Determination of Creep Parameters of Conductive Asphalt Concrete

2011 ◽  
Vol 306-307 ◽  
pp. 888-893 ◽  
Author(s):  
Shi Lin Yan ◽  
Wen Tao Li ◽  
Shao Peng Wu ◽  
Ling Pang
Keyword(s):  
Fatigue Life ◽  
Asphalt Concrete ◽  
Rheological Model ◽  
Fatigue Behavior ◽  
Constant Load ◽  
Burgers Model ◽  
Static Creep ◽  
Conductive Fillers ◽  
Energy Dissipated

The research on the conductive asphalt concrete(CAC) is to melt snow and ice on the pavement and improve the property of skid resistance. However, research at present mainly focuses on the electrical property not on the fatigue behavior which is also important to the application of CAC in the future. The specific rheological model is developed and the relation between creep and fatigue is investigated in this paper. By the single axial static creep test, the existed rheological model (Burgers model) and method of regression, the creep deformation of asphalt concrete is measured with time and parameters of the model are obtained. The results indicate that strain increases quickly with increasing time at initial loading phase, and then the change of strain tend to a stable value in a constant load. At unloading phase, strain decreases immediately and then keep another stable value which was greater than zero. The addition of conductive fillers improves the elastic properties and has no significant influence to the viscosity of asphalt concrete. In addition, the fatigue life can be predicted by the parameters of the Burgers model. The addition of conductive fillers improves energy dissipated, which leads to shorter fatigue life of conductive asphalt concrete compared to the control at levels of longer fatigue life.

scholarly journals Energy Dissipated in Fatigue and Creep Conditions

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4724
Author(s):  
Stanisław Mroziński ◽  
Zbigniew Lis ◽  
Halina Egner
Keyword(s):  
Fatigue Life ◽  
Constant Load ◽  
Test Results ◽  
Fatigue Load ◽  
P91 Steel ◽  
Fatigue Process ◽  
Energy Dissipated ◽  
Load Conditions

The paper presents the results of tests performed on samples made of P91 steel under combined variable and constant load conditions, at temperature T = 600 °C. The analysis of the test results was carried out with the use of the energetic description of the fatigue process. It was shown that the order of occurrence of the fatigue load and creep in the load program influences the fatigue life and the value of the energy cumulated in the sample until fracture.

Effects of Conductive Fillers on the Dynamic Response and Fatigue life of Conductive Asphalt Concrete

2007 ◽  
Vol 348-349 ◽  
pp. 145-148 ◽  
Author(s):  
Shao Peng Wu ◽  
Bo Li ◽  
Jian Qiu ◽  
Ning Li
Keyword(s):  
Fatigue Life ◽  
Asphalt Concrete ◽  
Dynamic Modulus ◽  
Load Cycle ◽  
Initial Crack ◽  
Asphalt Pavements ◽  
Negative Effects ◽  
Cycle Times ◽  
Dynamic Modulus Test ◽  
Conductive Fillers

It is currently interesting to use thermal or electrical conductive asphalt concrete for snow-melting and maintenance of asphalt pavements in winter. The addition of conductive fillers may have negative effects on the mechanical properties of asphalt concrete. The performance of conductive asphalt concrete is greatly affected by the initial crack and its propagation. Laboratory tests for neat and conductive asphalt concrete include Dynamic Modulus Test (DMT) and Indirect Tensile Fatigue Test (ITFT). DMT tests indicates that the value of dynamic modulus of asphalt concrete decreases with the increasing graphite content. It means that the conductive asphalt concrete achieves lower stiffness. It can be concluded from ITFT tests that the fatigue life (load cycle times) of conductive asphalt concrete is more than neat ones when stress level is under 1.0 MPa. Meanwhile higher fatigue resistance of conductive asphalt concrete is observed when carbon fibers (2 weight % of total aggregate) were added together with 22% graphite, especially at low stress levels.

