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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Clamped vs. free beam modal analysis
Registered Member I should mention that the motivation for viewing modeshapes as a sum of traveling waves is simply to understand the resonant frequencies as was first mentioned by Amar. If we look at the pinned/pinned case, we can see that the wave travels twice the length of the beam in one cycle. We conclude that the resonant frequency is F = c / (2*L) where c is the speed of the wave in the beam, which is a constant (characteristic of the beam material and cross section). If we look at the pseudo... [ more ]
Registered Member Thanks Walt. The pinned/pinned diagram shows a decomposition of a standing wave ("Total") into the sum of a forward-travelling wave and backward travelling wave. The total (purple curve) does in fact have 0 displacement at each boundary as required by the pinned/pinned boundary condition. The forward and reverse travelling waves at each boundary have non-zero magnitude of equal magnitude and opposite sign (which of course sums to 0). This corresponds to a reflection with inversion at the... [ more ]
Registered Member El'Pete, Why does the Pinned/Pinned modes (above 1st mode) have displacements at the beam ends if they are pinned and restricted from motion? I am very impressed with your animation! Walt [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
dampening pump skids to reduce resonation
Registered Member What is the vibration frequency of the vertical motion on the I-beam skid? Does it make the speed of the pump shown or something else that shares the skid? Is there a lot of pipe motion as well? Did you inspect all pipe supports and hangers? A 2-step approach could be considered: 1) Epoxy grout under I-beams (possibly raising about 1/2" or more to get suitable grout thickness along with epoxy-set anchor bolts. 2) Cement non-shrink or epoxy (preferred) grout to fill entire I-beam skid frame. [ more ]
Registered Member That's the ultimate fix which we discussed for all the pump sets originally with the client in regards to their loss of motors and pumps. It is a history of mechanical repair including alignment, sanding down diameters of shafts for interference fit instead of heating coupling bushing in oil bath [ more ]
Registered Member Considering the obvious (at least to me) problem the movie shows, I am not at all surprised of the history. This could be a classic case history of fixing the root-cause problem to solve all the issues noted. Time will tell Please keep this forum informed of what you find as you go forward. Regards Jim P [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
ODS Software alternative
Registered Member What is the price of Clearmotion software? Walt [ more ]
Registered Member Also clearmotionsystems has ODS software, it free 30 day trial. http://www.clearmotionsystems.com/index.php I tried it, it's good. [ more ]
Registered Member There are two more very easy softwares for ODS witre model animation (operation deflection shapes). I hope I am right, there is a possibility to enter for each corner point and measurement direction an amplitude and phase angle (for one speed per model). Both mentioned softwares are hardware dongle protected. - Vibshape software VMI company http://www.vmiab.com/products/software/vibshape/ - PTK software from Adash company. On English page they call it Animated Deflection Shapes software ... [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Motor & Gearbox Phase/Amp readings for ODS
Registered Member Sorry for disappearance. I am back from surgery. I'll get an animation done as soon as I can. [ more ]
Registered Member Dave, Thanks for the info. I have just send him a message. [ more ]
Registered Member Just an FYI, Dan Ambre of Full Spectrum Diagnostics would be able to solve this issue or assist you in finding the problem. They too are located in MN... Dave [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Kiavash's Animation
Registered Member Hi, Thanks dear Jon, I will attend your comment, Thank you for bubble chart. [ more ]
Registered Member Hi Kiavash, Please verify your accelerometer orientation. When I did the preceeding animation, I assumed some of your readings were taken with the acceleromter normal to the surface. This will change some of the phase readings 180. An easy way to document this is to place arrows showing the normal directions. If the accelerometer is placed opposite to your established norm, the phase reading should be corrected. If the reading is more than 180°, subtract 180°. If the reading is less than... [ more ]
Registered Member Dear Jon McFadden, Please Simulate this data, This is more complete, Tell your analysis please [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Recommended Transducer & Mounting
Registered Member Hi Walt, I normally use a single accelerometer, but there are times when you can't get a reading without adding another surface. I use my "cube" on long rails where I am taking an axial reading and there isn't a surface to collect the data from. Before I modified the "cube", I would omit the data in that axis. [ more ]
Registered Member I assume that adding a triaxial base with 3-magnets to a triazial accelerometer is an attempt to keep the accelerometer orientation consistent with the structure's coordinates for any/all measurement points. While I assume that this configuration can or has worked for some situations, I do not like it for the following reasons: 1) May be too heavy for some structures 2) May affect frequency response for tests at higher frequencies 3) It may not accomodate mounting on all measurement surfaces... [ more ]
