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1

Limiting the cracking of MCE mixtures used in base layers

Skotnicki Łukasz, Kuźniewski Jarosław

Roads and Bridges - Drogi i Mosty

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2025

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Vol. 24, no. 4

417--429

EN

The subject of the analysis conducted in the article are mineral-cement-emulsion (MCE) mixtures containing reclaimed asphalt pavement (RAP). The mixtures contain innovative road binders based on cement-dusty by-products (UCPP). These binders, used instead of conventional cement, can reduce the stiffness of the resulting conglomerate, which will reduce thermal cracking in the road pavement base layers. UCPP binders can also contribute to the decarbonization of the MCE mixture production process. The conducted research demonstrated a significant effect of UCPP binders on the mechanical properties of recycled MCE mixtures. Crack propagation was analyzed using the SCB and UTST methods. As a result of the research, the binders were selected which most effectively limited cracking and its growth rate. These analyses contribute to a detailed understanding of the effective use problem of MCE mixtures with reclaimed asphalt in road pavement construction.

PL

Przedmiotem przeprowadzonych w artykule analiz są mieszanki mineralno-cementowo-emulsyjne (MCE) zawierające destrukt asfaltowy (RAP). W mieszankach zastosowano innowacyjne spoiwa drogowe oparte na ubocznych cementowych produktach pylastych (UCPP). Spoiwa te stosowane w zamian klasycznego cementu mogą ograniczyć sztywność otrzymanego konglomeratu, co wpłynie na zmniejszenie spękań temperaturowych w warstwach podbudowy nawierzchni drogowych. Spoiwa UCPP mogą również przyczynić się do dekarbonizacji procesu produkcji mieszanek MCE. W przeprowadzonych badaniach wykazano znaczący wpływ spoiw UCPP na właściwości mechaniczne recyklowanych mieszanek MCE. Analizowano propagację spękań w badaniach metodą SCB oraz UTST. W wyniku przeprowadzonych prac wytypowano spoiwa, które w największym stopniu pozwalały na ograniczenie spękań i prędkości ich przyrostu. Powyższe analizy przyczyniają się do szczegółowego rozpoznania problemu dotyczącego efektywnego stosowania mieszanek MCE z destruktem asfaltowym w konstrukcji nawierzchni drogowych.

2

Internet Rzeczy w monitorowaniu zmęczenia materiałów konstrukcyjnych

Konieczna Kinga

Inżynieria Materiałowa

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2025

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Vol. 46, nr 6

24--32

PL

Przegląd literaturowy dotyczący inżynierii materiałowej i technologii IoT w kontekście monitorowania zmęczenia. Omówiono dostępne czujniki i architekturę systemów oraz przeanalizowano metody przetwarzania sygnału i algorytmów prognostycznych. Porównano także rozwiązania z punktu widzenia inżynierskiego (czułość, trwałość, koszty, gotowość technologiczna) oraz zidentyfikowano kluczowe wyzwania i kierunki dalszych badań.

EN

A review, with. 76 refs., of materials science and IoT technology in the context of fatigue monitoring. Available sensors and system architectures were discussed, and signal processing methods and prediction algorithms were analyzed. The solutions were also compared from an engineering perspective (sensitivity, durability, cost, technology readiness), while key challenges and directions for further research were identified

3

TIG Welding Crack Sensibility Analysis of Co-Based Superalloys

Liu Y., Zhao Yan, Guan Jianjun, Yang Yanhong, Zhu Jiaojiao

Archives of Metallurgy and Materials

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2025

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Vol. 70, iss. 1

269--274

EN

The microstructure of alloy phases and hot crack propagation under TIG (tungsten inert gas) welding of Co-based superalloys are investigated. The μ-phase, β-phase and carbides are grown in the superalloy, and the μ-phase is mainly precipitated. The microhardness of the μ phase is higher than the β phase and the matrix. During TIG welding, the arc crater cracks in the molten pool are all intergranular. The equiaxed crystals are existed in the fusion zone, and the dendrites are appeared in the heat affected zone. The microcracks in the heat-affected zone and closed to the base metal are preferentially initiated in the region of the μ phase, and continuously extend to the matrix along the growth direction of the μ phase.

