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Question 2 [39] Vraag 2 [39] The output shaft shown below is made from 1020 CD steel, and transmits a torque via a reduction spur gear of PCD = 80 mm and pressure angle 20° that is keyed onto the shaft. The shaft drives a system which develops a centrifugal force (mar) = 1 kN at the operating speed, with a resisting torque of 120 Nm. Die onderstaande uittree-as is gemaak van 1020 CD- staal en dra 'n wringkrag oor via 'n reduksie reguittand rat van PCD = 80 mm en drukhoek 20° wat op die skag met 'n spy bevestig is. Die as dryf 'n stelsel aan wat 'n sentrifugale krag (mar) = 1 kN ontwikkel by die werksnelheid, met 'n weerstandswringkrag van 120 Nm. (a) Draw the bending moment diagrams due to alternating and mean forces, and determine the moments at the keyway. [10] (a) Teken die buigmomentdiagramme as gevolg van wissel- en gemiddelde kragte, en bepaal die momente by die spygleuf. [10] (b) (b) Assume that the critical point lies at the end- mill keyseat (at the gear) of size 8 mm wide and 3 mm deep. Using the Soderberg fatigue failure criterion, together with DE theory for calculating effective stresses, (as opposed to the DE-ASME Elliptic fatigue failure criterion), determine the factor of safety for infinite life. [17] Aanvaar die kritiese posisie is die ent-frees spygleuf (by die rat) wat 8 mm breed en 3 mm diep is. Deur gebruik te maak van die meer konserwatiewe Soderberg uitputtingsfaling maatstaf, saam met DE-teorie vir die berekening van effektiewe spannings, (in teenstelling met die DE-ASME Elliptiese uitputtingsfaling maatstaf), bepaal die maksimum wringkrag wat oorgedra kan word vir 'n oneindige leeftyd. [17] (c) (c) If the torque is doubled, determine the number of cycles to failure. [12] As die wringkrag verdubbel word, bepaal die aantal siklusse tot faling. [12] Centrifugal force /Sentrifugaalkrag = 1 kN Ø40 Ø30 Alle afmetings in mm. Laer breedte = 20 mm. Alle filetradiusse = 2 mm. Input shaft 240 Gear PCD = 80 Rat SSD = 80 60 100 All dimensions in mm. Bearing width= 20 mm. All fillet radii = 2 mm.