Registered Member We have the 3143D1 permanently installed on a number of motors. The selection of that transducer was before my time here. At this time, we are just trying to stay consistent. It's much easier to get an accelerometer from our stock than trying to get a purchase requisition fulfilled. The 3063B is a bigger (twice the size) of the 3143D1. Steve [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
ME Scope M# Links
Registered Member Hey Jim, Yes... they matched. I have actually modeled this installation in another ODS software (Clear Motion) before and now that I have an ME Scope license I only modeled a portion of the installation so I actually have more data than I need. By importing that extra data which didn't match any points, it created the error message. Was a good learning experience. ME Scope software is so powerful.... amazing tool to have. Glad I have a license now. Thanks and have a good weekend, KB [ more ]
Registered Member Good to hear. I've done that myself. I try to learn by my mistakes and, if that were true 100% of the time, I would be really "smahht" by now BTW - Did the points/M#'s in question start with where the error code began? J [ more ]
Registered Member So I found out that this actually wasn't an error, and it wasn't killing my animations. I was bringing in data in the data block that was not assigned to a point.... this created the error message. When I ran my interpolation calculations for each substructure, everything worked out fine. Animations looks great now. Thanks, KB [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Nodes and Anti-nodes
Registered Member you want to place a brace at an antinode. determining which bending mode will come down to the frequency at which the component is vibrating. If you have determined there is 3 bending modes on a pump discharge pipe. Say the first is at 1700cpm, the second occurs at 2250cpm and the third at 3890cpm. The motor driving the pump is on a VFD and has an operating range from 1500 to 1785RPM. Measured vibration on the pipe is highest when machine shaft speed approaches 1700RPM. In this case the 1st... [ more ]
Registered Member Changing stiffness, mass, or damping at a node point would not significantly affect natural frequencies or vibration levels at that point or other parts of the structure. Walt [ more ]
Registered Member The word "node" is a corruption of "no displacement". So there is no movement at a node. Therefore there is not going to be a benefit to making a change (other than perhaps a mass change) to a node. Best regards, Tom Murphy [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
SKF Machine ODS
Registered Member My understanding is that MEScope will run on most box's. Which is good. [ more ]
Registered Member Hi Aubrey, The SKF Machine ODS software is actually MESCope V4.XX with specific drivers for the older CMVA series of data collectors. The software is now running at V5.XX and the drivers have been removed. However the CMXA series of data collectors (Microlog GX and AX) run a specific module for Modal and ODS readings and the data is directly imported into V5. In addition to this if you have a Microlog AX with the recorder module you can not only do ODS measurements in the frequency domain... [ more ]
Registered Member Thanks Dave, That is the direction I hope we go. Aubrey [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
ME'scope and Solidworks
Registered Member I had an epiphany! I can realign the complete imported structure to conform to the Z axis being vertical simply by using the "X" and "Z" spin boxes. By doing this, I don’t have to re-orient vibrant’s supplied sub-structures and I can continue to use the axis orientation I am used to using. Let the dog wag the tail. Another hint for more accurate graphics is to use polygons to create round objects. They are imported more accurately than round objects. By using an even number of faces, you can... [ more ]
Registered Member I have several machines with common problems. Instead of creating a Structure file for each, I add the structure to the same folder as the other sub-structures supplied by Vibrant. This way you can multiply the time savings for individual parts that can be reused. Another trick that is simple to do is to zero the entire structure vertically and horizontally. This is done by: 1. going to the points view of the machine and selecting the point that you would like to zero the machine on. 2. [ more ]
Registered Member .STL type files can be imported from Solidworks into ME’scope. Only the triangular surfaces and points are imported. Lines are not. All the surfaces are imported with their color black. This can be changed to a more useful color by selecting "Surface Triangles", double clicking on the spreadsheet column heading "color" and clicking on the color you would like. In Solidworks, use the command “File/Save As”, “As file type”, STL. In the dialog box, click the options button and change the... [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
coherence measurement
Registered Member thanks dear dave for useful information [ more ]
Registered Member http://www.calpoly.edu/~cbirds...ng%20%20Analysis.pdf Top of page 11 Think of it this way, you are comparing two signals and you want to know if the frequency on sensor A is the same as sensor B. IF the frequency is the same coming into both sensors then there should be a coherence value of .95-1.0.....IF the frequency is not the same then coherence could be from .6 to 0..... An indication of a natural frequency in an FRF plot would be a peak present at a given frequency, and at that... [ more ]
