7/27/2019 17 - Understanding Model Types

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Theory and Mechanica Model Topics Understanding Model Types  – Lecture 

UnderstandingModelTypes.mp3 Understanding Model Types

There are four model types available in Pro/ENGINEER Wildfire

Mechanica.

3-D 2-D Plane Stress

2-D Plane Strain 2-D Axisymmetric

Lecture Notes 

7/27/2019 17 - Understanding Model Types

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Model Types

There are four model types available in Pro/ENGINEER Wildfire Mechanica

  3-D: The 3-D model is used when none of the other idealized model types canbe used. It consists of three-dimensional elements and represents the mostcomplex model type available. Because it makes no assumptions, it can be usedto represent all types of design models.

  2-D Plane Stress: The 2-D Plane Stress model is a two-dimensional idealizedmodel that is much thinner in one coordinate direction as compared to the othertwo coordinate directions. To use this type of model in Mechanica, the usermust specify a coordinate system and a surface that lies in the XY plane of theselected coordinate system. The Mechanica analysis proceeds by creating a two-dimensional analysis model that assumes no stresses in the Z direction. Modelsthat lend themselves well to this type of analysis are thin plates that aresubjected to in-plane loads (loads in the X and Y directions only).

  2-D Plane Strain: The 2-D Plane Strain model is a two-dimensional idealized

model that is much thicker in one coordinate direction as compared to the othertwo coordinate directions. To use this type of model in Mechanica, the usermust specify a coordinate system and a surface (in the case of solid model) oredges/curves (in the case of shell models) that lie in the XY plane of theselected coordinate system. The Mechanica analysis proceeds by creating a two-dimensional analysis model that assumes no strains in the Z direction. Modelsthat lend themselves well to this type of analysis are prismatic shapes likebeams or pressure vessels that are long in the Z direction and have a crosssection that does not vary appreciably in the Z direction.

  2-D Axisymmetric: The 2-D Axisymmetric model can be used for models thatare symmetric about an axis. This model type requires all aspects of the

analysis model (loads, constraints, and geometry) to be symmetric about theaxis. To use this type of model in Mechanica, the user must specify a coordinatesystem and a surface (in the case of a solid model) or edges/curves (in the caseof a shell model) that lie in the XY plane of the selected coordinate system. Allof the geometry must be in the X >= 0 section of the plane, and all of the loadsand constraints must be specified in the XY plane. Models that lend themselveswell to this type of analysis are tanks, flanges, and hubs.