scholarly journals Fatigue Analysis of Threaded Components with Cd and Zn-Ni Anticorrosive Coatings

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1455
Author(s):  
Jefferson Rodrigo Marcelino dos Santos ◽  
Martin Ferreira Fernandes ◽  
Verônica Mara de Oliveira Velloso ◽  
Herman Jacobus Cornelis Voorwald
Keyword(s):  
Stress Concentration ◽  
Stress Ratio ◽  
Fatigue Behavior ◽  
Base Material ◽  
Experimental Tests ◽  
Fatigue Tests ◽  
Element Analysis ◽  
Aisi 4140 ◽  
Stress Concentration Effect ◽  
Zinc Nickel

The influence of the electrodeposition of cadmium and zinc-nickel and the stress concentration effect on the fatigue behavior of AISI 4140 steel threaded components were studied. Axial fatigue tests at room temperature with a stress ratio of R = 0.1 were performed using standard and threaded specimens with and without nut interface under base material, cadmium, and zinc-nickel-coated conditions. Finite element analysis (FEA) was used, considering both elastic and elastoplastic models, to quantify the stress distribution and strain for threaded specimens with and without a nut interface. The numeric results were correlated to the experimental fatigue data of threaded components with and without the nut interface, to allow the oil & gas companies to extrapolate the results for different thread dimensions, since the experimental tests are not feasible to be performed for all thread interfaces. Scanning electron microscopy (SEM) was used to analyze the fracture surfaces. The stress concentration factor had a greater influence on the fatigue performance of threaded components than the effect of the Cd and Zn-Ni coatings. The fatigue life of studs reduced by about 58% with the nut/stud interface, compared to threaded components without nuts. The elastoplastic FEA results showed that studs with a stud/nut interface had higher stress values than the threaded specimens without a nut interface. The FEA results showed that the cracks nucleated at the regions with higher strain, absorbed energy, and stress concentration. The substitution of Cd for a Zn-Ni coating was feasible regarding the fatigue strength for threaded and smooth components.

scholarly journals Application of DIC Method in the Analysis of Stress Concentration and Plastic Zone Development Problems

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3460 ◽  
Author(s):  
Paweł J. Romanowicz ◽  
Bogdan Szybiński ◽  
Mateusz Wygoda
Keyword(s):  
Heat Treatment ◽  
Stress Concentration ◽  
High Strength Steels ◽  
High Strength ◽  
Experimental Tests ◽  
Theoretical Models ◽  
Material Behavior ◽  
Image Correlation ◽  
Stress Concentrations ◽  
Element Analysis

The paper presents the assessment of the possibility and reliability of the digital image correlation (DIC) system for engineering and scientific purposes. The studies were performed with the use of samples made of the three different materials—mild S235JR + N steel, microalloyed fine-grain S355MC steel, and high strength 41Cr4 steel subjected to different heat-treatment. The DIC studies were focused on determinations of dangerous zones with large stress concentrations, plastic deformation growth, and prediction of the failure zone. Experimental tests were carried out for samples with different notches (circular, square, and triangular openings). With the use of the DIC system and microstructure analyses, the influence of different factors (laser cutting, heat treatment, material type, notch shape, and manufacturing quality) on the material behavior were studied. For all studied cases, the stress concentration factors (SCF) were estimated with the use of the analytical formulation and the finite element analysis. It was observed that the theoretical models for calculations of the influence of the typical notches may result in not proper values of SCFs. Finally, the selected results of the total strain distributions were compared with FEM results, and good agreement was observed. All these allow the authors to conclude that the application of DIC with a common digital camera can be effectively applied for the analysis of the evolution of plastic zones and the damage detection for mild high-strength steels, as well as those normalized and quenched and tempered at higher temperatures.