Registered Member Sure, you can do a transfer function of slid (did you mean skid?) compared to pump housing. Coherence is a measure of causality between input and output. Let's say you measure the COH = ~1 between the ?skid? and pump. In this case, the relationship between the two are the same but not sure what useful information that gives me or whether it helps me figure out the problem. As Gary stated, it is used primarily in impact/modal testing to provide confidence in the cause/effect (e.g. impact to... [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
New ODS animation movie of a Ball Mill
Registered Member hi tony, i am using me scope ves software for ods. how large structures are built in structure .. i am unable to find full fledges tools for creating the models.. is there any other software so that we can build structures there and import to me scope...please help [ more ]
Registered Member Hi Tony: That rotating ball mill is a thing of beauty! How do you animate the rotating cylinder? Is the movement on the left rotating ring interpolated? [ more ]
Registered Member Josh, I did not see your question until now. I did not find anything unusual with the ball mill ODS. I was looking for loose bolted joints and fractures at concrete pour joints. I have reposted the movie. The movie in my original post was corrupted and did not play completely. Also included in the zip file is another ODS of a different ball mill that had a concrete fracture as well as loose or stretched bolts below the pinion bearing. Call if I can help. [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Where I can learn the ODS
Registered Member ODS is more involved than reading a tutorial. If you purchased MeScope through Emerson, it should have come with training. Contact Tony Dematteo with 4X Diagnostics. [ more ]
Registered Member http://maintenanceforums.com/e...004131/m/64420271663 [ more ]
Registered Member http://www.vibetech.com/go.cfm.../content/training/x? [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Point labels not showing up in ME'Scope
Registered Member Hi Alok, I was hoping someone with a 2130 would answer your questions. I use a CSI 2120-2 data collector. I use the Advanced 2-Channel DLP to do the data collection. The 2120-2 can't store cross phase data without the DLP. I have a PCB modal hammer. Vibrant Tech's ME'scope-VES is the animation software I use. I would assume the 2130 would require it's version of the Advanced 2-channel DLP in order to store the cross phase data. Someone with a 2130 can answer your question with better... [ more ]
Registered Member THE ODS/MODAL Analysis seems to be useful in old Steel Plant where equipments are in deformed condition due to various types of catastrophic failures of equipment. We have CSI-2130 data collector. It has softwares of it. Please advise whether I should go for upgrading the 2130. Please give idea about seperate machine to be purchased or 2130 will be useful. [ more ]
Registered Member Hi Steve, Did you get the label problem figured out? Can you post the video with the <animate><contours><fill> and <values> turned "ON"? I am curious about the amplitude of the possible mode shape. [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
soft bearing balancing machine
Registered Member Soft Bearing Balancing Machines 1.PRQ Series soft bearing balancing machines are specially designed for high precision dynamic balancing test of micro-motor rotors 2.The system adopts DC variable speed drive device,realize stepless speed regulation 3.Bracket system uses soft bearing structure,high sensitive sensor,which achieve higher measurement accuracy. 4.Equip with advanced measuring system.Friendly man-machine interface,easy operation.It's highly praised by majority of end-users... [ more ]
Registered Member Think in turbochargers of cars engines a truck engines. [ more ]
Registered Member Hi Chiappero, Could you give me some understanding on the machine, eg. turbocharger:Size n capacity need to be addressed?Design is one thing but getting to get it work is most essential.Please include some of your previous turbocharger pictures as an example. [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Vertical Pump - Modal Analysis
Registered Member I have done this type of testing on large vertical pumps, but not with ME-Scope. Water inside and outside the pump column adds mass. A rule-of-thumb is to use twice the volume of water inside with same sump level to account for the mass of water outside the column. There can also be a difference in natural frequencies with the impeller support conditions between wet and dry. Pray that the stop logs hold back the water when you are standing knee deep in water, muscles, and gunk while... [ more ]
Registered Member Hi Jim, Thanks for looking at this and replying. I will most certainly look into the mass of water/ME' Scope issue. I am curious about this as well. The guy we've hired to do this testing is one of the best at Modal/ODS that I know of and has years and years of experience so I am the results we will get are as accurate as possible. Like you said, we will be using a combination of coast down testing, ODS, and Modal data to try to narrow down where those frequencies are and how much they shift... [ more ]
