03+04 - 2D Solids - 3D Solids

Question 1

2D trusses

Answer 1

• bar-like structures

- resist axial forces only

Question 2

Workflow for 2D trusses

Answer 2

• stiffness matrix for all e/
• global stiffness matrix
• global force vector
• BCs
• solve global eq° syst
• calc internal forces

Question 3

2D solids

Answer 3

• Hooke’s law of elastic solids
• Poisson’s ratio
• k = element stiffness matrix
• B = matrix linking nodal DOF and strains
• C = matrix linking stress and strains
  k = integr(B.C.B^T.dV)

Question 4

Triangular elements

Answer 4

• 3-node version = linear displacement field, 6 DOF

- 6-node version = quadratic displacement field, 12 DOF

Question 5

3D solids

Answer 5

• assumed solution is difficult to solve
• Hooke’s law
  k = integr(B.C.B^T.dV) can be used generally

Question 6

Tetrahedral elements

Answer 6

• 4-node = linear (12 DOF)

- 10-node = quadratic (30 DOF)