/ MEDIA STATEMENT / This content is not written by Creamer Media, but is a supplied media statement.
Acoustic Emission will locate microscopic and inaccessible defects
Find defects before they find you.
WHAT IS SHM?
SHM is the scientific process of non-destructively identifying four characteristics related to the fitness of a structure as it operates:
(a) Operational and environmental loads that act on the structure;
(b) Mechanical damage that is caused by that loading;
(c) Growth of damage in the structure as it operates; and
(d) Future performance of the structure as damage accumulates.
The acoustic emission (AE) method uniquely fits the concept of SHM due to its capabilities to periodically or continuously examine structures and assess structural integrity during their normal operation.
BENEFITS OF SHM
SHM with confidence levels in excess of 99%, at any time.
Level of Confidence = Sensing + Diagnosism + Monitoring + Predictions
100% volumetric coverage of item based on sound physics as geometry and operations make it impossible for alternative methods.
Other Benefits Include:
Reduce Down Time;
Provide direction in outage Planning;
Identify specific areas for secondary NDT (VT, MT, UT, RT).
WHAT IS AE?
Primary NDT method within the ultrasonic family, that provides direction for secondary NDT Methods.
HOW DOES AE WORK
AE is the elastic energy spontaneously released by materials when they undergo deformation. Therefore AE is only effective while the material or structure is subjected to an applied stress.
COMPARISON WITH OTHER TECHNIQUES
AE is both a dynamic test for structural failures under a loading and a static test for corrosion detection.
Directly detects the growth of discontinuities as stimulus is applied on 100% of weld and base metal volumes of the structure.
The stress waves generated from a dynamic or static test are from the discontinuities in structure with no external inputs from human or equipment.
Provides direction for future tests, maintenance requirements or replacements.
AE can test any steel, concrete or FRP structure and includes: bridges, structures, boilers, pressure vessels, cranes, pontoons, dredgers, transformers, bins, silos and condition monitoring of bearings rotating below 60RPM.
Acoustic Emission Testing standards for other applications:
1. SHM –ASTM 2983:2019.
2. Metallic pressure vessels and piping – ASME V ART 12/ EN14584.
2. FRP vessels and piping ASME V ART 11.
3. Tank bottom for storage tanks EN15610.
4. Tank sidewall for storage tanks E1930-17.
5. Nuclear Equipment ASME V ART 13.
6. Partial Discharge in transformers.
STEPS TO CONDUCT AN AE TEST
AE- can be achieved by the following steps:
(1) AE- Procedure development: Collect design, operational, inspection and maintenance data to generate testing procedure.
(2) Loading: Apply mechanical or thermal loading or normal operations.
(3) Sensing: Conversion of stress waves into digital data.
(4) Acquisition: Acquire all sensing and loading data.
(5) Diagnosis: Use of artificial intelligence (AI) for data analysis.
(6) Recommendations: Repairs or further NDT with secondary methods or operate normally.
Dynamic test method in that it provides a response to discontinuity growth under an imposed structural stress or can sense passively and provide data.
Can detect and evaluate the significance of discontinuities throughout an entire structure during a single test.
Because of limited access required, discontinuities may be detected that are inaccessible to other methods.
Vessels and other structures can often be prequalified during an in-service test that requires little or no downtime.
May be used to prevent catastrophic failure of structures with unknown discontinuities by limiting maximum proof load (ASME PCC 2).
Will prevent conversion from non-destructive testing to destructive testing.
Product removal or surface preparation and cleaning is not a requirement .
Can be tested online, offline and continuously on complex geometry structures to establish specific material behaviour (ASME V-Art11,12,13)(BS/EN14584).
Can be used at low and high temperatures as noted in nuclear plants (ASME V-Art 13).
Successful in buried equipment where structure not visible (BS/EN 12819).
Cannot be used where background noise exceeds equipment and code requirements.
No AE generated when the discontinuity has a higher stress resistance than the applied load.
No deviations permitted as digital recording in micro second intervals.
In certain cases Kaizer effect requires a higher load than previously applied to regenerate stress waves.
Pr.Cert.Eng (ECSA: 200290009);
Mech, Trade Dip; Mech, Eng Dip;
GCC-Factories; IPE 344; CPB 077; CPPV 159;
ASNT Level III - Acoustic Emission Testing (ASNT NO: 194954)
For more information visit: www.se59.net
+27 82 376 1680