nI see you have solid bodies for the cart frame. This is not what you want to build a model because it will take too many elements to fill the solid bodies.nThere are two idealizations that result in reasonable number of elements in the model: shell elements and beam elements.nBeam elements result in the smallest model and is very easy to mesh and work with. The input geometry is the centerline of each tube. Make those centerlines meet at a common endpoint. The tube cross-section (OD and ID) are assigned to the beam element as a property of the element and those allow the FE model to compute the stiffness and stress in the elements.nHere is an example of a beam model: elements result in a larger model that requires a bit more work. A midsurface of each tube must be created in CAD. Any gaps at the ends of tube midsuface to the next tube midsurface at joints have to be closed by editing the surface geometry or by using Bonded Contact in Mechanical. This is more work than the beam element model, but delivers more detailed stress results at the tube joints.nHere is an example of a shell model: