Browsing by Author "Pearce, GM"

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    Effect of ultrasonic peening on fatigue crack propagation from a weld toe
    (International Institute of Welding, 2016-07-10) Hellier, AK; Prusty, BG; Pearce, GM; Reid, M; Paradowska, AM
    The objective of this work was to investigate the effect of ultrasonic peening on the fatigue propagation life for a semi-elliptical flaw at a T-butt weld toe. A number of T-butt joints have been fabricated from 10 mm thick A350 grade black mild steel plate. Through-thickness residual stresses at the weld toe have been measured using neutron diffraction for both as-welded and ultrasonically peened joints. Ultrasonic peening is relatively cheap, can be applied in-situ and offers significant improvements in the lifespan of welded components when applied correctly. Numerical analyses were conducted using BDKH stress intensity and HBC stress distribution parametric equations in conjunction with the Paris Law and Forman Equation fatigue crack growth models.
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    Effect of ultrasonic peening on residual stresses at a T-butt weld toe
    (Materials Research Forum LLC, 2016-07-03) Hellier, AK; Prusty, BG; Pearce, GM; Reid, M; Paradowska, AM; Simons, P
    The current paper presents the results of neutron diffraction measurements of the throughthickness residual stress field at the toe of a T-butt weld, made from 10mm thick A350 grade black mild steel plates, after successful ultrasonic peening. A single ultrasonic peening treatment was carried out at the weld toe. Residual stresses were measured using the KOWARI instrument at ANSTO. The neutron diffraction technique was chosen for this study because of its ability to measure three-dimensional residual stress deep within the component at high resolutions. Although the nominal yield stress of the A350 grade plate is 350 MPa the actual yield stress is generally higher, in this case averaging out to about 400 MPa. Ultrasonic peening was highly effective, leading to a residual stress redistribution with a maximum compressive stress of about 250 MPa at the weld toe surface and a maximum tensile stress of 220 MPa, at a depth of almost 3mm into the base plate. The resulting compressive residual stresses at the weld toe surface will almost certainly increase substantially both the fatigue initiation and propagation lives, or may prevent fatigue completely. Since A350 steel is widely used in buildings, bridges and offshore structures, ultrasonic peening shows great promise as an in-situ peening method in order to improve weld fatigue performance. © The Authors
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    Experimental and modelling approaches to the determination of fatigue crack growth from a structural steel T-butt weld toe
    (Engineers Australia, 2017-11-27) Tanulia, V; Prusty, BG; Pearce, GM; Hellier, AK; Li, H; Reid, M; Paradowska, AM
    T-butt welded joints are found in many structural steel applications including buildings, bridges and offshore structures and are susceptible to fatigue crack initiation and propagation,which often leads ultimately to fast fracture failure. An example ofthis was the I-35W bridge in Minneapolis, which collapsed in 2007 resulting in 13 fatalities, as shown in Figure 1 [1]. The experimental work for this project was conducted using A350 grade black mild steel plate. An ultrasonic peening treatment was applied to one T-butt specimen to introduce compressive residual stress at the weld toe, in order to reduce the effective fatigue crack propagation rate. The results generated from 3-D FEA modelling plus a FORTRAN program (implementing parametric stress intensity factor and crack propagation equations) will be compared with experimental fatigue test results. © (2017) by Engineers Australia
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    Residual stress effects on fatigue crack growth from a T-butt weld toe
    (University of Wollongong Australia, 2018-11) Hellier, AK; Li, H; Prusty, BG; Pearce, GM; Reid, M; Paradowska, AM
    A350 grade black mild steel is one of the most widely used structural materials in the world, being commonly found in buildings, bridges and offshore structures.Welding is commonly used to join two plates of structural steel and this often takes the form of a T-butt.In addition, other more complex geometrical joints are often simplified for stress analysis purposes by approximating them as 2-D T-butt plate models (e.g. skewed T-joints, cruciform welded joints, tubular welded joints, pipe–plate joints, etc.).However, all such welds are potentially susceptible to fatigue crack initiation and slow but accelerating growth arising as a result of fluctuating service loads, often eventually resulting in fast fracture.