Quantitative solution on dosage of repair agent for healing of cracks in materials: short capsule model vs. two-dimensional crack pattern

2011 ◽  
Vol 18 (1-2) ◽  
pp. 13-19 ◽  
Author(s):  
Zhong Lv ◽  
Huisu Chen ◽  
Haifeng Yuan
Keyword(s):  
Probability Distribution ◽  
Service Life ◽  
Cementitious Materials ◽  
Crack Pattern ◽  
Two Dimensional ◽  
Surface Cracks ◽  
Load Bearing Capacity ◽  
Modeling Technology ◽  
Geometrical Probability ◽  
Different Types

AbstractCracks are vitally detrimental to the load-bearing capacity of materials and further to the durability and service-life of various structures. Crack-repairing technology via embedded capsules with repair agent is becoming a promising approach to sustain the performance of structural materials. However, the appropriate dosage of capsulated repair agent for autonomic healing is not theoretically solved in the literature. In this study, taking cementitious materials as an example, the surface cracks in materials caused by various mechanisms are firstly simplified as linear cracks and zonal cracks in two-dimensional plane. Then, from the viewpoint of geometrical probability, the theoretical solutions on the exact dosage of capsules required are developed for different types of crack models via the knowledge of integral geometry and the concepts of probability distribution. Finally, reliability of these theoretical solutions is verified via computer modeling technology.

scholarly journals Methodology for the quantification of concrete sustainability

2018 ◽  
Vol 174 ◽  
pp. 01006 ◽  
Author(s):  
Břetislav Teplý ◽  
Tomáš Vymazal ◽  
Pavla Rovnaníková
Keyword(s):  
Decision Making ◽  
Life Cycle Assessment ◽  
Life Cycle ◽  
Environmental Impact ◽  
Service Life ◽  
Circular Economy ◽  
Point Of View ◽  
Raw Material ◽  
Load Bearing Capacity ◽  
Sustainability Management

Efficient sustainability management requires the use of tools which allow material, technological and construction variants to be quantified, measured or compared. These tools can be used as a powerful marketing aid and as support for the transition to “circular economy”. Life Cycle Assessment (LCA) procedures are also used, aside from other approaches. LCA is a method that evaluates the life cycle of a structure from the point of view of its impact on the environment. Consideration is given also to energy and raw material costs, as well as to environmental impact throughout the life cycle - e.g. due to emissions. The paper focuses on the quantification of sustainability connected with the use of various types of concrete with regard to their resistance to degradation. Sustainability coefficients are determined using information regarding service life and "eco-costs". The aim is to propose a suitable methodology which can simplify decision-making in the design and choice of concrete mixes from a wider perspective, i.e. not only with regard to load-bearing capacity or durability.

Bifurcation analysis of two-dimensional laminar flow through sudden expansion channel

2022 ◽  
Vol 13 (1) ◽  
pp. 0-0
Keyword(s):  
Laminar Flow ◽  
Expansion Ratio ◽  
Sudden Expansion ◽  
Two Dimensional ◽  
Governing Equations ◽  
Bifurcation Phenomena ◽  
Different Types ◽  
Fluent Software ◽  
Flow Through ◽  
Volume Method

In this work, bifurcation characteristics of unsteady, viscous, Newtonian laminar flow in two-dimensional sudden expansion and sudden contraction-expansion channels have been studied for different values of expansion ratio. The governing equations have been solved using finite volume method and FLUENT software has been employed to visualize the simulation results. Three different mesh studies have been performed to calculate critical Reynolds number (Recr) for different types of bifurcation phenomena. It is found that Recr decreases with the increase in expansion ratio (ER).

