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Materials Engineering Group

Research / Students / Bilal Ahmad

Bilal Ahmad

Student Project

Analysis of Fillet Weld Residual stresses

Academic supervisors

Prof. Mike Fitzpatrick

Prof. John Bouchard

Dr. Salih Gungor

Bilal Ahmad
Bilal Ahmad

Background :

I am Bilal Ahmad from Gujrat, Pakistan. I graduated with bachelors of science degree in Mechanical Engineering from University of Engineering and Technology Lahore, Pakistan. Further i completed postgraduate study in Civil Engineering (Advanced mechanics of materials and structures) from Bauhaus University Weimar, Germany in 2007. I was working in Pakistan Railways before joining the OU in March 2011.


PhD Project :

Welding is one of the significant causes of residual stresses in engineering components and structures. The residual stresses generated by the welding are often close to the yield strength of the material. The geometry of fillet welds is challenging for the determination of residual stresses. The fatigue tests of as-welded fillet joints depicts that crack initiates from the weld toe at attachment corner. To increase the fatigue life of welded specimens a number of post weld treatment techniques are available. Ultrasonic peening (UP) is a post weld residual stress improvement technique which also improves the weld toe geometry. Ultrasonic peening uses ultrasonic vibrations to produce 3-5 mm wide and 0.3-0.6 mm deep groove at the toe of weld. The ultrasonic peening results in higher fatigue life by imparting compressive residual stresses.

I have applied X-ray diffraction technique for measurement of on surface residual stresses in as-welded and ultrasonically peened specimen which shows that UP has imparted beneficial compressive stresses at and near the weld toe locations. Neutron diffraction technique shall be applied to quantify the residual stresses through thickness of base plate in two ultrasonically peened fillet weld specimens, one of which is subjected to in-service corrosive environment. These results shall provide the information about evolution of residual stresses after subjecting the UP fillet weld specimen to corrosive environment.

The research environment at Materials Engineering group is promising, encouraging and helping. My supervisors are at their best.




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