Effect of Fibers Orientation on the Fracture of Polymer Concrete Based on Quartz, Polyester and Jute Fabrics

2021 ◽  
Vol 406 ◽  
pp. 511-520
Author(s):  
Houria Benkharbeche ◽  
Mansour Rokbi ◽  
Zine El Abidine Rahmouni ◽  
Moustapha Ghebouli ◽  
Madani Grine ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Polymer Concrete ◽  
Plant Fibers ◽  
Micro Cracks ◽  
The Matrix ◽  
Layer Orientation ◽  
Jute Fabrics ◽  
Fibers Orientation

The main objective of this work is to highlight the influence of jute woven layer orientation on fracture parameters (energy release rate and stress intensity factor) of a polymer concrete laminate. The use of plant fibers, jute in this study, as reinforcements outside the polymer concrete, acquires mechanical properties, traction, and flexion, more than appreciable, however, other characteristics must be studied to ensure better integration on the market. The addition of plant fibers with different orientations is not without consequences on the mechanical behavior, in this case, on the resistance to cracking and its propagation. Fibered concretes have a very different behavior compared to non-fiber concretes, especially after the first cracking, where the fibers make their contribution by trying to stop the evolution and the propagation of micro-cracks within the matrix by making the concrete more ductile.

General Method for Optimizing Composite Patch Repairs

2015 ◽  
Vol 1120-1121 ◽  
pp. 670-674
Author(s):  
Abdelmadjid Ait Yala ◽  
Abderrahmanne Akkouche
Keyword(s):  
Mechanical Properties ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Optimization Problem ◽  
Composite Patch ◽  
Matlab Program ◽  
Patch Repairs ◽  
Selection Of ◽  
General Method

The aim of this work is to define a general method for the optimization of composite patch repairing. Fracture mechanics theory shows that the stress intensity factor tends towards an asymptotic limit K∞.This limit is given by Rose’s formula and is a function of the thicknesses and mechanical properties of the cracked plate, the composite patch and the adhesive. The proposed approach consists in considering this limit as an objective function that needs to be minimized. In deed lowering this asymptote will reduce the values of the stress intensity factor hence optimize the repair. However to be effective this robust design must satisfy the stiffness ratio criteria. The resolution of this double objective optimization problem with Matlab program allowed us determine the appropriate geometric and mechanical properties that allow the optimum design; that is the selection of the adhesive, the patch and their respective thicknesses.

Mechanical Properties and Fracture Analysis of a Plant Oil Storage Tank Accident

2015 ◽  
Vol 1120-1121 ◽  
pp. 1413-1418
Author(s):  
Shan Shan Fang ◽  
Li Jing Zhang ◽  
Gang Tao
Keyword(s):  
Mechanical Properties ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Storage Tank ◽  
Fracture Analysis ◽  
Dominant Factor ◽  
Collapse Mechanism ◽  
Plant Oil ◽  
Oil Storage ◽  
Oil Storage Tank

The collapse mechanism of plant oil storage tank was discussed in the paper. Observation made on the site indicated that No. 804 tank collapsed with disintegration. The incomplete penetration area was found by weld macro analysis. Stress intensity factor of crack in the tank which is calculated using the classical theory showed that the main reason for the accident was not the incomplete penetration weld. The hexane vapor explosion is presumably the dominant factor leading to the accident by calculation and analysis. The count measures are also proposed to prevent the similar accidents.

Complex Variable Green’s Functions for Crack-Microcracks Interactions

2011 ◽  
Vol 465 ◽  
pp. 123-128 ◽  
Author(s):  
M. Chabaat ◽  
H. Ayas
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Stress Field ◽  
Main Crack ◽  
Green's Functions ◽  
Green’S Functions ◽  
Complex Variables ◽  
Mode I ◽  
Micro Cracks

In this study, interaction between a main crack and a surrounding layer of micro cracks is considered. A stress field distribution induced during these interactions is obtained using Muskhelshvili’s complex variables formalism which relies on the Green's functions. The effect of amplification and shielding on the resulting stress field is shown, herein, through a study of mode I Stress Intensity Factor (SIF). To quantify these effects, orientations as well as positions of microcracks with respect to the main crack is taken into consideration. Obtained results are compared and agreed with those of other researchers.

scholarly journals Synthesis, microstructure, mechanical properties and luminescence of a ceramics Gd(NbxTa1−x)O4

