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This page is maintained by Ryan Simmons, at Ryan.Simmons@nasa.gov.This page was last updated on December 18, 1995.
It is of interest to know the level of force impacting the entire instrument through the spacecraft due to vibrational input. In the case of MOLA, the force would come from the spacecraft, through the three feet, and on into th entire insturment. Knowing this force will tell us if we have reached or are close to our design limit loads. Then, during testing, we will know what input level not to exceed.
These responses are recovered at the model's shaker point. From the charts, lbrms (pounds rms) values can be determined. These values show whether the forces being applied to the instrument from random vibration could be high. Force response recoveries are used to determine at what frequencies high loading will occur so that the test levels can be lowered (notched) at those frequencies. The rms values are given with each chart.
A relatively new procedure called Force Limiting is now being used by NASA and industry. Force limiting actively lowers the random input levels during testing when the response force reaches a certain upper limit. All this is done in real time as the test is occuring.
Back to the MOLA Random Vibration Page. Back to the MOLA Mechanical Analysis Home Page
This page is maintained by Ryan Simmons, at Ryan.Simmons@nasa.gov.