Frattura ed Integrita Strutturale最新文献_第6页

The Metallurgical hydrogen as an indicator and cause of damage to rolled steel: Hydrogen diagnostics of fracture 冶金氢作为轧钢损伤的指示物和原因:断裂的氢诊断

Frattura ed Integrita Strutturale Pub Date : 2022-12-21 DOI: 10.3221/igf-esis.63.23

V. Polyanskiy, V. Loginov, Y. Yakovlev, A. Polyanskiy, Vecheclav Olekov, Gregory Rostovykh

引用次数: 0

A method and apparatus for inspecting large flat composite parts by using the Infrared LST technique 一种利用红外LST技术检测大型扁平复合材料零件的方法和装置

Frattura ed Integrita Strutturale Pub Date : 2022-12-21 DOI: 10.3221/igf-esis.63.11

V. Vavilov, A. Chulkov, D. Nesteruk, D. Burleigh, A. Moskovchenko

引用次数: 0

The earth-fill dam state express investigation using mechanical vibrations produced by HPP 利用高压电机产生的机械振动对土坝状态进行研究

Frattura ed Integrita Strutturale Pub Date : 2022-12-21 DOI: 10.3221/igf-esis.63.05

G. Antonovskaya, N. Kapustyan

{"title":"The earth-fill dam state express investigation using mechanical vibrations produced by HPP","authors":"G. Antonovskaya, N. Kapustyan","doi":"10.3221/igf-esis.63.05","DOIUrl":"https://doi.org/10.3221/igf-esis.63.05","url":null,"abstract":"The usage of mechanical vibrations produced by the hydropower plant (HPP) turbine may be used for seismic sounding of large-scale constructions as the earth-fill dam and its abutment contacts. Such vibrations are monochromatic oscillations on main frequencies and their harmonics produced by turbine. Seismic sensors installed on the dam's crest and inside it, if it possible, and in the area of abutment contacts register microseisms include HPP turbine operation vibrations which may be extracted by seismic data processing, i.e., filtering. We discuss two data processing possibilities: symphonious filter as the hardware one and power spectrum calculation as digital one. We consider the two case of earth-fill dams state investigations. There are the Chiryurt HPP dam (Republic of Dagestan, Russia, 9.5 m high) and the Nurek HPP dam (Tajikistan, 300 m high). We show the possibilities of seismic express investigations using signals of main frequencies produced by HPP turbine for dam sounding. For Chiryurt dam the extra fluid filtering in the central part of the dam was revealed. Nurek dam abutment contact monitoring showed the temporal variation of its stress-strain state associated with deformation variation 10-5-10-6 presumably due to regional seismicity.","PeriodicalId":38546,"journal":{"name":"Frattura ed Integrita Strutturale","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44175171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Numerical nonlinear analysis of RC beans with un-strengthened and CFRP-strengthened opening drilled under service loads within shear zones 剪切区内使用荷载作用下未加固和加固开孔RC豆的非线性数值分析

Frattura ed Integrita Strutturale Pub Date : 2022-12-21 DOI: 10.3221/igf-esis.63.17

Magdy A. Khalaf, Louay Aboul-Nour, M. Khater, Marwa Ibrahim

{"title":"Numerical nonlinear analysis of RC beans with un-strengthened and CFRP-strengthened opening drilled under service loads within shear zones","authors":"Magdy A. Khalaf, Louay Aboul-Nour, M. Khater, Marwa Ibrahim","doi":"10.3221/igf-esis.63.17","DOIUrl":"https://doi.org/10.3221/igf-esis.63.17","url":null,"abstract":"Current research paper deals with reinforced concrete (R.C.) beams numerical modeling and suggested strengthening procedure if it is required to create an opening within their shear zones. Strengthening is assumed to be achieved during different service load application conditions. Reinforced Concrete beams with rectangular or circular opening in shear zone; as critical regions; sustain two concentrated system of loads are tested till failure before and after performing suggested opening assessing technique by means of Carbon Fibers Reinforced Polymer sheets (CFRP). The main aim of this research is simulating real practice situation where the beam is subjected to service loads, supported temporary by means of hydraulic jacks, opening is created and strengthening is performed then jacking supports are released. Results of achieved numerical nonlinear modeling are introduced and influence of strengthening achieving on improving assessed beams almost structural behavior such as initial cracking loads, load deflection curves, cracking patterns, failure loads & modes for reference (without opening), main un-strengthened control beams, and CFRP strengthened opening beams are introduced and analyzed in details. Some important conclusions & recommendations for designer and executive engineers are stated.","PeriodicalId":38546,"journal":{"name":"Frattura ed Integrita Strutturale","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44730588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Improvement of crack tip position estimation in DIC images by image processing methods 图像处理方法对DIC图像裂纹尖端位置估计的改进

