The molecular weight dependence of fatigue crack propagation in polycarbonate

1980 ◽  
Vol 15 (3) ◽  
pp. 635-645 ◽  
Author(s):  
G. Pitman ◽  
I. M. Ward
Keyword(s):  
Molecular Weight ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Molecular Weight Dependence

Comments on ?The molecular weight dependence of fatigue crack propagation in polycarbonate?

1982 ◽  
Vol 17 (5) ◽  
pp. 1533-1537 ◽  
Author(s):  
Michael T. Hahn ◽  
Richard W. Hertzberg ◽  
John A. Manson ◽  
Clare M. Rimnac ◽  
I. M. Ward
Keyword(s):  
Molecular Weight ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Molecular Weight Dependence

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.

scholarly journals Effect of Molecular Weight and Orientation on Fatigue Crack Propagation of Polyimide Resin.

1999 ◽  
Vol 65 (639) ◽  
pp. 2293-2298
Author(s):  
Mituo NOTOMI ◽  
Kikuo KISHIMOTO ◽  
Toshikazu SHIBUYA ◽  
Hisashi INABA ◽  
Atsushi MORITA
Keyword(s):  
Molecular Weight ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation
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