ShankeNBake
Aerospace
- Jan 17, 2012
- 1
I am a new engineer (MSME) at my place of work, primarily doing vibration/shock testing. I have been assigned a project to investigate the cause(s) of a resonance in one of our vibration cells. The resonance occurs around 50 Hz, and only appears when our shaker is rolled over and providing horizontal input to our slip plate (not when operating in the vertical direction). The shaker is an Unholz-Dickie T1000, and the slip plate dimensions are approximately 36" x 44". Other than my undergrad vibrations coursework, my only experience in this field is what I've gained over the past 3-4 months of work here, so any help investigating this issue would be helpful.
Apparently this resonance has been around for awhile, and there is anecdotal testimony from the long-timers here that the resonance is coming from the slab, the trunnions, is internal to the shaker itself, etc depending on who you ask. Are any of these areas more likely culprits than the others? Any that can be ruled out offhand? My first thought it the shaker itself is not likely the culprit. It has been apart for maintenance multiple times over the years, with many parts replaced and inspected for unusual damage/wear. I would think some of this maintenance would have eliminated (or at least changed) the resonance if it were in fact being caused by something internal to the shaker.
Speculation aside, I will need to gather data to help determine the true cause. What techniques/tools might you suggest to evaluate the system and determine where this resonance is coming from? My first thought is to populate the shaker assembly itself with 16 accels (max channels our controller/recorder can handle) on various suspect areas, excite the resonance, and see what the data says (hopefully something stands out). I suspect however that there are more elegant techniques with which I am unfamiliar that might give more useful data.
As the new guy at my first 'real' career-path job, I'd really like to make an impression with the engineering and management staff here, and I think getting some solid answers to a problem that our lab has just been 'dealing with' with for a decade or more would go a long ways towards doing that. Any information, guidance, suggested reading, etc. etc. you guys can provide would be MUCH appreciated.
Apparently this resonance has been around for awhile, and there is anecdotal testimony from the long-timers here that the resonance is coming from the slab, the trunnions, is internal to the shaker itself, etc depending on who you ask. Are any of these areas more likely culprits than the others? Any that can be ruled out offhand? My first thought it the shaker itself is not likely the culprit. It has been apart for maintenance multiple times over the years, with many parts replaced and inspected for unusual damage/wear. I would think some of this maintenance would have eliminated (or at least changed) the resonance if it were in fact being caused by something internal to the shaker.
Speculation aside, I will need to gather data to help determine the true cause. What techniques/tools might you suggest to evaluate the system and determine where this resonance is coming from? My first thought is to populate the shaker assembly itself with 16 accels (max channels our controller/recorder can handle) on various suspect areas, excite the resonance, and see what the data says (hopefully something stands out). I suspect however that there are more elegant techniques with which I am unfamiliar that might give more useful data.
As the new guy at my first 'real' career-path job, I'd really like to make an impression with the engineering and management staff here, and I think getting some solid answers to a problem that our lab has just been 'dealing with' with for a decade or more would go a long ways towards doing that. Any information, guidance, suggested reading, etc. etc. you guys can provide would be MUCH appreciated.
