Influence of Semi-Circular Cracks on Threaded Connection Fatigue by Means of Kitagawa-Takahashi Diagram and El Haddad Equation

2015 ◽  
Vol 665 ◽  
pp. 133-136
Author(s):  
Stipica Novoselac ◽  
Todor Ergić ◽  
Dražan Kozak ◽  
Aleksandar Sedmak
Keyword(s):  
Fatigue Behavior ◽  
Multiaxial Fatigue ◽  
Fe Model ◽  
Stress Criterion ◽  
Threaded Connection ◽  
Threaded Connections ◽  
Rainflow Cycle Counting ◽  
Circular Surface ◽  
The Time Domain ◽  
Thread Root

Evaluation of semi-circular surface crack influence on threaded connection fatigue behavior, made of 42CrMo4 heat treatable steel, was carried out. Crack diameters were defined as 0.02, 0.05, 0.1, and 0.15 mm. Influence of semi-circular surface cracks was investigated by means of Kitagawa–Takahashi diagram and El Haddad equation. Assessments were done for survival probability of 99% on detailed FE model with normal metric thread profile and preload force at 70% of force at bolt yield point. The most critical location on threaded connections usually are thread roots which contain a very high notch effect. In order to accurately consider multiaxial stress field in thread root, multiaxial fatigue stress criterion based on a critical plane theory for fatigue assessment, was used. Mean stress influence was taken into account by means of Haigh diagram. Variable amplitude loading history of low-high (Lo-Hi) sequence spectrum was analyzed with the numerical algorithm of Rainflow cycle counting in the time domain. Fatigue damage was calculated according to the modified Palmgren-Miner linear damage accumulation hypothesis.

Effects of Taper Variation on Conical Threaded Connections Load Distribution

2002 ◽  
Vol 124 (2) ◽  
pp. 320-329 ◽  
Author(s):  
S. Baragetti, Ph.D.
Keyword(s):  
Stress Gradient ◽  
Experimental Tests ◽  
Surface Damage ◽  
Threaded Connection ◽  
Threaded Connections ◽  
Contact Loads ◽  
Finite Element Procedure ◽  
Numerical Finite Element ◽  
Thread Root ◽  
Fatigue Failures

Threaded connections are used in a lot of mechanical and civil engineering applications and, nowadays, are perhaps the most developed and economical way to join two elements made of any kind of material. It is well known that when a bolt is screwed into a threaded hole, the first threads engaged bear more than half of the axial load induced by the make-up torque. This overload in correspondence with the first threads engaged, together with the steep stress gradient induced by the notch effect at the thread root, is the cause of dramatic fatigue failures. Moreover, it is on the first threads engaged, because of the presence of high contact loads on the flanks of the threads, that galling can arise and promote surface damage if the threaded connection has to be screwed and unscrewed many times. The object of this paper is to propose a numerical finite element procedure, confirmed by means of full-scale experimental tests, which makes it possible to quantify the effects induced by varying the taper of rotary shouldered connections (RSCs), in terms of stress state, loads carried by the threads and pressure on the thread flanks. RSCs are conical threaded connections used in the oil industry and the aim of the procedure is to provide the designer with a useful tool able to minimize the dangerous effects of galling and overload.

An Experimental Evaluation for Four Multiaxial Fatigue Approaches

2014 ◽  
Vol 627 ◽  
pp. 425-428
Author(s):  
Dan Jin ◽  
Da Jiang Tian ◽  
Qi Zhou Wu ◽  
Wei Lin
Keyword(s):  
Low Cycle Fatigue ◽  
Multiaxial Fatigue ◽  
304 Stainless Steel ◽  
Normal Strain ◽  
Cycle Fatigue ◽  
Critical Plane ◽  
Maximum Shear Strain ◽  
Rainflow Cycle Counting ◽  
Tubular Specimens ◽  
Damage Rule

A series of tests for low cycle fatigue were conducted on the tubular specimens for 304 stainless steel under variable amplitude and irregular axial-torsional loading. Rainflow cycle counting and linear damage rule are used to calculate fatigue damage and four approaches, e.g. SWT(Smith-Watson-Topper), KBM(Kandil-Brown-Miller), FS(Fatemi-Socie), and LKN(Lee-Kim-Nam) approach are employed to predict the fatigue life. The maximum shear strain plane, the maximum normal strain plane, and the maximum damage plane are considered as the critical plane, respectively. The effects of the choice of the critical plane on previous approaches are discussed. It is shown that comparing with the maximum shear/normal strain approach, the predictions are improved by using the maximum damage plane approach, part nonproportional paths for SWT, AV and part nonproportional paths for KBM, TV paths for FS. But for LKN, the prediction results are nonconservative for some paths than that of the maximum shear/normal strain approach.

scholarly journals Multiaxial fatigue behavior of additive manufactured Ti-6Al-4V under in-phase stresses

2019 ◽  
Vol 18 ◽  
pp. 914-920 ◽  
Author(s):  
Danilo A. Renzo ◽  
Emanuele Sgambitterra ◽  
Pietro Magarò ◽  
Franco Furgiuele ◽  
Carmine Maletta ◽  
...  
Keyword(s):  
Fatigue Behavior ◽  
Multiaxial Fatigue ◽  
Phase Stresses

Evaluation of the Effect of Different Mean Stress Levels on the Fatigue Resistance of OCTG Premium Threaded Connections

2017 ◽  
Author(s):  
Yoshinori Ando ◽  
Yosuke Oku ◽  
Masaaki Sugino ◽  
Carol Johnston
Keyword(s):  
Fatigue Life ◽  
Primary Root ◽  
Initiation Site ◽  
Mean Stress ◽  
Standard Material ◽  
Root Cause ◽  
Threaded Connection ◽  
Threaded Connections ◽  
Stress Levels ◽  
Scale Test

Identification of the effect of mean stress for fatigue performance of the premium threaded connection for the OCTG pipes, was conducted via full-scale test. API standard material [grade L80-1] was used for the test. The nominal pipe outside diameter and wall thickness were 244.48 mm (9-5/8 inch) and 11.99 mm (0.472 inch), respectively. The fatigue life of the specimens tested with no mean stress was longer than that of the specimens tested with a tensile mean stress. Through-wall cracks were found at the imperfect thread area of the male embodiment, but the crack initiation site depended on the mean stress. However, the primary root cause of the failure on both mean stress levels can be regarded as the fretting fatigue. Fatigue life was also able to be estimated using modified Goodman relation.