Registered Member If I'm not mistaken, Vibrant Technologies has a version of MeScope that allows the user to input variables (e.g. mass of water) and make assessments of what you are looking for. You might want to contact them directly. For the modal test, are you impacting above ground and obtaining response data from the support column below ground? I've not done that but would be very curious how well the data comes out. So when the ODS is performed (now there is the added mass of the water in the wetted... [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Mescope newbie
Registered Member Thanks for that Dave, I have read a bit further on and can see how this relates. [ more ]
Registered Member Yes, HVA or XYZ at each measurement location. While standing at the back of the machine, looking toward the machine, the right hand side is positive and the left hand side is negative, depending on how you mount your sensor. So if you collect Z and the sensor is pointing away from you call it positive Z, while standing in the same location and the sensor is pointing toward you then it is a negative Z. Dave [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Impact test on Base plate
Registered Member Hi Nicolas, I like Jim's post here with regard to your question - in particular 400 lines of resolution being applied - definitely more than enough resolution and huge time saving. For baseplates and larger surfaces I have use a small fractional hp variable rpm d/c motor. I have a fly-wheel type rotor fitted to the shaft with a known amount of unbalance weight to create vibration. I place the motor in position - secure it and begin tuning (via attached rheostat controller) through different... [ more ]
Registered Member regarding the impact test, spend some time bumping the machine in different locations while moving the accel. Watch the response in all three axis and eventually you will be able to determine a good driving point for the entire test. Once you find the driving point that excites all your measurement points in each planer you can use that for the fixed location. I usually use 400 lines for a 200hz fmax. that gives you frequency resolution of 30 lines which is more than adequate resolution and... [ more ]
Registered Member Reciprocity is a true property. After all we measure magnitudes ratio and relative phase. I prefer to use roving accelerometer for the following reason: one wants to make sure that he is NOT impacting a node prior to the test. Once you have verified that it is not the case and you ARE in fact inparting energy, you can proceed with the test. Fixed impact location also is convenient to ensure that direction of impact has components in all 3 axes. [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
DO or DON't you use Operational Deflection Shape Testing?
Registered Member We currently do not do ODS, But we are actually getting ME'Scope installed and are soon going to be tapping into the power of that tool. Hope to be able to contribute to this part of the forums soon. [ more ]
Registered Member After rereading this post, maybe I should use the term "advanced" technique ie. the extension of phase analysis. [ more ]
Registered Member Hi Josh, if you are using "relative" in a geological term, then perhaps yes. I have read documents dating back 50 years using this technique. I first put my hands on software for this in 1988 - then using an HP300 series computer with an IEEE interface to a spectrum analyser. The hardware took a leap forward about 4 years later and the only real changes since then seem to be just at the edges. It is an extremely useful tool and I have helped baffled engineers solve many problems with it. Tom [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Examples
Registered Member Walt - I agree with your concern and will attempt to recollect the data and pay close attention to sensor orientation. In regards to using a tri-axial as described in the other thread, I'm having a hard time seeing how to get data in 3 directions at some measurement points. How do you do it with a single axis transducer? Another question: We are coming out of an outage, and the sister pump is now in service. Is it worthwhile to collect modal data with the other pump in service? My only other... [ more ]
Registered Member Hi Steve, I would like to discuss this privately using an e-mail if you're willing. Your animation shows horizontal radial being in the "Y" direction. Your Vertical is the "Z" direction. Your Axial is in the "X" direction. This is why I have been asking for you to look in the "Y" axis data. I don't know if you reviewed this thread, but here is a tidbit I learned the hard way: Accelerometer Orientation [ more ]
Registered Member Steve, I question the polarity (phase) of your measurement points on motor. It shows the motor case to be distorting, and I doudt this is occuring. Points 59 & 60 horizontal motion should be outward when base points 73 & 74 vertical motion is upward. We discussed triaxial accelerometer mounting issues in the previously mentioned Link. It is difficult to keep the accelerometer axis (data channels) and their polarity properly matched to the structures coordinate system (+X, +Y, +Z). I... [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
How can we use Poor man ODS with CSI2115 single channel analyzer
Registered Member CsI 2115 can collect Phase data , i have not used but we have the option Phase analysis in our instrument . could you please explain the procedure step by step . [ more ]
