Automated Defect Prevention

2007 ◽  
Author(s):  
Dorota Huizinga ◽  
Adam Kolawa
Keyword(s):  
Defect Prevention

The Effects of Wheelset Position and Operating Environment on Rolling Contact Fatigue

2008 ◽  
Author(s):  
Scott M. Cummings ◽  
Paul Krupowicz
Keyword(s):  
Environmental Factors ◽  
Impact Load ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Contact Forces ◽  
Rolling Contact ◽  
Minor Role ◽  
Operating Environment ◽  
Lead Position ◽  
Defect Prevention

The Wheel Defect Prevention Research Consortium (WDPRC) conducted analyses of wheel impact load detector (WILD) data to explore how wheelset position and operating environment affect rolling contact fatigue (RCF). The typical three-piece freight car truck used in North America produces higher tangential wheel/rail contact forces on the wheelset in the lead position than on the wheelset in the trail position of a truck as a car negotiates a curve. An analysis of WILD data shows that these higher forces are contributing to more shelling damage on wheelsets that are consistently in the lead position of a truck. Datasets in which the cars are frequently oriented with the A-end leading show the largest percentage of elevated WILD readings in the lead position of the lead truck (axle 4) followed by the lead position of the trail truck (axle 2). Likewise, datasets in which the cars are frequently oriented with the B-end leading show the largest percentage of elevated WILD readings in the lead position of the lead truck (axle 1) followed by the lead position of the trail truck (axle 3). Additionally, datasets in which there is an equal mix of car orientations show a much more evenly distributed location of elevated WILD readings. Another analysis of WILD data from five trainsets of nearly identical cars shows that any differences in wheel tread damage due to component differences are insignificant in comparison to the differences in wheel tread damage associated with environmental factors. While this analysis does not address component specification differences that could potentially have a large influence on shelling (such as M-976 trucks in comparison to standard trucks), it does show that environmental factors can play a large role in wheel tread damage. Car routing and loading characteristics were investigated as possible wheel damage factors. It appears that cars running on routes through terrain with longer, steeper grades may be prone to increased wheel shelling, probably due to thermal mechanical shelling (TMS). Side-to-side imbalanced loading appears to play a minor role in wheel shelling for two of the five trainsets.

Implementing the Defect Prevention Process in the MVS Interactive programming organization

1990 ◽  
Vol 29 (1) ◽  
pp. 33-43 ◽  
Author(s):  
J. L. Gale ◽  
J. R. Tirso ◽  
C. A. Burchfield
Keyword(s):  
Interactive Programming ◽  
Defect Prevention

Use of Family History Information for Neural Tube Defect Prevention

2011 ◽  
Vol 42 (5) ◽  
pp. 296-308
Author(s):  
Ridgely Fisk Green ◽  
Joan Ehrhardt ◽  
Margaret F. Ruttenber ◽  
Richard S. Olney
Keyword(s):  
Family History ◽  
Neural Tube ◽  
Neural Tube Defect ◽  
Family History Information ◽  
History Information ◽  
Defect Prevention

Parametric Simulation of Rolling Contact Fatigue

2008 ◽  
Author(s):  
Scott M. Cummings ◽  
Patricia Schreiber ◽  
Harry M. Tournay
Keyword(s):  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Wear Model ◽  
Primary Methods ◽  
Vehicle Performance ◽  
Track Geometry ◽  
Advantages And Disadvantages ◽  
Defect Prevention ◽  
Design Speed

Simulations of dynamic vehicle performance were used by the Wheel Defect Prevention Research Consortium (WDPRC) to explore which track and vehicle variables affect wheel fatigue life. A NUCARS® model was used to efficiently examine the effects of a multitude of parameters including wheel/rail profiles, wheel/rail lubrication, truck type, curvature, speed, and track geometry. Results from over 1,000 simulations of a loaded 1,272 kN (286,000-pound) hopper car are summarized. Rolling contact fatigue (RCF) is one way that wheels can develop treads defects. Thermal mechanical shelling (TMS) is a subset of wheel shelling in which the heat from tread braking reduces a wheel’s fatigue resistance. RCF and TMS together are estimated to account for approximately half of the total wheel tread damage problem [1]. Other types of tread damage can result from wheel slides. The work described in this paper concerns pure RCF, without regard to temperature effects or wheel slide events. Much work has been conducted in the past decade in an attempt to model the occurrence of RCF on wheels and rails. The two primary methods that have gained popularity are shakedown theory and wear model. The choice of which model to use is somewhat dependent on the type of data available, as each model has advantages and disadvantages. The wear model was selected for use in this analysis because it can account for the effect of wear on the contacting surfaces and is easily applied to simulation data in which the creep and creep force are available. The findings of the NUCARS simulations in relation to the wear model include the following: • Degree of curvature is the single most important factor in determining the amount of RCF damage to wheels; • The use of trucks (hereafter referred to as M-976) that have met the Association of American Railroads’ (AAR) M-976 Specification with properly maintained wheel and rail profiles should produce better wheel RCF life on typical routes than standard trucks; • In most curves, the low-rail wheel of the leading wheelset in each truck is most prone to RCF damage; • While the use of flange lubricators (with or without top of rail (TOR) friction control applied equally to both rails) can be beneficial in some scenarios, it should not be considered a cure-all for wheel RCF problems, and may in fact exacerbate RCF problems for AAR M-976 trucks in some instances; • Avoiding superelevation excess (operating slower than curve design speed) provides RCF benefits for wheels in cars with standard three-piece trucks; • Small track perturbations reduce the overall RCF damage to a wheel negotiating a curve.

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