scholarly journals DEVELOPMENT OF A C-SHAPED FATIGUE SPECIMEN

1978 ◽  
pp. 609-615
Author(s):  
B. Mukherjee
Keyword(s):  
Fatigue Specimen

scholarly journals An Ultra-High Frequency Vibration-Based Fatigue Test and Its Comparative Study of a Titanium Alloy in the VHCF Regime

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1415
Author(s):  
Wei Xu ◽  
Yanguang Zhao ◽  
Xin Chen ◽  
Bin Zhong ◽  
Huichen Yu ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Fatigue Test ◽  
High Frequency ◽  
High Efficiency ◽  
Fatigue Tests ◽  
Loading Frequency ◽  
Fatigue Specimen ◽  
Ultra High Frequency ◽  
High Frequency Vibration ◽  
Testing Data

This paper proposes an ultra-high frequency (UHF) fatigue test of a titanium alloy TA11 based on electrodynamic shaker in order to develop a feasible testing method in the VHCF regime. Firstly, a type of UHF fatigue specimen is designed to make its actual testing frequency reach as high as 1756 Hz. Then the influences of the loading frequency and loading types on the testing results are considered separately, and a series of comparative fatigue tests are hence conducted. The results show the testing data from the present UHF fatigue specimen agree well with those from the conventional vibration fatigue specimen with the loading frequency of 240 Hz. Furthermore, the present UHF testing data show good consistency with those from the axial-loading fatigue and rotating bending fatigue tests. But the obtained fatigue life from ultrasonic fatigue test with the loading frequency of 20 kHz is significantly higher than all other fatigue test results. Thus the proposed ultra-high frequency vibration-based fatigue test shows a balance of high efficiency and similarity with the conventional testing results.

Tensile Properties of 7075 Aluminum Alloys Subjected to Pre-Fatigue in Humid Environment

2014 ◽  
Vol 794-796 ◽  
pp. 538-543 ◽  
Author(s):  
Hiroyuki Yamada ◽  
Masaki Tsurudome ◽  
Nagahisa Ogasawara ◽  
Keitaro Horikawa
Keyword(s):  
Aluminum Alloys ◽  
Tensile Properties ◽  
High Humidity ◽  
Fatigue Specimen ◽  
Impact Tests ◽  
Humid Environment ◽  
Fatigue Deformation ◽  
High Humidity Environment ◽  
The Impact ◽  
Humidity Environment

The tensile properties of the quasi-static and the impact tests for 7075 aluminum alloys subjected to pre-fatigue deformation in a humid environment were investigated. An impact tensile test of the pre-fatigue deformed specimens was performed by means of the Split Hopkinson pressure bar method. Within the authors set of experiments, the flow stress in both the quasi-static and the impact tests was unaffected by the pre-fatigue deformation. On the other hand, it was shown that the ductility of the pre-fatigue specimen was slightly lower than that of the non-fatigue specimen. Additionally, the pre-fatigue specimen in a high-humidity environment had a lower ductility than in a low-humidity environment. The ductility of the quasi-static test was decreased as compared with the impact test. It is thought that the ductility loss occurred due to changes in the microstructure, such as dislocations caused by the presence of hydrogen in the specimen due to pre-fatigue deformation in a high-humidity environment.

Effects of Carbon Fibre Geogrid Reinforcement on Propagation of Cracking in Pavement and Augmentation of Flexible Pavement Life

2014 ◽  
Vol 891-892 ◽  
pp. 1533-1538 ◽  
Author(s):  
Amir Barry Dizaj ◽  
Hasan Ziari ◽  
Mahmood Ahmadi Nejhad
Keyword(s):  
Fatigue Life ◽  
Service Life ◽  
Crack Propagation ◽  
Carbon Fibre ◽  
High Speed ◽  
Flexible Pavement ◽  
Fatigue Specimen ◽  
Four Point Bending ◽  
Bending Loading

Most of the distresses in flexible pavement are due to cracking and rutting. Geogrids distribute the street and loads to adequate area and cause augmentation bearing capacity. This project surveys the function of carbon and Glass fiber Geogrids on Delay of Crack propagation in flexible pavement and placement configuration in pavement structure. Four point bending loading applied to beams with dimension 50.8*63.5*381 mm and 6.5 mm tolerance (AASHTO TP8-96). According to the received specimen from cutting slabs of case study toward chart fatigue life, for each condition reinforced and unreinforced beams 3 sample in 4-strain level were experimented. Simulatedrepeated loading with a frequency 10 Hz simulate high-speed traffic was applied to beam fatigue specimen. Based on definition (AASHTO T321-07) assumed achieving to 50% first bending stiffness for end of the fatigue life indicate a significant reduction in the rate of crack propagation in reinforced samples with carbon geogrids compared to unreinforced ones, augmentation service life is up to 3.5fold and placing the geogrid at a one-third depth of overlay thickness from the bottom provide the maximum service life.

Finite Element Study of Residual Stresses in a plate T-Joint Fatigue Specimen

1990 ◽  
Vol 204 (2) ◽  
pp. 127-134 ◽  
Author(s):  
D H B Mok ◽  
R J Pick
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Applied Load ◽  
Small Region ◽  
Finite Element Code ◽  
Fatigue Specimen ◽  
Numerical Predictions ◽  
Weld Toe ◽  
Element Study

Using the finite element code ABAQUS to make numerical predictions, this paper studies the crack shape development and thickness effects on a series of welded plate T-joint fatigue specimens. It was found that redistribution of the residual stress only occurs in a small region near the weld toe, the extent depending greatly on the magnitude of the applied load.

Thermal Shock on Cylinder Head Induced by High Power Laser

2012 ◽  
Vol 170-173 ◽  
pp. 266-269
Author(s):  
Ming Pang ◽  
Chang Zhen Liu ◽  
Zhi Min Xie ◽  
Guang Hui Xu
Keyword(s):  
Cast Iron ◽  
Thermal Shock ◽  
Cylinder Head ◽  
Ccd Camera ◽  
Optical Microscope ◽  
High Power Laser ◽  
Power Laser ◽  
Fatigue Specimen ◽  
Graphite Cast Iron ◽  
Scanning Electron

Experiment of thermal shock was conducted by laser on cylinder head of graphite cast iron. Infrared pyrometers were mounted on the top of the workbench to sample the transient surface temperatures. The high resolution CCD camera was employed to sample transient images of the cylinder head. Microstructure of thermal shocking specimen was characterized by scanning electron microscopy (SEM) and optical microscope (OM). Mechanical properties of thermal fatigue specimen were evaluated by hardness. Results show that microstructure and hardness are not obviously changed, which mean that cylinder head of graphite cast iron has performance stabilization within the rang of thermal shocking temperature.

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