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 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.

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.

Prediction of Initiation Toughness Under Small Scale Yielding (SSY) and J0.2BL vs. Q Fracture Locus Using Local Approach Methodologies in 304SS

2012 ◽  
Author(s):  
A. Wasylyk ◽  
A. H. Sherry ◽  
J. K. Sharples
Keyword(s):  
Fracture Toughness ◽  
Small Scale ◽  
Initiation Toughness ◽  
Single Edge ◽  
Small Scale Yielding ◽  
Local Approach ◽  
Three Point Bending ◽  
Fracture Locus ◽  
Scale Yielding ◽  
Cracked Specimens

Structural integrity assessments of structures containing defects require valid fracture toughness properties as defined in national and international test standards. However, for some materials and component geometries, the development of valid toughness values — particularly for ductile fracture — is difficult since sufficiently large specimens cannot be machined. As a consequence, the validity of fracture toughness properties is limited by the development of plasticity ahead of the crack tip and the deviation of crack tip conditions at failure from small scale yielding. This paper described the use of local approach models, calibrated against invalid test data, to define initiation toughness in 304 stainless steel pipe material. Three fracture toughness geometries were tested, shallow cracked single edge cracked specimens tested under three point bending, deep cracked single edge cracked specimens tested under three point bending, and deep cracked single edge cracked specimen tested under tension. Initiation toughness and J-Resistance curves were defined for each specimen using the multi-specimen technique. All initiation toughness values measured were above the specimen validity limits. The fracture conditions at initiation were analysed using three local approach models: the Generalised Rice & Tracey, High Constraint Rice & Tracey and the Work of Fracture. The adequacy of local approaches to define the fracture conditions under large strains in 304 stainless steels was demonstrated. A modified boundary layer analysis combined with the local approach models was used to predict the “valid” initiation toughness under small scale yielding condition in this material by defining a J-Q fracture locus. The analytically derived fracture locus was compared to the J-Q values obtained experimentally and shown to be consistent.

Effect of Rare Earth Oxide and Rare Earth-Alumina-Silica Glass on Mechanical Properties of Liquid Phase Sintered Alumina Ceramics

2005 ◽  
Vol 290 ◽  
pp. 246-249 ◽  
Author(s):  
Jaroslav Sedláček ◽  
Dušan Galusek ◽  
Pavol Šajgalík
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Rare Earth ◽  
Liquid Phase ◽  
Rare Earth Oxide ◽  
Aluminosilicate Glass ◽  
Alumina Ceramics ◽  
Beneficial Effects ◽  
Rare Earth Addition ◽  
The Impact

The microstructure evolution and mechanical properties of alumina doped with rare earth oxide and rare earth-aluminosilicate glass has been investigated in order to understand better the impact of rare earth addition on hardness and fracture toughness. The aims of the present work are to examine the possibly beneficial effects of selected rare earth oxide added to alumina by two different routes in enhancing mechanical properties. The specific systems considered in this work were as follows: liquid phase sintered alumina containing RE2O3 (RE = La, Y) and RE2O3 – Al2O3 – SiO2 glassy phase up to 5 wt. %. The Vickers hardness and fracture toughness have been compared with the undoped alumina.

scholarly journals Study on the Static and Dynamic Fracturing Properties of Marble after Being Damaged Dynamically

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yunqiu Liu ◽  
Anqi Fu ◽  
Binsong Jiang ◽  
Liyuan Yu ◽  
Xiaobing Wang
Keyword(s):  
Fracture Toughness ◽  
Impact Loading ◽  
Split Hopkinson Pressure Bar ◽  
Cumulative Damage ◽  
Bending Tests ◽  
Three Point Bending ◽  
Cyclic Impact Loading ◽  
Loading Tests ◽  
Cyclic Impact ◽  
The Impact

