<p>The objective of this research is to develop
recommendations on calibration standards, scanning procedures, and acceptance
criteria for phased array ultrasonic testing (PAUT) of complete joint
penetration butt welds within the AWS D1.5 Bridge Welding Code. These recommendations include the development
of a rational acceptance criteria which is based in engineering analysis and
fracture mechanics. It is expected that
the updated scanning procedures and acceptance criteria will result in improved
reliability for bridges and improved consistency in bridge fabrication quality.</p><p><br></p>
<p> </p>
<p>While PAUT was included in the 2015 edition of AWS
D1.5 in Annex K, the acceptance criteria for this procedure was developed as an
adaptation of an existing conventional ultrasonic testing (UT) acceptance
criteria in AWS D1.1. Therefore, the
acceptance criteria in AWS D1.5:2015 is a workmanship-based criteria and is not
based on engineering analysis of the criticality of weld flaws. The scanning procedures and application of
PAUT inspections of bridge welds according to this procedure differ greatly
from the scanning procedures outlined in AWS D1.5 for conventional UT
inspections. Previous research has shown
that differences in flaw rejection are possible for PAUT and conventional UT
ultrasonic methods under the AWS D1.5:2015 approach.</p><p><br></p>
<p> </p>
<p>In order to develop recommendations for improved
calibration standards, scanning procedures, and acceptance criteria for PAUT
within AWS D1.5, this research project utilized both analytical techniques and
experimental testing. This research
project included determination of target critical flaw sizes for routine detection
and rejection through fitness-for-service evaluations. This was followed by a round robin ultrasonic
testing program in order to collect data on the variability of inspection
results of eleven weld samples with nineteen weld flaws using different
ultrasonic inspection techniques. Next,
calibration requirements were developed to account for differences in
ultrasonic attenuation and shear wave velocity between calibration blocks and
test objects. Development of these
requirements included experimental testing of base metals and weld metals,
along with simulations of ultrasonic inspection using commercial software. Finally, minimum requirements for weld
scanning procedures, reference standard reflectors, and corresponding amplitude
limits for detection and rejection of target critical weld flaws were developed
using ultrasonic inspection simulations and verified through experimental
testing of weld samples with known weld flaws.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/7366943 |
| Date | 03 January 2019 |
| Creators | Curtis J. Schroeder (5930243) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/Inspection_of_Steel_Bridge_Welds_Using_Phased_Array_Ultrasonic_Testing/7366943 |
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