Effects of Residual Stresses on the High Cycle Fatigue Behavior of Ti-6Al-4V

2010 ◽  
Author(s):  
Yu-Jia Li ◽  
Fu-Zhen Xuan ◽  
Zheng-Dong Wang ◽  
Shan-Tung Tu
Keyword(s):  
Residual Stress ◽  
Fatigue Limit ◽  
Stress Ratio ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
X Ray Diffraction ◽  
Surface Residual Stress ◽  
Manufacturing Techniques ◽  
Stress Ratios ◽  
Effect Of Surface

Axial force-controlled fatigue tests are conducted at various stress ratios (R) on Ti-6Al-4V specimens prepared by two different manufacturing techniques (hard turning plus polishing with and without vacuum stress relieve anneal carried out after polishing). Residual stress is measured by using X-ray diffraction. Results indicate that the surface compressive residual stress lead to an increase of fatigue limit at a given life and stress ratio. This effect decreases with increasing stress ratio R. At R = 0.6, the effect of surface residual stress on fatigue limit fades away. In addition, the location of crack initiation shifts from surface to interior when the stress ratio changes from −1 to 0.6.

High-Cycle Fatigue Behavior of Type 4340 Steel Pressurized Blocks Including Mean Stress Effect

2019 ◽  
Author(s):  
Elie A. Badr ◽  
Joanne Ishak
Keyword(s):  
Stress Ratio ◽  
Fatigue Behavior ◽  
Fatigue Loading ◽  
Fatigue Tests ◽  
Ultimate Stress ◽  
Stress Effect ◽  
Mean Stress ◽  
Test Results ◽  
Linear Correction ◽  
The Mean

Abstract Mean stress effects in pressurized steel blocks were examined under constant amplitude fatigue loading. The tests were performed to provide experimental data needed to study the effect of mean stress on fatigue lives of subject specimen, and to substantiate the use of analytical expressions to account for the mean stress. The mean stress was the result of subjecting the specimens to an autofrettage pressure which induced compressive residual stresses at the crossbore intersection of the specimens. Fatigue tests were carried out under both tensile and compressive mean stress levels. Test results were compared to several mean stress accounting relationships such as the Smith-Watson Topper, Bergmann and Seeger, modified Goodman, Gerber and Soderberg. Test results indicated that the modified Goodman equation is favorable in accounting for the effect of both tensile and compressive mean stresses on fatigue life (up to a compressive mean stress to ultimate stress ratio of −0.2). The behavior under compressive mean stress to ultimate stress ratio of less than −0.2 indicated that a linear correction relationship was required.

scholarly journals Multiaxial Fatigue Behavior of High-Density Polyethylene (HDPE) Including Notch Effect: Experiments and Modeling

2019 ◽  
Vol 300 ◽  
pp. 05001 ◽  
Author(s):  
Mohammadreza Amjadi ◽  
Ali Fatemi
Keyword(s):  
High Density Polyethylene ◽  
Fatigue Behavior ◽  
Equivalent Stress ◽  
Fatigue Tests ◽  
Multiaxial Fatigue ◽  
High Density ◽  
Analytical Models ◽  
Axial Torsion ◽  
Stress Concentration Effect ◽  
Von Mises

High-Density Polyethylene (HDPE) is used in many industries with many applications from automotive industry to biomedical implants. It can be manufactured using different processing techniques including compression molding, injection molding, and blow molding. Multiaxial loading and non-proportionality between different loading sources are inevitable in many applications. It is shown that the common multiaxial fatigue criteria such as von Mises equivalent stress are not able to correlate the multiaxial fatigue data. In this study, multiaxial fatigue behavior of neat HDPE is investigated using hollow tubular specimens through experimental fatigue tests. Axial, torsion, and combined in phase and out-of-phase axial-torsion fatigue tests were conducted. Stress concentration effect on multiaxial fatigue behavior was also studied. Experimental results and analytical models used to account for the aforementioned effects are presented and discussed in this paper.

