Fatigue Crack Propagation in Weld Zone of CPVC Pipe Fittings at Different Temperatures

2001 ◽  
Vol 21 (6) ◽  
Author(s):  
N. Merah ◽  
Z. Khan ◽  
K. Mezghani ◽  
M.O. Budair ◽  
M. Younas
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Weld Zone ◽  
Different Temperatures ◽  
Pipe Fittings

Fatigue Crack Propagation Behavior of Friction Stir Welded 6061-T651 Al Alloy

2007 ◽  
Vol 124-126 ◽  
pp. 1321-1324
Author(s):  
Seong Jin Hong ◽  
Sang Shik Kim ◽  
Chang Gil Lee ◽  
Sung Joon Kim
Keyword(s):  
Residual Stress ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Stress Measurement ◽  
Weld Zone ◽  
Al Alloy ◽  
K Value ◽  
Friction Stir ◽  
Low K

Fatigue crack propagation (FCP) behavior of friction stir welded (FSWed) 6061-T651 Al alloy was examined with the fatigue crack growing either along the dynamically recrystallized zone (DXZ) at variable K or perpendicular to the DXZ at a constant K value of 7.5, 10 and 15 MPa√m, respectively. The FCP rates in the DXZ tended to be significantly lower than those in the PM particularly in low K regime. Compressive residual stress reducing effective K cannot be solely responsible for the enhanced FCP resistance. The fine recrystallized grains in the DXZ causing intergranular fatigue failure appeared to be detrimental to the FCP behavior of FSWed 6061-T651 specimen. The constant K fatigue test across the weld zone showed that substantial crack retardation occurred far beyond the heat affected zone (HAZ) at low K regime. The FCP behavior of FSWed 6061-T651 is discussed based on residual stress measurement and fractographic observation.

High Cycle Fatigue and Fatigue Crack Propagation Behaviors of Modified A7075-T73 Alloy

2014 ◽  
Vol 52 (4) ◽  
pp. 283-291 ◽  
Author(s):  
Gwan Yeong Kim ◽  
Kyu Sik Kim ◽  
Joong Cheol Park ◽  
Shae Kwang Kim ◽  
Young Ok Yoon ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
High Cycle Fatigue ◽  
Cycle Fatigue

scholarly journals Structure, processing and performance of ultra-high molecular weight polyethylene (IUPAC Technical Report). Part 4: sporadic fatigue crack propagation

2020 ◽  
Vol 92 (9) ◽  
pp. 1521-1536
Author(s):  
Clive Bucknall ◽  
Volker Altstädt ◽  
Dietmar Auhl ◽  
Paul Buckley ◽  
Dirk Dijkstra ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
High Molecular Weight ◽  
Fatigue Crack Propagation ◽  
Crack Tip ◽  
Individual Growth ◽  
Paris Equation ◽  
Number Of Cycles ◽  
Ultra High Molecular Weight

AbstractFatigue tests were carried out on compression mouldings supplied by a leading polymer manufacturer. They were made from three batches of ultra-high molecular weight polyethylene (UHMWPE) with weight-average relative molar masses, ${\overline{M}}_{\mathrm{W}}$, of about 0.6 × 106, 5 × 106 and 9 × 106. In 10 mm thick compact tension specimens, crack propagation was so erratic that it was impossible to follow standard procedure, where crack-tip stress intensity amplitude, ΔK, is raised incrementally, and the resulting crack propagation rate, da/dN, increases, following the Paris equation, where a is crack length and N is number of cycles. Instead, most of the tests were conducted at fixed high values of ΔK. Typically, da/dN then started at a high level, but decreased irregularly during the test. Micrographs of fracture surfaces showed that crack propagation was sporadic in these specimens. In one test, at ΔK = 2.3 MPa m0.5, there were crack-arrest marks at intervals Δa of about 2 μm, while the number of cycles between individual growth steps increased from 1 to more than 1000 and the fracture surface showed increasing evidence of plastic deformation. It is concluded that sporadic crack propagation was caused by energy-dissipating crazing, which was initiated close to the crack tip under plane strain conditions in mouldings that were not fully consolidated. By contrast, fatigue crack propagation in 4 mm thick specimens followed the Paris equation approximately. The results from all four reports on this project are reviewed, and the possibility of using fatigue testing as a quality assurance procedure for melt-processed UHMWPE is discussed.

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