scholarly journals Effect of Nesfatin-1 on Rat Humerus Mechanical Properties under Quasi-Static and Impact Loading Conditions

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 333
Author(s):  
Anna Skic ◽  
Iwona Puzio ◽  
Grzegorz Tymicki ◽  
Paweł Kołodziej ◽  
Marta Pawłowska-Olszewska ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bone Structure ◽  
Critical Energy ◽  
Bending Test ◽  
Ovariectomized Rats ◽  
Loading Conditions ◽  
Sem Images ◽  
Three Point Bending ◽  
The Impact

The investigations on the response of bone tissue under different loading conditions are important from clinical and engineering points of view. In this paper, the influence of nesfatin-1 administration on rat humerus mechanical properties was analyzed. The classical three-point bending and impact tests were carried out for three rat bone groups: control (SHO), the humerus of animals under the conditions of established osteopenia (OVX), and bones of rats receiving nesfatin-1 after ovariectomy (NES). The experiments proved that the bone strength parameters measured under various mechanical loading conditions increased after the nesfatin-1 administration. The OVX bones were most susceptible to deformation and had the smallest fracture toughness. The SEM images of humerus fracture surface in this group showed that ovariectomized rats had a much looser bone structure compared to the SHO and NES females. Loosening of the bone structure was also confirmed by the densitometric and qualitative EDS analysis, showing a decrease in the OVX bones’ mineral content. The samples of the NES group were characterized by the largest values of maximum force obtained under both quasi-static and impact conditions. The energies absorbed during the impact and the critical energy for fracture (from the three-point bending test) were similar for the SHO and NES groups. Statistically significant differences were observed between the mean Fi max values of all analyzed sample groups. The obtained results suggest that the impact test was more sensitive than the classical quasi-static three-point bending one. Hence, Fi max could be used as a parameter to predict bone fracture toughness.

scholarly journals FDEM Modelling of Rock Fracture Process during Three-Point Bending Test under Quasistatic and Dynamic Loading Conditions

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Huaming An ◽  
Yushan Song ◽  
Hongyuan Liu
Keyword(s):  
Fracture Toughness ◽  
Dynamic Loading ◽  
Fracture Process ◽  
Loading Rate ◽  
Rock Fracture ◽  
Mesh Size ◽  
Bending Test ◽  
Loading Conditions ◽  
Three Point Bending ◽  
Dynamic Loading Conditions

A hybrid finite-discrete element method (FDEM) is proposed to model rock fracture initiation and propagation during a three-point bending test under quasistatic and dynamic loading conditions. Three fracture models have been implemented in the FDEM to model the transition from continuum to discontinuum through fracture and fragmentation. The loading rate effect on rock behaviour has been taken into account by the implementation of the relationship between the static and dynamic rock strengths derived from dynamic rock fracture experiments. The Brazilian tensile strength test has been modelled to calibrate the FDEM. The FDEM can well model the stress and fracture propagation and well show the stress distribution along the vertical diameter of the disc during the Brazilian tensile strength test. Then, FDEM is implemented to study the rock fracture process during three-point bending tests under quasistatic and dynamic loading conditions. The FDEM has well modelled the stress and fracture propagation and can obtain reasonable fracture toughness. After that, the effects of the loading rate on the rock strength and rock fracture toughness are discussed, and the mesh size and mesh orientation on the fracture patterns are also discussed. It is concluded that the FDEM can well model the rock fracture process by the implementation of the three fracture models. The FDEM can capture the loading rate effect on rock strength and rock fracture toughness. The FDEM is a valuable tool for studying the rock behaviour on the dynamic loading although the proposed method is sensitive to the mesh size and mesh orientation.

The Effects of MgO Addtion on the Mechanical Properties and the Phase Composition of Al2O3-TiC-TiN Ceramic Materials

2012 ◽  
Vol 457-458 ◽  
pp. 3-6
Author(s):  
Yu Huan Fei ◽  
Chuan Zhen Huang ◽  
Han Lian Liu ◽  
Bin Zou
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Composition ◽  
Flexural Strength ◽  
Ceramic Materials ◽  
Bending Test ◽  
Vickers Indentation ◽  
Volume Percent ◽  
Sintered Ceramic ◽  
Three Point Bending

Al2O3-TiN-TiC ceramic materials with different MgO content were fabricated by hot-pressing technique. The MgO volume percent was varied from 0vol% to 5vol%. Three point bending test was applied to get the flexural strength and the Vickers indentation was applied to get the Vickers hardness and the fracture toughness. The phase composition of the ceramics was analyzed by XRD. The effects of the content of MgO on the mechanical properties and the phase composition of Al2O3-TiN-TiC were investigated. The results shows that the addition of MgO can change the phase composition of the sintered ceramic materials which displayed with diverse solid solutions and intermetallic compounds. The convertion of the mechanical properties can also be explained by the XRD results.