4

Mechanisms of mining induced inrush of pressurized water in the floor containing faults

Zhang Baoliang, Zhang Wei, Shen Baotang, Gao Yang, Liu Mingming

Journal of Theoretical and Applied Mechanics

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2024

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Vol. 62 nr 3

573--585

EN

Investigating the propagation of the seepage path of confined water in the floor is an impor- tant means to determine the conditions of water inrush from the mine floor for deep mines with high water pressure. In order to better understand the mechanisms of water inrush due to the hidden fault floor above a confined water body, an integrated study including analyt- ical analysis, and similarity simulation experiments were conducted. The study focuses on the distribution of mining induced stress in the floor, the propagation of hidden faults, and the evolution process of water inrush channels during longwall coal seam extraction.

5

Effect of the Material Gradation on the Fracture Trajectory in Ceramic/Metal Functionally Graded Materials

Bouchelarm Mohammed A., Chafi Meriem Asmaa, Boulenouar Abdelkader, Benseddiq Noureddine

Archives of Metallurgy and Materials

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2024

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Vol. 69, iss. 3

955--963

EN

This paper is based on a 2D numerical study of crack initiation and growth in ceramic/metal functionally graded materials (FGMs) under mixed mode condition. The finite element method is used for modeling the crack growth trajectory. Two types of ceramic/metal FGMs are considered to explore the effect of the material gradation on the fracture trajectory. The variation of the material properties is declared in a program by defining the material parameters at the center of the elements. After a numerical evaluation of the fracture parameters, the Maximum Tangential Stress (MTS) criterion is used for the prediction of crack propagation direction with respect to the crack axis. The difference in the crack growth trajectory can be related to the influence of the material gradient. In addition, it was found that the easiest way for the crack propagation is when the crack is perpendicular to the material gradation. A crack located on the rigid side of the specimen deviates less compared to the one on the soft side.

6

A risk assessment method of aircraft structure damage maintenance interval considering fatigue crack growth and detection rate

Zhang Zhuzhu, Mao Haitao, Liu Yulin, Jiao Peng, Hu Wenlin, Shen Pei

Eksploatacja i Niezawodność

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2023

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Vol. 25, no. 1

art. no. 3

EN

The accurate assessment of aircraft structure damage risk is the premise of establishing reasonable, economic and reliable maintenance intervals. While many studies have proposed damage risk assessment methods for aircraft structures, these methods lack the quantification of risk. This paper proposed a risk assessment method of aircraft structure damage maintenance interval considering fatigue crack growth rate and crack detection rate. The damage process of aircraft structure was simulated by Monte Carlo simulation to realize the quantitative assessment of aircraft structure damage risk and maintenance interval. Taking an aircraft fleet as an example, the damage risk of its wing structure was simulated and analyzed. The results show that if the risk is controlled within a reasonable range, the maintenance interval should be shortened to 16 flight hours. At the same time, through the analysis of the risk classification standard and the crack detection rate, the quantitative evaluation of the risk classification standard was realized.

7

Study on the influence of joint dip angle and spacing on rock fragmentation by TBM double disc cutters

Kang Yiqiang, Yang Renshu, Yang Liyun, Li Yougliang, Yao Man, Gu Shirui

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 4

art. e222, 1--15

EN

Tunnel boring machines’ construction efficiency is significantly affected by the formation of joints. Indentation tests were performed to explore the influence of joints on rock fragmentation by double cutters on a gray sandstone. The process of rock fragmentation was captured by the digital image correlation method. Simulations based on the cohesive element with zero thickness were then conducted to simulate the failure process and evolution of jointed rock under the action of double cutters. A mechanical model is established to deduce the stress evolution in a rock mass by double disc cutters with different penetration depths. The action mechanism and mechanical influence of joints on rock fragmentation were determined. The results show that, under the action of double cutters, the rock with joints is more ready broken than the intact rock mass. The joint acts as a weak interface in the rock mass. Finally, the rock mass is destroyed along the vertical joint, forming rock slag with the joint as the boundary. When the joint dip angle is about 30°, the interaction force between the rock mass and the cutter is low, and the rock fragmentation efficiency is high. And the spacing of joints is also a key factor in the rock-breaking efficiency of double cutters.

