Effect of Mineral Fillers on Fatigue Resistance and Fundamental Material Characteristics: Mechanistic Evaluation

2003 ◽  
Vol 1832 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Yong-Rak Kim ◽  
Dallas N. Little ◽  
Injun Song
Keyword(s):  
Fatigue Resistance ◽  
Damage Mechanics ◽  
Fatigue Behavior ◽  
Continuum Damage Mechanics ◽  
Hydrated Lime ◽  
Mechanical Tests ◽  
Asphalt Binders ◽  
Test Results ◽  
Linear Viscoelastic ◽  
Mineral Fillers

Complex characteristics of fatigue behavior were evaluated on the basis of test results and their mechanical analyses. The dynamic shear rheometer was used to characterize fundamental linear viscoelastic properties of asphalt binders and mastics. Various dynamic mechanical tests using cylindrical sand–asphalt samples mixed with pure binders, mastics, or both were also performed to estimate viscoelastic characteristics and fatigue behavior. To assess the filler effect, two distinctly compositionally different asphalt binders, AAD-1 and AAM-1, and two fillers, limestone and hydrated lime, were selected. Test results were analyzed using viscoelastic theory, a fatigue prediction model based on continuum damage mechanics, and a rheological composite model. The role of fillers in fatigue resistance was quantified, and induced mechanisms due to filler addition were investigated. The effect of hydrated lime, which is highly binder specific, as a filler was further discussed by comparing test results from hydrated lime filler and test results from limestone filler.

Analysis of Multi-Axial Creep–Fatigue Damage on an Outer Cylinder of a 1000 MW Supercritical Steam Turbine

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
Weizhe Wang
Keyword(s):  
Steam Turbine ◽  
Fatigue Damage ◽  
Damage Mechanics ◽  
Hydrostatic Stress ◽  
Fatigue Behavior ◽  
Axial Stress ◽  
Outer Cylinder ◽  
Continuum Damage Mechanics ◽  
Transfer Coefficients ◽  
Creep Fatigue

A multi-axial continuum damage mechanics (CDM) model was proposed to calculate the multi-axial creep–fatigue damage of a high temperature component. A specific outer cylinder of a 1000 MW supercritical steam turbine was used in this study, and the interaction of the creep and fatigue behavior of the outer cylinder was numerically investigated under a startup–running–shutdown process. To this end, the multi-axial stress–strain behavior of the outer cylinder was numerically studied using Abaqus. The in-site measured temperatures were provided to validate the heat transfer coefficients, which were used to calculate the temperature field of the outer cylinder. The multi-axial mechanics behavior of the outer cylinder was investigated in detail, with regard to the temperature, Mises stress, hydrostatic stress, multi-axial toughness factor, multi-axial creep strain, and damage. The results demonstrated that multi-axial mechanics behavior reduced the total damage.

Effects of different design parameters on the stone-impact resistance of automotive windshields

2005 ◽  
Vol 219 (9) ◽  
pp. 1059-1067 ◽  
Author(s):  
X Sun ◽  
M A Khaleel
Keyword(s):  
Damage Mechanics ◽  
Impact Resistance ◽  
Continuum Damage Mechanics ◽  
Element Model ◽  
Design Parameters ◽  
Continuum Damage ◽  
Mechanics Model ◽  
Linear Viscoelastic ◽  
Glass Surfaces ◽  
Vinyl Butyral

A constitutive model based on continuum damage mechanics is used to study the stone-impact resistance of automotive windshields. An axisymmetric finite element model is created to simulate the transient dynamic response and impact-induced damage tensors for laminated glass layers subject to stone-impact loading. The windshield glass consists of two glass outer layers laminated by a thin poly(vinyl butyral) (PVB) layer. The constitutive behaviour of the glass layers is simulated using the continuum damage mechanics model with linear damage evolution. The PVB layer is modelled with a linear viscoelastic solid. The model is used to predict and examine damage patterns on different glass surfaces for different windshield designs including variations in ply thickness and curvatures.

scholarly journals Fatigue performance evaluation of bitumen mastics reinforced with polyolefins through a dissipated energy approach

2020 ◽  
Vol 70 (338) ◽  
pp. 217
Author(s):  
C. Roman ◽  
M. A. Delgado ◽  
M. García-Morales
Keyword(s):  
Performance Evaluation ◽  
Fatigue Resistance ◽  
Fatigue Behavior ◽  
Energy Approach ◽  
Fatigue Performance ◽  
Dissipated Energy ◽  
Morphological Evidence ◽  
Polymer Distribution ◽  
Linear Viscoelastic ◽  
Dynamic Time

