the influence of honeycomb core compression on the mechanical properties of sandwich structures. These structures consist of prepreg facing layers and two different material types of honeycomb and are produced by modified compression molding called Crush-Core technology. Produced structures are mechanically tested in three-point bending test and subjected to low-velocity impact and Charpy impact test.


2010 ◽  
Vol 177 ◽  
pp. 447-450 ◽  
Author(s):  
Xin Zhang ◽  
Yi Wen Hu ◽  
Yin Wu ◽  
Wen Jie Si

The purpose of this study was to evaluate the crystal phase formation behavior and its influence on the mechanical properties of LiO2-SiO2-P2O5 glass-ceramics system. High temperature XRD was used to analyze the crystal phase formation in situ. The crystalline phases in the material both before and after heat-treatment were also analyzed. The flexural strength was measured by three-point bending test according to ISO 6872:2008(E). The SEM analysis showed that the high strength of the glass-ceramics is attributed to the continuous interlocking microstructure with fine lithium disilicate crystallines.


1997 ◽  
pp. 211-220
Author(s):  
Yuzou Kuriyagawa ◽  
Shyouichi Akiba ◽  
Tetsukazu Kida ◽  
Sumio G. Nomachi

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Haoliang Huang ◽  
Guang Ye

In this research, self-healing due to further hydration of unhydrated cement particles is taken as an example for investigating the effects of capsules on the self-healing efficiency and mechanical properties of cementitious materials. The efficiency of supply of water by using capsules as a function of capsule dosages and sizes was determined numerically. By knowing the amount of water supplied via capsules, the efficiency of self-healing due to further hydration of unhydrated cement was quantified. In addition, the impact of capsules on mechanical properties was investigated numerically. The amount of released water increases with the dosage of capsules at different slops as the size of capsules varies. Concerning the best efficiency of self-healing, the optimizing size of capsules is 6.5 mm for capsule dosages of 3%, 5%, and 7%, respectively. Both elastic modulus and tensile strength of cementitious materials decrease with the increase of capsule. The decreasing tendency of tensile strength is larger than that of elastic modulus. However, it was found that the increase of positive effect (the capacity of inducing self-healing) of capsules is larger than that of negative effects (decreasing mechanical properties) when the dosage of capsules increases.


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