The method of repairing OHE damaged ancient painted murals based on machine vision

2021 ◽  
pp. 1-15
Author(s):  
Hao Li
Keyword(s):  
Machine Vision ◽  
Two Dimensional ◽  
Traditional Methods ◽  
Dimensional Image ◽  
Two Dimensional Image ◽  
Different Types ◽  
Damage Data ◽  
Incomplete Damage

Traditional mural repair methods only observe the texture of murals when segmenting the repair area, but ignore the extraction of a mural damage data, resulting in incomplete damage crack information. For this reason, the method of repairing the damaged murals based on machine vision is studied. Using machine vision, it can get two-dimensional image of a mural, preprocess the image, extract the damaged data of a mural, and then divide the repair area and repair degree index. According to different types of damage, it can choose the corresponding repair methods to achieve the repair of damaged mural. The results show: Compared with the reference [1] method and reference [2] method, the number of repair points and repair cracks extracted by the proposed method is more than that of the two traditional methods, which can more accurately and comprehensively extract the repair information of murals.

Discriminating intra-parasequence stratigraphic units from two-dimensional quantitative parameters

2021 ◽  
Vol 91 (8) ◽  
pp. 887-911
Author(s):  
Manuel F. Isla ◽  
Ernesto Schwarz ◽  
Gonzalo D. Veiga ◽  
Jerónimo J. Zuazo ◽  
Mariano N. Remirez
Keyword(s):  
High Frequency ◽  
Two Dimensional ◽  
Facies Associations ◽  
Different Types ◽  
Lateral Extent ◽  
Successive Wave ◽  
Shell Bed ◽  
Definition Of ◽  
High Resolution Sequence Stratigraphy ◽  
Bounding Surfaces

ABSTRACT The intra-parasequence scale is still relatively unexplored territory in high-resolution sequence stratigraphy. The analysis of internal genetic units of parasequences has commonly been simplified to the definition of bedsets. Such simplification is insufficient to cover the complexity involved in the building of individual parasequences. Different types of intra-parasequence units have been previously identified and characterized in successive wave-dominated shoreface–shelf parasequences in the Lower Cretaceous Pilmatué Member of the Agrio Formation in central Neuquén Basin. Sedimentary and stratigraphic attributes such as the number of intra-parasequence units, their thickness, the proportions of facies associations in the regressive interval, the lateral extent of bounding surfaces, the degree of deepening recorded across these boundaries, and the type and lateral extent of associated transgressive deposits are quantitatively analyzed in this paper. Based on the analysis of these quantified attributes, three different scales of genetic units in parasequences are identified. 1) Bedset complexes are 10–40 m thick, basin to upper-shoreface successions, bounded by 5 to 16 km-long surfaces with a degree of deepening of one to three facies belts. These stratigraphic units represent the highest hierarchy of intra-parasequence stratigraphic units, and the vertical stacking of two or three of them typically forms an individual parasequence. 2) Bedsets are 2–20 m thick, offshore to upper-shoreface successions, bounded by up to 10 km long surfaces with a degree of deepening of zero to one facies belt. Two or three bedsets stack vertically build a bedset complex. 3) Sub-bedsets are 0.5–5 m thick, offshore transition to upper-shoreface successions, bounded by 0.5 to 2 km long surfaces with a degree of deepening of zero to one facies belt. Two or three sub-bedsets commonly stack to form bedsets. The proposed methodology indicates that the combination of thickness with the proportion of facies associations in the regressive interval of stratigraphic units can be used to discriminate between bedsets and sub-bedsets, whereas for higher ranks (bedsets and bedset complexes) the degree of deepening, lateral extent of bounding surfaces, and the characteristics of associated shell-bed deposits become more effective. Finally, the results for the Pilmatué Member are compared with other ancient and Holocene examples to improve understanding of the high-frequency evolution of wave-dominated shoreface–shelf systems.

scholarly journals Kernel density estimation and its application

2018 ◽  
Vol 23 ◽  
pp. 00037 ◽  
Author(s):  
Stanisław Węglarczyk
Keyword(s):  
Probability Density Function ◽  
Probability Distribution ◽  
Density Estimation ◽  
Kernel Density Estimation ◽  
Real Life ◽  
Kernel Estimation ◽  
Kernel Density ◽  
Two Dimensional ◽  
2D Histogram ◽  
Function Shape

