Shaft Design - Angled Gear Force on Shaft - Example 2

[@ozkilinctaha]

Most useful video about the fatigue criteria for the shaft I ever seen.

[@medhathamed2328]

Your videos are amazing. I always watch them when I can't understand something, and I always know that I won't be disappointed. Thanks for the great effort.

[@LessBoringLectures]

Happy to hear that! Share with others!

[@jon7160]

@1:35 why did you use cosine instead of sine if the standard formula for Torque is F*sin(theta)*r

[@necipacar7716]

That is very helpful

[@whenyouslip]

how we determine of kf and kfs

[@sammycornish6389]

What about the radial component of the force ? The tangential component is used to calculate torque. But can you use both the radial and tangential component to determine bending moments in 2 different planes and then get the square root of the sum ?

[@LessBoringLectures]

Yes, exactly that! Radial and tangential components are used to find the resulting forces (root of the sum of squares) that cause bending moments on the shaft. For gears that are not spur gears (bevel, helical, worm, etc.), the axial force will cause compression or tension in certain sections of the shaft as well. The axial force component is also important for bearings selection.

[@laraszabo-banicz4339]

He got d=0.0574 m but then wrote 5.74 mm. Isn’t it supposed to be 57 mm (which seems pretty big)?

[@angelleal3005]

How much would the whole exercise change if the shaft is positioned completely vertical.

[@joaofelipegueiros3743]

Can anyone explain why the Mean moment is zero?

[@carultch]

Label the top and bottom of the shaft, with A and B respectively. Consider this section of the shaft, subject to a positive bending moment that makes the shaft "smile". The A-fibers will be in compression, and the B-fibers will be in tension. Now spin the shaft 180 degrees, and apply the same loading situation. Now the B-fibers are on the top, and are in compression, and the A-fibers are on the bottom and are in tension. The bending moment that the shaft fibers are experiencing, is now equal and opposite, to what they experienced before. You therefore have completely reversed loading, as far as the bending moment is concerned. It cycles from A-fibers in tension and B-fibers in compression, to the exact opposite, with every rotation of the shaft. Normally, the weight of the shaft, the weight of the rotors, and the radial loads associated with gears/pulleys/sprockets/etc, will cause an amplitude to the bending moment, but not a mean bending moment. An example where you WOULD have a non-zero mean bending moment, is if you had an eccentrically-mounted rotor on the shaft. Suppose it is heavy enough that the mass and centrifugal effect would cause a significant load. The apparent centrifugal force caused by this lop-sided rotor would continuously load one group of fibers in tension, and the opposite group of fibers in compression, since its heavy side always pulls outward on the shaft, due to the centrifugal effect.

[@tstvideo1]

Could it also have been moment at C is 0 ?

[@carultch]

@@tstvideo1 Not in this problem.

[@jasonbraganza1074]

Can I hire you for 2 hours of your time to help me with some similar problems? If so please contact me. I'm a 5th year engineering student who's in need to some tutoring.