Abstract
The challenges of geometric representation for Additive Manufacturing are many. Material properties can vary through the object and lattice structure and internal voids can be used to improve the product performance. State-of-the-art CAD-tools, are not well suited for Additive Manufacturing as they are based on boundary structures where a solid object is represented by the surfaces of the inner and outer hulls of an object. The boundary structure approach was developed more that 3 decades ago to support design for subtractive/abrasive processes, processes that incrementally remove material from a solid block of raw material.
IsoGeometric Analysis (IGA) was introduced in 2005 by prof. Tom Hughes [1] to bridge the gap between CAD and Finite Element Analysis. The shape functions of finite elements were replaced by B-splines, introducing higher order continuity between elements and near exact reproduction of all CAD-shapes. However, going from boundary structure CAD models to 3-variate B-spline based IGA-models is similar in complexity of going from CAD-models to FEM-models. This triggered research into 3-variate B-spline/NURBS based CAD-models that could be directly used in IGA. 3-variate B-spline/NURBS based CAD-models allow the description of continuously varying properties inside an object. This can be done through addition 3-variate B-spline functions representing the desired properties. These functions are connected to the geometry through a shared parametrization.
For objects to be built from multi materials, is easy to see that such fields can be used for specifying the material mixture imitating RGB in colour representation. However, these fields also has a potential to be used as parameters for procedural generation of lattice structures: Required density; required geometry or property anisotropy, etc.
The CAxMan-project [2] addresses analysis based design for additive manufacturing using the representations and approach of IsoGeometric Analysis, taking aspect of additive processes into consideration already during design. The approach builds on the extension of ISO 10303-209 edition 3 [3] with respect to IsoGeometric Analysis and locally refined splines. The talk will address the approach of CAxMan and present results achieved. The CAxMan project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 680448”
References
[1] T.J.R. Hughes, J.A. Cottrell, and Y. Bazilevs, Isogeometric analysis: CAD, Finite elements, NURBS, exact geometry, and mesh refinement, Comput. Methods Appl. Mech. Engrg., 194 (2005), pp. 4135-4195.
[2] http://www.caxman.eu
[3] https://www.iso.org/standard/59780.html
IsoGeometric Analysis (IGA) was introduced in 2005 by prof. Tom Hughes [1] to bridge the gap between CAD and Finite Element Analysis. The shape functions of finite elements were replaced by B-splines, introducing higher order continuity between elements and near exact reproduction of all CAD-shapes. However, going from boundary structure CAD models to 3-variate B-spline based IGA-models is similar in complexity of going from CAD-models to FEM-models. This triggered research into 3-variate B-spline/NURBS based CAD-models that could be directly used in IGA. 3-variate B-spline/NURBS based CAD-models allow the description of continuously varying properties inside an object. This can be done through addition 3-variate B-spline functions representing the desired properties. These functions are connected to the geometry through a shared parametrization.
For objects to be built from multi materials, is easy to see that such fields can be used for specifying the material mixture imitating RGB in colour representation. However, these fields also has a potential to be used as parameters for procedural generation of lattice structures: Required density; required geometry or property anisotropy, etc.
The CAxMan-project [2] addresses analysis based design for additive manufacturing using the representations and approach of IsoGeometric Analysis, taking aspect of additive processes into consideration already during design. The approach builds on the extension of ISO 10303-209 edition 3 [3] with respect to IsoGeometric Analysis and locally refined splines. The talk will address the approach of CAxMan and present results achieved. The CAxMan project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 680448”
References
[1] T.J.R. Hughes, J.A. Cottrell, and Y. Bazilevs, Isogeometric analysis: CAD, Finite elements, NURBS, exact geometry, and mesh refinement, Comput. Methods Appl. Mech. Engrg., 194 (2005), pp. 4135-4195.
[2] http://www.caxman.eu
[3] https://www.iso.org/standard/59780.html