2020 ◽  
Vol 10 (01n02) ◽  
pp. 2060014
Author(s):  
O. B. Shcherbina ◽  
S. M. Masloboeva ◽  
N. I. Steblevskaya ◽  
M. V. Belobeletskaya ◽  
V. V. Efremov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Solid Solutions ◽  
Sol Gel ◽  
Luminescent Properties ◽  
Exciting Radiation ◽  
Small Addition ◽  
Mode I

Ceramic solid solutions GdNbx[Formula: see text]O4 ([Formula: see text]–1) were synthesized by sol–gel. Morphological particularities of microstructure were studied, strength characteristics (Young’s modulus) and stress intensity factor for mode I [Formula: see text] were evaluated. The latter is a criterion of crack resistance of the material. Luminescent properties of solid solutions GdNbx[Formula: see text]O4 were researched under UV exciting radiation. A comparatively small addition of Ta ([Formula: see text]) was shown to increase luminescence intensities of centers [Formula: see text]–O−. An addition of Ta to GdNbO4 leads to creation of solid solution [Formula: see text][Formula: see text]O4. Intensity of these centers is 3–6.5 times larger than that of GdNbO4 and GdTaO4.

scholarly journals THE INVESTIGATION AND PECULIARITIES OF CALCULATION OF TRANSPORT MACHINE ELEMENTS MADE OF AUSTEMPERED DUCTILE IRON

Transport ◽  
2003 ◽  
Vol 18 (4) ◽  
pp. 162-167 ◽  
Author(s):  
Mindaugas Leonavičius ◽  
Algimantas Krenevičius ◽  
Marijonas Šukšta ◽  
Jukka Posa
Keyword(s):  
Mechanical Properties ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Ductile Iron ◽  
Fatigue Crack Initiation ◽  
Austempered Ductile Iron ◽  
Compact Specimen ◽  
Complete Evaluation ◽  
Growth Ratio

In this article the statical and cyclical strength investigations of austempered ductile cast iron (ADI) are presented. ADI material becomes more and more popular. Ductile iron is lighter than steel and its mechanical properties are better. ADI has good resistance to fatigue, high tensile strength, toughness and ductility. The fatigue crack initiation generally occurs in the graphite matrix. In the work the kinetic fatigue diagrams, longevity distributions laws and the mathematical model of crack growth ratio are described. The blanks of material were cut from a tooth of gear. Structure of the material consists of bainite and spherical graphite. The mechanical properties of ADI were obtained with assessment of chemical composition. The detennined statical mechanical properties of two different ADI materials are presented. The compact specimen was produced in order to detennine a threshold stress intensity factor. According to the investigations the stress intensity factor (threshold) is ΔK th = 9,8 MPa√m for the ADI 6.2.02 and ΔK th = 8,6 MPa√m for the ADI 9.4.02. The carried out investigations are insufficient for the complete evaluation of austempered ductile iron for the production of transport equipment elements.

scholarly journals Evolution of the Mechanical Properties and Cracking Pattern of Cementitious Composites Reinforced with Hooked Steel Fibers

2020 ◽  
Vol 16 (1) ◽  
pp. 119-130
Author(s):  
Hamid Ranjbar ◽  
Ali Jadidi ◽  
Hosein Amerei
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Bending Strength ◽  
Tensile Specimen ◽  
Steel Fibers ◽  
Micro Cracks ◽  
The Matrix ◽  
Materials Used ◽  
Cracking Pattern

AbstractDegradation and disintegration of concrete depend on the formation of cracks and micro cracks intensively. With increase loading, micro cracks are linked together and form cracks. To solve the problem and to provide the homogenous condition, a series of thin fibers having been spread through the volume of concrete are used in the several last decades and they are called as fibers. In the study, the steel fibers integrated in the different percentages of weight have been investigated. The performance of fibers has been studied how to increase compressive strength, tensile strength, and bending strength. To survey compressive strength, tensile strength, and bending strength in the produced concrete, three plans of mixtures including the different percentages of the steel fibers have been examined. The results show that compressive strength in the concrete reinforced with steel fibers relies mainly on the quality of mortar. The added steel fibers cause the inconsiderable changes in the compressive strength of concrete. The results demonstrate that the concrete reinforced with steel fibers increase tensile strength considerably. The more the volume of steel fibers is, the more tensile strength is. Pozzolanic materials used in the specimens reinforced in steel fibers improve tensile strength. To investigate bending strength of the specimens reinforced with steel fibers, the study has used 4-point loading system. Generally, steel fibers used in the concrete increase bending strength of the concrete. The results indicate the increased steel fibers enhance bending strength in three plans of mixtures. Among the specimen reinforced with steel fibres, the most mechanical properties are related to the plans including 1, 1.5, and 2 percentages of dramix hooked steel fibers in the study. To examine crack pattern of the matrix tensile specimen reinforced with the different percentages of fibers, parameters such as the number of cracks, width of cracks, and distance between them are investigated.

