scholarly journals A new fatigue damage model for pavement concrete beams bearing multi-level bending loads

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255048
Author(s):  
Liang Lei ◽  
Shi Xingang ◽  
Cui Yunhua ◽  
Wang Lefan ◽  
Yan Xiangcheng
Keyword(s):  
Fatigue Life ◽  
Damage Accumulation ◽  
Concrete Beams ◽  
Damage Model ◽  
Testing Machine ◽  
Concrete Specimen ◽  
Fatigue Loading ◽  
Single Stage ◽  
Emission Signal ◽  
Bending Load

MTS-810 material testing machine and acoustic emission signal analyzer were adopted to explore the mechanical behavior of concrete beams broken by the static load and the nonlinear cumulative damage law of concrete beams broken by fatigue bending from single-stage loading. Then, by introducing the Ramesh Talreja’s Damage Criterion, the damage rule of single-stage loading was extended to the damage accumulation rule under multi-stage loading, and the results were verified by the results of two-stage and three-stage fatigue loading tests. Two main conclusions are achieved: first, affected by four-point bending load, the fatigue life of the concrete specimen is in line with the law of the two-parameter Weibull distribution, namely the higher the stress level is, the shorter the fatigue life is. Second, an obvious nonlinear relationship was discovered in the damage of concrete. The model deduced in this paper and the Palmgren-Miner linear damage accumulation model were adopted to compare the test results of flexural fatigue under single, two and three stage loads. The calculation results of this model were more reliable.

A Multi-Level Low Cycle Fatigue Damage Model for Forging Die Material

2006 ◽  
Vol 514-516 ◽  
pp. 804-809
Author(s):  
S. Gao ◽  
Ewald Werner
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Low Cycle Fatigue ◽  
Damage Model ◽  
Fatigue Loading ◽  
Cycle Fatigue ◽  
Die Material ◽  
Multi Level ◽  
Loading Sequence ◽  
Forging Die

The forging die material, a high strength steel designated W513 is considered in this paper. A fatigue damage model, based on thermodynamics and continuum damage mechanics, is constructed in which both the previous damage and the loading sequence are considered. The unknown material parameters in the model are identified from low cycle fatigue tests. Damage evolution under multi-level fatigue loading is investigated. The results show that the fatigue life is closely related to the loading sequence. The fatigue life of the materials with low fatigue loading first followed by high fatigue loading is longer than that for the reversed loading sequence.

scholarly journals Experimental Study on Flexural Fatigue Properties of Reinforced Concrete Beams after Salt Freezing

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Jianxi Yang ◽  
Tianmei Zhang ◽  
Quansheng Sun
Keyword(s):  
Reinforced Concrete ◽  
Fatigue Life ◽  
Concrete Beams ◽  
Damage Model ◽  
Reinforced Concrete Beams ◽  
Fatigue Properties ◽  
Test Beam ◽  
Residual Deflection ◽  
Freeze Thaw ◽  
Quick Freezing

In order to study the fatigue behavior decay law of reinforced concrete structures in cold region under the action of chlorine salt and freeze-thaw, 150-time water freeze-thaw and salt freeze-thaw cycles of reinforced concrete beams were carried out by the quick freezing method, and then the fatigue properties of the test beams were obtained by the four-point bending fatigue test. The fatigue life of the test beam without freeze-thaw is 1,074,282 times, and the fatigue life of the test beam after freeze-thaw is reduced; the minimum fatigue life of fatigue failure is 493,972. The test results show that the residual deflection of the test beam is similar to the relative dynamic elastic modulus, which accords with the damage and failure mechanism of concrete, and the growth rate of residual deflection accords with the law of the block model. The fatigue damage model of reinforced concrete specimens is established, the nonlinear fitting of the damage model is carried out according to the test data, the fitting correlation coefficient is more than 0.98, which indicates that the model can better reflect the damage degree of concrete, and the method of predicting the life of in-service concrete beam is put forward in combination with the concrete damage model.

scholarly journals Fatigue behaviour of fibre-reinforced composite T-joints

2018 ◽  
Vol 165 ◽  
pp. 07004
Author(s):  
Ying Wang ◽  
Constantinos Soutis
Keyword(s):  
Fatigue Life ◽  
Testing Machine ◽  
Fatigue Loading ◽  
Maximum Load ◽  
Fatigue Behaviour ◽  
Control Mode ◽  
Static Properties ◽  
T Joints ◽  
Pull Out ◽  
Reinforced Composite

