Cyclic Strain Accumulation of Plain Stainless Steel Pressurized Cylinders Subjected to Dynamic Bending Moment

2008 ◽  
Vol 8 (18) ◽  
pp. 3129-3138 ◽  
Author(s):  
M. Zehsaz ◽  
S.J. Zakavi ◽  
H. Mahbadi ◽  
M.R. Eslami
Keyword(s):  
Stainless Steel ◽  
Bending Moment ◽  
Cyclic Strain ◽  
Strain Accumulation ◽  
Dynamic Bending

Response and cyclic strain accumulation of pressurized piping elbows under dynamic in-plane bending

1996 ◽  
Vol 31 (2) ◽  
pp. 135-151 ◽  
Author(s):  
K Yahiaoui ◽  
D G Moffat ◽  
D N Moreton
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Dynamic Response ◽  
Internal Pressure ◽  
Material Properties ◽  
Cyclic Strain ◽  
Testing Procedure ◽  
Strain Accumulation ◽  
Seismic Excitations ◽  
Outside Diameter

Eight pairs of carbon and stainless steel, long and short radius welding elbows were tested under conditions of steady internal pressure and in-plane, resonant dynamic moments that simulated seismic excitations. The elbows had an outside diameter of 60.3 mm and thicknesses of 3.91 and 5.54 mm. The material properties are reported, and the testing procedure and experimental programme fully described. The dynamic response of the comonents indicates that the stainless steel elbows behave differently from the carbon steel elbows. The cyclic strain accumulation for each component is assessed and ratios of applied to limit moments of the elbows at onset of ratcheting are given for each material. While the gross deformation range increased with level of input in testing, no permanent overall swelling or ovalization was recorded; this is contrasted with similar results reported in the general literature.

Ratcheting assessment of corroded elbow pipes subjected to internal pressure and cyclic bending moment

2021 ◽  
pp. 030932472198989
Author(s):  
Ali Salehi ◽  
Armin Rahmatfam ◽  
Mohammad Zehsaz
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
Internal Pressure ◽  
Bending Moment ◽  
Axial Direction ◽  
Hoop Strain ◽  
Cyclic Bending ◽  
High Fatigue ◽  
The Impact ◽  
Cyclic Bending Moment

The present study aimed to study ratcheting strains of corroded stainless steel 304LN elbow pipes subjected to internal pressure and cyclic bending moment. To this aim, spherical and cubical shapes corrosion are applied at two depths of 1 mm and 2 mm in the critical points of elbow pipe such as symmetry sites at intrados, extrados, and crown positions. Then, a Duplex 2205 stainless steel elbow pipe is considered as an alternative to studying the impact of the pipe materials, due to its high corrosion resistance and strength, toughness, and most importantly, the high fatigue strength and other mechanical properties than stainless steel 304LN. In order to perform numerical analyzes, the hardening coefficients of the materials were calculated. The results highlight a significant relationship between the destructive effects of corrosion and the depth and shape of corrosion, so that as corrosion increases, the resulting destructive effects increases as well, also, the ratcheting strains in cubic corrosions have a higher growth rate than spherical corrosions. In addition, the growth rate of the ratcheting strains in the hoop direction is much higher across the studied sample than the axial direction. The highest growth rate of hoop strain was observed at crown and the highest growth rate of axial strains occurred at intrados position. Altogether, Duplex 2205 material has a better performance than SS 304LN.

The use of a bree simulation to investigate strain accumulation in 316 stainless steel at temperatures between room temperature and 500°c

1989 ◽  
Vol 24 (2) ◽  
pp. 95-102 ◽  
Author(s):  
D J Brookfield ◽  
D N Moreton
Keyword(s):  
Stainless Steel ◽  
Transition Temperature ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Cyclic Change ◽  
Strain Accumulation ◽  
Temperature Behaviour ◽  
Design Rules ◽  
Axial Tension ◽  
Applied Stresses

This paper details tests undertaken to determine the 1 per cent strain accumulation boundary in stainless steel type 316 strip subjected to constant axial tension and a cyclic change of curvature. Boundaries are obtained for temperatures between 300 and 500°C. These are compared with two design rules, both of which are shown to be conservative. Additionally, the temperature at which the transition from the characteristic room temperature behaviour of continued ratchetting to the ‘shakedown’ observed at elevated temperatures is investigated. Results obtained indicate that this transition temperature is influenced by the magnitude of the applied stresses.