scholarly journals Effect of Silane Treatment on Mechanical Properties of Polyurethane/Mesoscopic Fly Ash Composites

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 741 ◽  
Author(s):  
Qin ◽  
Lu ◽  
He ◽  
Qi ◽  
Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Fly Ash ◽  
Weight Percent ◽  
Bending Test ◽  
Fracture Toughness Test ◽  
Three Point Bending ◽  
Roof Fall ◽  
Bond Property ◽  
Polyether Polyol

In view of the accidents such as rock mass breakage, roof fall and coal slide in coal mines, polyurethane/mesoscopic fly ash (PU/MFA) reinforcement materials were produced from polymethylene polyphenylene isocyanate (PAPI), the polyether polyol, flame retardant, and MFA using stannous octanate as a catalyst. 3-Glycidoxypropyltrimethoxysilane (GPTMS) was grafted on MFA surface, aiming to improve the mechanical properties of PU/MFA composites. The analyses of infrared spectroscopy and compression resistance reveal that the GPTMS can be successfully attached to the surface of MFA, and the optimum modification dosage of GPTMS to MFA is 2.5 wt % (weight percent). On this basis, the effect of GPTMS on the mechanical properties of PU/MFA reinforcement materials during the curing process was systematically investigated through a compression test, a fracture toughness test, a three-point bending test, a bond property test, and a dynamic mechanics analysis. The results show that the compression property, fracture toughness, maximum flexural strength, and bond strength of PU/MFA composites increase by 21.6%, 10.1%, 8.8%, and 19.3%, respectively, compared with the values before the modification. Furthermore, the analyses of scanning electron microscope and dynamic mechanics suggest that the coupling agent GPTMS can successfully improve the mechanical properties of PU/MFA composites because it eliminates the stress concentration and exerts a positive effect on the crosslink density and hardness of PU/MFA composites.

scholarly journals The effect of consolidation treatment on selected mechanical properties of sandstone

2021 ◽  
Vol 1205 (1) ◽  
pp. 012012
Author(s):  
E Gajdos ◽  
M Sperl ◽  
Z Slizkova ◽  
M Drdlova
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Notch Toughness ◽  
Mining Site ◽  
Three Point Bending ◽  
Consolidation Treatment ◽  
Liquid Products ◽  
Strength And Durability ◽  
The Impact ◽  
Cracked Specimens

Abstract An investigation was made into selected mechanical properties of sandstone of Božanov mining site in Czechia using both natural specimens of the sandstone and specimens impregnated with consolidants – liquid products aimed at improving strength and durability of degraded stones. Experiments in three-point bending of notched and cracked specimens made it possible to determine (i) the quasi-static notch toughness as well as the fracture toughness of specimens when they were subjected to static loading, and (ii) the impact fracture toughness and total energy of fracture when specimens were subjected to impact loading. The results of the tests are presented and are discussed with a view to the effects of consolidants.

scholarly journals The Cooling Media Influence on Selected Mechanical Properties of Steel

2020 ◽  
Vol 23 (4) ◽  
pp. 183-189
Author(s):  
Radim Šmak ◽  
Jiří Votava ◽  
Adam Polcar
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Cooling Capacity ◽  
Structural Transformations ◽  
Bending Test ◽  
Metallic Materials ◽  
Three Point Bending ◽  
Cooling Medium ◽  
Cooling Media ◽  
The Impact

AbstractThe aim of experiment was to analyse the structural transformations and changes in mechanical properties of K720 steel during heat treatment (quenching). Three types of cooling medium were selected. The heating parameters and subsequent delays at the recrystallisation temperature were the same for all samples and were observed in a laboratory furnace. Water with the highest cooling capacity was selected as the benchmark cooling medium. Subsequently, the hardening oil TK – 46 was used. Sunflower oil was selected as the last quenching medium, which can be considered an ecological replacement of quenching oil with possibility of biological disposal. The microstructure and microhardness of individual samples were subjected to a metallographic evaluation and evaluated according to ČSN EN ISO 6507, respectively. The impact toughness analysis was performed according to the ČSN EN ISO 148-1 and a three-point bending test was performed according to ČSN EN ISO 7438. This test specifies a method for determining the ability of metallic materials to undergo plastic deformation in bending. The bend test includes subjection of round, square, rectangular or polygonal cross-section to plastic deformation by bending, without changing the direction of loading, until the specified angle of bend is reached.