Polymers are known to improve the fatigue resistance of sphalt mastics. However, undesirable results can be obtained if the polymer is not successfully integrated into the bitumen binder. The goal of this work is to evaluate the effect of the addition of three selected polyolefins on their mastic’s fatigue performance. Low and high density polyethylenes (LDPE and HDPE) and polypropylene (PP) were chosen and used at the concentration of 4 wt.%. A dissipated energy approach was used in order to analyze the fatigue resistance, at 25 ºC, of the three composites studied. Dynamic time sweeps at and above the linear viscoelastic threshold were carried out. Based on that, the results demonstrated a better improvement when the LDPE was considered. For that binder, fluorescence optical microscopy observations at 25 ºC provided morphological evidence of a more homogeneous bitumen-polymer distribution which could be behind the improved fatigue behavior.

scholarly journals A continuum damage mechanics-based approach for the high cycle fatigue behavior of metallic polycrystals

2018 ◽  
Vol 28 (6) ◽  
pp. 838-856 ◽  
Author(s):  
Charles Mareau ◽  
Franck Morel
Keyword(s):  
Normal Stress ◽  
Damage Mechanics ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Constitutive Relations ◽  
Continuum Damage Mechanics ◽  
Elastic Behavior ◽  
Internal Stresses ◽  
Continuum Damage ◽  
Cycle Fatigue

Polycrystalline elasto-plasticity models provide a general framework for investigating the effect of microstructural heterogeneities (e.g. grains, inclusions, pores) on the high cycle fatigue behavior of metallic materials. In this work, continuum damage mechanics is used to construct a set of constitutive relations to describe the progressive degradation of certain mechanical properties at the grain scale. The damage is considered to be coupled with the elastic behavior of the material. Special care is taken to include the anisotropic aspect of fatigue damage and the effect of intragranular internal stresses. The constitutive relations are then implemented within a self-consistent model to evaluate intergranular interactions. Finally, the model is used to investigate the high cycle fatigue behavior of polycrystalline copper. It is shown that the influence of certain loading conditions on the high cycle behavior is correctly reproduced. Specifically, the application of a mean shear stress does not result in an increase in damage; however, a mean normal stress is damaging. That is, a decrease in the fatigue resistance is predicted when the mean normal stress is increased.

Influence of Chemical Constituents of Asphalt Binders on Their Rheological Properties

2019 ◽  
Vol 2673 (6) ◽  
pp. 458-466 ◽  
Author(s):  
K. Lakshmi Roja ◽  
Eyad Masad
Keyword(s):  
Rheological Properties ◽  
Chemical Constituents ◽  
High Density ◽  
Asphalt Binders ◽  
Composition Analysis ◽  
Test Results ◽  
Aging Index ◽  
Linear Viscoelastic ◽  
Frequency Sweep Test ◽  
Rheological Test

The goal of this study is to investigate the chemical constituents and rheological properties of three different binders used in the State of Qatar. Binders were designated as WL (source 1, low density), WH (source 1, high density) and AH (source 2, high density). Binder composition analysis was carried out using the saturates, aromatics, resins and asphaltene determinator (SAR-AD) technique. The percentages of saturates, aromatics, resins and asphaltenes were measured, and from those, the total pericondensed aromatics (TPA), absorbance aging index (AAI), and colloidal instability index (CII) were obtained and their relationship to rheological test results was investigated. In the rheological investigation, the linear viscoelastic properties of these binders were evaluated using a frequency sweep test. The rutting characteristics were evaluated using the percentage of recovery and non-recoverable creep compliance values from the multiple stress creep and recovery (MSCR) test, while the fatigue resistance was assessed using the linear amplitude sweep (LAS) test. The WL binder was found to have the highest stiffness, which is associated with the highest TPA content. From the MSCR test, the AH binder had the lowest rut resistance. This binder also had the lowest CII value, which represents the balanced chemical composition of this material. Out of the three binders, WH had the highest AAI value which is related to the least fatigue life as measured in the LAS test.

Low Cycle Fatigue Study for GH901 Material Based on Damage Mechanics Theory

2014 ◽  
Vol 711 ◽  
pp. 40-43 ◽  
Author(s):  
Yong Qi Wang ◽  
Hai Bing Zhang
Keyword(s):  
Fatigue Damage ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Continuum Damage Mechanics ◽  
Practical Method ◽  
Test Results ◽  
Cycle Fatigue ◽  
Mechanics Model

The low cycle fatigue damage of turbine disc which is made of GH901 material is systematic analyzed and studied in the article that is based on the theory of continuum damage mechanics and fatigue testing, we improved the common Lemaitre’s low cycle fatigue damage mechanics model, the damage evolution law that the model describes is in good agreement with the test results throughout the course of the fatigue damage. The simplified analysis method for low cycle fatigue damage evolution and life prediction is proposed based on the GH901 low cycle damage features, the practical method of getting damaged material’s constants by existing data is proposed as well.