A split Hopkinson pressure bar (SHPB) system was first used to perform the cyclic impact loading tests on notched semicircular bend (NSCB) marble specimens. Then, static and dynamic three-point bending tests were conducted on these dynamically damaged specimens, respectively. In the cyclic impact loading tests, the dynamic elastic modulus decreases gradually as the impact number increases, but dynamic cumulative damage exhibits a growing trend. In the static and dynamic three-point bending tests, when dynamic cumulative damage is less than 0.345, the dynamic fracture toughness values are larger than the static fracture toughness values, but the experimental data exhibit the opposite results when dynamic cumulative damage ranges from 0.345 to 0.369. Through the quantitative analysis of fracture surface morphologies, the roughness and area of the fracture surfaces increase with an increasing dynamic cumulative damage. Under the same dynamic cumulative damage of the specimens, both the roughness and area of the surfaces fractured by static three-point bending are larger than those fractured by dynamic three-point bending.

Applied Research of the Flexible Epoxy Resin Curing Agent

2012 ◽  
Vol 535-537 ◽  
pp. 2499-2502
Author(s):  
X. Wang ◽  
S. R. Zheng ◽  
R. M. Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Fracture Surface ◽  
Epoxy Resin ◽  
Epoxy Resins ◽  
Applied Research ◽  
Curing Agent ◽  
Structural Adhesives ◽  
Resin Curing ◽  
The Impact

Epoxy resin structural adhesives modified by flexible curing agent. Dependening on the mechanical properties of epoxy resins on the flexible curing agent content was studied. The impact fracture toughness was discussed in terms of fracture surface fractography.

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.

Stress corrosion and mechanical properties of zinc coating on 304 stainless steel

2021 ◽  
Vol 63 (3) ◽  
pp. 209-218
Author(s):  
Hua Zhang ◽  
Sihan Zheng ◽  
Yue Wang ◽  
QiLiang Li ◽  
Jie Tao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Stainless Steel ◽  
Stress Corrosion ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
Zinc Coating ◽  
304 Stainless Steel ◽  
Three Point Bending ◽  
Indentation Tests

Abstract The effect of stress corrosion on the mechanical properties of the coating in the zinc coating/304 stainless steel substrate system was investigated by three-point bending, slow strain rate tensile (SSRT) and nano-indentation tests. Studies have shown that fracture toughness was improved when the coating was thick but weakened when the coating was thin. At varied coating thicknesses (80 μm, 160 μm, 240 μm, 320 μm, 400 μm), the decline rates of the fracture toughness were 77.48 %, 71.82 %, 66.67 %, 55.48 % and 51.52 %, respectively, and those for the critical strain of crack initiation were 94.97 %, 91.88 %, 88.42 %, 76.19 % and 74.33 %, respectively. In addition, simulations were made to analyze the crack propagation of zinc coating in coating/substrate system under tensile loading by ABAQUS, which proved the accuracy of the experiment.

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.

Preparation of Pigmented Glass for Infiltration and Investigation of its Physical and Mechanical Properties

2012 ◽  
Vol 512-515 ◽  
pp. 1802-1806
Author(s):  
Huai Xiu Lu ◽  
Yuan Fu Yi ◽  
Bin Deng ◽  
Long Quan Shao ◽  
Li Sheng Zhao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Bending Strength ◽  
Porous Alumina ◽  
Physical And Mechanical Properties ◽  
Alumina Crucible ◽  
Three Point Bending ◽  
Scanning Electron

Aim To explore pigmented glass for infiltration and investigate its physical and mechanical properties. Methods The pigmented glass was prepared by melting glass components in an alumina crucible at 1400°C for 2h. The thermal properties were tested using a Setaram-TGDTA 92 analyzer; three point bending strength and fracture toughness were also tested; the microstructure of the glass was studied using a scanning electron microscope. Results The thermal expansion coefficient over the range 20–600 °C was 6.2 × 10-6 °C -1, Tg was about 690 °C, the density, bending strength, fracture toughness and Vickers hardness were 2.23 g/cm3, 118 MPa, 1.22 MPam1/2, and 7.4 GPa respectively. Conclusion The pigments have no detrimental effects on the physical and mechanical properties; thus the pigmented glass for infiltration has favorable physical and mechanical properties and also good compatibility with presintered porous alumina.

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