BrianC
Active member
The problem is as follows...
In a cyclic operation, an A313 stainless steel wire helical spring has an outside diameter of 0.5 inch and a wire diameter of 0.08 inch with 30 active coils. The critical frequency is most nearly...?
The MERM gives a straight fwd equation (eq. 52.19) for the fundamental frequency of a steel spring with fixed ends. Since the problem states that the spring is under cyclic loading, I assumed the ends were fixed to a surface. In addition, Shigley gives an equations for a spring with one end free.
Now...the 6MS problem was solved by the author with the basic equation f = (1/2pi)*(k/m)^0.5. Where m is the mass of the active portion of the spring.
The 6MS solution solved for f = 63 Hz, while the MERM equation gave f = 212 Hz. The equation given by Shigley for a spring with one end fixed and the other free gives approximately the same answer as the MERM equation. Can anyone explain the application of these different spring critical frequency equations?
In a cyclic operation, an A313 stainless steel wire helical spring has an outside diameter of 0.5 inch and a wire diameter of 0.08 inch with 30 active coils. The critical frequency is most nearly...?
The MERM gives a straight fwd equation (eq. 52.19) for the fundamental frequency of a steel spring with fixed ends. Since the problem states that the spring is under cyclic loading, I assumed the ends were fixed to a surface. In addition, Shigley gives an equations for a spring with one end free.
Now...the 6MS problem was solved by the author with the basic equation f = (1/2pi)*(k/m)^0.5. Where m is the mass of the active portion of the spring.
The 6MS solution solved for f = 63 Hz, while the MERM equation gave f = 212 Hz. The equation given by Shigley for a spring with one end fixed and the other free gives approximately the same answer as the MERM equation. Can anyone explain the application of these different spring critical frequency equations?