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Recent content by bjpil

  1. bjpil

    Best vibration+noise FEA

    PLBM, Not sure how well NEiNastan works with Sysnoise but I assume it is the same as MSCNastran. All you need is to export out a punch file or an op2. The question I would ask is how good is NEiNastran's dynamic solver? I know MSCNastran is very good up to a certain frequency. I have more...
  2. bjpil

    Best vibration+noise FEA

    For what it’s worth, I use MSC/Nastran for the vibration analysis and then import the results into LMS Sysnoise for the noise analysis. Never have had an opportunity to correlate the results and I’ve only used it for metals. The two software work well together. BJP
  3. bjpil

    Convergence criterea for flow analysis

    Anyone have a good opinion on a convergence criteria for a flow analysis using FE. Thanks, BJP
  4. bjpil

    Verify plastic material through testing

    dwightdixon , Thanks for your input but as I have found over the years, many specifications are 1) over written, 2) may not include new material, 3) may lump too many applications into one large specification or 4) they may be poorly written which all may results in unnecessary cost increase to...
  5. bjpil

    Failure investigation question

    Metengr (and others), You are absolutly correct that these above statements are good and I appreciate everyones help on this. I personally could not believe that there was a technique using an acid and some dye to predict what the stress level is on the metal away from any fracture which this...
  6. bjpil

    Failure investigation question

    Hello All, I was talking to a metallurgist last night and he was trying to convince me that there is a process to determine the stress of a part after it has failed such as an airplane crash. He said that an acid and dyes are put on the specimen and then the specimen is examined through a...
  7. bjpil

    Thermal (radial) expansion of a ring

    Here is another analogy. If I fill a ballon with air at a certain temperature, volume, and pressure, i.e. PV=nRT. If I change the temperature and hold the pressure the same then volume must change. BJP
  8. bjpil

    Screw fatigue in bending.

    Just a thought, if you have access to a lab could you not test several your assembly on a shaker table at both a low cycle fatigue until failure and then at a high cycle fatigue. From this you could then create your own SN curve for the assembly using some statistical equations. BJP
  9. bjpil

    Verify plastic material through testing

    wow, thanks BJP
  10. bjpil

    Verify plastic material through testing

    Pat and RND2, Thanks for the help, you have both given me more to think about. The table RND2 provided kind of makes me question the Nylon that I was thinking of using. The injection molder quoted a "Wide spec 30 glass nylon 6/6", whatever that means. The injection molder also proposed...
  11. bjpil

    Verify plastic material through testing

    rnd2, Thanks for the interest. It is going to be a oil splash guard to help direct the oil. It will be held in place by four or five bolts. I have not figured out what temperatures it will see but I assume from -50 F at cold weather start up to about 250 F at max engine temperature. It is not...
  12. bjpil

    Verify plastic material through testing

    Pat, Thanks for the tips and your examples of nylon, it gives me more confidence that I am going down the right path. But since I have very little experience in plastics I need a better reference frame to help define the testing. When measuring for dimensional change I assume that using a...
  13. bjpil

    Verify plastic material through testing

    Hello, I need some advice on how to verify and spec out, through testing, a plastic part that will reside in an oil pan. What are some of the typical testing for something like this? I am currently just looking at testing a material and not the part. If it survives the initial testing then I...
  14. bjpil

    External aluminum thread

    Griffy, Thanks for your reply. Somebody beat me to the star. Your oil pan description is a very good example of the problem I think I may have if I go to this design. Do you know if this design is still used today so that I may check it out? Prototyping something like this could be very...
  15. bjpil

    External aluminum thread

    Cory, Thanks for your reply. You bring up a good point on galling. What I fear is that the part should have a service life of 10 years and in that time the filter will be replaced around 65 times. This is going to be a steel/aluminum mating condition. What I am worried about, probably...
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