1. What is the key characteristic of nonlinear FEA?
The principle of superposition applies The principle of superposition does not apply; response is not proportional to load Only linear materials are used Small deformations only
2. Which is NOT a source of nonlinearity in FEA?
Material plasticity Large deformations Linear elastic material with small strains Contact between bodies
3. What is material nonlinearity?
Large deformations Nonlinear stress-strain relationship (e.g., plasticity, hyperelasticity) Changing boundary conditions Mesh refinement
4. What is geometric nonlinearity?
Nonlinear material behavior Large deformations or rotations that change the structure's stiffness Nonlinear boundary conditions Nonlinear mesh
5. What solution method is typically used in nonlinear FEA?
Direct solution of [K]{u} = {F} Iterative methods (e.g., Newton-Raphson) Eigenvalue extraction Modal superposition
6. What is 'plasticity' in material nonlinearity?
Elastic deformation that recovers Permanent deformation after yielding Thermal expansion Creep at high temperature
7. What is 'hyperelasticity'?
Linear elastic behavior Nonlinear elastic behavior typical of rubber-like materials Plastic deformation Brittle fracture
8. What is a 'load step' in nonlinear analysis?
The total applied load A portion of the total load applied incrementally to trace the nonlinear response A boundary condition A material property
9. What is convergence in nonlinear FEA?
Mesh refinement When the iterative solution reaches equilibrium within a specified tolerance Applying more loads Changing material
10. Why is nonlinear FEA more computationally expensive than linear FEA?
It uses more elements It requires iterative solutions at multiple load increments with stiffness matrix updates It has more boundary conditions It uses different software