8

A cost-effective stereo camera-based system for measuring crack propagation in fibre-reinforced concrete

Mena-Alonso Álvaro, Latorre-Carmona Pedro, González Dorys C., Díez-Pastor José F., Rodríguez Juan J., Mínguez Jesús, Vincente Miguel A.

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 3

art. no. e192, 2023

EN

This paper shows a new low-cost technology for the measurement of crack propagation in quasi-fragile materials based on a stereo pair of cameras and LED light spots. The two cameras record the displacement experienced by a series of LED white lights. For each frame, the X, Y and Z 3D coordinates of all the centroids of the LED points are obtained. From this information, it is possible to determine the variation of the distance between any two of them. In this case, 2 strips of 12 LED lights each were arranged in such a way that the points of both strips coincided in pairs in height. The algorithm made it possible to monitor the increase in distance that occurred between each pair of lights at the same height. The paper shows the mathematical basis of this technological solution. A test has been carried out by installing this system in a concrete cube 150 mm side and subjected to a wedge-splitting test. The results show that it is possible to monitor the crack propagation (position of the crack front) during the test and to know the crack width too. At present, the accuracy of this technique is only limited by the camera resolution and the computer processing capability.

9

Numerical and Experimental Study of Crack Propagation in the Tensile Composite Plate with the Open Hole

Wysmulski Paweł

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no. 4

249--261

EN

In this study, the thin-walled plate with the central open hole made of carbon-epoxy composite was investigated. The plate was tested in tension to investigate the mechanism of crack formation in the composite structure. The studies were carried out using two individual methods: experimental and numerical. In the experiment test, load was measured as the function of plate elongation. The Plate elongation was analysed using the Aramis optical non-contact measurement system. In the numerical study, the FEM model reproducing the experimental conditions was developed in the Abaqus software. The cracking process was modelled using the XFEM method (extended finite element method). This procedure allowed the of the composite to be examined over the full range of the tensile load. The behaviour of the plate with a circular open hole was investigated before damage symptoms and the damage initiation load was determined. The study continued to analyse the initial cracking and delamination of the laminate layers, together with crack propagation leading to cracking of all the laminate layers (complete failure of the composite structure). The novelty of this study is that it uses the popular XFEM method to describe the cracking and failure of the composite structure. In addition, the study proposes the novel method for determining the crack initiation and failure loads of the composite plate under tension, and the results obtained thereby are verified numerically.

10

Sensitivity Analysis of the Nasgro Equation Based on the PZL-130 TC-II Orlik Trainer Aircraft Full Scale Fatigue Test

Reymer Piotr, Leski Andrzej, Kurdelski Marcin

Fatigue of Aircraft Structures

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2022

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Iss. 14

8--17

EN

The study investigates the sensitivity of numerical crack propagation estimations based on the Nasgro equation. The equation is widely used for crack propagation calculations since it considers the whole range of crack propagation speed from threshold to critical values of stress intensity factor range (∆K). The presented investigation is based on the actual results of the full scale fatigue test (FSFT) of the PZL-130 ‘Orlik’ TC-II aircraft. We provide a brief description of the test and the general approach followed in crack propagation estimations originally carried out after the test. The obtained results are verified in terms of variation of the input data. Overall results are compared and discussed.

