Spectacular Failures

[@aerodynamico6427]

You have mentioned in your earlier lecture that the arrival of the railways resulted in some structural catastrophes, but no example was provided. In the middle of the 19th century with the generalisation of the use of steam engines, especially for trains, engineers had to face a new kind of problem never really encountered before: some trains were suffering of severe damage, although the loading remained in the design range. One of the most famous accidents, the Versailles rail accident of 8 May 1842, was due to the rail axle failure of the leading locomotive. However at that time the failure could not be explained. One of the first engineers to investigate this issue was the German August Wöhler around 1860. His analysis led to the following conclusions: ● Failure did not occur at the first time the train was put into service, but after various times. ● Failure occurred at loads much lower than expected. His conclusion was that the incidents were due to the fact that a train axle is submitted to a cyclic loading/unloading. Indeed an axle is submitted to a shear load due the weight of the train car, which in turns induces a bending moment in the axle. As the axle is rotating, a point of the axle isl alternatively submitted to compression and to traction when lying above or below the neutral axis. Due to this cyclic loading, the axle experiences fatigue and the life of the structure is limited. Based on this observation Wöhler developed a theory based on an empirical approach: the total life theory. Details are available at the University of Liege Computational & Multiscale Mechanics of Materials website: www.ltas-cm3.ulg.ac.be/FractureMechanics/?p=overview_P1

[@pankajkumarpandey6658]

Sir You are simply great. I respect you by heart. I follow your lectures regularly.

[@kevinlovephysics]

Thank you Prof. Ramesh! very clear illustration!!

[@arihantjain1959]

thank you for giving an insight , clear knowledge bout the subject.... I am really thankful.. and breaking of glass is also done with the help of stress raising concept... thanks a lot...

[@nguyenvangiang245]

very excellent series, tks!

[@dk_3562]

He is a 💎.

[@PhuongNguyen-wf4tw]

Thank you for your lectures. How can I obtain the e-books that mentioned in lecture 01

[@sami25dz]

thinks prof ramesh

[@vijaypandey4596]

Really helpful

[@mogli802]

Excellent

[@MrMrandymania]

gr88