Hinge Point in MatLab Structural PDE Solver

Hi,

I am trying to model a system with the MatLab that has pressures applied on faces and a frictionless hinge, such that it moves according to the pressures until the forces are balanced by the forces from the top plate, as shown in the diagrams below. For reference, making the thin members extremely thin would achieve the same result, but the PDE Solver does not handle this well, and does not give the desired result. The bottom plate should move and rotate freely.

Is there something in the MatLab PDE solver that would be able to replicate this behaviour?

Thank you in advance!

George ❤

(This isn't as simple of aproblem as shown, since pressures in reality are on the bottom surfaces as well and the geometry is quite complicated, I have just simplified it for the diagram.)

Answer 1

[Shishir Reddy]

Hi George,

As per my understanding, you are trying to simulate a freely moving and rotating plate under pressure with hinge-like supports. But unfortunately, the MATLAB PDE Toolbox is not well suited for this kind of rigid-body dynamic behaviour.

The issue you are encountering where extremely thin members don't yield the expected result, is because the PDE Toolbox is fundamentally designed for deformable solid mechanics problems, not multibody dynamics.

A much better approach for this kind of system is to use Simscape Multibody. It’s built specifically for modeling mechanical systems with rigid bodies, joints (like frictionless hinges), and external forces or pressures. You can define your bottom plate as a rigid body, connect it to the upper structure with revolute joints, and apply distributed pressures. The simulation will naturally let it move and rotate until the system reaches force balance, which is exactly what you are aiming for.

For more information regarding Simscape Multibody, kindly refer the following documentation - https://www.mathworks.com/help/sm/getting-started-with-simmechanics.html

I hope this helps.