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S. Mandayam/ECE Dept./Rowan University
Development of an Acoustic Development of an Acoustic Emission Test Platform with a Emission Test Platform with a Biaxial Stress Loading System Biaxial Stress Loading System
Joseph Oagaro, Shreekanth Mandayam, John L. Schmalzel and Ronnie K. Miller
Electrical & Computer Engineering201 Mullica Hill RoadGlassboro, NJ 08028
(856) 256-5333http://engineering.rowan.edu/
Progress Report for the Period June 1 – August 31, 2003
PERF 95-11 STEERING COMMITTEE MEETINGAdams Mark Hotel, Denver, Colorado
September 17, 2003
S. Mandayam/ECE Dept./Rowan University
Project ObjectivesProject Objectives
• Design and develop test-platforms for performing Acoustic Emission (AE) measurements on defective pipe segments under bi-axial stress conditions
• Develop empirical relations between stress and AE signal parameters
S. Mandayam/ECE Dept./Rowan University
Test Platform Design CriteriaTest Platform Design Criteria
• Design Challenges• Rigid Frame
• Biaxial Loading of test specimen
• 30,000 psi (45,000 lbs) along Axis 1
• 15,000 psi (22,500 lbs) along Axis 2• Low cost
S. Mandayam/ECE Dept./Rowan University
Specimen FabricationSpecimen Fabrication• Provided by Shell Oil Co.• 0.5” Thick SA-516 grade 70
Steel Coupons• Simulated Cracks of varying
depths• .08”, .16”, and .32” deep
• Two sets of 3 specimens each
• Uniaxial and Biaxial Loading• simulates axial and hoop
stresses of a pressurized pipeline
• Duplicate specimens machined in-house with saw cut defects
S. Mandayam/ECE Dept./Rowan University
Construction History:Construction History: Version 1 Version 2 Version 1 Version 2
• Clamping method caused deformation of specimen producing spurious AE data
• Fixed connection caused bending moments and non-uniform loading of specimen
• Inability to reach desired load - 13.5ksi (20,000 lbs) max load
• Additional connections for new clamping brackets create extraneous noise producing false AE data
• Increased loading capability but still not full desired load – 20ksi (30,000 lbs) max load
S. Mandayam/ECE Dept./Rowan University
AE Test Platform Design: AE Test Platform Design: Version 3Version 3
Frame
Load Transducer
Specimen
HydraulicCylinders Specimen Clamping
Bracket
S. Mandayam/ECE Dept./Rowan University
Why Version 3?Why Version 3?• Hydraulic design
• Allows for increasing max load to 30 ksi (45,000 lbs) • Controlled loading environment• Negligible noise effects with hydraulic loading
• New clamping brackets• Single bracket piece – minimizes noise• Designed to withstand forces exceeding maximum
loading specs• 1” Pinned connections to specimens
• Allows for movement of specimen to linearize loading• Prevents deformation of specimen at connection
S. Mandayam/ECE Dept./Rowan University
Summary of ProgressSummary of Progress
• Additional test specimens identical (steel grade and dimensions) to those provided by Shell Oil have been fabricated
• Version 3 of the AE test platform with hydraulic loading has been built
• The platform has been tested to provided desired load of 45,000 lbs along Axis 1 and 22,500 lbs along Axis 2
• Initial test indicate repeatable loading with minimized extraneous noise
S. Mandayam/ECE Dept./Rowan University
Future PlansFuture Plans• Work with PAC personnel to conduct tests on both in-
house and Shell specimens with Version 3 test platform
• Parameterize AE signature differences between uni- and bi-axial loading of test specimens• Generate calibration curves and empirical relationships
quantifying 1-D and 2-D stress effects
• Generate final report summarizing all findings
• Provide recommendations for the design of a pressure vessel test platform