# hyper elasticity

## Mathematically exploring wrinkle evolution

Wrinkling is one of the most important mechanical deformation modes (for example, buckling and crumpling) that are omnipresent in our daily life: for instance, wrinkled fingers after soaking in water for a prolonged time, the folds within the brain, and metal wrinkles after a car collision, to name a few.

## Curvature tunes wrinkling in shells

Transverse wrinkles usually emerge in a uniaxially stretched elastic film and can be suppressed upon further tension, which is an instability-restabilization behavior due to the nonlinear competition between stretching energy and bending energy. Here, we show that curvature can effectively and precisely tune the wrinkling localization and amplitude.

## 2D Mooney Rivlin Strain Energy Function

Hi,

I want to model a tissue using the Mooney Rivlin strain energy function. However, I am currently working in 2D (plane stress or plane strain would do). I only found the 3D material model for the strain energy density function online. What modifications should I make for converting it to 2d? I read that there is only 1 parameter required for the 2D case as opposed to the 3D case. What is the equation of this function? Is there any relation between the parameter C10 and C01 of the 3D case, and C1 of the 2D case for the same material?