Edward Walter Parkes, M.A., Ph.D., A.M.I.C.E. University Lecturer, Cambridge University Engineering. Laboratory work on model
steel, brass, and duralumin beams struck by moving masses has shown that good agreement can be obtained between predictions of rigid-plastic analysis and experiment for
deformations remote from point of impact; agreement can also be obtained for deformations close to struck section provided variation of strain rate throughout structure does not exceed following values: steel 102, brass 103, duralumin 104.