A shaft made from ductile material is subjected to combined bending and twisting moments. Calculations based on which one of the following failure theories would give the most conservative values?
Identify the WRONG statement:
Axels do not transmit any torque and are subjected to the effect of bending loads only. A shaft not only supports a revolving part but also transmits torsional moment.
The greatest twisting moment which a shaft section can resist is given by
For a hollow shaft of inner diameter band outer diameter D, the modulus of rupture is
The maximum shear Stress calculated by using the torsion formula is called modulus of rupture
A solid circular shaft of diameter d is subjected to a pure torsional load T. When the same load is applied to a hollow shaft of outside diameter d and ratio of inside to outside diameter is the ratio of stress in the solid to that in the hollow shaft will be
Shaft design is generally made for the torsional moment kt T where factor kt takes into account the nature of load, for suddenly applied loads with shocks, the factor kt is usually taken as '
kt = 1 for gradually applied or steady loads
kt=1 -1.15 for suddenly applied load with minor shocks
kt = 1.5 - 3.0 for suddenly applied load with heavy shocks
A shaft of elliptical section (semi-major axis a and semi-minor axis b) is subjected to twisting moment T. The maximum shear stress occurs at the ends of minor axis and is given by
Some of the mechanical properties are
1. sufficiently high strength
2. low sensitivity to stress concentration
3. wear resistant
4. good machinability
5. ability to withstand shock and impact loads
The desirable properties for a shaft and axle material are
The shaft consists of a number of shafts which are connected in axial direction by means of couplings called as
Consider the following statements regarding keys:
1. Key is used to connect the transmission shaft to rotating machine elements.
2. Key is used to connect the transmission shaft to reciprocating machine elements.
3. The primary function of the key is to transmit the torque from the shaft to the hub of the mating element and vice versa.
4. The keyway on the shaft results in better stress distribution.
Which of the above statements are valid?
The key way results in stress concentration in the shaft and the part becomes weak.