STRESSES AND DEFORMATIONS IN OVERLAPPED DIESEL-ENGINE CRANKSHAFTS - PART-1 - EXPERIMENTAL RESULTS

Single-throw, epoxy resin models of five overlapped crankshafts with s ide-by-side connecting rods have been loaded in pure torsion or bendin g. Bending loads considered are those due to the radial or tangential components of the connecting rod force and those due to pure radial be nding or radial bending due to journal displacement. After the photoel astic frozen-stress cycle, deformations and stresses in the crankpin a nd journal fillets were measured. The principal stresses were determin ed over the whole highly stressed (toroidal) fillet surfaces. At each angular position around the crankpin and journal the magnitude, meridi onal position and direction of the greatest principal stress were obta ined. In torsion these maxima were fairly constant with angular positi on, whereas in bending they varied linearly, as in a simple beam in be nding. The results were expressed as stress concentration factors base d on nominal stresses in a bar of the same diameter as the crankpin.