Fatigue Life Properties of Circumferentially-Notched Bar of Austenitic Stainless Steel With Various Concentration Factors

2018 ◽  
Author(s):  
Naoaki Nagaishi ◽  
Michio Yoshikawa ◽  
Saburo Okazaki ◽  
Hisao Matsunaga ◽  
Junichiro Yamabe ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Stress Concentration ◽  
Austenitic Stainless Steel ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Stress Ratio ◽  
Ambient Air ◽  
Fatigue Tests ◽  
Concentration Factors

Fatigue tests were performed using three types of round-bar specimens of Type 304, meta-stable, austenitic stainless steel. The specimens had circumferential notch with stress concentration factors, Kt, of 2, 3 or 6.6. Load controlled fatigue tests were conducted at stress ratio, R, of 0.1 and −1 in ambient air at room temperature. At R of 0.1, fatigue life was decreased with an increase in the stress concentration factor. Conversely, at R of −1, the stress concentration factor had little influence on the fatigue life. To understand the mechanism of the stress ratio effect, local deformation behavior at and beneath the notch root during the fatigue test was computed by means of finite element analysis considering that the plastic constitutive model describes the cyclic stress-strain response.

Fatigue Behavior of Corroded Structural Steel Members in Boundary with Concrete

2007 ◽  
Vol 348-349 ◽  
pp. 245-248
Author(s):  
Shigenobu Kainuma ◽  
Naofumi Hosomi ◽  
In Tae Kim
Keyword(s):  
Fatigue Life ◽  
Stress Concentration ◽  
Structural Steel ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Steel Plates ◽  
Structural Members ◽  
Analytical Results ◽  
Steel Members ◽  
Corrosion Pit

In this research, fatigue tests were carried out to investigate the fatigue behavior of corroded structural members in boundary with concrete. Specimens were corroded by accelerated exposure tests and then used in the fatigue tests. FEM analyses were also performed on the models of the corroded surfaces of the specimens and the simulated corrosion surfaces to investigate the stress concentration at the corrosion pit in the boundary. The experimental and analytical results clarified the fatigue behaviors of corroded steel plates in boundary with concrete. The method for evaluating and predicting the fatigue life of corroded steel members were also proposed.

Different Methods for Fatigue Assessment of T Welded Joints Used in Ship Structures

2007 ◽  
Vol 51 (02) ◽  
pp. 150-159 ◽  
Author(s):  
V. Crupi ◽  
E. Guglielmino ◽  
A. Risitano ◽  
D. Taylor
Keyword(s):  
Welded Joints ◽  
Fatigue Behavior ◽  
Experimental Tests ◽  
Ship Structures ◽  
Element Analysis ◽  
Fatigue Assessment ◽  
Endurance Limits ◽  
Thermographic Analysis ◽  
Using Data ◽  
Cycle Endurance

The aim of this work is the prediction of high-cycle fatigue behavior in welded joints, which represent regions of weakness in the ship structures. The traditional methods for fatigue assessment of welded joints have some limitations. Some new methods were recently developed by Taylor: the crack modeling method (CMM) and the theory of critical distances methods (TCD). Experimental tests were carried out to define the high-cycle endurance limits of aluminum T-shaped welded joints. Using data obtained from finite element analysis (FEA), the fatigue strength was evaluated according to the CMM and the TCD. Thermographic analysis was also carried out during the experimental tests to assess the high-cycle endurance limits of the welds by means of the Risitano method (RM). The previous methods were also applied to a specific case, fatigue in T joints containing a drilled hole at different angles, which allowed us to study a typical industrial design problem involving two different features. Good predictions were achieved using all the methods.

Effects of chromic acid anodizing on fatigue behavior of 7050 T7451 aluminum alloy

2021 ◽  
Vol 63 (9) ◽  
pp. 805-810
Author(s):  
Çağrı İlhan ◽  
Rıza Gürbüz
Keyword(s):  
Aluminum Alloy ◽  
Stress Ratio ◽  
Chromic Acid ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Constant Amplitude ◽  
Aluminum Oxide Layer ◽  
Fatigue Life Reduction ◽  
Selection Of ◽  
Scanning Electron