Registered Member My understanding is that the CSI-2115 analyzer can measure shaft speed and phase. Here is a link to an old paper describing the 2115 for balancing: http://www.osti.gov/scitech/biblio/552750/ Kishore, if the vibration frequency of interest is at 1x shaft speed, then you can do ODS test with 2115 by measuring shaft speed (tachometer connected to BNC on analyzer) and vibration amplitude filtered at 1x shaft speed. I use Excel Scatter Plot to make scaled X-Y plots of vibration amplitude and... [ more ]
Registered Member If I recall correctly, the 2115 will not collect phase data, just velocity and peakvue. You need to have an analyzer that has the ability to collect phase data with a strobe/photo cell/laser/2nd channel as the trigger Dave [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
structure health monitoring
Registered Member Structural Health Monitoring is monitoring a structure (like a bridge, building or dam} for changes that may indicate damage or degradation of that structure. While the structure is static, it is subjected to dynamic forces; wind will blow over the bridge or against the building, waves will hit the dam or oil platform, cars will also drive across bridges. These dynamic forces will excite vibrations in the structure. The forces excite modes of vibration in the structure and Structural Health... [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Starting ODS and Modal Analysis for 3rd party
Registered Member Software for ODS called Me'Scope But if you have CSI 2130 you also need ODS DLP and special option for AMS MHM called Advanced Vibration Analysis Software (included in MHM Platinum). There was package included all parts called "Master Vibration Expert Package for A2130". Accels and Modal Hammers need to be choosen according objects to get Shapes of. Regards, Kos [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
CSI 2140 TRIAX SETUP - ODS
Registered Member Just an update, I solved my issue, you have to use the correct two channel splitter for that port I.E the gray and black one, the other one will not work. [ more ]
Registered Member I am a little confused on this as well, I have the triax set up an channels a,b,c and a accelerometer via the two channel splitter cable set up on D, but when I go to take a measurement it says on of the transducers is not connected, any ideas? [ more ]
Registered Member Well, I not did it by myself, but yes connect it using the "C - D" Splitter and other Turck. Konstantin [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
vibxpert and ODS
Registered Member I have been using the Vibxpert to complete ODS and Modal projects in MEscope for a few years. I have used this on mostly pumps and motors and their supporting structure. Some of the larger project required several hundred measurement points. I have used the current line drive accelerometers that come with the VXP and aftermarket ICP accelerometers receiving good results with both. Since the device is only 2 channels it takes a while to complete data collection. X Y and Z has to be recorded... [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Doesn't hurt to ask
Registered Member Jim, No, I don't think anyone stole it. I was just hoping someone found it and then asked someone they knew that was into Modal/ODS what the heck it was for. I know I will find it in the last place I look! [ more ]
Registered Member You don't think someone on this forum took it do you? Come on people, fess up A while back I couldn't find my MeScope key either for a few hours till I found it where I last put it. Funny how that happens. I then attached a tel # tag on the end with a note of an reward for return. Lets hope I never have to rely on it... Jim P [ more ]
Registered Member Danny, I took such good care of that of that key. I kept it in the same pouch in my computer bag as my passport. Loaded up a new computer one day with the software and went to get the key....no can find. I am awaiting my next ODS/Modal job and then it will cost the customer approx. $2300.00 more. [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
ODS with triaxial sensor
Registered Member Thanks for your help.Aubrey [ more ]
Registered Member I think I understand what you are talking about now. I have a very limited experience with ODS but here is my $.02. As you are saying, setup a either a tachometer, if you want to animate at machine speed or a whole multiple, or a reference accelerometer. If you are using the reference accelerometer. set it on a point that gives you the best signal of that frequency. Sometimes the greatest amplitude is not the best if the signal comes and goes. I was once taking a readings on a screw conveyor... [ more ]
Registered Member Thanks Aubrey. I do not understand it. What I want to know how to make a ODS with atriaxial accelerometer, a uniaxial accelerometer and a four-channel analyzer. And how to select an appropriate reference. Thanks [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
ODS SIMULATOR
Registered Member The MeScope software from Vibrant Technology will allow you to create a "Shape Table" and then type in your phase and amplitude that you have collected with your analyzer. [ more ]
Registered Member Bubble charts are a way to go. Before getting a good animation program, this was the tool I used. In order to use the 2120 or 2130 to collect the phase data, a DLP will have to be purchased. Otherwise, you will have to manually record the data. On the thread Aubrey references, Tony gives good advice. [ more ]
Registered Member Here is a link to a "Poor Man's ODS" thread here on the site: Poor Man's ODS Aubrey [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Paper machine calender stack ODS.
