Ultra-high three-point bending fatigue fracture characteristics of CFRP modified by MWCNTs and fatigue life data analysis

2021 ◽  
Vol 259 ◽  
pp. 113468
Author(s):  
Junliang Ding ◽  
Li Cheng
Keyword(s):  
Data Analysis ◽  
Fatigue Life ◽  
Fatigue Fracture ◽  
Fracture Characteristics ◽  
Bending Fatigue ◽  
Three Point Bending ◽  
Life Data

The Effect of Morphology and Distribution of Sulfides on Mechanical Properties and Fatigue Life of Non-Quenched and Tempered Steel

2008 ◽  
Vol 51 ◽  
pp. 11-20
Author(s):  
Ming Tu Ma ◽  
Guo Zhong Li ◽  
Zhi Gang Li ◽  
Hong Zhou Lu
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Fatigue Fracture ◽  
Rolling Direction ◽  
Impact Fracture ◽  
Fatigue Properties ◽  
Bending Fatigue ◽  
Quenched And Tempered Steel ◽  
The Impact ◽  
Tempered Steel

The effect of morphology and distribution of sulfides on tensile, impact and bending fatigue properties of non-quenched and tempered steel 49MnVS3 has been investigated in this paper. Microscopic structure and morphology of sulfides are observed, and impact fracture and fatigue fracture have been analyzed by SEM. The results show that the morphology of sulfides is mostly strip and distributes in ferrite, which affects mechanical properties and fatigue life. The length direction of sulfide strip is parallel to the rolling direction of steel. When the length of sulfide is short relatively and is approximate to the shape of particles. The impact properties and bending fatigue performance of 49MnVS3 are higher. Under those conditions, there are more ductile characteristics in their impact fracture and the fatigue fracture. The reasons for the effect of sulfide morphology on the mechanical and fatigue properties are explained.

Fatigue Life Prediction of CFRP Laminates under Variable Stress Amplitude and Frequency

2007 ◽  
Vol 334-335 ◽  
pp. 445-448 ◽  
Author(s):  
Masayuki Nakada ◽  
Junji Noda ◽  
Yasushi Miyano
Keyword(s):  
Fatigue Life ◽  
Cyclic Loading ◽  
Life Prediction ◽  
Statistical Approach ◽  
Stress Amplitude ◽  
Fatigue Tests ◽  
Fatigue Life Prediction ◽  
Bending Fatigue ◽  
Cfrp Laminates ◽  
Three Point Bending

This paper is concerned with the fatigue life prediction of CFRP laminates under variable cyclic loading using the linear cumulative damage (LCD) rule with statistical approach. Three-point bending fatigue tests for plain-woven CFRP laminates were carried out undervarious cyclic loading with constant and variable stress amplitude and frequency. As results, the applicability of LCD rule to the flexural fatigue life was confirmed for this CFRP laminates.

scholarly journals Three-Point Bending Fatigue Test of TiAl6V4 Titanium Alloy at Room Temperature

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Juraj Belan ◽  
Lenka Kuchariková ◽  
Eva Tillová ◽  
Mária Chalupová
Keyword(s):  
Fatigue Life ◽  
Fatigue Test ◽  
Room Temperature ◽  
Fatigue Tests ◽  
Dynamic Force ◽  
Bending Fatigue ◽  
Three Point Bending ◽  
Bending Fatigue Test ◽  
Number Of Cycles ◽  
Test Loading

A polycrystalline alpha-beta TiAl6V4 alloy in the annealed condition was used for the three-point bending fatigue test at frequency f∼100 Hz. The static preload Fstat. = −15 kN and variable dynamic force Fdyn. = −7 kN to −13.5 kN were set as fatigue test loading parameters. The fatigue life S-N curve presented the stress amplitude σa as a function of a number of cycles to fracture Nf. A limiting number of cycles to run out of 2.0 × 107 cycles were chosen for the 3-point fatigue tests of rectangular specimens. In addition, the Smith diagram was used to predict the fatigue life. The alpha lamellae width has a significant influence on fatigue life. It is assumed that the increasing width of alpha lamellae decreases fatigue life. A comparison of fatigue results with given alpha lamellae width in our material to the results of other researchers was performed. The SEM fractography was performed with an accent to reveal the initiation sites of crack at low and high load stresses and mechanism of crack propagation for the fatigue part of fracture.

scholarly journals Energy-Based Approach to Predict Fatigue Life of Asphalt Mixture Using Three-Point Bending Fatigue Test

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1696 ◽  
Author(s):  
Yazhen Sun ◽  
Chenze Fang ◽  
Jinchang Wang ◽  
Zuoxin Ma ◽  
Youlin Ye
Keyword(s):  
Fatigue Life ◽  
Mathematical Models ◽  
Strain Energy ◽  
Asphalt Mixture ◽  
Fatigue Tests ◽  
Bending Fatigue ◽  
Three Point Bending ◽  
Average Value ◽  
Bending Fatigue Test ◽  
Fatigue Equation

The three-point bending fatigue tests were carried out in order to accurately predict the fatigue life of an asphalt mixture based on the plateau value (PV) of the dissipated strain energy ratio (DSER). The relations of the dissipated strain energy (DSE) to the stress-strength ratio, temperature and loading rate were studied, and the constructions of the mathematical models of DSE and DSER were completed based on the change laws of the DSE. The relation of the fatigue life to the PV was determined based on the analysis of damage evolution, based on which the fatigue equation was established and used to predict the fatigue life. The results show that the change laws of DSE and DSER can be well described by the proposed mathematical models. The PV is defined as the average value of the DSER in the second stage and the fatigue life decreases in power function with the increase of PV, based on which the fatigue equation of Nf = A(PV)B was established, and the established fatigue equation is very close to that is used in the MEPDG. The fatigue equation can well predict the fatigue life asphalt mixture.