Kernel density estimation is a technique for estimation of probability density function that is a must-have enabling the user to better analyse the studied probability distribution than when using a traditional histogram. Unlike the histogram, the kernel technique produces smooth estimate of the pdf, uses all sample points' locations and more convincingly suggest multimodality. In its two-dimensional applications, kernel estimation is even better as the 2D histogram requires additionally to define the orientation of 2D bins. Two concepts play fundamental role in kernel estimation: kernel function shape and coefficient of smoothness, of which the latter is crucial to the method. Several real-life examples, both for univariate and bivariate applications, are shown.

The Strength Evaluation and Reliability Analysis of Periodic Symmetric Struts Support

2011 ◽  
Vol 462-463 ◽  
pp. 1164-1169
Author(s):  
Jing Xiang Yang ◽  
Ya Xin Zhang ◽  
Mamtimin Gheni ◽  
Ping Ping Chang ◽  
Kai Yin Chen ◽  
...  
Keyword(s):  
Distribution Function ◽  
Probability Distribution ◽  
Stress Distribution ◽  
Least Squares ◽  
Reliability Analysis ◽  
Least Squares Method ◽  
Nonlinear Least Squares ◽  
Distribution Model ◽  
Different Types ◽  
Nonlinear Least Squares Method

In this paper, strength evaluations and reliability analysis are conducted for different types of PSSS(Periodically Symmetric Struts Supports) based on the FEA(Finite Element Analysis). The numerical models are established at first, and the PMA(Prestressed Modal Analysis) is conducted. The nodal stress value of all of the gauss points in elements are extracted out and the stress distributions are evaluated for each type of PSSS. Then using nonlinear least squares method, curve fitting is carried out, and the stress probability distribution function is obtained. The results show that although using different number of struts, the stress distribution function obeys the exponential distribution. By using nonlinear least squares method again for the distribution parameters a and b of different exponential functions, the relationship between number of struts and distribution function is obtained, and the mathematical models of the stress probability distribution functions for different supports are established. Finally, the new stress distribution model is introduced by considering the DSSI(Damaged Stress-Strength Interference), and the reliability evaluation for different types of periodically symmetric struts supports is carried out.

Research of the Load Bearing Capacity of Shape-Optimized Metal Inserts Embedded in CFRP under Different Types of Stresses

2017 ◽  
Vol 742 ◽  
pp. 636-643 ◽  
Author(s):  
Florentin Pottmeyer ◽  
Markus Muth ◽  
Kay André Weidenmann
Keyword(s):  
Bearing Capacity ◽  
Residual Strength ◽  
High Speed ◽  
Systematic Research ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Temperature Cycles ◽  
Pull Out ◽  
Different Types ◽  
Impact Energies

An efficient implementation of lightweight design is the use of continuous carbon fiber reinforced plastics (CFRP) due to their outstanding specific mechanical properties. Embedded metal elements, so-called inserts, can be used to join metal-based attachments to structural CFRP parts in the context of multi-material design. They differ from other mechanical fasteners and have distinctive benefits. In particular, drilling of the components to be joined can be avoided and, depending on the preforming, fiber continuity can be maintained using such elements. Thus, no local bearing stress is anticipated. Previous work published by the authors [1] dealt with a systematic research of the influence of different types of stresses on the load bearing capacity of welded inserts. This contribution aims at the investigation of the performance of shape-optimized inserts under the same types of loading to compare with the results of the welded inserts serving as a reference. For that purpose, the respective load bearing capacities were evaluated after preinduced damages from impact tests and thermal cycling. In addition, dynamic high-speed tensile tests (pull-out) were conducted under different loading velocities. It is shown that the load bearing capacities increased up to 19% for high velocities (250 mm/s) in comparison to quasi-static loading conditions (1.5 mm/min) showing an obvious strain rate dependency of the CFRP. Quasi-static residual strength measurements under tensile loading identified the influence of the respective preinduced damages of the insert. Influence of the thermal loading condition was evaluated by placing the specimens in a climate chamber and exposing it to various numbers of temperature cycles from-40 °C to +80 °C with a duration time of 1.5 hours each. Here, it turned out that already 10 temperature cycles decreased the quasi-static load bearing capacity up to 31%. According to DIN EN 6038 the specimens were loaded with different impact energies and the residual strength were measured carrying out pull-out tests. It could be shown that the damage tolerance is significantly lower for the shape-optimized insert due to failure-critical delamination. The optimized insert also endured lower impact energies and the influence on the performance was higher.