Influence of Confinement on Ceramic’s Mechanical Properties

2016 ◽  
Vol 848 ◽  
pp. 249-255
Author(s):  
Xiao Cong Hang ◽  
Yun Kai Li
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Boron Carbide ◽  
Fracture Process ◽  
Hot Spot ◽  
Efficiency Factor ◽  
Bending Test ◽  
Depth Of Penetration ◽  
Constraint Force ◽  
Three Point Bending

The wide use of ceramic material in engineering is restricted by its brittleness, so the strengthening and toughening of ceramics is always a hot spot of research in material area. And in general, the modification of ceramics is achieved by changing its internal microstructure. In this paper the influence of confinement on the mechanical properties of ceramics and the specific use of this method were investigated. Firstly, the influence of confinement on ceramic’s fracture process was analyzed in theory. Then the three-point bending test was conducted using two types of ceramics, viz. Zirconia and Alumina. The experimental results showed that the fracturing load of zirconia increased from 4.3298 to 5.4639KN as the confinement was increased from 0 to 150MPa, 26.19% increase was found in the confined specimen. The same trend was observed in alumina, whose fracturing load increased from 3.0446 to 5.0259KN as the confinement was increased from 0 to 150MPa, 65.07% increase was found. After that, a series of ballistic experiments were performed. The target in this experiment was boron carbide ceramic, and it was confined by 45 steel. The results showed that with the constraint force was bigger, the ballistic efficiency factor was better and the depth of penetration was smaller. In other words, the confinement can increase the defensible performance of the target. In summary, the ceramic’s fracture toughness, defensible performance and ballistic efficiency factor can be increased by adding confinement to it.

scholarly journals EPOXY/TITANATE MODIFIED NANOSILICA COMPOSITES: MORPHOLOGY, MECHANICAL PROPERTIES AND FRACTURE TOUGHNESS

2018 ◽  
Vol 56 (2A) ◽  
pp. 133-140
Author(s):  
Ho Ngoc Minh
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Impact Test ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Bending Test ◽  
Tetrabutyl Titanate ◽  
Single Edge ◽  
Modified Silica ◽  
Three Point Bending

In this paper, the effect  of modified nanosilica as a reinforcement agent on the performance of epoxy resin using tetrabutyl titanate (TBuT) hardener were investigated. Morphology of the epoxy/modified silica composites was determined by Scanning Electron Microscopy (SEM) method. Impact strength and flexural strength of the composites were measured by Charpy impact test and three-point bending test mode methods, respectively. Fracture toughness and fracture energy were calculated according to pre-cracked, single edge notched method with specimens in three-point bending geometry and suitable equations. The mechanical properties and fracture toughness of composites were significantly enhanced with loading nanosilica content to 5 wt.%. 

Mechanical Properties of Zirconia Toughened Alumina Composites with TZP Partially Nanostructured Sintered by Liquid Fase

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
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Weibull Modulus ◽  
Bending Test ◽  
Sintering Aid ◽  
Zirconia Composites ◽  
Alumina Composites ◽  
Grain Size And Shape ◽  
Zirconia Toughened Alumina ◽  
Zirconia Powders

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.

scholarly journals Mechanical Properties of Spruce Wood Extracted from GLT Beams Loaded by Fire

2021 ◽  
Vol 13 (10) ◽  
pp. 5494
Author(s):  
Lucie Kucíková ◽  
Michal Šejnoha ◽  
Tomáš Janda ◽  
Jan Sýkora ◽  
Pavel Padevět ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Cross Section ◽  
Negative Impact ◽  
Tensile Tests ◽  
Thermal Recovery ◽  
Bending Test ◽  
Small Scale ◽  
Spruce Wood ◽  
The Impact

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.

Effect of toughened polyamide-coated carbon fiber fabric on the mechanical performance and fracture toughness of CFRP

2021 ◽  
pp. 002199832199945
Author(s):  
Jong H Eun ◽  
Bo K Choi ◽  
Sun M Sung ◽  
Min S Kim ◽  
Joon S Lee
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Photoelectron Spectroscopy ◽  
Mechanical Performance ◽  
Epoxy Composites ◽  
Scanning Calorimetry ◽  
Internal Damage ◽  
Impact Tests ◽  
Flexural Tests ◽  
The Impact

In this study, carbon/epoxy composites were manufactured by coating with a polyamide at different weight percentages (5 wt.%, 10 wt.%, 15 wt.%, and 20 wt.%) to improve their impact resistance and fracture toughness. The chemical reaction between the polyamide and epoxy resin were examined by fourier transform infrared spectroscopy, differential scanning calorimetry and X-ray photoelectron spectroscopy. The mechanical properties and fracture toughness of the carbon/epoxy composites were analyzed. The mechanical properties of the carbon/epoxy composites, such as transverse flexural tests, longitudinal flexural tests, and impact tests, were investigated. After the impact tests, an ultrasonic C-scan was performed to reveal the internal damage area. The interlaminar fracture toughness of the carbon/epoxy composites was measured using a mode I test. The critical energy release rates were increased by 77% compared to the virgin carbon/epoxy composites. The surface morphology of the fractured surface was observed. The toughening mechanism of the carbon/epoxy composites was suggested based on the confirmed experimental data.

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