In this paper a study was carried out on the fatigue life of fibre-reinforced composite T-joints subjected to a tensile pull-out loading. The composite T-joints have been made of glass fabric infused with epoxy resin using a vacuum assisted resin transfer moulding technique. Methods such as the use of veil layers, tufting techniques and 3D weave have been employed to improve the interlaminar fracture toughness of the composite T-joints. All the tests were conducted in an Instron testing machine using a specially designed test fixture. Fatigue tests were performed in a load control mode with a stress ratio of R = σmin/σmax = 0.1. The cyclic loading pattern was a sinusoidal wave with a frequency of 6 Hz. The specimens were cycled at a series of constant maximum load values up to failure. Fatigue loads versus life data for each T-joint type were produced at various maximum applied loads. The 3D weave T-joints were found to have the best performance in both static and fatigue loading. Increasing the static properties increases fatigue life performance; the increasing rate in fatigue life is changed with the number of stress cycles. The location for the through-thickness reinforcement plays an important role in improving fatigue life of the Tjoints. Fatigue life is significantly improved if the web is reinforced in through-thickness direction. A finite element (FE) failure model was also created using ABAQUS to determine the location where delamination is initiated and its subsequent propagation.

Experimental and numerical investigation of the effect of gaps on fatigue behavior of unidirectional carbon/epoxy automated fiber placement laminates

2016 ◽  
Vol 51 (6) ◽  
pp. 759-772 ◽  
Author(s):  
Yasser Mahmoud Elsherbini ◽  
Suong V Hoa
Keyword(s):  
Fatigue Life ◽  
Applied Stress ◽  
Fatigue Behavior ◽  
Damage Model ◽  
Fatigue Loading ◽  
Fatigue Tests ◽  
Experimental Results ◽  
Fiber Placement ◽  
Automated Fiber Placement ◽  
Induced Defects

Automated fiber placement (AFP) process provides high potential to repeatability and flexibility required for manufacturing of complex parts in many industries. Performance of such parts can be influenced by AFP manufacturing induced defects such as gaps and overlaps. In this work, the effect of gaps on fatigue behavior of unidirectional carbon/epoxy laminates was investigated. Tension–tension fatigue tests were conducted on defected samples and compared to reference samples free from defects. Infrared thermography technique was used for monitoring of damage propagation during fatigue loading. Moreover, a fatigue progressive damage model (FPDM) was developed and applied to laminates containing gaps to predict fatigue damage progression and failure. The experimental results revealed that the effect of gaps depends on the maximum applied stress during fatigue. The higher is the applied stress, the higher is the reduction in fatigue life. Good agreement was found between the results of fatigue life prediction from the FPDM and the experimental results for defected specimens.

scholarly journals New Nonlinear Cumulative Fatigue Damage Model Based on Ecological Quality Dissipation of Materials

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Hongsong Li ◽  
Yongbao Liu ◽  
Xing He ◽  
Wangtian Yin
Keyword(s):  
Fatigue Life ◽  
Cyclic Loading ◽  
Fatigue Damage ◽  
Damage Model ◽  
Fatigue Loading ◽  
Ecological Quality ◽  
Aircraft Structures ◽  
Variable Amplitude ◽  
Fatigue Damage Accumulation ◽  
Cumulative Fatigue Damage

The failure of many aircraft structures and materials is caused by the accumulation of fatigue damage under variable-amplitude cyclic loading wherein the damage evolution of materials is complicated. Therefore, to study the cumulative fatigue damage of materials under variable-amplitude cyclic loading, a new nonlinear fatigue damage accumulation model is proposed based on the ecological quality dissipation of materials by considering the effects of load interaction and sequence. The proposed new model is validated by the test data obtained for three kinds of material under multilevel fatigue loading. Compared with the Miner model and Kwofie model, the proposed model can more effectively analyse the accumulative damage and predict fatigue life of different materials under variable-amplitude cyclic loading than others. The study provides a basis for predicting fatigue life accurately and determining reasonable maintenance periods of aircraft structures.

scholarly journals Investigation of Flexural Fatigue Behavior of Concrete Beams Reinforced with Intelligent CFRP-OFBG Plates

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Langni Deng ◽  
Yang Liu ◽  
Ling Liao ◽  
Hong Xie ◽  
Xiaoxia Huang ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Fatigue Failure ◽  
Concrete Beams ◽  
Fatigue Behavior ◽  
Damage Model ◽  
Experimental Tests ◽  
Fatigue Properties ◽  
Polymer Optical Fiber ◽  
Cycle Number ◽  
Experimental Findings

