I am simulating a vibrating device that is supported by springs.
The device is first installed on the springs and the static load of the device's weight is supported by the springs. A linear static load step gives me the stresses throughout the device as a result of the static loading.
When the device operates, an unbalanced mass rotates and produces a sinusoidal force that causes the device to bounce around (this is deliberate). I've modeled this as a quasi-static load step with inertia relief. This gives me the stresses throughout the device as a result of the accelerations during operating.
How can I combine the results from both load steps so that I can get the total stresses throughout the device during operation? I don't want to neglect the static stresses that are present before the device starts vibrating.