Thermomechanical Fatigue Behavior of NiTi Wires

2013 ◽  
Vol 738-739 ◽  
pp. 311-315
Author(s):  
Antonio Isalgué ◽  
Javier Fernández ◽  
Nuria Cinca ◽  
I.G. Cano ◽  
Ramón Grau ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Smart Materials ◽  
Fatigue Behavior ◽  
Testing Machine ◽  
Constant Load ◽  
Niti Wire ◽  
Structural Fatigue ◽  
Mechanical Cycling ◽  
Thermal Actuation ◽  
Niti Wires

Applications of the functional, smart materials SMA need a careful evaluation of the working conditions and fatigue life. Structural fatigue failure in NiTi usually comes from a surface defect inducing crack growth, and this means that fatigue has to be studied for concrete applications, with the correct samples, as the state of the material presents size effects. Testing machine experiments on Ni-rich pseudoelastic wires indicate that the main parameter controlling the fatigue life in the traction-traction experiments is the effective stress on the NiTi wire. Long wire life (in the million cycle regime) can be achieved under limited stresses (under 170 MPa) in traction-traction tests. Also, experiments have been done on thermal actuation of NiTi wire under traction at constant load. Long actuator life (larger than 400000 cycles) can be achieved at low stresses (around 100 MPa), coherently with the results from the mechanical cycling.

scholarly journals Fatigue Life for Type 316L Stainless Steel under Cyclic Loading

2013 ◽  
Vol 701 ◽  
pp. 77-81
Author(s):  
Khairul Azhar Mohammad ◽  
Edi Syam Zainudin ◽  
S.M. Sapuan ◽  
Nur Ismarrubie Zahari ◽  
Ali Aidy
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
316L Stainless Steel ◽  
Load Ratio ◽  
Constant Load ◽  
Fatigue Tests ◽  
Constant Frequency ◽  
Technology Market ◽  
Constant Load Amplitude

The paper presents the determination of fatigue life of 316L stainless steel at room temperature. Plenty of steel in the world has been investigated for a lot of application in the science and technology market. The mechanisms of fatigue of 316L stainless steels were studied and investigated. Fatigue tests of specimens were performed in accordance with ASTM E466-96. The fatigue tests were performed in constant load amplitude, constant frequency of 5 Hz with load ratio R=0.1. Fracture surface of specimens were examined by using Scanning Electron Microscope (SEM). The results showed that the endurance fatigue limit of 316L stainless steel was 146.45 MPa.

An Investigation on Flexural Fatigue Behavior of CFRP Quasi-Isotropic Laminates

2020 ◽  
Author(s):  
K. Panbarasu ◽  
V. R. Ranganath ◽  
Raghu V. Prakash
Keyword(s):  
Fatigue Life ◽  
Failure Modes ◽  
Fatigue Behavior ◽  
High Amplitude ◽  
Constant Load ◽  
Cfrp Laminates ◽  
Lower Load ◽  
Carbon Fibre Reinforced Plastic ◽  
Constant Load Amplitude ◽  
Low Amplitude

Abstract In this study, AS4/914 grade carbon fibre reinforced plastic (CFRP) laminates with two different quasi-isotropic (QI) layup sequences are compared for their performance under four point bend flexure fatigue loads. The QI laminates were designated and fabricated as Laminate-1 (L1) [0/45/-45/90]2S and Laminate-2 (L2) [0/90/45/-45]2S, respectively. These laminates were designed, such that the 0° layers are placed at a similar position in both the laminate systems by changing the other layers. During the test, load and displacement data was monitored online along with instantaneous number of constant load amplitude (CLA) fatigue cycles to calculate the stiffness degradation. Three load levels of 90%, 80%, and 70% of the ultimate flexure strength (UFS) were chosen for assessing the flexure fatigue behavior of the laminates. A few tests were also attempted under variable amplitude loads: (i) high amplitude cycles followed by low amplitude and (ii) low amplitude cycles followed by high amplitude to examine load sequence effect on fatigue life, if any, as compared to the fatigue life under CLA. It has been observed that the laminate L1 performs better under higher amplitudes, while the laminate L2 shows increased life under lower load and variable amplitudes. The results obtained in the form of data plots and failure modes, supported by microscopic images, are discussed in the paper.

