Official Answer
Answer
While often used interchangeably, they are distinct. Relaxation is the reduction in load $P$ over time while the spring is held at a constant deflection $f$. Creep is the increase in deflection $f$ over time while the spring is held at a constant load $P$. In most wave spring applications (e.g., preloading a bearing), the spring is held at a constant height, so relaxation is the primary concern. The rate of relaxation follows the Arrhenius equation: $Rate = A \cdot e^{-Q/RT}$. In critical aerospace applications, we must derate the initial load by 5-10% to account for the expected relaxation over the component's service life, especially if operating near the material's thermal limit.