Influence of Porosity on the Integrity Properties of Butt Welded Super Duplex Stainless Steel Umbilical Tube

2015 ◽  
Author(s):  
Xiaoxue An ◽  
Alan Dobson ◽  
Chun Yip Chan
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Bending Moment ◽  
Steel Tube ◽  
Design Codes ◽  
Super Duplex Stainless Steel ◽  
Acceptance Criteria ◽  
Hydraulic Fluids ◽  
Weld Root ◽  
Main Component

Super Duplex Stainless Steel (SDSS) tube is the main component in steel tube umbilicals for the transportation of hydraulic fluids and chemicals, or gas injection into the subsea well. The umbilical tube is made from seamless tube joined together by girth weld. Therefore, porosity is one of the main weld defects that could be discovered within the welds, and these defects can have significant impact on the execution of the whole project, in term of both schedule and cost. This paper reviews the design codes and standards relating to the porosity acceptance criteria, and discusses the recent investigation on the influences of porosity (number, size and location) to the stress distribution within the weld. The study was performed using both FEA and practical fatigue test. The results demonstrated that the distance of the pores to the weld surface is a critical parameter to the increase and localisation of stress as the pore starts to interact with the weld root or cap. In addition, significant pore stress interaction has been observed when a bending moment is introduced to the weld. The study has demonstrated that the current porosity acceptance criteria applied to umbilical manufacture in the subsea industry are typically conservative and can be modified.

Overview of Proposed High Temperature Design Code Cases

2016 ◽  
Author(s):  
Peter Carter ◽  
T.-L. (Sam) Sham ◽  
Robert I. Jetter
Keyword(s):  
High Temperature ◽  
Yield Stress ◽  
Creep Damage ◽  
Cyclic Strain ◽  
Inelastic Strain ◽  
Cyclic Creep ◽  
Strain Accumulation ◽  
Temperature Dependent ◽  
Common Basis ◽  
Creep Fatigue

Proposals for high temperature design methods have been developed for primary loads, creep-fatigue and strain limits. The methodologies rely on a common basis and assumption, that elastic, perfectly plastic analysis based on appropriate properties reflects the ability of loads and stress to redistribute for steady and cyclic loading for high temperature as well as for conventional design. The cyclic load design analyses rely on a further key property, that a cyclic elastic-plastic solution provides an upper bound to displacements, strains and local damage rates. The primary load analysis ensures that the design load is in equilibrium with the code allowable stress, taking into account: i) The stress state dependent (multi-axial) rupture criterion, ii) The limit to stress re-distribution defined by the material creep law. The creep-fatigue analysis is focused on the cyclic creep damage calculation, and uses conventional fatigue and creep-fatigue damage calculations. It uses a temperature-dependent pseudo “yield” stress defined by the material yield and rupture data to identify cycles which will not cause creep damage > 1 for the selected life. Similarly the strain limits analysis bounds cyclic strain accumulation. It also uses a temperature-dependent pseudo “yield” stress defined by the material yield and creep strain accumulation data to identify cycles which will not cause average (membrane) inelastic strain > 1% for the design life. The paper gives an overview of the background and justification of these statements, and examples.

Dynamic Behavior of Submarine Pipelines Under Laying Operation

1982 ◽  
Vol 104 (4) ◽  
pp. 313-318 ◽  
Author(s):  
N. Suzuki ◽  
N. Jingu
Keyword(s):  
Experimental Study ◽  
Dynamic Behavior ◽  
Water Depth ◽  
Forced Oscillation ◽  
Bending Moment ◽  
Scale Model ◽  
Regular Waves ◽  
Wave Response ◽  
Dynamic Bending

Theoretical and experimental study on dynamic behavior of submarine pipelines under laying operation with articulated stingers is described in this paper. Wave response tests in regular waves and forced oscillation tests in still water were conducted using the 1/20 scale model of 406.4 mm o.d. (16 in. o.d.) pipeline laid in 150 m (500 ft) water depth. The results show that: 1) the maximum dynamic bending moment of pipeline MDmax occur at a stinger roller, 2) dynamic bending moment of pipelines MD at shorter periods are larger than those at longer periods, 3) the values of MD in an over-bend region depend highly upon stinger motion, 4) those of MD in a sag-bend region are less than MD max in an over-bend region, 5) the values of MD/HMY increase as the stinger volume increases and that 6) stinger motion at shorter periods are different from those at longer periods.

A COMPARISON OF WEAR PROPERTIES OF WATER LUBRICATED NBR AND PTFE SLIDING BEARINGS

Tribologia ◽  
2019 ◽  
Vol 283 (1) ◽  
pp. 29-35
Author(s):  
Ewa PIĄTKOWSKA
Keyword(s):  
Stainless Steel ◽  
Working Conditions ◽  
Material Properties ◽  
Bending Moment ◽  
Wear Properties ◽  
Sliding Bearings ◽  
Specialized Equipment

The excessive wear of a journal shaft can be caused by many factors, for example, working conditions (e.g., temperaturę, slip speed, the type of lubricant), pressure, the type of material used on the bearings and shafts and their roughness, as well as contamination remaining in the system. This paper presents the roughness profiles co-operating with a rubber (NBR) and polytetrafluoroethylene (PTFE) bushes. The conditions of cooperation between the two materials tested in the sliding combination with the stainless steel journal were the same in each pair of bearings (PV); therefore, the comparison of their wear depends only on the material properties of the bush and the deformation of the journal shaft caused by the bending moment. To assess the size of the journal shaft, they were tested using a profilograph. In addition to the journal shaft, bearings were also evaluated, the wear level of which was noticed without the use of specialized equipment.

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