Frattura ed Integrita Strutturale Pub Date : 2022-12-21 DOI: 10.3221/igf-esis.63.06

Najat Zekriti, F. Majid, Hachimi Taoufik, Y. Tounsi, R. Rhanim, I. Mrani, H. Rhanim

{"title":"Improvement of crack tip position estimation in DIC images by image processing methods","authors":"Najat Zekriti, F. Majid, Hachimi Taoufik, Y. Tounsi, R. Rhanim, I. Mrani, H. Rhanim","doi":"10.3221/igf-esis.63.06","DOIUrl":"https://doi.org/10.3221/igf-esis.63.06","url":null,"abstract":"The study presents and compares an application of two procedures to identify the crack tip location in PVC Sent samples under a uniaxial tensile test based on the image processing method. An IDS camera captures several photos of the PVC surface as part of the image analysis procedure. All relevant data on crack initiation and propagation is collected and assessed using ImageJ software using image processing methods for detecting cracks. However, the second procedure involves a developed algorithm detecting the discontinuity using digital image correlation (DIC) measurement. Although, because of the experimental conditions, the acquisition of images by the digital camera is never perfect. This noise comes from several sources, including the digital camera, image distortion due to lens magnification or lens angle, the shape and size of the pattern, and electronic noise; ... This article discusses image enhancement methods to overcome these objectionable characteristics using and comparing several filters: Gaussian, median, and Unsharp Mask filters. The performance of the Gaussian filter is better than the Median and Unsharp mask filters. This research demonstrates that DIC is an effective technique for monitoring deformation and understanding the failure mechanism with the best-suited filter.","PeriodicalId":38546,"journal":{"name":"Frattura ed Integrita Strutturale","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49038889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Method for weak zones location at the coal-bed – host rock joint relative to the problem of sudden outbursts: theory and laboratory experiment 针对突突问题的煤层-围岩节理薄弱带定位方法:理论与室内试验

Frattura ed Integrita Strutturale Pub Date : 2022-12-21 DOI: 10.3221/igf-esis.63.02

L. Nazarova, L. Nazarov

{"title":"Method for weak zones location at the coal-bed – host rock joint relative to the problem of sudden outbursts: theory and laboratory experiment","authors":"L. Nazarova, L. Nazarov","doi":"10.3221/igf-esis.63.02","DOIUrl":"https://doi.org/10.3221/igf-esis.63.02","url":null,"abstract":"Within the framework of a geomechanical model that describes the deformation of a rock mass during the subhorizontal coal-bed extraction, the mechanism for the formation and implementation of a sudden outburst is substantiated: as working face gets close to the weak zone of coal-bed – host rock joint, areas of tensile stresses arise, which creates the prerequisites for face space spalling and coal loss with methane. The inverse problem of determining the conditions at the horizontal boundaries of a coal-bed is formulated and solved using tomography data (longitudinal wave velocity V distribution) and the empirical dependence of V on the mean normal stress σ. Lab tests results on stepwise compression of parallelepipeds made of artificial geomaterials are presented. Tomography of the specimens was performed by acoustic sounding data, and the distribution of velocities V* was found. Using the pre-established empirical dependence V(σ) for geomaterial, the distribution σ*=V-1(V*) in the specimen was calculated, which served as input data for inverse problem of determining the shear stresses σxy at the “specimen faces – press platens” joints. Lab data inversion confirmed the possibility of identifying weak zones of the boundaries where σxy=0. These zones are associated with probable nucleus of failure and sudden outbursts.","PeriodicalId":38546,"journal":{"name":"Frattura ed Integrita Strutturale","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45898103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Delamination effect on the mechanical behavior of 3D printed polymers 分层对3D打印聚合物力学行为的影响

Frattura ed Integrita Strutturale Pub Date : 2022-12-21 DOI: 10.3221/igf-esis.63.03

