Technical Reports

Residual Stress Measurements of Retrofitted Tank Car Weldments

  • 01
  • Apr
  • 1992
AUTHOR: R.K. Larson Jr., R.L. Florom and B.R. Rajkumar
OFFICE: RPD
SUBOFFICE: RPD-30
REPORT NUMBER: DOT/FRA/ORD-92/05
SUBJECT: Hazardous Materials
KEYWORDS: tank car reinforcement; weld-induced tank shell stress; stress measurement using drillable strain gages; effect of service on weld stress
ABSTRACT: A series of residual stress measurements were made on two tank cars that were retrofitted with stiffener beams. The measurements were made on the tank shell exterior in the vicinity of fillet skip welds, which were used to attach the stiffener beams to the tank structure. One of the cars had been newly retrofitted; the second car was operated for five years in revenue service after the retrofit application. The measured stresses on the newly retrofitted car were substantially higher than on the car which had seen service indicating that some shakedown of the weld stresses may occur during the service life of the car. However, significant tensile stresses (on the order of 30 ksi) were measured in the vicinity of the fillet welds having a throat size greater than .25 inch. It is recommended that the stress measurements he performed on several other tank cars in order to confirm that the stresses that were observed in the two test cars are representative for the fleet of cars that is under study.

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