Development of a Simple Fatigue Cracking Test for Asphalt Binders

2017 ◽  
Vol 2632 (1) ◽  
pp. 79-87 ◽  
Author(s):  
Fujie Zhou ◽  
Pravat Karki ◽  
Soohyok Im
Keyword(s):  
Fatigue Test ◽  
Fatigue Resistance ◽  
Asphalt Binder ◽  
Fatigue Cracking ◽  
Asphalt Binders ◽  
Index Test ◽  
Test Results ◽  
Long Time ◽  
Aging Conditions ◽  
Binder Aging

Current Superpave® PG specification uses parameter | G*|sin(δ) to quantify asphalt binder fatigue resistance. The parameter’s effectiveness has been debated for a long time. AASHTO recently adopted the linear amplitude sweep test as a provisional standard, AASHTO TP 101-12. The authors evaluated the sensitivity of this standard to different aging conditions: unaged original binders, rolling thin-film oven-aged binders, and 20- to 80-h pressure aging vessel–aged binders. Test results showed, in many cases, longer predicted fatigue lives for more-aged binders. Thus this study developed a simple fatigue cracking test for asphalt binders. In this new test, the pure linear amplitude sweep (PLAS) test, peak shear strain was increased linearly from 0% to 30% over a course of 3,000 oscillatory cycles. A new fatigue parameter, the fatigue resistance energy index (FREI), was derived with fracture mechanics. The PLAS test and FREI parameter were sensitive to both binder aging conditions and rejuvenator type and dosage. Four laboratory mixtures were employed to evaluate the correlation between this new binder fatigue test and the two mixture cracking tests: the Texas overlay test and the Illinois flexibility index test. The results showed that the PLAS and FREI correlated well with the mixture cracking tests. Additionally, the proposed method was preliminarily verified with the FHWA accelerated loading facility test, and a fair relationship with the full-scale fatigue test data was observed. It is obvious that the PLAS and associated FREI need further validation through more field test sections.

Prediction of Asphalt Mix Fatigue Life with Viscoelastic Material Properties

2003 ◽  
Vol 1832 (1) ◽  
pp. 139-147 ◽  
Author(s):  
Hyun Lee ◽  
Y. Richard Kim ◽  
Seung Lee
Keyword(s):  
Fatigue Life ◽  
Viscoelastic Material ◽  
Material Properties ◽  
Viscoelastic Properties ◽  
Damage Mechanics ◽  
Fatigue Behavior ◽  
Continuum Damage Mechanics ◽  
Asphalt Mixes ◽  
Fatigue Model ◽  
Asphalt Mix

A simplified fatigue model is presented that can predict the fatigue life of asphalt mixes using viscoelastic properties only. This fatigue model was originally developed with the elastic-viscoelastic correspondence principle and continuum damage mechanics and was reduced to a simple version that can predict fatigue life with viscoelastic properties only. On the basis of the experimental study conducted on 12 different types of asphalt mixes, it was observed that the fatigue behavior of asphalt mixes is affected by both the viscoelastic properties and the fatigue characteristics, but mostly by the viscoelastic properties. In addition, it was found that the coefficient of conventional strain-based fatigue models could be expressed in terms of viscoelastic material properties. In the verification study, the fatigue model was able to predict the fatigue life of various types of mixes at the same level of prediction accuracy without change in model coefficients. The fatigue model was also able to accurately predict the changes in the fatigue life of an asphalt mix due to the changes in the volumetric mix properties.

Linking fatigue response of asphalt binders, mastics, and asphalt concrete mixture modified by nano-silica and synthesized polyurethane

2020 ◽  
Vol 30 (1) ◽  
pp. 103-122
Author(s):  
Mana Motamedi ◽  
Gholamali Shafabakhsh ◽  
Mohammad Azadi
Keyword(s):  
Fatigue Life ◽  
Asphalt Concrete ◽  
Damage Mechanics ◽  
Asphalt Binder ◽  
Continuum Damage Mechanics ◽  
Fatigue Performance ◽  
Concrete Mixture ◽  
Asphalt Binders ◽  
Continuum Damage ◽  
Nano Silica

Asphalt concrete is composed of stone, sand, filler, and asphalt binder. Fatigue can be considered as a phenomenon affecting both the binder (asphalt binder or mastic) and the mixture. The purpose of this study was to investigate the fatigue damage response in asphalt binders, mastics, and asphalt concrete mixtures modified with nano-silica and synthesized polyurethane. The continuum damage mechanics method and phenomenological approaches in this study were used to investigate the fatigue performance. Obtained results indicated that the effect of the synthesized polyurethane on improving the fatigue life was far greater than that of nano-silica. The damage process in asphalt binders differed from that in the mastic and asphalt concrete mixture. Damage intensity parameter is an appropriate criterion for evaluating fatigue performance of asphalt binders and mastics. Concerning the fatigue of asphalt concrete mixture, the results of this study indicated a better convergence between the fatigue parameters of mastics and asphalt concrete mixture compared to asphalt binders, especially with increasing aging. Also, there was greater convergence between the fatigue life of the asphalt concrete mixture and asphalt binder and mastics in the method of continuum damage mechanics as compared to the phenomenological approach.

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