# Modelling and Simulation of Traditional Craft Actions
## 3 Simulation Elements
### Material Properties  
Material properties express the functionality and manufacturability of materials. They may be functions of one or more independent variables, some of them being environmental conditions. Each material property is represented as a vector of one or more values. Most materials are isotropic; that is, their properties are equally expressed in different directions. When this approximation is insufficient (e.g., for wood or marble), materials are called orthotropic and treated independently per direction, and a definition of the intrinsic orientation of the material within the workpiece is additionally required. In Table 2, we classify material properties according to the affordance they avail and the action types defined in Section 3.1. Density is always accounted for as it determines the weight and momentum of objects. [PERSON]'s modulus measures how stiff a material is by comparing the amount of force applied to an object with how much it deforms. It is used for materials under stretching or compressing and is measured in Pascals (Pa). Elastic modulus is a broader term that includes [PERSON]'s modulus along with other measures like the shear modulus (resistance to twisting) and bulk modulus (resistance to volume changes). Ductility is a physical property of a material that describes its ability to be stretched, pulled, or drawn into a thin wire or thread without breaking. Ductility under tension involves tensile stress (pulling apart), while ductility under compression involves compressive stress (pushing together) [59]. Besides choosing the appropriate material property for \begin{table}
\begin{tabular}{c c c} \hline \hline  & **General (Move)** & \\ \hline Density & Mass per unit volume. & kg/m\({}^{3}\) \\ \hline Friction & The ratio of the force of friction between two bodies and the force pressing them together (normal force) & Unitless \\ \hline \hline \multirow{4}{*}{Hardness} & **Strength (Subtract, Form)** & \\ \cline{2-3}  & Ability to withstand localised permanent deformation & \\  & and/or resistance to deformation. & [PERSON] \\ \hline Tensile, compressive, & Parameters that describe material strength under & \\ shear strength & different loading conditions. & [PERSON] \\ \hline \multirow{4}{*}{Ductility} & Ability to undergo significant plastic deformation before & \\  & rupture or failure, measured by elongation at break and & \\  & reduction in area. & \\ \hline \hline \multicolumn{3}{c}{**Plasticity and Elasticity (Form, Interlock)**} & \\ \hline Elastic Modulus & Resistance to non-permanent, or elastic, deformation. & [PERSON] \\ \hline Young Modulus & Stiffness of material. & [PERSON] \\ \hline \multirow{2}{*}{Poisson Ratio} & Deformation (expansion or contraction) of a material in & \\  & directions perpendicular to the specific direction & \\  & of loading. & \\ \hline Tensile Strength & Amount of load or stress that a material can handle until & \\  & it stretches and breaks. & [PERSON] \\ \hline \multirow{2}{*}{Yield Strength} & Stress corresponds to the yield point (at which the & \\  & material begins to deform plastically). & [PERSON] \\ \hline Hardness & Ability to withstand localised permanent deformation & \\  & (resistance to deformation). & [PERSON] \\ \hline \multirow{2}{*}{Ductility} & Ability to be stretched, pulled, or drawn into a thin wire & \\  & or thread without breaking. & \\ \hline \multirow{2}{*}{Toughness} & The ability to absorb energy and deform plastically & \\  & before fracturing. & Joules/m\({}^{3}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Classification of material properties. the action, when studying ductile phenomena, the origin and pre-processing of the specific material need to be considered as fine-grained materials achieve higher compressive extensibility compared to annealed materials [60]. In some cases, we choose to disregard some material properties for simplification of simulation. First, properties irrelevant to the mechanical actions are not considered, such as electrical or magnetic properties.