Abstract The effect of chromic acid anodizing (CAA) surface treatment on 7050 T7451 aluminum alloy was presented in this study in terms of fatigue behavior. CAA is a treatment against corrosion by producing aluminum oxide layer (Al2O3) at the surface. However, fatigue performance of 7050 T7451 is affected by the coating. In this study, eight different CAA processes were examined with regard to etching stage of pre-treatments by using an alkaline etchant and/or acid etchants with various immersion times. Optical microscopic examinations were applied in order to determine pitting characteristics for the selection of CAA process parameters before fatigue tests. A CAA process was selected among eight processes in terms of pitting characteristics in order to apply fatigue specimens. Four fatigue test groups were determined to investigate bare condition of 7050 T7451 and sub-stages of the CAA particularly. Constant amplitude axial fatigue tests were conducted on specimens at 91 Hz at stress ratio (R) -1 until run-out criteria, which was 106 cycles. Fatigue life reduction was determined due to pretreatments of CAA. Fracture surfaces of the specimens were examined by scanning electron microscope (SEM) to investigate morphology and crack initiation sites.

Low-Cycle Fatigue Behavior of Small Slice Specimens of Zircaloy-4 at Elevated Temperature

2006 ◽  
Vol 324-325 ◽  
pp. 1241-1244 ◽  
Author(s):  
Li Xun Cai ◽  
Yu Ming Ye
Keyword(s):  
Elevated Temperature ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Cyclic Hardening ◽  
Cyclic Softening ◽  
Fatigue Tests ◽  
Uniaxial Strain ◽  
Transverse Strain ◽  
Test Results ◽  
Element Analysis

A series of strain fatigue tests were carried out on small bugle-like slice-specimens of Zr-4 alloy at 20 and 400. According to Elastic and Plastic Finite Element Analysis and assumption of local damage equivalence, a strain formula was given to transform transverse strain of the specimen to uniaxial strain. Based on the test results of the alloy and the strain transform formula, M-C (Manson-Coffin) models to be used for estimating uniaxial fatigue life of Zr-4 alloy were obtained. The results show that, the alloy mainly behaves as cyclic softening at 20 and as cyclic hardening at 400, and the elevated temperature can lead serious additional fatigue damage of the alloy and the effect of the elevated temperature impairs gradually with increasing of amplitude strain. A conclusion is helpful that prediction life by using M-C model based on traditional strain transform equation is quite conservative when uniaxial strain amplitude is less than 0.5%.

scholarly journals Microstructure and Fatigue Behavior of 2205/316L Stainless Steel Dissimilar Welded Joints

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 93
Author(s):  
Saúl Leonardo Hernández-Trujillo ◽  
Victor Hugo Lopez-Morelos ◽  
Marco Arturo García-Rentería ◽  
Rafael García-Hernández ◽  
Alberto Ruiz ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Welded Joints ◽  
316L Stainless Steel ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Base Material ◽  
Fatigue Tests ◽  
Solidification Mode ◽  
Tension And Compression ◽  
Weld Toe

The relation among microstructure and fatigue behavior of 2205/316L stainless steel dissimilar welded joints was investigated. Plates of 6.35 mm in thickness with a single-V joint configuration were gas metal arc welded (GMAW) in a single pass by feeding at 6 m/min an ER2209 filler wire with a heat input of 1.2 kJ/mm. Grain growth in the high temperature-heat affected zone (HT-HAZ) occurred mostly at the mid-height of the plates, delimiting the width of this region up to ~1.28 and ~0.73 mm of the 2205 and 316L plates, respectively. Dilution of the 316L plate with the ER2209 filler altered the solidification mode in this side of the weld and led to a significant content of austenite along the fusion line. Fatigue tests were performed using sinusoidal waveform at room temperature applying uniaxial cyclic loading, between constant stress limits within the elastic deformation of tension and compression (Δσ) with stress ratio R = −0.3. With stress ranges of 98% and 95% the fatigue specimens rapidly failed in much less than 106 cycles. The failure crack initiated at the surface of the 316L in the HT-HAZ near the weld toe. Surface analyses of unbroken specimens before and after fatigue testing revealed a significant increment in roughness of the 316L base material owing to the formation of intrusions and extrusions.

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