A Comprehensive Study on Burst Pressure Performance of Aluminum Liner for Hydrogen Storage Vessels

2021 ◽  
Vol 143 (4) ◽  
Author(s):  
Serkan Kangal ◽  
A. Harun Sayı ◽  
Ozan Ayakdaş ◽  
Osman Kartav ◽  
Levent Aydın ◽  
...  
Keyword(s):  
Internal Pressure ◽  
Axial Strain ◽  
Cylindrical Part ◽  
Pressure Vessels ◽  
Fe Analysis ◽  
Burst Pressure ◽  
Experimental Investigations ◽  
Fe Model ◽  
Stress Criterion ◽  
Analytical Approaches

Abstract This paper presents a comparative study on the burst pressure performance of aluminum (Al) liner for type-III composite overwrapped pressure vessels (COPVs). In the analysis, the vessels were loaded with increasing internal pressure up to the burst pressure level. In the analytical part of the study, the burst pressure of the cylindrical part was predicted based on the modified von Mises, Tresca, and average shear stress criterion (ASSC). In the numerical analysis, a finite element (FE) model was established in order to predict the behavior of the vessel as a function of increasing internal pressure and determine the final burst. The Al pressure vessels made of Al-6061-T6 alloy with a capacity of 5 L were designed. The manufacturing of the metallic vessels was purchased from a metal forming company. The experimental study was conducted by pressurizing the Al vessels until the burst failure occurred. The radial and axial strain behaviors were monitored at various locations on the vessels during loading. The results obtained through analytical, numerical, and experimental work were compared. The average experimental burst pressure of the vessels was found to be 279 bar. The experimental strain data were compared with the results of the FE analysis. The results indicated that the FE analysis and ASSC-based elastoplastic analytical approaches yielded the best predictions which are within 2.2% of the experimental burst failure values. It was also found that the elastic analysis underestimated the burst failure results; however, it was effective for determining the critical regions over the vessel structure. The strain behavior of the vessels obtained through experimental investigations was well correlated with those predicted through FE analysis.

MULTIAXIAL FATIGUE CRITERIA APPLIED TO A POLYCHLOROPRENE RUBBER

2012 ◽  
Vol 85 (1) ◽  
pp. 80-91 ◽  
Author(s):  
J. L. Poisson ◽  
S. Méo ◽  
F. Lacroix ◽  
G. Berton ◽  
N. Ranganathan
Keyword(s):  
Large Strain ◽  
Fatigue Behavior ◽  
Viscoelastic Model ◽  
Type Specimen ◽  
Multiaxial Fatigue ◽  
Dissipated Energy ◽  
Rubber Part ◽  
Phase Angles ◽  
Fatigue Criterion ◽  
Important Objective

Abstract Due to their interesting mechanical behavior and their diversity, rubber materials are more and more used in industry. Indeed, formulating a multiaxial fatigue criterion to predict fatigue lives of rubber components constitutes an important objective to conceive rubber products. An experimental campaign is developed here to study the multiaxial fatigue behavior of polychloroprene rubber. To reproduce multiaxial solicitations, combined tension–torsion tests were carried out on a dumbbell-type specimen (an axisymmetric rubber part bonded to metal parts with a reduced section at mid-height), with several values of phase angles between tension and torsion. A constitutive model is needed to calculate multiaxial fatigue criteria, and then analyze fatigue results. A large strain viscoelastic model, based on the tension–torsion kinematics, is then used to determine the material's stress–strain law. Dissipated energy density is introduced as a multiaxial fatigue criterion, and compared with those usually used in the literature. A multiaxial Haigh diagram is then built to observe the influence of Rd-ratio (ratio of the axial displacement's minimum to the axial displacement's maximum) on the multiaxial fatigue lives of polychloroprene rubber.

Multiaxial fatigue behavior of additively manufactured Ti6Al4V alloy: Axial–torsional proportional loads

2020 ◽  
Author(s):  
Danilo A. Renzo ◽  
Emanuele Sgambitterra ◽  
Pietro Magarò ◽  
Franco Furgiuele ◽  
Carmine Maletta ◽  
...  
Keyword(s):  
Fatigue Behavior ◽  
Multiaxial Fatigue ◽  
Ti6al4v Alloy

scholarly journals Multiaxial fatigue behavior of 2618 aluminum alloy

2019 ◽  
Vol 300 ◽  
pp. 09003
Author(s):  
Benaïssa Malek ◽  
Catherine Mabru ◽  
Michel Chaussumier
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Internal Pressure ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Multiaxial Fatigue ◽  
Mean Stress ◽  
Research Project ◽  
Pressure Tests

The purpose of the present research project is to study multiaxial fatigue behavior of 2618 alloy. The influence of mean stress on the fatigue behavior under tension and torsion is particularly investigated. Fatigue tests under combined tensile-torsion, in or out of phase, as well as combined tensile-torsion-internal pressure tests have also been conducted. Multiaxial fatigue results are analyzed according to Fatemi-Socie criterion to predict the fatigue life.

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