Fatigue Characteristics of Nonferrous Bolts at Elevated Temperature

2014 ◽  
Vol 627 ◽  
pp. 265-268 ◽  
Author(s):  
Shinji Hashimura ◽  
Tetsuya Torii ◽  
Takefumi Otsu
Keyword(s):  
Elevated Temperature ◽  
Ambient Temperature ◽  
Fatigue Limit ◽  
Creep Deformation ◽  
Tensile Force ◽  
Fatigue Tests ◽  
Clamping Force ◽  
Creep Tests ◽  
Fatigue Characteristics ◽  
Force Reduction

In order to investigate fatigue characteristics of nonferrous bolts at elevated temperature, fatigue tests of bolted joints which were tightened with three kinds of nonferrous bolts were been conducted at 100°C atmosphere. The test bolts were made of A5056 aluminum alloy and AZ31 and AZX912 magnesium alloy. Creep tests of the bolts at 100°C atmosphere were also conducted. The results showed that the fatigue limit of A5056 bolt was the highest of all regardless of the ambient temperature. The fatigue limits of AZ31 bolt and AZX912 bolt also were a half of the fatigue limit of A5056 bolt at both ambient temperature. Bolt clamping force losses due to creep deformation were observed for all bolts during fatigue tests at elevated temperature. Hence as additional tests, the creep tests which was controlled either the tensile force or the displacements respectively were conducted. As the results it was seen that the clamping force losses for all bolts were remarkably large although the each creep deformation was different for each bolt material. Therefore the results indicates that we have to pay attention to the clamping force reduction due to creep deformation if we use the nonferrous bolt in high temperature.

Fatigue Characteristics of Bolted Joint under Transverse Vibration ~Influence of Bolt Tightening Conditions on Transverse Fatigue Strength~

2010 ◽  
Vol 452-453 ◽  
pp. 609-612
Author(s):  
Shinji Hashimura ◽  
YU Kurakake ◽  
Shinichi Umeno
Keyword(s):  
Fatigue Strength ◽  
Fatigue Limit ◽  
Transverse Vibration ◽  
Bending Moment ◽  
Fatigue Tests ◽  
Bolted Joint ◽  
The Real ◽  
Thread Length ◽  
Fatigue Characteristics

Fatigue tests under transverse vibration were performed for three separate tightening conditions to investigate the grip length and the engaging thread length in this study. The relationships between the apparent fatigue limit (the highest amplitude of transverse vibration force which can be applied to the bolted joint without generating fatigue) and the real fatigue limit of bolt material also were investigated. Results showed that apparent transverse fatigue limit decreased if the grip length was long. And relationships of the apparent fatigue limit and the real fatigue limit were different in each tightening conditions depending on the bending moment at the root of the first thread.

scholarly journals Corrosion Fatigue Damages of Rebars under Loading in Time

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3416
Author(s):  
Yaroslav Blikharskyy ◽  
Jacek Selejdak ◽  
Nadiia Kopiika
Keyword(s):  
Fatigue Limit ◽  
Tensile Force ◽  
Corrosion Damage ◽  
Experimental Tests ◽  
Simultaneous Action ◽  
Aggressive Environment ◽  
Area Reduction ◽  
Fatigue Characteristics ◽  
Chemical Composition Of Steel

Nowadays, a relatively small number of studies concern the study of corrosion processes in reinforced concrete structures under load. Additionally, rather little research has been carried out concerning changes in the stress–strain state parameters of structures under the simultaneous action of aggressive environment and load. This issue requires additional experimental and theoretical investigation. Determination of mechanical properties, fatigue characteristics and susceptibility to corrosion cracking was performed on samples of reinforcing St3GPF steel. The chemical composition of steel was determined by structural analysis. The spectral method for the determination of alloying elements and impurities in steels is based on the excitation of iron atoms and admixtures by electric discharge, decomposition of radiation into a spectrum, followed by its registration on photoplate with the use of electrograph. Experimental tests of samples in an aggressive environment under the action of statically applied tensile force showed that corrosion damage has little effect on the strength characteristics. At the same time, the decrease in area reduction and the decrease in strain were recorded. Additionally, the action of cyclic loads in an aggressive environment leads to a significant reduction in the fatigue limit to values from 20 to 24% of the yield strength of the original samples, which is 2–3 times lower than the fatigue limit of undamaged samples.

A Study of Self-Loosening and Fatigue Failure of Bolted Joint under Transverse Vibration - Influences of Property Class of Bolt and Plastic Region Tightening

2007 ◽  
Vol 353-358 ◽  
pp. 2037-2040 ◽  
Author(s):  
Shinji Hashimura
Keyword(s):  
Fatigue Limit ◽  
Fatigue Failure ◽  
Transverse Vibration ◽  
Plastic Region ◽  
Fatigue Tests ◽  
Bolted Joints ◽  
Bolted Joint ◽  
Transverse Vibrations ◽  
Fatigue Characteristics ◽  
Long Life

In our previous study, loosening-fatigue tests under small transverse vibrations had been performed to elucidate bolt behavior and loosening-fatigue mechanism in the long life region. In this study, the influences of bolt property class and the plastic region tightening on loosening-fatigue characteristics under transverse vibration have been investigated. Result shows that bolt property class has little influence on the loosening-fatigue limits under transverse vibration. Result also shows that the transverse loosening-fatigue limit of the bolt which has been tightened to within the plastic region is lower than the transverse loosening-fatigue limit of the bolt that has been tightened to within the elastic region. This result is the opposite of the result of the axial fatigue characteristics of bolted joints.

