Lifting Analysis FEA

[Anonymous]

Hello,

I recently bought a book from Wasim Younis (Up and Running with Autodesk Inventor FEA ) and I am now studing the DP-16 Chapter 18 which is the lifting analysis for an offshore container.

I had a few questions regarding this analysis maybe I can get better clarifications from some members experts in simulation.

1.- When he applies the load for 4 points of lifting, he applies the total distributed load of F=2.5xtotal mass x 9.8 (as per code), which includes the tare mass (body mass) but at the same time the gravity is taken into account.

Wouldn't this action be doubling the body load/mass if I consider gravity and plus I apply a distributed load (F) to the floor, which includes the tare mass?.

2.-The custom constraints applied to the 4 corners of the container to avoid larger displacements are not very clear for me (uplift none) does this mean no separation using a spring? or why this is allowable for this particular case anyways?

@JDMather Sir, did you have the opportunity to take a look into this excersice and explain a bit more this analysis?

I am attaching the model for better understanding.

Thank you all for your help.

[admaiora · Accepted solution]

Hi,

1- Gravity load is for the structure of the container

65 tons is the total load (only the material, the content in the container, that is not modeled, not the structure)

2- Solver can't work if the system is not stable and stabilized  (math)

So you can constraint the system and leave free only one direction of freedom (the other are constrained with a virtual spring with a certain stiffness). It's just a a smart common way to get close to reality in some case.