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  1. BATman2

    Laser Welding of 304L Stainless Steel

    I have a supplier that is proposing to change a large spot welded structure to laser welded. Structural issues aside, does anyone have any experience with volumetric inspection of laser welds (excluding x-ray)? Any suggestions on how to go about that? The sample provided to me shows a very...
  2. BATman2

    SST Bolt Shear and Tension Values

    todd2ny, I presume you are using the common abbrev. for stainless. If so the attached document may help. Batman2http://files.engineering.com/getfile.aspx?folder=057e3cd7-b1e8-4c2e-b562-12a7da7ff33d&file=Stainless_Steel_fasteners.pdf
  3. BATman2

    Friction Coefficient when using rivets

    6060842, Huck fasteners (pin and collar and BOM types) apply significant tension to the assembly. In fact, the tension is designed into the fasteners. http://www.alcoa.com/fastening_systems/commercial/en/product_category.asp?cat_id=739 Yes, combined loading needs to be considered. Tension...
  4. BATman2

    Impact Pressure/Energy for indentation

    donsrno1, Consider using hardness testing formulas.. http://www.calce.umd.edu/general/Facilities/Hardness_ad_.htm Brinell Hardness Test Brinell hardness is determined by forcing a hard steel or carbide sphere of a specified diameter under a specified load into the surface of a material and...
  5. BATman2

    Impact Pressure/Energy for indentation

    donsrno1, I would conduct a simple small scale quasi-static test to start. Depending on the pressure distribution, amount, and the spacing of the "particles", gross deformation might also be of concern at 1mm of copper. To measure the depth of the indentation after test, I would apply dental...
  6. BATman2

    Torque Audit on Fasteners with Loctite

    Screwman, I fully agree with respect finding the actual torque. I'm basically looking a method to check for untighten nuts that have Loctite without damaging a properly installed joint. At this point, the supplier is experimenting as follows: 1) Measure torque required to break Loctite only...
  7. BATman2

    Simulating Bolts in Analysis

    6060842, I would stick with hand calculations for the fasteners and then testing if the joints/loading in question is complicated. There are many factors to consider that you may or may not capture in your model, it will only be as good as your assumptions. Unless you know all the details...
  8. BATman2

    Torque Audit on Fasteners with Loctite

    Dik, In process. Thanks, BATman2
  9. BATman2

    Torque Audit on Fasteners with Loctite

    I have a situation that requires a supplier to "check" if a large (60mm) nut has been "tightened". Ideally, I would like to confirm installation torque (400 N-m), or at least something very close to that. The nut has Loctite 243 applied and is in a very tight space. I am concerned that damage...
  10. BATman2

    Knockdown Factor For Cold Worked Material

    SparWeb, Good response!! If the damage is truly localized, could a flat doubler plate be used without excessive stiffness? If the double spans over the joint, it would also address the joint issue. I would be in favor of testing a mock up repair for static and fatgiue strength, assuming...
  11. BATman2

    Knockdown Factor For Cold Worked Material

    Alexeu, Not an aircraft type and there are details I like to know but.... 1) Assuming the skin hardenable material like 5000 series AL, I would say no, it has been locally hardened by the cold working. If its a heat treatable alloy, there should be no change. 2) No matter how flat you think...
  12. BATman2

    Fastener Torque vs Clamping Force

    Jilwoodward, EXACTLY right. You need to start somewhere considering the function of the joint, range of parameter, marigins etc. The torque-tension relationship is an estimate and must be treated as such when designing a joint. If clamp load it must be known, the only way is to test the...
  13. BATman2

    stainless bolt properties

    Yarsky, Start with the following link: http://mdmetric.com/fastindx/t28u.pdf I suggest you follow Metengr's comment regarding grade selection. Also, check the Industrial Fasteners Institute (IFI) manual Inch Fastener Standards There is a section on Corrosion medium vs. materials and plenty...
  14. BATman2

    Fastener Torque vs Clamping Force

    Diamondjim, While turn of nut would seem to be a better approach, it too has issues (what doesn't..) Take a look at the following discussion: http://www.eng-tips.com/viewthread.cfm?qid=87855&page=1 Thread 87855 If the stiffness of the joint is relatively low, turn of nut will not provide...
  15. BATman2

    Fastener Torque vs Clamping Force

    Diamondjim and RJeffery, I fully agree with your points except the twisting force, that too would be affected. This is a typical formula used to estimate torque. Obtaining a proper value on friction alone is diffcult, The only thing that counts is bolt stretch. If you must know the clamping...
  16. BATman2

    Fastener Torque vs Clamping Force

    Flamby, The obvious is now stated. Note that Swall is correct but did not offer guidance on the clamp load, no offense to Swall). If the wrong value is used the joint can loosen or bolt will fail. Selection of clamp load is often the biggest issue, not units. T (in-lbs) = K *Dia (in)*W...
  17. BATman2

    Fastener Torque vs Clamping Force

    AirRide04, Handbooks typically state: T = (K*D*W)/12 T=torque D= dia. W = Clamp load K=0.09 to 0.3 depending on factors affecting friction. 0.3 for non-plated fastener, 0.12 if anti-seize compound is used. Typcially W = 75% of proof load of fastener Batman2
  18. BATman2

    Verifying Engineering Analysis

    Badlam, EXCELLENT LINK. Thanks very much!!! Batman2
  19. BATman2

    Verifying Engineering Analysis

    Leju, In our consultancy, we do a combination of everything noted by the others in the posts above. In addition, we require the electronic files from the models to be submitted for our review. We then check everything to confrim, at least, there's nothing being "hidden". Sub-modeling of...
  20. BATman2

    Including preload in shear/tension interaction

    Screwman, Thanks. In our business (rail) we tend to over-design for sure out of necessity to ensure no failures and because the real loads are not always truly known. Interesting discussion from all. Usfse - nice BAT pun. Batman2[bat]

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