Registered Member Sorry for the delay, again, Mike. The phase relationship between the transducers is averaged and the result should be pretty accurate and taken care of automatically. No effort on your part. The amplitudes are individual and each is averaged. The only thing you need to worry about is the position of the roving transducer. You must keep it in the same relationship. If you can't, then you must tell the software. On my advanced two channel software, this is done by placing a minus sign in front... [ more ]
Registered Member Thanks again Jon. I am still struggling a little with this, forgive me if my questions are a bit basic. This ODS is still relatively new to me. Do you have to trim the data you import as a data block so it all starts with the same phase relationship to the fixed transducer, or does the software do that automatically? For example concidering a single freq, Say your data block waveform for point 1 starts at the waveform peak, and for point 2 it starts in the trough, even though these are in... [ more ]
Registered Member Successful ODS and Modal analysis data collections are done with 2 channel analyzers. The best way to collect the data is using a fixed and a roving transducer. The data you are collecting is repeatable, not transient, so the phase relationship should be close enough that simultaneous data collection isn’t necessary from roving location to roving location. Since the readings are averaged, transient data disappears. Make a drawing with a small enough grid to capture mode shapes in the... [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Turbo Generator set ODS
Registered Member Hi Planty, Sorry for the delay. I've been off for several days. The structure file wasn't that important. It was just support for the animation I posted. You should be able to easily recreate it using your select tools. As you may have already discovered, Me'scope is based on the points. To make sub-groups, you "display/points", use the alt key and left key to select the points in a particular part of the machine. Use your "ctrl" key to select individual points you can't get using the "alt"... [ more ]
Registered Member Thank Jon, The structure file wont open in my version of ME scope ( V 2.0.0.24) Neither would it open in word or excel. Maybe the newer programs have more import file formats? Can you please send as a standard tab delimited file, if possible. If I group the structure into components does that prevent interpolation of non connected components. This has been something I have had to manually fix in some models. Points seem to be interpolated to measured points depending on how close they are... [ more ]
Registered Member Here is the modified structure file [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
ODS Model Measurement Points
Registered Member Thanks Aubrey, I have noticed that he has many posts on these forums. Glen [ more ]
Registered Member It may get an answer quicker if you sent an email straight to one of the "go to" guys on the board. If they are not too swamped they will answer you back with a great answer. Tony Dematteo, tony.dematteo@4Xdiagnostics.com" has helped me out on a couple of occasions. Aubrey [ more ]
Registered Member Thanks for the starting tips Tom. The project on the fans which was given to me has never been attempted here before (Me'Scope was purchased for it) and issues with IT has left little time for completion before my placement terminates so I need all the help I can get. I have access to our vibration data so will be able to find the dominant frequencies. At the moment I think they are around 22Hz (From mills) and running speed of about 25Hz. I will be using a triax and speedvue for phase. How... [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
ODS Software
Registered Member could you please expalain the procedure and analysis by using MS excel ODS ,Do need full. Thanks in advance . [ more ]
Registered Member Thak you very much. Kind regards [ more ]
Registered Member I use MS Excel to plot mode shapes. It is not for animation or for 3D, but it it works well for basic machine structures. If you already have Excel, then it is "free"! Walt [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
ODS & Modal Animation Examples posted
Registered Member Tony, your name is too long. Pls shorten it to avoid scrolling too many times when reading long posts. [ more ]
Registered Member Hello VRG ODS testing is able to identify a wide variety of mechanical faults and resonance issues such as looseness, soft foot, broken welds, misalignment, unbalance, bending resonance modes, torsional resonance modes, structural weakness and foundation problems. The ODS doesn’t care if the machine problem is non-linear like a broken weld or loose bolt. ODS shows everything that is happening on the machine. The ODS animation will show the antinode lines in the animation when you turn on the... [ more ]