F. Majid, T. Hachimi, H. Rhanim, R. Rhanim

{"title":"Delamination effect on the mechanical behavior of 3D printed polymers","authors":"F. Majid, T. Hachimi, H. Rhanim, R. Rhanim","doi":"10.3221/igf-esis.63.03","DOIUrl":"https://doi.org/10.3221/igf-esis.63.03","url":null,"abstract":" This study aims to assess the delamination effect and predict the evolution of damage in 3D printed specimens to investigate the mechanical behavior occurring due to the delamination of the layers of 3D printed thermoplastic polymers. Thus, additively manufactured ABS samples are subjected to tensile tests Made for different thicknesses of specimens by subtracting layer by layer. The mechanical behavior of the layers and the adherence between the layers are studied in this paper. The deposition of the layers is modeled as a laminated material. The delamination effect on the resistance of printed material is evaluated experimentally by comparing the mechanical characteristics of homogenously printed specimens, and laminated layers gathered together. Thus, the global resistance is reduced significantly due to the lack of adherence. Besides, crack growth, and critical intensity factor investigation are based on damage and rupture mechanics theories. Furthermore, the results allowed us to evaluate the energy behavior of the 3D printed material subjected to static loads and subsequently predict the evolution of the damage and find out the impact of layers' delamination. Indeed, we determined three stages of damage along with the critical life fraction leading to the failure of the specimen.","PeriodicalId":38546,"journal":{"name":"Frattura ed Integrita Strutturale","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45821269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Stress Intensity Factor of convex embedded polygonal cracks 凸嵌埋多边形裂纹的应力强度因子

Frattura ed Integrita Strutturale Pub Date : 2022-12-21 DOI: 10.3221/igf-esis.63.07

P. Livieri, F. Segala

引用次数: 0

Study of the slant fracture in solid and hollow cylinders: Experimental analysis and numerical prediction 实心和空心圆柱体的斜断裂研究:实验分析和数值预测

Frattura ed Integrita Strutturale Pub Date : 2022-12-21 DOI: 10.3221/igf-esis.63.15

Nassima Ben chabane, Nassim Aguechari, M. Ould Ouali

{"title":"Study of the slant fracture in solid and hollow cylinders: Experimental analysis and numerical prediction","authors":"Nassima Ben chabane, Nassim Aguechari, M. Ould Ouali","doi":"10.3221/igf-esis.63.15","DOIUrl":"https://doi.org/10.3221/igf-esis.63.15","url":null,"abstract":"This paper is devoted to the numerical and experimental study of ductile fracture in bulk metal forming of the 2017A-T4 aluminum alloy. From an experimental standpoint, the ductile fracture of the 2017A-T4 aluminum alloy is investigated under compressive load. Two cross-sections of solid and hollow specimens are considered. The mechanical behavior and the microstructure of the 2017A-T4 aluminum alloy were characterized. It is found that the well-known barrel shape is obtained when a compressive load is applied. Analyses of fracture topographies show a ductile fracture with dimples under tension and coexistence of ductile fracture with dimples and slant under compression. The classical physically-based Gurson-Tvergaard-Needleman (GTN) model and its extension to incorporate shear mechanisms to predict failure at low-stress triaxiality are considered. These two models have been extended to take into account the thermal heating effect induced by the mechanical dissipation within the material during the metal forming process. The two models have been implemented into the finite element code Abaqus/Explicit using a Vectorized User MATerial (VUMAT) subroutine. Numerical simulations of the forging process made for hollow and solid cylindrical specimens show good agreement with experimental results. In contrast with the GTN model, the modified GTN model incorporating shear mechanisms can capture the final material failure.","PeriodicalId":38546,"journal":{"name":"Frattura ed Integrita Strutturale","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44867739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Numerical analysis of repaired wall loss defect pipelines for optimum composite wrap thickness 修复壁损缺陷管道复合材料最佳包层厚度的数值分析

Frattura ed Integrita Strutturale Pub Date : 2022-12-21 DOI: 10.3221/igf-esis.63.14

Muhammed Khaise, S. De Barros, N. Rohem, M. Banea, S. Budhe

{"title":"Numerical analysis of repaired wall loss defect pipelines for optimum composite wrap thickness","authors":"Muhammed Khaise, S. De Barros, N. Rohem, M. Banea, S. Budhe","doi":"10.3221/igf-esis.63.14","DOIUrl":"https://doi.org/10.3221/igf-esis.63.14","url":null,"abstract":"The paper presents the numerical analysis of failure pressure of wall loss defect metallic pipelines and validate it with experimental results. An optimization of composite thickness for repair of wall loss defect pipeline is also carried out using numerical analysis. A nonlinear explicit FE code with constitutive models for metallic steel and composite material to failure modelling was used. Three different cases: non-defective pipe, wall loss defective pipe and composite repaired of defective pipe are considered. It was found that the numerical results are in good agreement with the analytical results in all the three cases. The theoretical failure pressure determined by ISO/TS 24817 standard for wall loss defect pipe is highly conservative compared to the numerical failure pressure for the given composite repair thickness. Additionally, the numerical study on optimization of repair thickness revealed that lower composite repair thickness can also sustain the designed failure pressure (composite repair thickness of 8.4 mm can sustain the same designed pressure instead of 16.1 mm thickness), which implies there is scope to further reduce the composite thickness, which ultimately reduce the repair cost.","PeriodicalId":38546,"journal":{"name":"Frattura ed Integrita Strutturale","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43240319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1