The image shows a model for static analysis (1/4 section of two stacked cylinders). The lateral sides and bottom are frictionless-constrained against normal movement. A negative pressure is applied to the top of the top cylinder. The interface between the two cylinders is bonded. (I will try to post an image link separately.)

Notes –

- The model was constructed in Mecway FEA. (I can post a link if needed.)
- The mesh is the default. (I realize the mesh is rather coarse but I want to resolve, in general, the problem of nodal mismatch at interface surfaces.)
- The H200c_static_bonding_static_load.inp file was generated by Mecway FEA. Dropbox - H200c_static_bonding_static_load.inp - Simplify your life

When I run ccx on this inp file I get an error –

*ERROR in cascade: the DOF corresponding to node 306 in direction 1 is detected on the

dependent side of a MPC and a SPC

This error is given in the calculix source code – https://stuff.mit.edu/afs/athena/software/calculix_v2.7/CalculiX/ccx_2.7/src/cascade.c (search there for “ERROR in cascade: the DOF”).

Node 306 is located at (X,Y,Z) = (0,50,10)mm which is a corner of the bottom surface of the top cylinder at the interface between the two cylinders.

If I delete the constraints on the lateral sides then the analysis finishes but, of course, the results are incorrect.

Since this model’s configuration should not be uncommon, I think there should be a solution. (After resolving for static analysis I would then proceed to modal analysis.)

Thanks,

Don C.

# ========================================================================

CalculiX Version 2.16, Copyright(C) 1998-2019 Guido Dhondt

CalculiX comes with ABSOLUTELY NO WARRANTY. This is free

software, and you are welcome to redistribute it under

certain conditions, see gpl.htm

You are using an executable made on Sun, Jan 19, 2020 10:23:46 PM

The numbers below are estimated upper bounds

number of:

nodes: 610

elements: 238

one-dimensional elements: 0

two-dimensional elements: 0

integration points per element: 4

degrees of freedom per node: 3

layers per element: 1

distributed facial loads: 37

distributed volumetric loads: 0

concentrated loads: 0

single point constraints: 282

multiple point constraints: 307

terms in all multiple point constraints: 5815

tie constraints: 0

dependent nodes tied by cyclic constraints: 0

dependent nodes in pre-tension constraints: 0

sets: 10

terms in all sets: 569

materials: 2

constants per material and temperature: 2

temperature points per material: 1

plastic data points per material: 0

orientations: 0

amplitudes: 2

data points in all amplitudes: 2

print requests: 0

transformations: 0

property cards: 0

STEP 1

Static analysis was selected

Decascading the MPC’s

#
*ERROR in cascade: the DOF corresponding to

node 306 in direction 1 is detected on the

dependent side of a MPC and a SPC

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