This question should take about 10 minutes to complete. It is an introductory level question.
A thin sheet of maraging steel has a tensile strength of 1950 MPa. Calculate the percentage reduction in strength due to the presence of a crack in the sheet, which is 4 mm long and orientated perpendicular to the stressed direction.
For this steel, E can be taken as 200 GPa, the energy of fracture surface as 2 J/m2, and the work of plastic deformation of each crack tip is 2x104 J/m2.