Registered Member Dear Tony The ODS animations are really good. I am not an expert on ODS or Modal analysis. I always wonder that how, ODS, which I believe ( pl correct me if wrong ), only shows how a machine is moving ( dancing ) help a customer to solve structural problems. It does not give me nodes / antinodes which are required to decide where to stiffen and where not. MEscope has some advanced softwares which also gives solution as to where and howmuch stiffening is required to solve problem. What I want... [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Blower Data
Registered Member Thanks, Tony. Here is a picture of the machine xRacer is concerned about. [ more ]
Registered Member I agree that it may be a weak frame. Anytime a structure looks bent or twisted in ODS animation the problem is either weakness or resonance. One way to tell for sure is to test for resonance (measure phase and magnitude during run-up or coast-down, negative averaging, peak hold bump test single channel or dual channel impact testing). Another way to tell if the ODS animation indicates resonance vs. weakness is to look at the animation of another frequency (if available in the test data). If... [ more ]
Registered Member I would check your blower pulley for eccentricity and runout. The frame is weak because there is no corner bracing. This may be the reason for the possible misalignment of the pulleys. Check the frame for a resonance in the "Y" direction (note the possible mode shape through 1,2,3,4,5) and the blower support around 26 and 27 in the vertical "Z" direction with bump tests. [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
ODS DATA - TURBINE/GENERATOR SHAFTS
Registered Member Hi Tony, Thanks for taking time to get me up to speed on ME'Scope utilizing Bently Nevada prox probes. This opens up a whole new world for me. It's amazing to view the orbits through the frequency ranges. I am just experimenting on my BN rotor kit - Looking forward to getting out in the field and doing some actual turbine/generator shafts. Again, Thanks and Happy New Year! - Mike (Data Dog) [ more ]
Registered Member Hello Data Dog In ME'scope... Create your shaft. It can be a line connecting two points or a cylinder. Either way, keep the coordinates RECTANGULAR. By default, "Z" will be vertical and "X" or "Y" will be horizontal (depending on your view of the shaft). You can change the software to make "X" or Y" vertical if you wist. I wouldn't bother. Assign the data from one of the two prox probes on a bearing to the "Z" and the other prox data to "X" or "Y". If the probes are 45 degrees from vertical,... [ more ]
Registered Member Steve, Thanks for the feedback. Tony, Your turbine/generator shaft(s)ODS is exactly what I am trying to duplicate. In the ME'Scope Software - Measurement Axes (Rectangle, Cylindrical , Spherical, Machine -??). Also, how do you set up the 90 degree (45 Left - 45 Right) to include polarity? I am having difficulty in getting the orbital pattern. Thanks for sharing your animation - nice job. -Mike [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Hoffman Type Blower Problem
Registered Member Hi John, In this case, I used the same values for the feet, instead of getting discrete readings for each of the 4 corners. To clarify, the front left foot used the reading for #5, the rear left foot used reading #6, the right rear used the reading for #7 and the right front foot used the reading for #8. That is why there is no distortion to any of the motor feet. Access to all four corners of each foot was not possible. If the feet were moving out of sync with the base, I would be checking... [ more ]
Registered Member Hi Joh, I notice you have a constraints problem with the motor feet and the plate they attach to. (The feet rise above and fall below the plate.) I have been using a B&K system and having put in the constraint equations for a similar situation, is does not apply them. I'm wondering if I have to "Group" the feet and the plate before they work ? Any thoughts ? Cheers John Morey [ more ]
Registered Member Hi Ron, Yes, the support is sheet metal formed into a "U". The bends are not quite 90˚, however. The static view shows the correct angle since this is important. Can another possible problem be seen in the animation? [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
using a vb8 for ODS
Registered Member Thanks I did end up using a shape table because my cross channel spectrum for ODS is not enabled in my vb7 and it is an older instrument with out a USB port for down loading UFF data. Worked very well, just had to input data manually regards Gary [ more ]
Registered Member Hi Gary, I might have misread your question, but there is an option for 'cross spectrum' in ME'Scope trace window. If you want to import ODS phase and magnitude data that you collected at a single frequency you can do that in a shape table instead of a trace. Hope this helps! Gerard [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Newbie ODS/Modal. Any tips?
