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  1. Stress_Eng

    Splice Theory Question

    I think you'll have something like this. Edit As SWComposites highlights, the moment is resolved into a 'tension' & 'compression' couple. The approach shown in the above FBD takes moments about the contact abutment point Pa (compression) and assumes the bolts take the tension, proportioned...
  2. Stress_Eng

    Weld Size Calculation for Plate Welded Perpendicularly to RHS Beam

    I don’t know how significant this is, but don’t forget that the beam bends, resulting in rotation at the free end. The rotation and the length of the plate will result in a horizontal offset between the point of load application and the N/A of the beam at the free end, causing a moment.
  3. Stress_Eng

    Interpolating Points

    Just one of meany ways to interpolate data!
  4. Stress_Eng

    Engineering designation of critical parts

    One company I worked at had an entry in the drawing, identifying the 'CLASS' of part. Class 1 was 'Structural', in that the part had to be certified (means of compliance, be it by analysis, test, etc). Then there was CLASS 2 and CLASS 3. Class 3 was non-structural, non-load bearing, etc. Having...
  5. Stress_Eng

    NPT thread strength - Stress Distribution / Tensile Area

    Thinking about the posted question, the thread load distribution through the length of the engaged thread will be influenced by the taper in the two parts of the joint. I would think however, the distribution would be similar to a typical thread, but with the first and last few threads...
  6. Stress_Eng

    Flat Plate Bending Weld Stress

    If you’re welding in a circular plate, you could use the equations in Roark. The cylinder rotational support can be used by equating cylinder and circular plate gradients at the intersection. The cylinder will be modelled by two cylinders, one pressurised, the other not. Again, equate gradients...
  7. Stress_Eng

    NPT thread strength - Stress Distribution / Tensile Area

    I found this subject interesting and investigated it some time back (15+ years). Although I reviewed standard thread types (Metric and UNJ), and I agree that the taper will influence the load per thread through the axial joint (differing cross sections along thread engagement), I would think the...
  8. Stress_Eng

    1/2 loading for 1/2 model in ansys?

    As a suggestion, visualize the full vessel and draw a line on it where the cut would be. Then apply each load individually and visualize the deformed shape. You need the line to remain on the cut plane (deformed shape to be a mirror image about the plane). If the line doesn’t stay on the plane...
  9. Stress_Eng

    Tapped axial holes on tube

    My basic calculations (not checked or validated), assuming 350 lbf tension load per bolt, a BM of approximately 346 lbf.in per bolt (114.63 lbf.in/in x 3.02in) and no preload, indicates approx. 60% of the joint will gap. To keep the joint closed (prior to onset of gapping), a preload of approx...
  10. Stress_Eng

    Tapped axial holes on tube

    Preloading has a big part to play in fatigue. Does fatigue need to be considered? Does the part see any cyclic loading? Preloading is also to stop the joint from gapping. Sufficient gapping will alter bolt loading (all bending on bolts, no load sharing in joint). Edit - When it comes to hoop...
  11. Stress_Eng

    Tapped axial holes on tube

    Once you've derived the radial SF and BM at the base of the cylinder, the BM can be reacted in two different ways. The first is by contact bearing along the threaded length and the second is by prying action. As a hand analysis approach, you could cover both. The prying action will increase the...
  12. Stress_Eng

    Tapped axial holes on tube

    Just pointing out, if a hand analysis is going to be carried out, to determine the loading at the bolts, Roark has a section on cylinders with equations that can carry out an analysis similar to that conducted in the attachments. The attachments were just to give an indication of the possible...
  13. Stress_Eng

    Tapped axial holes on tube

    Just as an addition to the previous post. Results if the pressure is seen over the full height of the cylinder. (Zero radial displacement at both ends, zero rotational restraint at top and full rotational restraint at base) Distributed shear at base = 68.42 lbf/in Distributed BM at base =...
  14. Stress_Eng

    Tapped axial holes on tube

    Did some cylinder calc's using assumptions (method not checked). I think earlier in the post you said you'd like to make your part out of Aluminum. Used inputs. E = 10007.6 ksi (used 69 GPa) Poisson's ratio = 0.33 Vertical cylinder length = 12.008in (assumed, used 305mm) Unpressurized length at...
  15. Stress_Eng

    Tapped axial holes on tube

    Having a quick look at the assy, and knowing the assy is to be pressurized, the initial thoughts are to determine the interfacing actions of the parts at the bolted joint. You can view your part as a thin walled cylinder connected to a circular plate at the top. The pressure will tend to make...
  16. Stress_Eng

    Tapped axial holes on tube

    Could you include a picture of the component when assembled (define boundary conditions, + bolt preload) to its interfacing structure. Also, can you show in a diagram how the component is loaded.
  17. Stress_Eng

    Tapped axial holes on tube

    Could you show a picture of the part and how the tube is going to be loaded. How many bolts, are they evenly pitched? I can only mention that thread radial loading will occur (under preload and axial loading conditions). If the remaining wall thickness deflects radially under these loading...
  18. Stress_Eng

    Structural Integrity of Pump and Engine Skid Frame

    As I'm in a different industry, I wouldn't want to give you anything that isn't recognized. I do suggest asking your work colleagues about the use of the Bolt Group Analysis (BGA) method, and if there's a standard approach to the analysis of a bolted flange attachment (possible inclusion of...
  19. Stress_Eng

    Structural Integrity of Pump and Engine Skid Frame

    As a hand calc, you could beam your two Ref. point loads / torques to the frame (use of BGA). Your frame looks symmetric, so look at one side (neglect cross members). It looks like your torques will load the center of the frame the most. If shown to be the highest applied frame loads, assume the...
  20. Stress_Eng

    Bolts in Shear on Circumferential Bolt Pattern

    You could view the FBD as something like this. Pb is the bolt tension load, keeping the two parts together, and Pa1 or Pa2 will be the abutment load, causing the prying load. Obviously there's internal pressure. The shear is due to the differential pressure load. There's bolt bending and there's...

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