Ride Frequencies and Spring Rates

Problem 1: A monotube damper has a gas charge pressure of 400psig (2.758MPa) (Note: lpsi-6.895kPa). If the damper has a bore diameter of 40mm and a rod diameter of 10mm what would be the maximum compression damping force that could be safely expected of the damper? Assume the chamber above the piston would not want to get under Opsig.

Problem 2: The vehicle in Problem 3&4 of Homework 2 requires a rear coil spring design and is decided it needs a total travel of 5 inches at the wheel hub to safely traverse the road conditions it is expected to see. Using the 1.67:1 mechanical advantage design a coil spring that can fit within a design space that provides a maximum of 12cm diameter for clearance of the spring outside diameter. Using ¾ coil nest open-end construction what is free length and the-installed length at static load? Show your work. (Note: 4.448N-1lbf; 2.54cm-linch)

Problem 3: If the targeted critical damping ratio for the above suspension is determined to be 0.30, what is the target damping rate for the shock absorber that will be mounted coaxially with the spring?

Bonus Points(10): For Problem 1 - If more force is needed in compression damping what options could be used? Are there any compromises with the options?