Influence of specimen geometry on fracture toughnesses of concrete based on boundary effect model

2021 ◽  
pp. 103135
Author(s):  
Yanhua Zhao ◽  
Nana Yin ◽  
Bohan Xu ◽  
Ye Tao
Keyword(s):  
Boundary Effect ◽  
Specimen Geometry ◽  
Effect Model

Size effect research of tensile strength of bamboo scrimber based on boundary effect model

2020 ◽  
Vol 239 ◽  
pp. 107319
Author(s):  
Peng Xie ◽  
Wen Liu ◽  
Yucun Hu ◽  
Xinmiao Meng ◽  
Jiankun Huang
Keyword(s):  
Tensile Strength ◽  
Size Effect ◽  
Boundary Effect ◽  
Effect Model ◽  
Bamboo Scrimber

scholarly journals Critical comparison of the boundary effect model with cohesive crack model and size effect law

2019 ◽  
Vol 215 ◽  
pp. 193-210 ◽  
Author(s):  
Christian Carloni ◽  
Gianluca Cusatis ◽  
Marco Salviato ◽  
Jia-Liang Le ◽  
Christian G. Hoover ◽  
...  
Keyword(s):  
Size Effect ◽  
Boundary Effect ◽  
Cohesive Crack ◽  
Crack Model ◽  
Cohesive Crack Model ◽  
Critical Comparison ◽  
Effect Model

Foreign Trade in Russia

2014 ◽  
Vol 3 (3) ◽  
pp. 1-18 ◽  
Author(s):  
Vasily Erokhin
Keyword(s):  
Economic Development ◽  
Foreign Trade ◽  
Trade Liberalization ◽  
Boundary Effect ◽  
Import Substitution ◽  
Economic Security ◽  
Structural Problems ◽  
Export Expansion ◽  
Effect Model ◽  
Level Of Economic Development

Until recently only one of the largest economies – Russia was not among the WTO members. Russia's accession into the WTO drew out hidden structural problems of national economy, low competitiveness of domestic producers, dependence on fossil-fuel exports, and regional disparities. The paper aims at overview of the existing distortions of Russia's foreign trade and their potential threats to sustainable economic development and national economic security in view of the running trade liberalization. Regional implementations of trade liberalization are investigated on the case of the Stavropol Krai, one of the southern regions of Russia with an average level of economic development. The Gravity model is implemented to analyze trade activities of the region; the Boundary Effect Model is utilized to evaluate the effects of trade liberalization on separate industries. Simulation allowed distributing regional commodities on their competitiveness depending on export quota and boundary effect, and accessing aftermaths of export expansion and import substitution.

scholarly journals Determination of Fracture Properties of Concrete Using Size and Boundary Effect Models

2019 ◽  
Vol 9 (7) ◽  
pp. 1337 ◽  
Author(s):  
Xiaofeng Gao ◽  
Chunfeng Liu ◽  
Yaosheng Tan ◽  
Ning Yang ◽  
Yu Qiao ◽  
...  
Keyword(s):  
Crack Length ◽  
Boundary Effect ◽  
Test Results ◽  
Fracture Test ◽  
Concrete Material ◽  
Material Parameters ◽  
Fracture Parameters ◽  
Effect Model ◽  
Different Types

Tensile strength and fracture toughness are two essential material parameters for the study of concrete fracture. The experimental procedures to measure these two fracture parameters might be complicated due to their dependence on the specimen size or test method. Alternatively, based on the fracture test results only, size and boundary effect models can determine both parameters simultaneously. In this study, different versions of boundary effect models developed by Hu et al. were summarized, and a modified Hu-Guan’s boundary effect model with a more appropriate equivalent crack length definition is proposed. The proposed model can correctly combine the contributions of material strength and linear elastic fracture mechanics on the failure of concrete material with any maximum aggregate size. Another size and boundary model developed based on the local energy concept is also introduced, and its capability to predict the fracture parameters from the fracture test results of wedge-splitting and compact tension specimens is first validated. In addition, the classical Bažant’s Type 2 size effect law is transformed to its boundary effect shape with the same equivalent crack length as Koval-Gao’s size and boundary effect model. This improvement could extend the applicability of the model to infer the material parameters from the test results of different types of specimens, including the geometrically similar specimens with constant crack-length-to-height ratios and specimens with different initial crack-length-to-height ratios. The test results of different types of specimens are adopted to verify the applicability of different size and boundary effect models for the determination of fracture toughness and tensile strength of concrete material. The quality of the extrapolated fracture parameters of the different models are compared and discussed in detail, and the corresponding recommendations for predicting the fracture parameters for dam concrete are proposed.

Seismic Dynamic Model Tests on Tunnel Lining Passing through the Fault

2013 ◽  
Vol 368-370 ◽  
pp. 1732-1737 ◽  
Author(s):  
Jia Mei Zhou ◽  
Qi Yan ◽  
Guo Wang Meng
Keyword(s):  
Relative Motion ◽  
Large Scale ◽  
Boundary Effect ◽  
Tunnel Lining ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
Force Load ◽  
Effect Model ◽  
Seismic Force ◽  
Seismic Behaviors

The seismic behaviors of tunnel lining passing through the fault are studied by means of large-scale shaking table tests under the load of Wolong-seismic wave. The model tunnel is installed into a model box with a length of 3.65 m, width of 1.5 m and height of 1.8 m. The sizes of model and prototype tunnel are designed by using the similar principles with a scale factor of 1:30. As the result shows, under the seismic force load, the tunnel lining has a delay of responding the seismic force when it crosses the faults geological belt. The time is 0.085seconds. Model box amplified table acceleration, the farther the distance from shaking table is, the more obvious amplification is. The seismic force load is horizontal, but the resistance applied by the faults geological belt is weak, resulting relative motion, collision, extrusion etc. so, the tunnel lining appears cracks. It is in accord with investigation conclusions of Wenchuan earthquake. Article also aims at some problems in the experiment such as: boundary effect, model box stiffness etc, and gives some suggestions.

Asymptotic Analysis of Boundary-Induced Size Dependence of Fracture Properties

2006 ◽  
Vol 324-325 ◽  
pp. 1209-1212
Author(s):  
Kai Duan ◽  
Xiao Zhi Hu
Keyword(s):  
High Strength Concrete ◽  
Size Dependence ◽  
Boundary Effect ◽  
Brittle Materials ◽  
High Strength ◽  
Asymptotic Model ◽  
Fracture Properties ◽  
Asymptotic Boundary ◽  
Effect Model ◽  
Fracture Tests

The recently-developed boundary effect concept and associated asymptotic model are used to explain the size effect phenomena in fracture of quasi-brittle materials. It is demonstrated that the size dependence of the fracture toughness and strength of quasi-brittle materials is indeed due to the influences of specimen boundaries on the failure mode and therefore, on the strength of the specimen. To verify the boundary effect concept, fracture tests on a high strength concrete reported by Karihaloo et al are analysed and predicted using the asymptotic model. The results show that the predictions of the asymptotic boundary effect model agree very well with those experimental results.

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