Fatigue of Unidirectional Cord-Rubber Composites

1999 ◽  
Vol 27 (1) ◽  
pp. 48-57 ◽  
Author(s):  
Y. Liu ◽  
Z. Wan ◽  
Z. Tian ◽  
X. Du ◽  
J. Jiang ◽  
...  
Keyword(s):  
Damage Accumulation ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Constant Load ◽  
Testing System ◽  
Rubber Composites ◽  
Cycle Frequency ◽  
Periodic Loading ◽  
Fatigue Damage Accumulation ◽  
Rubber Composite

Abstract A fatigue testing system is established with which the real-time recording of stress, strain, temperature, and hysteresis loss of rubbers or cord-rubber composite specimens subjected to periodic loading or extension can be successfully carried out. Several problems are connected with the experimental study of the fatigue of rubber composites. In constant extension cycling, the specimen becomes relaxed because of the viscoelasticity of rubber composites, and the imposed tension-tension deformation becomes complex. In this method, the specimen is unlikely to fail unless the imposed extensions are very large. Constant load cycling can avoid the shortcomings of constant extension cycling. The specially designed clamps ensure that the specimen does not slip when the load retains a constant value. The Deformation and fatigue damage accumulation processes of rubber composites under periodic loading are also examined. Obviously, the effect of cycle frequency on the fatigue life of rubber composites can not be ignored because of the viscoelasticity of constituent materials. The increase of specimen surface temperature is relatively small in the case of 1 Hz, but the temperature can easily reach 100°C at the 8 Hz frequency. A method for evaluating the fatigue behavior of tires is proposed.

Factors Influencing the Fatigue Behavior of Ferrous Laminates

1987 ◽  
Vol 109 (3) ◽  
pp. 244-251 ◽  
Author(s):  
J. Wittenauer ◽  
O. D. Sherby
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Carbon Steel ◽  
Fatigue Behavior ◽  
Layered Material ◽  
Factors Influencing ◽  
Ultrahigh Carbon Steel ◽  
Processing History ◽  
Crack Blunting ◽  
Similar Processing

Laminates based on ultrahigh carbon steel were prepared and found to exhibit enhanced fatigue life as compared to a monolithic reference material. This result was achieved through the insertion of weak interlaminar regions of copper into the layered material during preparation of the laminates. The presence of these regions allowed for the operation of a delamination mechanism in advance of the propagating fatigue crack. The result was interlaminar separation and associated crack blunting. Stress-life curves show that an increase in life by as much as a factor of four is achieved for these materials when compared to monolithic specimens of similar processing history.

scholarly journals Influence of turning tool wear on the surface integrity and anti-fatigue behavior of Ti1023

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110112
Author(s):  
Li Xun ◽  
Wang Ziming ◽  
Yang Shenliang ◽  
Guo Zhiyuan ◽  
Zhou Yongxin ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Plastic Deformation ◽  
Titanium Alloy ◽  
Fatigue Life ◽  
Tool Wear ◽  
Surface Integrity ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Machined Surface ◽  
Deformation Layer

Titanium alloy Ti1023 is a typical difficult-to-cut material. Tool wear is easy to occur in machining Ti1023, which has a significant negative effect on surface integrity. Turning is one of the common methods to machine Ti1023 parts and machined surface integrity has a direct influence on the fatigue life of parts. To control surface integrity and improve anti-fatigue behavior of Ti1023 parts, it has an important significance to study the influence of tool wear on the surface integrity and fatigue life of Ti1023 in turning. Therefore, the effect of tool wear on the surface roughness, microhardness, residual stress, and plastic deformation layer of Ti1023 workpieces by turning and low-cycle fatigue tests were studied. Meanwhile, the influence mechanism of surface integrity on anti-fatigue behavior also was analyzed. The experimental results show that the change of surface roughness caused by worn tools has the most influence on anti-fatigue behavior when the tool wear VB is from 0.05 to 0.25 mm. On the other hand, the plastic deformation layer on the machined surface could properly improve the anti-fatigue behavior of specimens that were proved in the experiments. However, the higher surface roughness and significant surface defects on surface machined utilizing the worn tool with VB = 0.30 mm, which leads the anti-fatigue behavior of specimens to decrease sharply. Therefore, to ensure the anti-fatigue behavior of parts, the value of turning tool wear VB must be rigorously controlled under 0.30 mm during finishing machining of titanium alloy Ti1023.

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