Fretting Fatigue Design of Connectors; a Fundamental Consideration of Interfacial Slip

2021 ◽  
Author(s):  
Hendrik Andresen ◽  
David Hills ◽  
Anders Wormsen ◽  
Kenneth A. Macdonal ◽  
Lorents Reinas
Keyword(s):  
Fretting Fatigue ◽  
Interfacial Slip ◽  
Fatigue Design ◽  
Fundamental Consideration

Fretting Fatigue Design of Subsea Connectors: A Generalised Approach to Testing

2020 ◽  
Author(s):  
H. Andresen ◽  
D. A. Hills ◽  
Anders Wormsen ◽  
K. A. Macdonald
Keyword(s):  
Crack Nucleation ◽  
Normal Load ◽  
Asymptotic Methods ◽  
Fretting Fatigue ◽  
Test Design ◽  
Frictional Contacts ◽  
Fatigue Design ◽  
Geometrical Features ◽  
Fatigue Data ◽  
Constant Normal Load

Abstract In this paper fretting fatigue is addressed as a potential design consideration for wellhead connectors. The study of near-edge relative motion for frictional contacts under constant normal load is described using analytical, numerical and asymptotic methods. Based on published fretting fatigue experimental data an argument is drawn for a generalised fretting fatigue test design. We do this by reducing the parameters responsible for crack nucleation to the smallest number possible and thereby revealing the fretting fatigue strength as a material property independent of geometrical features. Easy to apply recipes are described and thoughts on a potential apparatus are shared with the reader. Commercial potential lies in the wide-ranging applicability of experimental results across many prototypes and loadings once an appropriate amount of fretting fatigue data has been generated for the material in question.

Fretting Fatigue Design of Subsea Connectors: Matching Results Between Pairs of Tests

2020 ◽  
Author(s):  
L. E. Blades ◽  
D. A. Hills ◽  
A. Wormsen ◽  
K. A. Macdonald
Keyword(s):  
Life Prediction ◽  
Fatigue Crack Initiation ◽  
Fretting Fatigue ◽  
Fatigue Tests ◽  
Fatigue Design ◽  
Contact Loads ◽  
Design Documentation ◽  
Bending Loads ◽  
Set Up ◽  
Wave Induced

Abstract The upper end of a subsea wellhead system has an external wellhead hub profile. The standardised H4 profile is widely used. A wellhead connector is latched on the wellhead profile by use of locking devices with a matching internal profile (e.g. clamps, sections and dogs). Large contact loads are set up when latching the connector on this wellhead profile with the objective of withstanding internal pressure and wave-induced cyclic bending loads while avoiding hub separation. Fretting fatigue is an additional phenomenon to that of conventional high-cycle fatigue (fatigue crack initiation from the wellhead profile grooves) that should be addressed as part of the design documentation. Methods have been developed to match the key parameters in this contact to a laboratory test. Here, the strength of the effect of each of the matched loading parameters was assessed. Specimens were manufactured from wellhead housing and locking dog steels. The fretting fatigue tests were performed using loads representative of a preloaded connector. Validation of these methods would enable the use of fretting fatigue data determined for one geometry to be used in fatigue life prediction of another.

Fretting Fatigue Design of Connectors; Matching Results Between Pairs of Tests

2021 ◽  
Author(s):  
Luke Blades ◽  
David Hills ◽  
Anders Wormsen ◽  
Kenneth Macdonald
Keyword(s):  
Fretting Fatigue ◽  
Fatigue Design

On the fatigue design method for high-speed railway axles

2001 ◽  
Vol 215 (2) ◽  
pp. 73-82 ◽  
Author(s):  
K Hirakawa ◽  
M Kubota
Keyword(s):  
Fatigue Strength ◽  
High Speed ◽  
Fatigue Cracks ◽  
Fretting Fatigue ◽  
Brake Disc ◽  
Metal Fatigue ◽  
High Speed Railway ◽  
Fatigue Design ◽  
Railway Axle ◽  
The Press

Fatigue failure of the railway axle, which has been a source of difficulty for engineers since railroad service started in the early part of the nineteenth century, was the beginning of the study of metal fatigue. In order to maintain the safety of a high-speed railway system, a large number of investigations and experiments have been carried out by outstanding researchers ever since, and many improvements have been made in the material, manufacturing, heat treatment and design methods. In comparing Japan and Europe on the fatigue design philosophy of the high-speed railway axle, it is recognized that there is a difference between the Japanese Shinkansen and the European TGV and ICE. The critical parts for fatigue strength are the press-fitted parts which suffer from fretting fatigue damage, such as the wheel seat, gear seat and brake disc seat. In Europe, the larger diameter of the press-fitted part makes the fillet the critical part. In Japan, however, the fatigue strength of the press-fitted part is increased by an induction hardening method. Also, a stress-relief groove is made at the closely press-fitted part of the axle. For several years, no fretting fatigue cracks in Shinkansen axles have been detected by magnetic particle inspection. It is noted that improvements over many years have been successful in achieving the safety of high-speed railway axles. These problems will be studied in this paper.

Effect of contact pad rigidity and fretting fatigue design curve

2010 ◽  
Vol 63 (2-3) ◽  
pp. 181-186 ◽  
Author(s):  
Yoshiharu Mutoh ◽  
M. Jayaprakash ◽  
Kunio Asai ◽  
Kunihiro Ichikawa
Keyword(s):  
Fretting Fatigue ◽  
Design Curve ◽  
Fatigue Design

Issues of Capacity and Decision-Making in the Context of Delirium

2015 ◽  
Vol 24 (4) ◽  
pp. 140-145
Author(s):  
Kevin R. Patterson
Keyword(s):  
Decision Making ◽  
Patient Autonomy ◽  
Care Setting ◽  
Cognitive Change ◽  
Treatment Team ◽  
Precipitating Factors ◽  
Term Care ◽  
Decision Making Capacity ◽  
Fundamental Consideration

Decision-making capacity is a fundamental consideration in working with patients in a clinical setting. One of the most common conditions affecting decision-making capacity in patients in the inpatient or long-term care setting is a form of acute, transient cognitive change known as delirium. A thorough understanding of delirium — how it can present, its predisposing and precipitating factors, and how it can be managed — will improve a speech-language pathologist's (SLPs) ability to make treatment recommendations, and to advise the treatment team on issues related to communication and patient autonomy.

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