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  2.7-1 B A S I   C  A  NAL Y S I   S  Slide Line - Hertz Contact Stress 2.7    Slide Line - Hertz Contact Stress 2.7-2    Slide Line - Hertz Contact Stress B A S I   C  A  NAL Y S I   S  2.7-3 Model Description:  The Hertz contact stress problem provides a good example for 3-D slide line contact. The complete model data has been provided and the model is ready for analysis. However, the example will con-centrate on looking in detail at the modeling requirements and slideline definition. Before proceeding with the example, we will look at some general aspects of slide line modeling and analysis, then review the procedure for setting up a slideline model referring to the entries already defined in the Hertz contact stress model. Overall Considerations  Slideline contact is always performed as a nonlinear analysis, either static or transient dynamic methods can be used.  The slideline is always defined in the XY plane of the basic or local coordinate system that is referenced by the element property definition.  The definition of the master and slave segments is for naming purposes only, except in the case of unsymmetric penetration. In this case only slave nodes are checked for penetration into mas-ter segments.  The slide line is aligned with the referenced coordinate system z-axis, by applying the right hand rule when selecting master and slave nodes.  Initial penetration cannot be modeled with a slide line.  Symmetrical penetration is more accurate, but also more computationally intensive than unsym-metrical penetration.  Enforced displacement may yield better convergence than applied loads (not applicable with nonlinear transient analysis).  Error messages concerning initial penetration, even if not modeled, or displacements in a rigid body mode, indicate improper ordering of master and slave nodes. Check that the right hand rule law mentioned above has been observed.The model comprises a sphere of radius of 6 mm, modeled as a 10-degree segment of a semi-sphere using solid elements, with the appropriate boundary conditions applied. The material is assumed to be an isotropic high strength steel with a Young’s Modulus of 210,000 N/mm 2 , and a Poisson’s Ratio of 0.3. The rigid plane is modeled using plot elements, the nodes of which are completely constrained - the slide line elements are used to model the contact behavior in this case.    Slide Line - Hertz Contact Stress 2.7-4 Exercise Procedure:  1.Start MSC/NASTRAN for Windows 3.0.2 by double-clicking on the MSC/NASTRAN for Windows icon. For this exercise, you will select the New Model  option.The bulk of the model data already exists in the form of a FEMAP neutral file. The file can be imported into the database from the examples directory.   Your view screen should look similar to the following: Open Model File: New ModelFile/Import/FEMAP Neutral... File name; hertz.neuOpenOKView/Select...  Model Style:     Draw ModelModel Data... Group:     Select Group: 5..sphere + plateOKOKView/Rotate...DimetricOK
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