Coupled thermo-hygro-mechanical damage model for concrete subjected to high temperatures

2012 ◽  
Vol 33 (4) ◽  
pp. 465-482 ◽  
Author(s):  
Zhong-you Li ◽  
Yuan-xue Liu
Keyword(s):  
High Temperatures ◽  
Damage Model ◽  
Mechanical Damage

scholarly journals Numerical analysis of mechanical damage on concrete under high temperatures

2022 ◽  
Vol 15 (1) ◽  
Author(s):  
Lahis Souza de Assis ◽  
Matheus Fernandes Dal Sasso ◽  
Michèle Cristina Resende Farage ◽  
Flávia de Souza Bastos ◽  
Anne-Lise Beaucour
Keyword(s):  
High Temperatures ◽  
Thermal Loading ◽  
Damage Model ◽  
Mechanical Damage ◽  
Structural Complexity ◽  
Thermomechanical Behavior ◽  
Computational Tools ◽  
User Subroutine ◽  
Loading Effects ◽  
Abaqus Software

Abstract Concrete is a widespread material all over the world. Due to this material’s heterogeneity and structural complexity, predicting the behavior of concrete structures under extreme environmental conditions is a very challenging task. High temperatures lead to microstructural changes which affect the macrostructural performance. In this context, computational tools that allow the simulation of structures may assist the analysis, by reproducing varied situations of thermal and mechanical loading and boundary conditions. In order to contribute to this scenario, this study proposes a numerical methodology to simulate the thermomechanical behavior of concrete under temperature gradients, through inverse analyses and a user subroutine implemented in Abaqus software. Thermal loading effects were considered as loading data for a damage model. Experimental data available in the literature was adopted for adjustment and validation purposes. The preliminary results presented herein encourage further improvements so as to allow realistic simulations of such an important aspect of concrete’s behavior.

A Rational Methodology for Determination of Service Life for a Delayed Coker Drum

2015 ◽  
Author(s):  
John J. Aumuller ◽  
Jie Chen ◽  
Vincent A. Carucci
Keyword(s):  
Service Life ◽  
Low Cycle Fatigue ◽  
Damage Model ◽  
Mechanical Damage ◽  
Damage Mechanism ◽  
Modern Trend ◽  
Cold Spot ◽  
Chromium Alloy ◽  
Cycle Fatigue ◽  
Service Environment

Delayed unit coker drums operate in a severe service environment that precludes long term reliability due to excessive shell bulging and cracking of shell joint and shell to skirt welds. Thermal fatigue is recognized as the leading damage mechanism and past work has provided an idealized description of the thermo-mechanical mechanism via local hot and cold spot formation to quantify a lower bound life estimate for shell weld failure. The present work extends this idealized thermo-mechanical damage model by evaluating actual field data to determine a potential upper bound life estimate. This assessment also provides insight into practical techniques for equipment operators to identify design and operational opportunities to extend the service life of coke drums for their specific service environments. A modern trend of specifying higher chromium and molybdenum alloy content for drum shell material in order to improve low cycle fatigue strength is seen to be problematic; rather, the use of lower alloy materials that are generally described as fatigue tough materials are better suited for the high strain-low cycle fatigue service environment of coke drums. Materials such as SA 204 C (C – ½ Mo) and SA 302 B (C – Mn – ½ Mo) or SA 302 C (C – Mn – ½ Mo – ½ Ni) are shown to be better candidates for construction in lieu of low chromium alloy steel materials such as SA 387 grades P11 (1¼ Cr – ½ Mo), P12 (1 Cr – ½ Mo), P22 (2¼ Cr – 1 Mo) and P21 (3 Cr – 1 Mo).

scholarly journals Coupled Thermal-Mechanical Progressive Damage Model with Strain and Heating Rate Effects for Lightning Strike Damage Assessment

2019 ◽  
Vol 26 (5-6) ◽  
pp. 1437-1459 ◽  
Author(s):  
S. L. J. Millen ◽  
A. Murphy ◽  
G. Catalanotti ◽  
G. Abdelal
Keyword(s):  
Heating Rate ◽  
Thermal Loading ◽  
Damage Model ◽  
Applied Pressure ◽  
Mechanical Damage ◽  
Failure Criteria ◽  
Lightning Strike ◽  
Progressive Damage ◽  
Rate Effects ◽  
Progressive Damage Model

AbstractThis paper proposes a progressive damage model incorporating strain and heating rate effects for the prediction of composite specimen damage resulting from simulated lightning strike test conditions. A mature and robust customised failure model has been developed. The method used a scaling factor approach and non-linear degradation models from published works to modify the material moduli, strength and stiffness properties to reflect the effects of combined strain and thermal loading. Hashin/Puck failure criteria was used prior to progressive damage modelling of the material. Each component of the method was benchmarked against appropriate literature. A three stage modelling framework was demonstrated where an initial plasma model predicts specimen surface loads (electrical, thermal, pressure); a coupled thermal-electric model predicts specimen temperature resulting from the electrical load; and a third, dynamic, coupled temperature-displacement, explicit model predicts the material state due to the thermal load, the resulting thermal-expansion and the lightning plasma applied pressure loading. Unprotected specimen damage results were presented for two SAE lightning test Waveforms (B & A); with the results illustrating how thermal and mechanical damage behaviour varied with waveform duration and peak current.

Investigations of size effects in tensile tests based on a nonlocal micro-mechanical damage model

2003 ◽  
Vol 26 ◽  
pp. 230-243 ◽  
Author(s):  
Huang Yuan ◽  
Jian Chen ◽  
Klaus Krompholz ◽  
Folker H. Wittmann
Keyword(s):  
Size Effects ◽  
Damage Model ◽  
Mechanical Damage ◽  
Tensile Tests

Coupled thermal-mechanical damage model of laminated carbon fiber/resin composite subjected to lightning strike

2018 ◽  
Vol 206 ◽  
pp. 185-193 ◽  
Author(s):  
Qi Dong ◽  
Guoshun Wan ◽  
Lu Ping ◽  
Yunli Guo ◽  
Xiaosu Yi ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Resin Composite ◽  
Damage Model ◽  
Mechanical Damage ◽  
Lightning Strike

scholarly journals Acoustic Emission and Damage Characteristics of Granite Subjected to High Temperature

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
X. L. Xu ◽  
Z.-Z. Zhang
Keyword(s):  
Acoustic Emission ◽  
High Temperatures ◽  
Count Rate ◽  
Shear Failure ◽  
Rock Fracture ◽  
Mechanical Damage ◽  
Strain Curve ◽  
Effect Of Temperature ◽  
Compression Tests ◽  
Ae Signals

Acoustic emission (AE) signals can be detected from rocks under the effect of temperature and loading, which can be used to reflect rock damage evolution process and predict rock fracture. In this paper, uniaxial compression tests of granite at high temperatures from 25°C to 1000°C were carried out, and AE signals were monitored simultaneously. The results indicated that AE ring count rate shows the law of “interval burst” and “relatively calm,” which can be explained from the energy point of view. From 25°C to 1000°C, the rock failure mode changes from single splitting failure to multisplitting failure, and then to incomplete shear failure, ideal shear failure, and double shear failure, until complete integral failure. Thermal damage (DT) defined by the elastic modulus shows logistic increase with the rise of temperature. Mechanical damage (DM) derived by the AE ring count rate can be divided into initial stage, stable stage, accelerated stage, and destructive stage. Total damage (D) increases with the rise of strain, which is corresponding to the stress-strain curve at various temperatures. Using AE data, we can further analyze the mechanism of deformation and fracture of rock, which helps to gather useful data for predicting rock stability at high temperatures.

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