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40 Cards in this Set
- Front
- Back
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CAD
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Computer Aided Design
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Spline
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-long, smooth, and flexible strips of material
-used to define the shape of a ship’s hull. |
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NURBS
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-nonuniform rational B-splines
-used to model curves and surfaces -provide a mathematically precise representation of both standard analytic curves as well as freeform shapes |
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BIM
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-building information modeling
-model based technology linked with a database of project information -provides digital representation of the building process to facilitate compatibility and exchange of info in digital format -reflects the general reliance on database technology as the foundation. |
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CAM
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Computer Aided Manufacturing
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CAE
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Computer Aided Engineering
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CSG
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- representation scheme employed for describing solid models
-CSG representation stores the model data in terms of the solid primitives and the Boolean operations that are used to combine them -stored in tree structure -solid primitives are leaves -Boolean operators are branches -simple and compact -info on faces, edges, and vertices is not readily available |
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B-Rep
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-other representation scheme
-stores the boundaries of the solid (vertices, edges, faces) in the database and info regarding how these are connected -the outside of a face is determined by the order of its bounding edges -bounding edges of the face are stored in the database in a counterclockwise direction -used best with shading, hidden line removal, and other types of display. |
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Primitives
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- solid entities similar to the 2D line, circle, and arcs used in wireframe modeling
-examples are box, sphere, cylinder, cone wedge, and torus. |
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DOF
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- degrees of freedom
-solid part models have 6 -three in translation and three in rotation -unconstrained, free to translate along or rotate about any combination of the three coordinate axes. |
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FEA
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Finite Element Analysis; Stress Analysis
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CFD
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Computational Fluid Dynamics
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NC/CNC
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Numerically Controlled; Computer Numerically Controlled
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CAPP
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Computer Aided Process Planning
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PDM
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Product Data Management
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PLM
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Product Lifecycle Management
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Features
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-basic three dimensional building blocks for creating parts
-two types of model features -SKETCHED require that a sketch be made before feature can be created (extrude, revolve) -PLACED (hole, chamfer, fillet, shell, face draft) can be created without sketch geometry |
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Constraints
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-mathematical requirements imposed on the geometry of a 3D model
-two types -DIMENSIONAL (parametric dimensions) place limits on size or position of a feature -GEOMETRIC (parallelism, tangency, concentricity) place limits on the shape or position of a feature. |
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RP
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Rapid Prototyping
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FDM
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Fused Deposition Modeling
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SLS
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Selective Laser Sintering
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First commercial success of CAD system
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AutoCAD by AutoDesk (1982)
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Names of Parametric solid modeling tools (software)
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1. CREO (Pro/Engineer) by Parametric Technology Corporation (1988)
2. Midrange: AutoDesk Inventor, Dassault SolidWorks, Siemens SolidEdge 3. High-End: Dassault CATiA, PTC CREO, Siemens NX |
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Three major functions of 3D CAD design tool
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Part Modeling
Assembly Modeling Working Drawing |
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CAD downstream applications *****
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-CAD/CAE/CAM Integration
CAE CAM PDM/PLM -Rapid Prototyping STL FDM SLS 3D Printer |
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B-Rep Diagram
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see pic
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Parametric and Non-Parametric representation of curve
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See pic and ask lee
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Names of four free form curves
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Hermite Curves
Bezier Curves B-Spline Curves NURBS Curves |
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Characteristics of NURBS Surface
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1. Operations (rotations or translations) can be applied by applying them to their control points
2. They offer one common mathematical form for both standard analytical shapes and free-form shapes 3. They provide the flexibility to design a large variety of shapes 4. They reduce the memory consumption when storing shapes 5. They can be evaluated reasonably quickly |
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Two methods of building solid model
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1. Primitives
2. Sweep |
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Four major sweep operations
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1. Sweep
2. Extrusion 3. Revolve 4. Loft |
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Three major Boolean operations
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1. subtraction
2. union 3. intersection |
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Four display types in CAD system
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1. wireframe
2. hidden 3. shaded 4. rendered |
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Characteristics of parametric modeling
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1. Overcome dumb solids
2. Easy to modify 3. Manufacturing or geometric information are stored 4. Dimensions are parametric 5. Model history is available 6. Assembly environments |
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Three major RP technology
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Selective Laser Sintering
Fused Deposition Modeling 3D Printer |
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Common file format for RP technology
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STL- STereoLithography
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What type of problem does FEA/FEM solve? ****
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Structural analysis
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What type of problem does CFD solve? ****
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Fluid and Thermal Flow analysis
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What type of problem does Kinematics simulation solve? *****
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motion analysis and mechanism analysis
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What is the main purpose of utilizing CAM in production? *****
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A connection between machining and CAD
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