An Investigation on the Statical Strength of Solid Crankshafts

Abstract

One of the authors, S. Yamada, as a member of the 8 th Research Committee of the Shipbuilding Research Association of Japan, studied the statical strength of four throw solid crankshaft on actual bed plate. But precise investigation into the effect of web dimensions could not be found by the above study, because the results were considerably affected by bearing conditions as well as other unknown factors.In this investigation, therefore, single throw crankshafts having same web section modulus bt2=0.417 dc3 (dc= crank diameter) have been examined by means of the apparatus so contrived as to eliminate the above influences.From the results of the examinations, following conclusions have been deduced : (1) In load bending test, maximum fillet stress of crankshaft having web thickness t=0.56dc, is greater by about 10% than that having web thickness t =0.45 dc.(2) In web deflection test, however, maximum fillet stress is nearly equal in all crankshafts in spite of the change of web thicknesses.(3) The increment of web distance in both load bending and web deflection tests may be calculated quite accurately by correcting the length of crank radius (r) by a factor q (q <1).It is adequate to take q = 0.50 for the crankshafts used in this investigation.