Question

1.a Show that you understand what element distortion is by explaining the general problem caused by too distorted elements and drawing ideally and distorted elements of the following types: a) Solid tetrahedron b) Solid hexahedron c) Triangular 2D-element d) Quadrilateral 2D-element

1.b What are the thermal analysis equivalent parameters, and their corresponding units, of the following structural parameters ?

a) D isplacement

b) Strain

c) Stress

d) Load

e) Essential boundary conditions

f) Elastic supports   

Answer 1

In many nonlinear simulations the material in the structure or process undergoes very large deformations.
These deformations distort the finite element mesh, often to the point where the mesh is unable to provide accurate results or the analysis terminates for numerical reasons.These are more prodomient in  pure Lagrangian model of a problem is one where the mesh moves with the material,With this approach it is easy to track surfaces and to apply boundary conditions in the problem.The mesh may become very distorted if the material undergoes significant deformation,The quality of the results will deteriorate as the mesh becomes distorted. If many element are distorted then it is very difficult to produce convergence to the the solution. Plasticity, impact analyis like topic highly suffers from these types of problem.

Thermal analyis equivalent

Displacement: Temperature

Strain: Temperature Gradient

Stress: Heat flux

Load: Heat source

Essential boundary condition:Prescribed Temperature condition

Elastic support:Convection coefficient