NOTCH SENSITIVITY OF CIRCULAR RINGS SUBJECTED TO IMPACT LOADING

'Notch-sensitive regions' have been observed during a series of experi mental investigations into the dynamic plastic behaviour and failure o f thin-walled metallic radially notched circular rings with are-shaped supports subjected to concentrated impact loads. The experimental res ults show that the exterior notches at some regions have no effect on the deformation of the rings, but do have effect at the remaining regi ons. The notch-sensitive region is theoretically determined by using t he equivalent structures technique; fairly good agreement has been rea ched between the simple theory and the experimental results. Both dime nsional and theoretical analyses prove that whether a plastic hinge fo rmed or not at the notched section does not depend on the mean radius of the ring and the input kinetic energy. It depends on the weak coeff icient of the notched section and the angle of the support. Generally speaking, there are mainly three failure modes for a notched circular ring with are-shaped support under impact loading: Mode I, large inela stic deformation when the notch is outside the sensitive region, in th is case the ring deforms as a normal one; Mode II, large inelastic def ormation only at some part of the ring and tearing occurred at the not ched sections; Mode III, large inelastic deformation and total rupture occurred at the notched sections. It is believed that the present stu dy could assist the understanding of the dynamic behaviour and failure of other kinds of nonstraight components with macroscopic imperfectio ns under impulsive loading.