scholarly journals Cracking Safety Evaluation of Massive Concrete Structures

2011 ◽  
Vol 462-463 ◽  
pp. 1403-1408 ◽  
Author(s):  
A.A. Abdulrazeg ◽  
Parvin Khanazaei ◽  
Jamal Noorzaei ◽  
M.S. Jaafar ◽  
T.A. Mohammed ◽  
...  
Keyword(s):  
Concrete Structures ◽  
Safety Evaluation ◽  
Crack Development ◽  
Mass Concrete ◽  
Element Analysis ◽  
Massive Concrete ◽  
Rcc Dam ◽  
The Finite Element Analysis ◽  
Structural Stresses ◽  
Simplified Procedure

High temperatures generated in the concrete due to the hydration of cement induce thermal tensile stresses. If these stresses are not controlled, they cause cracks in mass concrete structures such as dams. Hence, the thermal and structural stresses needs to be checked against the possibility of cracking to evaluate the safety of the dam. This study deals with formulation and simplified procedure to predict the possibility of crack development in RCC dam. An existing 2-D code has been modified by implementing the crack prediction procedures. The applicability of the modified 2-D code has been shown by analyzing a real RCC dam called Zirdan dam situated in southeast of Iran. The predicted stresses which were obtained through the finite element analysis are examined against the crack development at Gaussian points and it was found that the dam is structurally safe.

Research on Safety Evaluation System of Reinforced Concrete Structures Based on the Blasting Damage

2014 ◽  
Vol 1065-1069 ◽  
pp. 1217-1221
Author(s):  
Guo Quan Zhu ◽  
Jun Lin Tao ◽  
Xiao Ling Liu
Keyword(s):  
Reinforced Concrete ◽  
Evaluation System ◽  
Concrete Structures ◽  
Safety Evaluation ◽  
Security Level ◽  
Reinforced Concrete Structures ◽  
Element Analysis ◽  
Database Technology ◽  
Maximum Crack ◽  
Evaluation Platform

The safety of reinforced concrete structures will be impacted by the explosions. Using the calculations result of finite element analysis software, combining with database technology, a security level evaluation platform of blasting damage in reinforced concrete structures is established. The platform assesses the safety of damaged structure from the remaining bearing capacity, maximum crack width and maximum deflection, etc. It gives the security level from different aspects of the structure and the integrated security level, and repair advice.

scholarly journals Building a nomogram to predict maximum temperature in mass concrete at an early age

2021 ◽  
Vol 263 ◽  
pp. 01008
Author(s):  
Trong - Chuc Nguyen ◽  
Van - Quang Nguyen ◽  
Nikolay Aniskin ◽  
Ba - Thang Phung ◽  
Quoc - Long Hoang
Keyword(s):  
Initial Temperature ◽  
Concrete Structures ◽  
Temperature History ◽  
Maximum Temperature ◽  
Early Age ◽  
Mass Concrete ◽  
The Finite Element Method ◽  
Thermal Cracks ◽  
Massive Concrete ◽  
Main Factor

During the construction of massive concrete structures, the main factor that affects the structure is temperature. The resulting temperature is the result of hydration of the cement and some other factors, which leads to the formation of thermal cracks at an early age. So, the prediction of temperature history in massive concrete structures has been a very important problem. In this study, with the help of numerical methods, a temperature nomogram was built to quickly determine the maximum temperature in concrete structures with different parameters such as size, cement content, and the initial temperature of the concrete mixture. The obtained temperature nomogram has been compared with the results of the finite element method and the model experiment gives reliable results. It can be used to predict maximum temperature in mass concrete structures to prevent the formation of thermal cracks.

A two degrees of freedom comb capacitive-type accelerometer with low cross-axis sensitivity

2019 ◽  
Vol 13 (3) ◽  
pp. 5334-5346
Author(s):  
M. N. Nguyen ◽  
L. Q. Nguyen ◽  
H. M. Chu ◽  
H. N. Vu
Keyword(s):  
Degrees Of Freedom ◽  
Proof Mass ◽  
Vibration Modes ◽  
Electrode Structure ◽  
Element Analysis ◽  
Mechanical Coupling ◽  
Fully Differential ◽  
Mode Effects ◽  
The Finite Element Analysis ◽  
Cross Axis

In this paper, we report on a SOI-based comb capacitive-type accelerometer that senses acceleration in two lateral directions. The structure of the accelerometer was designed using a proof mass connected by four folded-beam springs, which are compliant to inertial displacement causing by attached acceleration in the two lateral directions. At the same time, the folded-beam springs enabled to suppress cross-talk causing by mechanical coupling from parasitic vibration modes. The differential capacitor sense structure was employed to eliminate common mode effects. The design of gap between comb fingers was also analyzed to find an optimally sensing comb electrode structure. The design of the accelerometer was carried out using the finite element analysis. The fabrication of the device was based on SOI-micromachining. The characteristics of the accelerometer have been investigated by a fully differential capacitive bridge interface using a sub-fF switched-capacitor integrator circuit. The sensitivities of the accelerometer in the two lateral directions were determined to be 6 and 5.5 fF/g, respectively. The cross-axis sensitivities of the accelerometer were less than 5%, which shows that the accelerometer can be used for measuring precisely acceleration in the two lateral directions. The accelerometer operates linearly in the range of investigated acceleration from 0 to 4g. The proposed accelerometer is expected for low-g applications.

Tread Depth Effects on Tire Rolling Resistance

2001 ◽  
Vol 29 (3) ◽  
pp. 134-154 ◽  
Author(s):  
J. R. Luchini ◽  
M. M. Motil ◽  
W. V. Mars
Keyword(s):  
Finite Element Analysis ◽  
Common Knowledge ◽  
Rolling Resistance ◽  
Test Method ◽  
Tire Model ◽  
Element Analysis ◽  
Truck Tires ◽  
The Finite Element Analysis ◽  
Equilibrium Test ◽  
Depth Effects

Abstract This paper discusses the measurement and modeling of tire rolling resistance for a group of radial medium truck tires. The tires were subjected to tread depth modifications by “buffing” the tread surface. The experimental work used the equilibrium test method of SAE J-1269. The finite element analysis (FEA) tire model for tire rolling resistance has been previously presented. The results of the testing showed changes in rolling resistance as a function of tread depth that were inconsistent between tires. Several observations were also inconsistent with published information and common knowledge. Several mechanisms were proposed to explain the results. Additional experiments and models were used to evaluate the mechanisms. Mechanisms that were examined included tire age, surface texture, and tire shape. An explanation based on buffed tread radius, and the resulting changes in footprint stresses, is proposed that explains the observed experimental changes in rolling resistance with tread depth.

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