Effects of Constraint and Tensile Properties on the Fracture of Pressure Vessel Materials under Impact Loading


Dynamic finite element modeling of the fracture behavior of pressure vessel materials under impact loading was conducted to study the effects of ligament size and tensile properties on the crack extension (USE e) and propagation (USEDr) energies. The sum of USE e and USEor is the total energy absorbed, US.Ep, in complefe fracture of the specimen. ASTM standard (full size) and subsize precracked Charpy specimens with varying ligament sizes (b) were investigated for five materials with a wide range of ductility. It was found that for all materials studied the dependence of USEp on ligament size for half and third size specimens was similar, but quite different from flaat for full size specimens. USEp varied as b 2 for half and third size specimens. For full size specimens, it varied as b 2-5 for low ductility and as b 3"5 for high ductility materials. It was further found that the ratio, r, of crack extension and propagation energies decreased sharply with b for both low and high ductility materials if the ligament sizes were less than half the width. For larger ligament sizes, the value of r was close to 1 for all materials and specimen sizes. The crack extension energy did not show any systematic pattern in its variation a/a function of material ductility or specimen constraint. USE_, .......... t Jt however, did show a systemauc vanataon with hgament s~ze. For the highest ductlhty material, the full size USF_~ behaved as b 3"5 whereas USEpr for the half and third size specimens behaved appmx~'mately as b 2'5. For the lowest ituctility material, USEpr for all three sizes behaved approximately as b 2.


Nuclear Engineering and Radiation Science

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Technical Report

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© 1998 American Technical Publishers, All rights reserved.

Publication Date

01 Jan 1998

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