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  • Users: jetmaker
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  1. jetmaker

    Joint efficiency factors

    Anyone got a public domain resource on the joint efficiencies of staggered vs inline fastener patterns for lap joints in metallic structures? Thanks
  2. jetmaker

    Extracting element stiffness matrix for MAT9

    Looking for some help here. I have a composite laminate in which each ply is represented by a layer of solid elements. There are 8 plies total, with the stacking sequence being [0/45/-45/90]s. A generic MAT9 card is used. When the property field is assigned, a material CID aligned with the...
  3. jetmaker

    Unreasonable expectations???

    All, I am currently a contract engineer, employed in a skill which is in high demand at present. I am considering a direct position with my current employer, but their offer in terms of salary seems to undervalue my ability. Currently I am being paid 53% more than what their salary offer is...
  4. jetmaker

    Tension allowable for MS20615-4M

    Anyone have a public domain source for the tension allowable of a MS20615-4M rivet. That's a 1/8" protruding head Monel rivet. Thanks. jetmaker
  5. jetmaker

    Help analyzing Clamp Block overturning forces

    I am looking for some guidance/suggestions on how to solve the following problem. I have a clamp block which is used to hold hydraulic tubing and electrical wires at various locations along their run. A typical clamp block installation is shown in the attached figure. The clamp block assembly...
  6. jetmaker

    21-6-9 SS Static properties

    Looking for static and fatigue properties for 21-6-9 SS. Thanks, jetmaker
  7. jetmaker

    Static and Fatigue properties of 21-6-9 Cres Tubing

    Looking for some static and fatigue properties for 21-6-9 Cres tubing. The information needs to be public domain and referenceable. Thanks for your help. jetmaker
  8. jetmaker

    humping loads

    Can anyone give me some information on the quasi-static loads on rail cars due to humping shocks. I have dynamic values, but lack anyu information such as damping coeffs and impact durations, strokes, etc. My goal here is to calculate the g force applied to cargo. Thanks, jetmaker
  9. jetmaker

    Birdstrike calculation

    Looking for some help here. FAR 25.631 refers to bird strike damage but does not provide guidance on how to calculate the impact load. The kinetic energy can be calculated from 0.5*m*v^2, but to calculate the force requires that a distance be known. Any suggestions on how to solve this issue...
  10. jetmaker

    Reference for effective thickness of a radius filler

    Does anyone have a reference for the effective thickness of a radius filler used to strengthen a tension clip type joint? I think it is in some of the Lockheed Stress Memos or old Boeing BDMs. Thanks. jetmaker
  11. jetmaker

    Linear Buckling Solution

    Does anyone know if the linear buckling solution (SOL105) in NASTRAN accounts for bending due to load eccentricity? Problem I have is a C-channel loaded on the flanges such that it causes a bending load as well as axial compression in the web. Trying to determine if the eigenvalue accounts for...
  12. jetmaker

    Application of fastener preload in tension/shear interaction

    Morning folks, Looking for some opinions and thoughts here. I have a situation where I am using bolts/screws c/w a nut securing 2 parts together. The joint experiences a combination of shear and tension loads. Now the bolt tension and shear allowable data that I have is for the bolt itself...
  13. jetmaker

    Curved plate with normal load

    I'm looking for some information on the effect of curvature of a plate when subjected to a normal load. Here is the structure description: Curved C-Channel beam (3" deep) with tight curvature (r=4") about the stong axis. A uniform pressure is applied on the upper flange causing a bending of...
  14. jetmaker

    Variable Depth Plate Girder Beams

    I've got a variable depth beam where the hanuch is of the curved type and has a tight curvature. I am concerned that the lower flange (i.e curved flange) is at risk of failure due to high transvers loading caused by the secondary bending effects. The idea is to support the lower flange using...
  15. jetmaker

    Stiffener spacing for curved haunch

    I'm looking for some analysis to specify what the spacing need be for inner flange stiffening of a curved haunch. I have checked Blodgett, and can only find a criteria which states C <= 6*bf. Any help would be appreciated. Thanks, jetmaker
  16. jetmaker

    Interpreting FE Buckling Results

    Morning all. I have a thin plate that is being loaded eccentrically in compression which is resulting in combined axial and bending stresses. Running a SOL105 Linear Buckling analysis in NASTRAN, an eigenvector value of 19.124 is reported. If this load were strictly axial compression, then...
  17. jetmaker

    Use of FEA in showing FAR compliance

    Can someone provide a reference to the FAR or AC or AMDT that indicates what is required to demonstrate FEA compliance with section 25.307 of the FARs? Thanks, jetmaker
  18. jetmaker

    Sample Size in determining A and B-Basis allowables

    I seem to remember from my school days that there were different smaple sizes required if one was determining A vs. B-basis allowables. However, the latest data that I see indicates that a minimum sample size is 100 (assuming a standard distributions) from a minimum number of lots. This is...
  19. jetmaker

    Material Variability Factor for Composites

    Hi all, Wondering if someone can provide a little insight on the material variability factor that is used for composite materials under static test. Per 25.307(d) - Proof of Structures, "... appropriate material correction factors must be applied to the test results...". The standard that...
  20. jetmaker

    Tension/Pie Fittings

    I'm looking for an anlysis method for pie fittings loaded in tension. Most of the information I have is for angles or Tee fittings which when used, predict allowable fitting loads less than what I have for my pie fitting. Any help or suggestions would be appreciated. Regards, jetmaker

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