Registered Member Hello Old Friend- I too would suggest Tony. He's excellent. Also, there is another guy that I know that may be able to help. 1) You can email me - Keith F. has my email address. 2) You can come to the Vib Inst meeting this Thursday (4-26-12) and I will introduce you to the guy I know. 3) You can hire me to come and train your group on ME'scope and how to use it. Drop me an email sometime - we can catch up. Jeremy Cole [ more ]
Registered Member Hopefully we can breath some life back into this topic area of the forums. I am looking forward to expanding into this more specialized area of vibration work. Thanks again for everyones perspectives and suggestions. [ more ]
Registered Member Torptorp, As is true with most everything else, you can read the user's manual and make the technology physically work. However, it doesn't necessarily make you good at what you do. I agree with the training upfront to establish good practices. I would also recommend continuing to discuss methodology and findings either on this board, with carefully chosen "mentors" or both. I've seen my share of poor ODS and Modal projects (whether it was poor planning or a complete lack of understanding of... [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Accelerometer setup
Registered Member Hi Kiai, Yes, you can use different sensor sensitivitys. In your sensor setup, you select the parameters for whatever individual sensors you are using. What units you use depends on the frequency of concern. I normally use displacement since I am moslty concerned about low frequency problems. [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
ODS data
Registered Member Hi Jon Thanks for the info. [ more ]
Registered Member Depends on what method you use to collect the Phase/Amplitude data you are animating. You will be looking at a single frequency, but if you have collected a spectrum of data, you can move the frequency you are looking at. If you manually imput a single phase/amplitude at a specific frequency, then that's all you can animate. [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Mass and stiffness from compliance plots
Registered Member Both Dan Ambre and Tony DeMatteo have demonstrated what you are asking about. Send an e-mail to Tony for a duplicate application he provides in his class. Dan had an article published in Uptime Magazine, Nov/Dec 2008 that covered his diagnosis of a vertical pump issue. Link to some of Dan's information [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Motor Resonance Revisited
Registered Member Backside Quad View with contours. [ more ]
Registered Member Here is the backside view with contours. [ more ]
Registered Member Hi Steve, There is a bolt head between the feet of the fan support. Is this what holds the base to the main structure? The main movement looks like it is on the other side of the base and looks like a second mode shape. Turning on the "animate/contours/fill" would show where the maximum movement was taking place and turning on "animate/contours/values" would quantify the movements. Also, rotating the 3d view to the other side would give a better view of the problem area. Here is my... [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
ODS WITH SINGLE CHANNEL ANALYSER
Registered Member This is specific to CSI, but you can use the Model 444C Strobe instead of the photo tach to set the frequency you want to compare. This way you don't have to stop the machine to put reflective tape on. Using the Strobe allows you to set the frequency to other than harmonics of 1xSS. [ more ]
Registered Member IRD's E-shape also allows you to tell it how many shapes you want to display. It takes a while to get all the data. Dave [ more ]
Registered Member CSI equipment will allow you to monitor the phase of different orders of turning speed with a single piece of photo cell tape in the monitor peak verses phase function. It allows you to input the order of turning speed you are interested in. [ more ]
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Asset Condition ManagementPosts About Modal Analysis and Operation Deflection Shape (ODS)
Why this thread is needed?
Registered Member Excellent replies guys. We have used modal analysis several times to identify problems with large fans. It really helps people understand how a total system comes together to make a reliable asset. [ more ]
Registered Member There are methods of determining resonance that could be discussed. Examples: Impact testing Modal hammers Problems with balancing Programs used to animate ODS and Modal data like ME-Scope [ more ]
Registered Member Josh, The answer is yes and yes. Modal analysis can be used as follows: 1) in the design phase to verify analytical model 2) in the manufacture phase to verify or prove there are no resonant structure problems or interval faults (cracks or voids) 3) in the installation phase to verify structural response or to diagnose high vibrations 4) to assist in diagnosis and correction of high vibrations found by Simple survey. Modal analysis and the related Structure test methods are essential for... [ more ]
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