# The intentional breach of joined sheet

According to the highest shearing stress hypothesis, we can determine as follows:equation(31)σVM2=σmax-σminσVM2=σmax-σminand the factor of safety:equation(32)δ1,2=ReσVM1,2
Considering the residual stress in the rivet, we can write the condition as follows:equation(33)δred-load=Reσred-loadwhereequation(34)σred-load=σred1,2+σres.σred-load=σred1,2+σres.
3.2. Energy release rate during fracture
J-integral is a coefficient describing the rate of Retinyl glucoside released while the material fractures. This is specified as the change of potential energy dUp vs. gap growth caused by the plastic strain:equation(35)J=-dUpda.
The potential energy Up equals the difference of elastic energy of the system and the external force work. The elastic energy of the system equals the total strain energy W, integrated in area A with notch surrounded by any contour Γ:equation(36)Ua=∫ΩWdΩ.Ua=∫ΩWdΩ.
Fig. 4. Coordinate system.Figure optionsDownload full-size imageDownload as PowerPoint slide