scholarly journals Experimental Investigation of the Three-point Bending Fatigue Properties of Carbon Fiber Composite Laminates

2016 ◽  
Vol 1 (1) ◽  
pp. 1 ◽  
Author(s):  
Meihong He ◽  
Tao Yang ◽  
Xuejuan Niu ◽  
Yu Du
Keyword(s):  
Fatigue Life ◽  
Carbon Fiber ◽  
Stress Level ◽  
Fiber Composite ◽  
Fatigue Loading ◽  
Fatigue Properties ◽  
Loading Frequency ◽  
Carbon Fiber Composite ◽  
Bending Fatigue ◽  
Three Point Bending

The three point bending fatigue properties of carbon fiber epoxy matrix composite laminates were compared for fatigue loading stress levels of 75, 80 and 85%, and fatigue loading frequencies of 10, 15 and 20Hz, respectively. The experimental results showed that: the bending fatigue life of the composites obviously decreased with the increase of the fatigue loading stress level or the loading frequency. The fatigue damage accumulation process could be divided into three distinct stages according to the accumulation rate: fast, slow and then fast. When the loading stress level was increased from 75 to 85%, the duration of the third stage decreased from 40 to 10% of the overall fatigue life. When the loading frequency was increased from 10 to 20Hz, the duration of the third stage increased from 20 to 40% of the overall fatigue life. Matrix cracking, fiber breaking, interface debonding and delamination were identified as the main three-point bending fatigue damage modes of the carbon fiber composite material, and the stress level and the loading frequency were found to significantly influence the fatigue failure properties of the composites.

scholarly journals The Effect of Microstructure and Axial Tension on Three-Point Bending Fatigue Behavior of TC4 in High Cycle and Very High Cycle Regimes

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 68 ◽  
Author(s):  
Xuechun Bao ◽  
Li Cheng ◽  
Junliang Ding ◽  
Xuan Chen ◽  
Kaiju Lu ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Crack Initiation ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Cycle Fatigue ◽  
Bending Fatigue ◽  
Three Point Bending ◽  
Axial Tension ◽  
Very High

The effects of microstructure and axial tension on the fatigue behavior of TC4 titanium alloy in high cycle (HCF) and very high cycle (VHCF) regimes are discussed in this paper. Ultrasonic three-point bending fatigue tests at 20 kHz were done on a fatigue life range among 105–109 cycles of the alloys with equiaxed, bimodal and Widmanstatten microstructures. Experimental results without axial tension show that three typical shapes of S-N curves clearly present themselves for the three different microstructures. Moreover, the crack initiation sites abruptly shifted from surface to subsurface of the specimen in the very high cycle fatigue regime for equiaxed and bimodal microstructures. But for the Widmanstatten microstructure, both surface and subsurface crack initiation appeared in the high cycle fatigue regime, and the multi-points crack initiation was found in the bimodal microstructure. The subsurface fatigue crack originated from the αp grains in equiaxed and bimodal microstructures. However, it originated from the coarse grain boundary α in the Widmanstatten microstructure. Additionally, the S-N curve shape, fatigue life and fatigue crack initiation mechanism with axial tension are similar to that without axial tension. However, the crack origin point shifts inward with axial tension.

In-Situ Study on Coaxing During Vibration-Based Bending Fatigue of Inconel 625 and 718

2013 ◽  
Author(s):  
Onome Scott-Emuakpor ◽  
Jeremy Schwartz ◽  
Tommy George ◽  
Charles Cross ◽  
Casey Holycross ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Stress Amplitude ◽  
Test Procedure ◽  
Fatigue Loading ◽  
Fatigue Performance ◽  
Step Test ◽  
Inconel 625 ◽  
Bending Fatigue ◽  
Life Data ◽  
Cycles To Failure

This study observes coaxing effects on aerospace nickel alloys during vibration-based bending fatigue loading. The purpose of this analysis is to determine if Goodman diagrams can be constructed using bending fatigue life data at experimentally defined cycles to failure. The methodology for controlling the number of cycles to failure requires a series of understressing steps, where stress amplitude is incrementally increased at each step. This method, known as the step-test procedure, states that, for some materials, the stress amplitude corresponding to the controlled cycles-to-failure can be determined through linear interpolation between the failure step and the previous non-failure step. Using the step-test procedure, experimental bending fatigue life results were gathered from cold-rolled Inconel 625 and 718 plate specimens. These bending loads are applied with a vibration-based experimental method, known as the George fatigue method, which utilizes modal vibration for fatigue loading. The fatigue life results from the George fatigue method are compared to life data from previously published constant stress amplitude experiments to determine if coaxing affects the fatigue performance of the Inconel materials. Results show that Inconel 625 has an improved fatigue performance that could be attributed to several possible factors, including coaxing, while the Inconel 718 data is shown to be within a 50% confidence band of constant stress amplitude data from the same material stock. The findings in this study increases the knowledge necessary to attain more relevant and less conservative empirical data for designing against high cycle fatigue (HCF) failure of complex gas turbine engine components.

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