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How to use time-dependent explicit solver for highly nonlinear dynamic problems?

Posted Jan 21, 2024, 9:31 p.m. EST Studies & Solvers, Structural Mechanics, Modeling Workflow, Structural Dynamics Version 6.1 2 Replies

HC L solid mechanics
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Hi there,

I wonder how to use time-dependent explicit solver in Comsol for highly nonlinear dynamic problems.

I tried by modeling the compression of two bars who are in adhesive contact with decohesion law specified, but got an error before reaching any result:

  • Feature: Time-Dependent Solver 1 (sol1/t1) Explicit time stepping requires linear time-independent constraints.

I am aware that another thread in this forum has discussed this error over a decade ago. And @Ivar thought this error meant that the model was too nonlinear. I was wondering if someone could shed lights on this.

Anyway, my simplified model is set as follows.

The Solid Mechanics module in 2D domain is employed. A double bar, consisting of two individual bars in adhesive contact with decohesion law specified, is fixed at the left end, while its right end is prescribed to a ramped time-dependent displacement -rm1(t).

**The time-dependent sovler is adopted, and the 'solver type' in 'time stepping' is specified as 'explicit'.

Best, HCL

The two pictures are attached below, in case they are not properly shown above.

2 Replies Last Post Mar 21, 2024, 1:19 p.m. EDT
Henrik Sönnerlind COMSOL Employee

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Posted: 10 months ago Jan 23, 2024, 5:15 a.m. EST

We do not promote the use of the time explicit solver for general structural mechanics applications. The number of cases for which it is applicable is small. One of the limitations of that solver is the one that you have found. As the error message shows, you cannot have time-dependent constraints.

There are several other limitations.

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Henrik Sönnerlind
COMSOL
We do not promote the use of the time explicit solver for general structural mechanics applications. The number of cases for which it is applicable is small. One of the limitations of that solver is the one that you have found. As the error message shows, you cannot have time-dependent constraints. There are several other limitations.
Pierre Lafortune
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Posted: 8 months ago Mar 21, 2024, 1:19 p.m. EDT

Hi,

Do any of the solution proposed in Knowledge Base 1244 and 1245 could be a work around to simulate explicit dynamic with an explicit time scheme?

https://www.comsol.com/support/knowledgebase/1245 https://www.comsol.com/support/knowledgebase/1244

Thanks Pierre

Hi, Do any of the solution proposed in Knowledge Base 1244 and 1245 could be a work around to simulate explicit dynamic with an explicit time scheme? https://www.comsol.com/support/knowledgebase/1245 https://www.comsol.com/support/knowledgebase/1244 Thanks Pierre

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