MSR/articles/Videos descriptions.md

#description

# Finite element method
full notes : [[Finite element method]]

### Weak Formulation
[video](https://www.youtube.com/watch?v=xZpESocdvn4) *(30min)*

The weak formulation is the formulation of the differential equation so that it becomes solvable using the finite elements method.

This video shows how the weak formulation is derived from the initial problem, and its use.

### Mathematical Finite element method base
[video](https://www.youtube.com/watch?v=1wSE6iQiScg) *(40min)*

The finite element method is a mathematical method to be able to computationally solve a differential equation.

The core of the method is to discretise the problem, because computer cannot solve the problem analytically.

# Continuum mechanics
full notes : [[Continuum Mechanics]]

### Continuum mechanics
[video](https://www.youtube.com/watch?v=rhDkluTuWlQ) *(10min)*

This video goes over what is continuum mechanics, and the uses of fields to describe matter. It presents as well the boundary value problem.

### Strain tensor formula
[video](https://www.youtube.com/watch?v=X-H3Fwdm-kI) *(10min)*

The strain tensor is the symmetric part of the gradient of the displacement field vector.
This video manages to make this confusing statement a lot clearer.

### Visualizing the strain tensor
[video](https://www.youtube.com/watch?v=UQ4GnWACesY) *(10min)*

This video makes the physical effect of each element of the tensor more apparent.

### Stress and traction
[video](https://www.youtube.com/watch?v=NtTVEzZS3Bg) *(10min)*

In continuum mechanics, the force over an area is not the stress, it is traction. This video helps getting a clearer understanding of the stress tensor.

# Laminate analysis

### Composite materials course
[video](https://www.youtube.com/watch?v=j3rvtgqrGsQ) *(1h30)*

This video is a course on the analysis of composite laminate. Mainly the maths to compute the stress/strain relationship with discrete layers.
(see [[Layerwise Theories]])

## Modeling layered composite
[video](https://www.comsol.fr/video/modeling-layered-composite-structures-with-comsol-multiphysics-nov-29-2018) *(1h)*

This video exposes multiple models for composite laminates, for example equivalent single layer (eql) and layerwise (lw)
(see [[Composite laminate models]])


# Failure theories
full notes : [[Failure Theories]]

### Failure theories
[video](https://www.youtube.com/watch?v=xkbQnBAOFEg) (15min)

This video presents a few failure theories, and their physical meaning :

Ductile materials :
- Tresca
- von Mises

Brittle materials :
- Coulomb-Mohr

# Polymers

## What are elastomers ?
[video](https://www.youtube.com/watch?v=ZUlQXcm5A4o) (3min)

This video gives a brief overview of what are [[Elastomers]]

Elastomers are polymers which displays [[Viscoelasticity|viscoelastic]] properties, they have a larger elastic deformation domain than other polymers, because they are lightly-cross linked.

## Polymer course - part 1
[video](https://youtu.be/CF6x3UVD6_I?si=OCep-ABzbdi2thwv)
#### Homopolymers vs Copolymers
Homopolymers are constructed with a single repeating monomer
Copolymers are constructed with more than one monomer, can be :
- alternating # - * - # - *
- block # - # - # - * - * - *
- graft (with branches)
- random
#### Chain structure classification
Linear polymer chain : almost only thermoplastics
*(slide past one another)*

Branch polymer chain structure : usually thermoplastic, but depend on branches
*(slide, but can catch branches)*

Star polymer chain, all branches from one central monomer : thermoplastic/thermoset
 
Polymer networks,lot of cross linking : almost only thermosets

Interpenetrating polymer networks, that are intertwined.

#### Thermoplastics vs Thermosets

thermoplastic : heat -> mold -> cool -> strengthen
(can be recycled)

thermoset : heat -> burn
but better hold shape and strength when heated
(3d cross linking)