Plastic Pipes Conference Association # 2006 Washington DC
An accelerated method of determining the failure time of a polyethylene resin has been developed. The method requires determination of the minimum displacement rate, or the time at minimum displacement rate, using ASTM F 1473-01, followed by one of these procedures : (1) If failure has not yet occurred, cryogenically fracturing the resin specimen and examining it for slow crack growth to determine whether the anticipated, or desired, failure time is generally before or after the predicted failure time; or (2) Applying the minimum displacement rate, or the time at minimum displacement rate, in a formula to predict the failure time for the resin. The formula is based on the discovery of a power law relationship between the failure time and minimum displacement rate, or between failure time and the time at minimum displacement rate. Thus, it is not necessary to actually test all the way to failure using ASTM F 1473-01, thereby accelerating testing as much as 3.5 to 4.9 times faster, enabling more rapid development of new resins.
Author(s) : C. Corleto
A fracture mechanics based method to characterise rapid crack propagation properties of HDPE pipe resins has been developed. The new method is based on quasi-static finite element analysis solutions of energy release rate and displacement, of a modified single-endnotched bend specimen that minimizes dynamic effects...