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Reference documentation for deal.II version 9.1.1
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Namespaces | |
Contravariant | |
Covariant | |
Piola | |
Rotations | |
Functions | |
Special operations | |
template<int dim, typename Number > | |
Tensor< 1, dim, Number > | nansons_formula (const Tensor< 1, dim, Number > &N, const Tensor< 2, dim, Number > &F) |
A collection of operations to assist in the transformation of tensor quantities from the reference to spatial configuration, and vice versa. These types of transformation are typically used to re-express quantities measured or computed in one configuration in terms of a second configuration.
We will use the same notation for the coordinates \mathbf{X}, \mathbf{x}, transformations \varphi, differential operator \nabla_{0} and deformation gradient \mathbf{F} as discussed for namespace Physics::Elasticity.
As a further point on notation, we will follow Holzapfel (2007) and denote the push forward transformation as \chi\left(\bullet\right) and the pull back transformation as \chi^{-1}\left(\bullet\right). We will also use the annotation \left(\bullet\right)^{\sharp} to indicate that a tensor \left(\bullet\right) is a contravariant tensor, and \left(\bullet\right)^{\flat} that it is covariant. In other words, these indices do not actually change the tensor, they just indicate the kind of object a particular tensor is.
Tensor<1, dim, Number> Physics::Transformations::nansons_formula | ( | const Tensor< 1, dim, Number > & | N, |
const Tensor< 2, dim, Number > & | F | ||
) |
Return the result of applying Nanson's formula for the transformation of the material surface area element d\mathbf{A} to the current surfaces area element d\mathbf{a} under the nonlinear transformation map \mathbf{x} = \boldsymbol{\varphi} \left( \mathbf{X} \right).
The returned result is the spatial normal scaled by the ratio of areas between the reference and spatial surface elements, i.e.
\mathbf{n} \frac{da}{dA} \dealcoloneq \textrm{det} \mathbf{F} \, \mathbf{F}^{-T} \cdot \mathbf{N} = \textrm{cof} \mathbf{F} \cdot \mathbf{N} \, .
[in] | N | The referential normal unit vector \mathbf{N} |
[in] | F | The deformation gradient tensor \mathbf{F} \left( \mathbf{X} \right) |