What is digitalis 3d ?
Digitalis 3d aims to facilitate digital design of intricate lattice structures with controlled local and global properties. It comes as a plugin to the 3d modelling software Rhinoceros and its graphical algorithm editor Grasshopper and supports smart and flexible automatic generation of 3d lattices with finely tuned local structural, mechanical and porosity properties. From built-in interactions with established commercial finite element software to instantaneous porosity measures, digitalis provides a neat toolbox for evidence-based structural optimisation.
Digitalis enables users to harness the growing capabilities of additive manufacturing by providing control over individual strut geometry. This is of particular interest when the functionality of the constructs is directly impacted by their structure. As an example, digitalis is currently being used to design microscale scaffolds for bone tissue engineering with controlled mechanical stimulation of biological cell populations. Relying on smooth interactions with finite element solvers, digitalis also allows for reliable assessment of mechanical behaviour, enabling users to investigate novel structures.
Parametric design allows for a great freedom in creating homogeneous and heterogeneous lattice structures. Designs are automatically generated based on a number of user-defined parameters including arbitrary outer shape, unit cell topology, limit strut radii, porosity field, loading scenario, and target deformation under loading. Global and local design constraints enable the generation of intricate structures.
Porosity measures in computer aided design are often conducted using solid geometry differences (boolean operations) which rely on complex computations of surface intersections. These operations require significant computational power which slows down the design process, and do not always converge to the solution. Instead, mathematical functions have been implemented into digitalis to instantly estimate porosity within the structural cells based on their individual strut radii. This allows for quick evaluation of local and global porosity within the designs.
Digitalis supports translation of lattice designs and loading scenarios to and from finite element models made of beam and shell elements. Mechanical evaluation of the lattice designs such as stress/strain analyses or buckling tests can then be run in minutes. Currently supported finite element formats include Abaqus and Karamba.
Iterative structural adaptation algorithms drawing from published research have been implemented to automatically modify individual strut cross-sections in order for the designs to reach user-defined local or global properties such as target deformation under loading or specific porosity field.
In addition to its interactions with finite element software, digitalis is easily integrated within the Rhino/Grasshopper environment and its multiple open or commercial plugins, creating a wealth of opportunities for combining design refinement capabilities.