scholarly journals Investigation of Weight Fraction and Alkaline Treatment on Catechu Linnaeus/Hibiscus cannabinus/Sansevieria Ehrenbergii Plant Fibers-Reinforced Epoxy Hybrid Composites

2022 ◽  
Vol 2022 ◽  
pp. 1-9
Author(s):  
R. Rangaraj ◽  
S. Sathish ◽  
T. L. D. Mansadevi ◽  
R. Supriya ◽  
Raviteja Surakasi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Hybrid Composites ◽  
Weight Fraction ◽  
Alkaline Treatment ◽  
Fiber Composites ◽  
Hibiscus Cannabinus ◽  
Plant Fibers ◽  
The Matrix ◽  
Treated Fiber

The aim of the present work is to develop novel hybrid composites using areca, kenaf, and snake grass fibers as reinforcement and epoxy as the matrix. The areca, kenaf, and snake grass fibers were extracted from Catechu Linnaeus, Hibiscus cannabinus, and Sansevieria Ehrenbergii plants, respectively, and treated with 5% NaOH to improve the interfacial adhesion between the hydrophilic fiber and the hydrophobic matrix. Hybrid composites were developed by the compression molding technique and formulated based on the weight fraction of fibers. Tensile, flexural, and impact strength and hardness samples were prepared as per ASTM D 3039, ASTM D 790, ASTM D 256, and ASTM D 2240, respectively. The effects of alkaline treatment on developed hybrid composites were investigated. The developed hybrid composites with 20% wt. snake grass and 10% wt. areca fiber present interesting mechanical properties with a tensile strength of 58 MPa, flexural strength of 124 MPa, impact strength of 5.24 kJ/m2, and hardness of 88. The results indicate that maximum mechanical properties were obtained for alkaline-treated fiber composites with 20% wt. snake grass fiber compared to untreated fiber composites owing to better adhesion between the treated fiber and the matrix. The effect of alkaline treatment was analyzed by Fourier transform infrared. The fractured surfaces of tested samples were analyzed by scanning electron microscopy.

scholarly journals Investigation on the Effect of Crack Length on Mechanical Properties of Functionally Graded Materials

2010 ◽  
Vol 44-47 ◽  
pp. 2244-2248
Author(s):  
Gang Chen ◽  
Xi Yu Zhao ◽  
Peng Cheng Zhai
Keyword(s):  
Mechanical Properties ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Length ◽  
Pure Metal ◽  
Functionally Graded ◽  
Crack Tip Field ◽  
Graded Materials ◽  
Barrier Coating

In this article, the thermo-mechanical responses of ceramic/metal functionally graded thermal barrier coating(TBC) in work environment are analyzed by a finite element method. Both the crack-tip field and the stress intensity factor of functionally graded TBC are analyzed and calculated. It is discussed that the effect of crack length on mechanical properties of functionally graded TBC in the condition creep and no creep of pure metal. The numerical results indicate that the effect of crack length(a/t) is negligible to temperature distributions and the maximum displacements of whole model but remarkable to the 1st principal stress and stress intensity factor of crack region. Moreover, creep phenomenon of pure metal can relax the value of displacement, stress and stress intensity factor but do not alter their distribution.

Effect of the Size of the Reinforcement Phased on the Properties of Silica-Filled Composites

2007 ◽  
Vol 544-545 ◽  
pp. 267-270 ◽  
Author(s):  
Hyung Jin Kim ◽  
Sung Wi Koh ◽  
Jae Dong Kim ◽  
Byung Tak Kim
Keyword(s):  
Mechanical Properties ◽  
Stress Intensity Factor ◽  
Particle Size ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Flexural Strength ◽  
Critical Stress ◽  
Particle Diameter ◽  
Critical Stress Intensity Factor ◽  
Average Particle

In this study, the mechanical properties of silica-filled epoxy resin composites with average silica particle diameter of 6-33m were investigated at ambient temperature and pin-ondisc friction test was conducted for this. Experimental results demonstrated that mechanical properties such as flexural strength, flexural modulus and critical stress intensity factor depend on average particle diameter. The flexural strength decrease with increase of particle size whereas the critical stress intensity factor increases with increases of particle size. Wear rates of silica-filled composites are below a half those of unfilled epoxy. Fracture surface analysis was discussed based on SEM examination.

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