VM-WB-MECH-011: Large Deflection of a Circular Plate With Uniform Pressure

Fatmac

with a reasonable mesh and quadratic elements and non linear analysis, i get very close to the quoted target value and pretty much spot on the ansys value with both shell and solid elements. (top right is the solid elements, both discs on the left are shell but with varying density meshes). What interested me more, was how different the solution was using a linear analysis - max deflection was over 10% greater. I would not have consider a 1mm deflection over a 500mm dia as "large" deflection requiring non linear analysis - perhaps I need to change my thought process here -perhaps the deflection to thickness ratio is also an indicator of when NA is required???

Victor

Yes, a rule of thumb for requiring nonlinear analysis is deflection to thickness ratio greater than 1/2.

Consider an extreme case of a catenary. A chain has zero bending stiffness so it can't support any load at all without updating the stiffness to account for the change of geometry when its deflected. The "thickness" for the rule of thumb is zero so it always requires non-linear analysis.