11

Set-up of a Generalized Dataset for Crack-Closure-Mechanisms of Cast Steel

Horvath Michael, Oberreiter Matthias, Stoschka Michael, Leitner Martin

Journal of Casting & Materials Engineering

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2021

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Vol. 5, no. 4

84--88

EN

In components, crack propagation is subjected to crack-closure-mechanisms which affect the build-up of the relevant threshold stress intensity factor range during cyclic loading. As structural parts are exposed to service loads incorporating a variety of load ratios, a significant change of the long-crack threshold value occurs, leading to a severe stress ratio dependency of crack-closure-mechanisms. Thus, an extensive number of crack propagation experiments is required to gain statistically proven fracture mechanical parameters describing the build-up of closure effects as crack growth resistance curves. The article presents a generalized dataset to assess the formation of crack-closure-mechanisms of cast steel G21Mn5+N. Numerous crack propagation experiments utilizing single edge notched bending (SENB) sample geometries are conducted, incorporating alternate to tumescent stress ratios. The statistically derived, generalized crack growth resistance curve features the impact of closure effects on the crack propagation rate in a uniform manner. To extend the dataset to arbitrary load ratios, the long-crack threshold approach according to Newman is invoked. The generalized dataset for the cast steel G21Mn5+N is validated by analytical fracture mechanical calculations for the utilized SENB-sample geometries. Incorporating a modified NASGRO equation, a sound correlation of analytical and experimental crack propagation rates is observed. Moreover, the derived master crack propagation resistance curve is implemented as a user-defined script into a numerical crack growth calculation tool and supports a local, node--based numerical crack propagation study as demonstrated for a representative SENB-sample. Concluding, the derived dataset facilitates the calculation of fatigue life of crack-affected cast steel components subjected to arbitrary stress ratios.

12

Improvement of fracture toughness in dense ATZ composites prepared from zirconia powders with different yttria content

Grabowy Marek, Delikhovskyi Yurii, Wilk Agnieszka, Pędzich Zbigniew

Composites Theory and Practice

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2021

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R. 21, nr 4

161--168

EN

Alumina toughened zirconia (ATZ) composites with 2.3 vol.% Al2O3 (ATZ-B) and 12.3 vol.% Al2O3 (ATZ-10) were fabricated. The used starting zirconia powders were prepared as a mixture of powders with different yttria content. The alumina additive was commercially available Al2O3 powder. The specific preparation method and optimized sintering conditions allowed us to achieve ATZ products with exceptional properties. These properties were compared with 3Y-TZP sintered samples prepared from commercial powder (Tosoh). The structural and mechanical properties of the investigated ATZ composites were systematically studied. The microstructures were observed by scanning electron microscopy (SEM) on polished and thermally etched surfaces, then the micrographs were binarized and subjected to stereological analysis. Dense (> 99% of relative density), uniform and pore-free microstructures with homogeneously distributed Al2O3 inclusions without any visible agglomerates were obtained. The Vickers hardness and Young’s modulus were enhanced according to the rule of mixtures for the composites. The mechanical behaviour was especially oriented towards increasing the fracture toughness. The K1c parameter reached the extraordinary value of 12.MPa⋅m1/2 for ATZ-B and 9.8 MPa⋅m1/2 for ATZ-10. Comparatively, K1c of the 3Y-TZP reference material was 5.1 MPa⋅m1/2. The mechanisms contributing to the increase in K1c were identified to explain the reason for such a large improvement in the fracture toughness. The investigations were particularly focused on crack propagation analysis. The identified mechanisms include crack path deviation and mixed transgranular-intragranular crack migration (crack bridging), crack propagation through the Al2O3 grains and frequent changes in the fracture propagation directions of a high angle (close to even 90°). Nevertheless, the occurrence of t→m (tetragonal to monoclinic) transformation of the ZrO2 phase was considered to be the main toughening factor. Due to the specific method of preparation, leading to an intensification of yttrium diffusion during sintering, the final microstructure revealed very small grains of a tetragonal zirconia phase. These grains exhibited high transformability, which was the main reason for the distinctin crease in fracture toughness.

13

Experimental and theoretical study on the dynamic ejection process of a rock burst under a static load

Zheng Weiyu

Archives of Mining Sciences

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2021

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Vol. 66, no. 1

43--56

EN

As the duration of a rock burst is very short and the roadway is seriously damaged after the disaster, it is difficult to observe its characteristics. In order to obtain the dynamic characteristics of a rock burst, a modified uniaxial compression experiment, combined with a high-speed camera system is carried out and the process of a rock burst caused by a static load is simulated. Some significant results are obtained: 1) The velocity of ejected particles is between 2 m/s and 4 m/s. 2) The ratio of elastic energy to plastic energy is about five. 3) The duration from integrity to failure is between 20 ms and 40 ms. Furthermore, by analyzing the stress field in the sample with a numerical method and crack propagation model, the following conclusions can be made: 1) The kinetic energy of the ejected particles comes from the elastic energy released by itself. 2) The ratio of kinetic energy to elastic energy is between 6% and 15%. This can help understand the source and transfer of energy in a rock burst quantitatively.

14

Investigation of the correlation between crack propagation process and the peak strength for the specimen containing a single pre-existing flaw made of rock-like material

Yang Hengtao, Lin Hang, Wang Yixian, Cao Rihong, Li Jiangteng, Zhao Yanlin

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 2

458--478

EN

This paper investigated the relationship between the strength of fractured rock and the crack propagation process. A series of uniaxial compression tests were carried out on the rock-like material specimens with single pre-fabricated flaw. Moreover, DIC (digital image correlation) technology was utilized to monitor and analyze the failure process of specimens. The initiation of each crack was defined as a key event, and the relationship between several key events and the axial load of the specimen during the crack propagation was quantitatively analyzed. The time-sequence analysis of crack propagation was also conducted by selecting benchmark points on the both sides of major cracks. It can be found that only the wing crack propagation occurs and there is no obvious shear crack before the peak strength. When the first secondary crack initiated, the specimen reached its peak strength and the wing crack just reached its critical length. Beyond the peak strength, secondary cracks initiated and coalesced rapidly, which leads to the sudden failure of fractured rock. Therefore, the peak strength of the specimen can be assessed by taking the critical length of the steadily propagating wing crack as the condition which determines whether the specimen reaches the peak strength. Furthermore, the discrete element numerical simulation was also implemented to confirm the experimental results.

15

Investigation on the constraint effect on the fracture toughness assessment of stainless steel AISI 304L thin sheets

Bensaada Rachid, Almansba Madjid, Ferhoum Rabah, Sidhoum Zehra, Habak Malek

Journal of Theoretical and Applied Mechanics

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2020

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Vol. 58 nr 1

143--153

EN

The aim of the study is to assess the constraint effect induced by variation of geometric pa- rameters on fracture toughness of stainless steel 304L thin sheets. A combined experimental-computational method is used. Compact Tension (CT) tests are firstly done using a spe- cial device realized to avoid buckling problems. Finite element analysis is used including the GTN (Gurson-Tvergaard-Needleman) model based on micromechanical assumptions of ductile fracture to obtain crack propagation. The fracture toughness is evaluated using an in- cremental formulation of the J-Integral. The results obtained show a quantified dependency of the critical fracture toughness on the constraint effect.

16

Analysis of Ring Cracks in Ceramic Rolling Elements Using the Boundary Element Method

Karaszewski Waldemar

Tribologia

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2019

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nr 3

51--59

EN

Ceramic materials have been increasingly used in bearing systems for over a dozen years. This is due to the specific properties of ceramic materials, such as high hardness, corrosion resistance, the possibility of use in aggressive chemical environments, as well as due to the lower specific weight as compared to steel materials. However, the use of ceramic materials imposes many limitations. The main disadvantages include surface cracks and a low fracture toughness value. The paper presents a numerical analysis of crack propagation in silicon nitride balls. The directions of propagation were analysed for the cracks that are most commonly found on the surface of the commercially available ceramic balls. The directions were analysed along the crack front and considering the location of the crack in relation to the contact point of the balls in the rolling contact. The numerical calculations are based on a three-dimensional model of the ring crack. Numerical calculations were carried out using the boundary element method. Numerical solutions were compared with the results of experimental research.

PL

Materiały ceramiczne od kilkunastu lat znajdują coraz większe zastosowanie w układach łożyskowych. Wynika to z charakterystycznych właściwości materiałów ceramicznych takich jak: duża twardość, odporność na korozję, możliwość stosowania w środowiskach agresywnie chemicznych, a także z uwagi na mniejszy ciężar właściwy w porównaniu z materiałami stalowymi. Stosowanie materiałów ceramicznych wiąże się jednak z wieloma ograniczeniami. Głównymi ich wadami są pęknięcia powierzchniowe oraz niska odporność na kruche pękanie. W pracy przedstawiono analizę numeryczną propagacji pęknięć w kulkach ceramicznych wykonanych z azotku krzemu. Analizowano kierunki propagacji dla pęknięć kolistych, które najczęściej spotykane są na powierzchni handlowych kulek ceramicznych. Kierunki pęknięć analizowano wzdłuż czoła pęknięcia oraz względem położenia pęknięcia w stosunku do punktu styku współpracujących kulek w styku tocznym. Obliczenia numeryczne oparte zostały na trójwymiarowym modelu pęknięcia kolistego. Obliczenia numeryczne analizowano metodą elementów brzegowych. Rozwiązania numeryczne porównano z wynikami badań eksperymentalnych.

