PAT312, Section 13, December 2006 S13-1 Copyright 2007 MSC.Software Corporation SECTION 13 EQUIVALENCING VERIFYING AND EDITING

PAT312, Section 13, December 2006 S13-2 Copyright 2007 MSC.Software Corporation

PAT312, Section 13, December 2006 S13-3 Copyright 2007 MSC.Software Corporation EQUIVALENCING l Replaces nodes to tie elements together l Option, users choice: l Higher numbered node ID is retained, or l Lower numbered node is retained l Changes propagate through all selected FEM data l Element connectivity is realigned l LBCs updated l Equivalence algorithm is controlled by a tolerance parameter

PAT312, Section 13, December 2006 S13-4 Copyright 2007 MSC.Software Corporation EQUIVALENCE – TIE ELEMENTS TOGETHER AfterDuringBefore Uses cube or sphere to establish proximity

PAT312, Section 13, December 2006 S13-5 Copyright 2007 MSC.Software Corporation EQUIVALENCE FORM l Equivalencing can be applied to: l All - the whole model in database l Group – selected groups l List – a specific list of nodes l The equivalence tolerance is specified by the user. The default is the global model tolerance. l MSC.Patran will not collapse an element edge, e.g. quad shape to tria shape l Selected nodes can be excluded form Equivalencing l Tolerance Cube is the recommended method (speed)

PAT312, Section 13, December 2006 S13-6 Copyright 2007 MSC.Software Corporation

PAT312, Section 13, December 2006 S13-7 Copyright 2007 MSC.Software Corporation VERIFICATION AND EDITING

PAT312, Section 13, December 2006 S13-8 Copyright 2007 MSC.Software Corporation

PAT312, Section 13, December 2006 S13-9 Copyright 2007 MSC.Software Corporation IRREGULAR MESHES l Irregular meshes (elements) usually occur with: l Irregular geometry l Mesh transition l Irregularity or distortion is measured with respect to a basic shape, i.e. square, isosceles triangle, cube l Distorted elements generally result in less accurate answers l It is the USERS RESPONSIBILITY in carrying out element quality checks to specify the maximum allowable distortion

PAT312, Section 13, December 2006 S13-10 Copyright 2007 MSC.Software Corporation IRREGULARITY CHECKS l General mesh/element checks l Boundary or Crack detection l Elements Duplication l Normals l Nodal connectivity l Jacobian l ID l Element specific distortion checks l Deviation from basic shaped elements, i.e. taper l Curvature and singularity tests for quadratic elements l Color-coding based on result of check

PAT312, Section 13, December 2006 S13-11 Copyright 2007 MSC.Software Corporation VERIFY ELEMENT BOUNDARY l Plots the boundary as free edges, or optionally free faces l Free edge/face of an element is the edge/face of the element not common (tied to) with others l Cracks or free edges appear along geometric boundaries prior to equivalencing

PAT312, Section 13, December 2006 S13-12 Copyright 2007 MSC.Software Corporation VERIFY ELEMENT BOUNDARY EXAMPLE Free Edge display after Equivalencing Tet elements may cause lines to be dashed Finite Element Model Free Edge display before Equivalencing

PAT312, Section 13, December 2006 S13-13 Copyright 2007 MSC.Software Corporation VERIFY ELEMENT BOUNDARY FREE EDGES Tet Mesh Free edge display before equivalencing Free edge display after equivalencing Tet Mesh examples: Dashed (blank) area indicates more than one tet Solid line indicates only one tet

PAT312, Section 13, December 2006 S13-14 Copyright 2007 MSC.Software Corporation VERIFY ELEMENT BOUNDARY FREE EDGES (Cont.) Hex Mesh examples: Hex MeshFree edge display before equivalencing Free edge display after equivalencing * What would happen if geometry is not congruent?

PAT312, Section 13, December 2006 S13-15 Copyright 2007 MSC.Software Corporation DISTORTION CHECK OF HEX ELEMENTS l The Test Option gives an overview for the current group Object :

PAT312, Section 13, December 2006 S13-16 Copyright 2007 MSC.Software Corporation TYPICAL VERIFY FORM l Sketch describes the test. More information can be found in the on-line help (use Help Button) l Test threshold can be set by user. Default value usually provides good start l Normalize Button l Default is off: Slidebar represents actual value of verification test threshold l If on: Threshold value is normalized to lie between zero & 1. The value of zero will represent the most reliable configuration for this element type. l Control icon allows the option to highlight elements exceeding the reliability threshold, or click on the icon to switch to an automatic fix l Reset graphics will undo rendering. Render style and spectrum display will be returned to the setting they had before the apply button was hit

PAT312, Section 13, December 2006 S13-17 Copyright 2007 MSC.Software Corporation DISTORTION CHECKS RESULTS DISPLAY l Elements exceeding the threshold will be color-coded and listed in the history window l Plot failed Elements Only can be used to create a group of failed elements

PAT312, Section 13, December 2006 S13-18 Copyright 2007 MSC.Software Corporation SHOWING ELEMENTS l Display attributes of selected elements in spreadsheet l Additional information is available for cells with a dot at the corner

PAT312, Section 13, December 2006 S13-19 Copyright 2007 MSC.Software Corporation NODE EDITING EXAMPLE l To change the location of a node, first identify its new location by specifying coordinate values or by using the Select Menu options in Node Locations l Using Node List, identify the node to be relocated BeforeAfter 4 15,4 15 1st click 2nd click

PAT312, Section 13, December 2006 S13-20 Copyright 2007 MSC.Software Corporation NODE EDITING EXAMPLE l No topological congruency between the surfaces l How many nodes are there along the common boundary? l How could equivalencing be used to do the same thing? BeforeAfter

PAT312, Section 13, December 2006 S13-21 Copyright 2007 MSC.Software Corporation SHOWING NODES l Node coordinate locations and distance between any pair of nodes can easily be shown in MSC.Patran l Distance between any pair of nodes is listed with respect to coordinate directions and total distance

PAT312, Section 13, December 2006 S13-22 Copyright 2007 MSC.Software Corporation

PAT312, Section 13, December 2006 S13-23 Copyright 2007 MSC.Software Corporation

PAT312, Section 13, December 2006 S13-24 Copyright 2007 MSC.Software Corporation