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Examples for Linear Gaps modelling.

ron.kunz
Dear all,
I would like to study some examples with linear gap elements. We don`t have SOL400 available and to have a work around for i.e. objects touching or near eachother.
Could you provide wtih some examples or give location of study material? Thanks.
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    There isn't any difference in contact in 101 and 400. The difference is linear vs nonlinear assumptions (small vs large displacements) .
    The confusion comes from the iterative solver used for linear contact and for nonlinear analysis. A linear contact problem cannot be solved directly, so requires an iterative solution. Nonlinear analysis also uses an iterative solver. In other words, linear contact isn't nonlinear (like materiel non-linearity, large strain and large displacement ), but does require an iterative solution.
    The big differences are the linear assumptions in 101. Remember, everything in 101 is linear: linear materials, small strain elements, small displacements and small rotation assumptions. Users frequently overlook the influence of the small displacement assumption. It is a limitation with linear contact .
    Remember, with small displacements nodal locations are not updated during the solution (displacements are not added to the coordinates). With contact, this means nodes/elements on opposing contact bodies should remain "relatively close" (because the contact patch isn't updated). In other words, with 101 you can model the weight distribution of a box on a plate, but you cannot slide that box sideways to another location on the plate. (The contact is assumed to occur at the original contact patch on the plate.)
    This is the big difference compared to 400: You can model the large sliding with 400 because it includes large displacement and rotation affects. But, the difference is due to small vs large deformation, not the contact.
     
    Also, regarding, NLPARM...that is an old way to specify iterative solver options. NLSTEP was introduced several years ago, and has many advantages over NLPARM. For example, the CTRLDEF field is used to easily set 101 convergence parameters (LCPERF or LCACCU).
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  • 0
    There isn't any difference in contact in 101 and 400. The difference is linear vs nonlinear assumptions (small vs large displacements) .
    The confusion comes from the iterative solver used for linear contact and for nonlinear analysis. A linear contact problem cannot be solved directly, so requires an iterative solution. Nonlinear analysis also uses an iterative solver. In other words, linear contact isn't nonlinear (like materiel non-linearity, large strain and large displacement ), but does require an iterative solution.
    The big differences are the linear assumptions in 101. Remember, everything in 101 is linear: linear materials, small strain elements, small displacements and small rotation assumptions. Users frequently overlook the influence of the small displacement assumption. It is a limitation with linear contact .
    Remember, with small displacements nodal locations are not updated during the solution (displacements are not added to the coordinates). With contact, this means nodes/elements on opposing contact bodies should remain "relatively close" (because the contact patch isn't updated). In other words, with 101 you can model the weight distribution of a box on a plate, but you cannot slide that box sideways to another location on the plate. (The contact is assumed to occur at the original contact patch on the plate.)
    This is the big difference compared to 400: You can model the large sliding with 400 because it includes large displacement and rotation affects. But, the difference is due to small vs large deformation, not the contact.
     
    Also, regarding, NLPARM...that is an old way to specify iterative solver options. NLSTEP was introduced several years ago, and has many advantages over NLPARM. For example, the CTRLDEF field is used to easily set 101 convergence parameters (LCPERF or LCACCU).
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