scholarly journals Early-Age Cracking in Concrete: Causes, Consequences, Remedial Measures, and Recommendations

2018 ◽  
Vol 8 (10) ◽  
pp. 1730 ◽  
Author(s):  
Md. Safiuddin ◽  
A. Kaish ◽  
Chin-Ong Woon ◽  
Sudharshan Raman
Keyword(s):  
Service Life ◽  
Concrete Structures ◽  
Real Life ◽  
Early Age ◽  
Structural Elements ◽  
Remedial Measures ◽  
Curing Conditions ◽  
Factors Affecting ◽  
Different Types ◽  
Service Conditions

Cracking is a common problem in concrete structures in real-life service conditions. In fact, crack-free concrete structures are very rare to find in real world. Concrete can undergo early-age cracking depending on the mix composition, exposure environment, hydration rate, and curing conditions. Understanding the causes and consequences of cracking thoroughly is essential for selecting proper measures to resolve the early-age cracking problem in concrete. This paper will help to identify the major causes and consequences of the early-age cracking in concrete. Also, this paper will be useful to adopt effective remedial measures for reducing or eliminating the early-age cracking problem in concrete. Different types of early-age crack, the factors affecting the initiation and growth of early-age cracks, the causes of early-age cracking, and the modeling of early-age cracking are discussed in this paper. A number of examples for various early-age cracking problems of concrete found in different structural elements are also shown. Above all, some recommendations are given for minimizing the early-age cracking in concrete. It is hoped that the information conveyed in this paper will be beneficial to improve the service life of concrete structures. Concrete researchers and practitioners may benefit from the contents of this paper.

scholarly journals Google matrix analysis of worldwide football mercato

2018 ◽  
Author(s):  
José Lages ◽  
Justin Loye ◽  
Célestin Coquidé ◽  
Guillaume Rollin
Keyword(s):  
Large Scale ◽  
World Wide ◽  
Matrix Analysis ◽  
Two Dimensional ◽  
Network Nodes ◽  
Pagerank Algorithm ◽  
Google Matrix ◽  
Football Clubs ◽  
The World ◽  
Different Types

The worldwide football transfer market is analyzed as a directed complex network: the football clubs are the network nodes and the directed edges are weighted by the total amount of money transferred from a club to another. The Google matrix description allows to treat every club independently of their richness and allows to measure for a given club the efficiency of player sales and player acquisitions. The PageRank algorithm, developed initially for the World Wide Web, naturally characterizes the ability of a club to import players. The CheiRank algorithm, also developed to analyze large scale directed complex networks, characterizes the ability of a club to export players. The analysis in the two-dimensional PageRank-CheiRank plan permits to determine the transfer balance of the clubs in a more subtle manner than the traditional import-export scheme. We investigate the 2017-2018 mercato concerning 2296 clubs, 6698 player transfers, and 147 player nationalities. The transfer balance is determined globally for different types of player trades (defender, midfielder, forward, …) and for different national football leagues. Although, on average, the network transfer flows from and to clubs are balanced, the discrimination by player type draws a specific portrait of each football club.

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