17

Numerical study of cracking a medium elastic iscoplastique of polyacetal

Reffas Sid Ahmed, Benguidiab Mohamed, Sikula Ondrej, Adjlout Houari, Lebbal Habib

Mechanics and Mechanical Engineering

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2019

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Vol. 23, nr 1

125--129

EN

The objective of this work is the analysis of the fracture behavior of a SENB cylinder with a defect where stress triaxiality is more severe. Numerical simulations are carried out in a 2D mode, to overcome a disadvantageous hypothesis plane strain or plane stress. The mesh sensitivity studies were also undertaken but are not presented here. Indeed, only the results for the most relevant mesh are the subject of the discussion.

18

Crack growth path simulation in a cement mantle of THR using crack box technique

Boulenouar Abdelkader, Bendida Nadjet

Journal of Theoretical and Applied Mechanics

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2019

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Vol. 57 nr 2

317--329

EN

A numerical method for 2D LEFM crack propagation simulation in a cement mantle of the total hip replacement (THR) is presented. This work is based on the implementation of the displacement correlation technique (DCT) and the maximum circumferential stress (MCS) theory in a finite element code, using the Ansys Parametric Design Language (APDL). At each crack increment length, the crack direction angle is evaluated as a function of stress intensity factors (SIFs). The crack box technique is investigated for crack propagation simulation. The advantage of this technique is facilitation of the automatic remeshing of the structure during crack extension. In this paper, we analyzed the mechanical behavior of cracks initiated in the cement mantle by evaluating the SIFs. The effect of the cavities and the initial crack directions on the crack growth path has been highlighted.

19

Life Prediction Mechanism of Ladle Composite Structure Body Based on Simulation Technology

Li Gongfa, Jiang Du, Sun Ying, Jiang Guozhang, Tao Bo

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 4

1555--1562

EN

Ladle plays an important role in the metallurgical industry whose maintenance directly affects the production efficiency of enterprises. In view of the problems such as low maintenance efficiency and untimely maintenance in the current ladle passive maintenance scheme, the life prediction mechanism for ladle composite structures is established which bases on the stress analysis of steel shell and ladle lining in the production process, combining conventional fatigue analysis and extended fracture theory. The mechanism is accurate and effective according to the simulation results. Through which, the useful life of steel shell can be accurately predicted by detecting the crack length of it. Due to the large number of factors affecting the life of the lining of the ladle, it is difficult to accurately predict the life of the ladle lining, so a forecasting mean based on the thermal shock method is proposed to predict the service life of the ladle lining in this paper. The life prediction mechanism can provide data support and theoretical guidance for the active maintenance of the ladle, which is the prerequisite for scientifically formulating ladle initiative maintenance program.

20

Investigation of acoustic emission response and fracture morphology of rock hydraulic fracturing under true triaxial stress

Yue Yuqing, Peng Shoujian, Liu Yixin, Xu Jiang

Acta Geophysica

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2019

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Vol. 67, no. 4

1017--1024

EN

Hydraulic fracturing technique has been used to exploit hydrocarbons resources in the past years. To investigate the mechanism of hydrofracturing process, a true triaxial hydraulic fracturing device combined with acoustic emission (AE) system is employed to study the crack initiation and propagation under different injection rates. Furthermore, a 3D scanner is employed to obtain the morphology of the fractured surface when the fracturing test completes. The results show that in hydraulic fracturing, the cracks propagating mostly perpendicular to the direction of the minimum horizontal principal stress. A lower injection rate corresponds to the peak value of the AE count occurring at a later time and a large value of the cumulative AE count, indicating greater damage and a complicated crack propagation path. With the injection rate increased, the earlier the microcracks occur, the shorter the fracturing time of the specimen is, and the fatter the fracture morphology.