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  1. Lee.Conti

    Yield Strength for Plastic

    Thanks a lot for the sharing! Especially @rickfischer51. Honestly, I try to understand polymer from metal and understand that it is different. Polymer shows nonlinear elasticity before yield compared to metal, correct me if it is not true. I was using 0.2% to define the yield but the polymer...
  2. Lee.Conti

    Yield Strength for Plastic

    Hi, I understand from the textbook "Designing with Plastic, Erhard", yield strength is the peak of Stress Strain curve, where the slope is zero. I would like to check if this means before reaching to the top, it is still elastic for plastic? As if compared to metal, the peak of the stress...
  3. Lee.Conti

    Joint FEA Stress

    Thanks Ng2020, rb1957 (always :) ) It is similar to lap joint under bending condition. after model washer into FEM, I see the stress even higher... Was expecting some localized yielding and and the stress near bolt head is below yield... But it seems there are some red area with higher than...
  4. Lee.Conti

    Joint FEA Stress

    Under static condition, the bolt hole stress shows some stress above yield, localized, the stress near the bolt head is below yield... Should we use tensile strength instead of yield to do margin of safety check? I see the area underneath bolt head may experience little yield under bolt...
  5. Lee.Conti

    Should it be HCF or LCF?

    Hi rb1957, I agree with you as the further I check back, it might be defined that way ---> LCF for GAG... However, for some LCF, it is using Miner's rule. I believe that should be the right way.
  6. Lee.Conti

    Should it be HCF or LCF?

    Yeah... I could understand when is the HCF coming... For LCF that I had been doing, we just pick the max stress from the LCF loading... and use S-N curve for fatigue analysis... and the required life cycles is min 10,000 cycles or even more per customer requirement...Does it mean LCF here not...
  7. Lee.Conti

    Should it be HCF or LCF?

    Hi rb1957, for the connector, it would the inertia will be applied for 6 times in three directions in the testing
  8. Lee.Conti

    Should it be HCF or LCF?

    @Lifedivergence, I have multiple questions... 1. The connector is a clamp, something like the picture It hold two parts under two type of loading... one is vibration profile, another one is acceleration in mini second - shock I was wondering if HCF is a concern and then using Goodman...
  9. Lee.Conti

    Should it be HCF or LCF?

    Thanks LiftDivergence for your sharing! really appreciate it. As usual, thank for your respond, rb1957! @rb1957, we will conduct the test with the acceleration profile, limited cycles as per test specification but not really for fatigue check...
  10. Lee.Conti

    Should it be HCF or LCF?

    Another question... I have been doing LCF and HCF for the condition if the cycles less than 100K, it is LCF. HCF usually 10^8. But from the textbook, LCF is for the cycles less than 1000 cycles ... so, it is dependent of the industry or product?
  11. Lee.Conti

    Should it be HCF or LCF?

    I am required to check a fatigue life for a connector holding two parts under an acceleration in mini seconds. I wonder if this should be HCF? I have done HCF and LCF for other product, call it A, but the load condition is different. Product A experiences Temperature, Pressure and Acceleration...
  12. Lee.Conti

    Hinge Joint FEM

    Thanks gentlemen!
  13. Lee.Conti

    Hinge Joint FEM

    I am modeling a cantilever beam to carry a weight with a support (black line). I want to check the impact of modeling the hinge at the end... if I use MPC element to allow rotation, I can almost two times deflection downwards from frictional contact at the hinge. I understand in reality, there...
  14. Lee.Conti

    Gap Condition vs Gap Element

    Hi, anyone has used gap condition in dynamics analysis such as transient? I wonder if it is comparable to use full transient with contact elements than gap condition? Thanks!
  15. Lee.Conti

    Fastener Pattern Force Hand Calc vs FEM

    Hi ESPcomposites, do you mean not to constrain the four points directly but consider using spring element there?
  16. Lee.Conti

    Fastener Pattern Force Hand Calc vs FEM

    If I run a bracket in FEA, I constrain four fasteners in all 6 DOF... can I take the reaction forces and moments for bolt assessment?
  17. Lee.Conti

    Fastener Pattern Force Hand Calc vs FEM

    Maybe I did not say it clearly... I now catch what ESP and you said that in my model, it is not rigid in the first model but in our calculation, we assume it is rigid for force/ moments transferring... Now I re-run the FEA using RBE3... I can get the same results as hand calculation...
  18. Lee.Conti

    Fastener Pattern Force Hand Calc vs FEM

    Thanks for your reminder... that is right... it is considered rigid in classical calculation unless I use RBE in FEA to distribute the forces... Thanks!
  19. Lee.Conti

    Fastener Pattern Force Hand Calc vs FEM

    Hi Ng2020, it is a very simple example... 3D not gonna make much different as above. I shifted the applied force at the centroid of bolts with moment force manually, I can get the reaction forces pretty close to hand calculation... Does it mean that it does not transfer the moment to the...
  20. Lee.Conti

    Fastener Pattern Force Hand Calc vs FEM

    Thanks ESPcomposites, I am using RBE2 with a node at the center of the hole. I run two type of constrains with all DOF fixed and translational fixed only but reaction forces are about the same...

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