The fatigue properties of concrete beams reinforced with carbon fiber-reinforced polymer-optical fiber Bragg grating (CFRP-OFBG) plates under three-point bending constant cyclic loading were experimentally studied. According to the experimental findings, the mechanism of fatigue failure in reinforced beams was presented, and the corresponding empirical equations were established for the prediction of the fatigue lives of these components. Besides, based on the real-time monitoring data of the intelligent CFRP-OFBG plates, a fatigue accumulative damage model was established using flexural bending stiffness for the prediction of fatigue life. Through example verification, it was found that the fatigue life predicted by the model had less error and was safer than the fatigue failure cycle number of the reinforced beam obtained by experimental tests.

scholarly journals A Modified Model for Nonlinear Fatigue Damage Accumulation of Turbine Disc Considering the Load Interaction Effect

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 919 ◽  
Author(s):  
Huang ◽  
Ding ◽  
Li ◽  
Zhou ◽  
Huang
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Damage Accumulation ◽  
Damage Model ◽  
Modified Model ◽  
Damage Models ◽  
Fatigue Damage Accumulation ◽  
Turbine Disc ◽  
Damage Accumulation Model ◽  
Nonlinear Damage Model

Fatigue damage accumulation theory is one of the core contents in structure fatigue strength design and life prediction. Among them, the nonlinear damage model can overcome the shortcomings of the linear damage model, which takes the loading sequence effect into account. Besides, the loading interaction cannot be ignored for its profound influence in damage accumulation behavior. In the paper, some commonly-used methods of the linear and nonlinear fatigue damage accumulation theory are investigated. In particular, a modified nonlinear fatigue damage accumulation model which considers the effects of loading sequences as well as loading interactions on fatigue life is developed, and a load interaction parameter is obtained by analyzing damage models which assumes that the load logarithm ratio between adjacent stress levels can characterize this phenomenon. Finally, the modified model is employed to predict the fatigue life of high pressure turbine disc. Moreover, comparison is made between the experimental data as well as the predicted lives using the Miner’s rule, the Ye’s model, and the modified model.

Damage Mechanics Based Fatigue Life Prediction for 63Sn-37Pb Solder Material

2000 ◽  
Author(s):  
Y. Wei ◽  
C. L. Chow ◽  
M. K. Neilsen ◽  
H. E. Fang
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Damage Accumulation ◽  
Damage Mechanics ◽  
Damage Model ◽  
Hysteresis Loops ◽  
Cyclic Softening ◽  
Softening Behavior ◽  
Fatigue Damage Accumulation ◽  
Theory Of Damage

Abstract This paper presents a method of TMF analysis based on the theory of damage mechanics to examine the fatigue damage accumulation in 63Sn-37Pb solder. The method is developed by extending a viscoplastic damage model proposed earlier by the authors (Wei, et al 1999, 2000). A computer simulation is carried out to calculate hysteresis loops at three different strain ranges. The damage-coupled fatigue damage model is applied to predict the cyclic softening behavior of the material and the prediction is found to agree well with the experiment. With a proposed failure criterion based on the concept of damage accumulation, the TMF model is also found to predict successfully the fatigue life of 63Sn-37Pb solder.

Comparative Approaches for Fatigue Life Estimation of Aluminium Alloy for Aerospace Applications

2018 ◽  
Vol 10 (4) ◽  
Author(s):  
R. Vijayanandh ◽  
K. Naveen Kumar ◽  
G. Raj Kumar ◽  
B. Sanjeev ◽  
Hariharan Balachander ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Aluminium Alloy ◽  
Reference Model ◽  
Dynamic Properties ◽  
Testing Machine ◽  
Tensile Loading ◽  
Limit Values ◽  
Aerospace Applications ◽  
Bending Load

The objective of this paper is to estimate the fatigue life behaviour of Al 7075-T6 using experimental and numerical methods for the purpose of aerospace applications. In this paper, initially static properties for the specimens are determined using Universal Testing Machine (UTM) under tensile loading. The cyclic bending load is applied on the material using fatigue test and the dynamic properties are determined. Experimental and numerical studies are carried out to determine the fatigue strength and endurance limit values of aluminium alloy 7075-T6 at different types of loading. The fatigue strength and structural integrity of the aluminium alloy 7075 - T6 are investigated using S-N curve. In numerical simulation, the reference model of this paper has been modelled by CATIA and thereby it is imported into ANSYS workbench 16.2 to investigate the stress distribution and number of cycles to failure of an aluminium alloy 7075-T6 under tensile loading. The mechanical properties are evaluated using both the approaches and finally the comparative study is carried out.

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