Fatigue Behavior Analysis of Cruciform Welded Joints by Infrared Thermographic Method

2011 ◽  
Vol 197-198 ◽  
pp. 1395-1399 ◽  
Author(s):  
Xing Lin Guo ◽  
Jun Ling Fan ◽  
Yan Guang Zhao
Keyword(s):  
Stainless Steel ◽  
Fatigue Limit ◽  
Welded Joints ◽  
Traditional Method ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Structural Components ◽  
Structural Evaluation ◽  
Fatigue Characteristics ◽  
Good Agreement

Fatigue tests were carried out at different stress levels on cruciform welded joints made from mastensitic stainless steel. The purpose of the present paper was to verify the validity of the thermographic method and to extend its capability on welded structural evaluation, considering the real operating situations. Due to limitations of the traditional fatigue test, the infrared thermographic technique was developed to predict and assess the fatigue limit and the entire S-N (Stress-Life) curve of cruciform welded joints. Through the comparison, the predictions of the fatigue behavior by the thermographic method (TM) manifested good agreement with the traditional method. The present research paper concludes that the TM as a promising method enables us to rapidly obtain reliable fatigue characteristics of welded structural components.

scholarly journals Effect of micro-notches on fatigue strength of electrodeposited nanocrystalline nickel thin films

2018 ◽  
Vol 165 ◽  
pp. 04011
Author(s):  
Keisuke Tanaka ◽  
Yuta Murase ◽  
Hirohisa Kimachi
Keyword(s):  
Thin Films ◽  
Fatigue Strength ◽  
Fatigue Limit ◽  
Stress Ratio ◽  
Fatigue Crack Initiation ◽  
Fatigue Tests ◽  
Fine Grained ◽  
Nickel Thin Films ◽  
Nano Crystalline ◽  
Fictitious Crack

The effect of micro-notches on the fatigue strength of nickel thin films was studied. Two types of thin films with 10 μm thickness were produced by electrodeposition using sulfamate solution without and with brightener: ultra-fine grained film (UFG) with the grain size of 384 nm and nano-crystalline grained film (NCG) with that of 17 nm. Micro-sized notches introduced by FIB had the width of 2 μm and various depths from 8 to 150μm. Fatigue tests were conducted under the stress ratio of 0.1. The fatigue strength decreased with increasing depth of notches. NCG had much higher strength than UFG compared at the same notch depth. Notches as small as 8μm did reduce the fatigue strength of both UFG and NCG. The fatigue limit was controlled by the initiation of cracks and no non-propagating crack was observed in specimens fatigued below the fatigue limit. A model of fictitious crack successfully predicted the reduction of the fatigue limit due to micro-notches. The characteristic crack length of NCG was much smaller than the UFG, while the fatigue strength of defect-free NCG was larger than that of UFG. SEM observation of fracture surfaces was conducted to reveal micromechanisms of fatigue crack initiation.

scholarly journals Evaluation for Clamping Force Reduction of Bolted Joints under Relaxation of Jointed Body.

1999 ◽  
Vol 65 (640) ◽  
pp. 4826-4831
Author(s):  
Masayuki NAKAMURA ◽  
Hideaki NAGASHIMA ◽  
Masatomo OONO ◽  
Yoshikatsu ENOKIDA
Keyword(s):  
Bolted Joints ◽  
Clamping Force ◽  
Force Reduction

Effect of Pre-Strain and Roller Working on Torsional Fatigue Properties of a Structural Steel

2011 ◽  
Vol 295-297 ◽  
pp. 2227-2230
Author(s):  
Cong Ling Zhou
Keyword(s):  
Residual Stress ◽  
Fatigue Limit ◽  
Work Hardening ◽  
Compressive Residual Stress ◽  
Strain Ratio ◽  
Fatigue Tests ◽  
The Other ◽  
Fatigue Properties ◽  
Torsional Fatigue ◽  
Stress Work

In this study, fatigue tests have been performed using two kinds of specimens made of 25 steel. One is pre-strained specimen with pre-strain ratio changing from 2% to 8% by tension, the other is roller worked with deformation of 0.5 mm and 1.0 mm in diameter direction. In the case of pre-strained specimen, the fatigue limit increases according to increase of tensile pre-strain, the fatigue limit of 8% pre-strained specimen is 25% higher than that of non-pre-strained one; in the case of roller worked specimen, the fatigue limit of R05 and R10 is 126% and 143% to that of non-roller worked specimen, respectively. These remarkable improvements of fatigue limit would be caused by the existence of compressive residual stress, work-hardening and the elongated microscopic structures.

Evaluation of the Heat Treatment Role for Light Aluminum Alloys Subjected to Creep and Low Cycle Fatigue

2010 ◽  
Vol 638-642 ◽  
pp. 455-460 ◽  
Author(s):  
A. Rutecka ◽  
L. Dietrich ◽  
Zbigniew L. Kowalewski
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Low Cycle Fatigue ◽  
Numerical Models ◽  
Cyclic Hardening ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Lower Stress ◽  
Creep Tests ◽  
Different Temperatures

The AlSi8Cu3 and AlSi7MgCu0.5 cast aluminium alloys of different composition and heat treatment were investigated to verify their applicability as cylinder heads in the car engines [1]. Creep tests under the step-increased stresses at different temperatures, and low cycle fatigue (LCF) tests for a range of strain amplitudes and temperatures were carried out. The results exhibit a significant influence of the heat treatment on the mechanical properties of the AlSi8Cu3 and AlSi7MgCu0.5. An interesting fact is that the properties strongly depend on the type of quenching. Lower creep resistance (higher strain rates) and lower stress response during fatigue tests were observed for the air quenched materials in comparison to those in the water quenched. Cyclic hardening/softening were also observed during the LCF tests due to the heat treatment applied. The mechanical properties determined during the tests can be used to identify new constitutive equations and to verify existing numerical models.

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