FEM Structural Analysis
Stress, deformation, and buckling analysis
Overview
Structural analysis evaluates how your design responds to mechanical loads. confBuild supports four structural analysis types, from simple linear static to advanced nonlinear and buckling simulations.
Static Linear
Standard stress & displacement
Static Nonlinear
Large deformations & plasticity
Buckling
Critical load factors
Prestress
Initial stress states
Static Linear Analysis
The most common analysis type. Computes stress and displacement under static loads assuming linear elastic material behavior and small deformations.
When to Use
- Standard load-bearing components under normal service loads
- Deformations are small relative to the part dimensions
- Material remains in the elastic range (below yield strength)
- Quick design validation and safety factor checks
Configuration
analysisType
static_linear
Analysis type selector
No additional parameters needed — this is the simplest analysis to set up.
Output Fields
stress_von_mises
Von Mises equivalent stress (MPa)
stress_principal_1/2/3
Principal stresses
displacement_magnitude
Total displacement
displacement_x/y/z
Component displacements
Static Nonlinear Analysis
Handles large deformations and material plasticity using an iterative Newton-Raphson solver.
When to Use
- Large deflections where geometry changes significantly under load
- Material undergoes plastic deformation (beyond yield)
- Rubber, elastomers, and other hyperelastic materials
- Post-buckling behavior analysis
Configuration
analysisType
static_nonlinear
Analysis type selector
nonlinearMaxIterations
20
Maximum Newton-Raphson iterations
nonlinearTolerance
1e-6
Convergence tolerance
Buckling Analysis
Determines the critical load at which a structure becomes unstable and buckles. Returns buckling load factors and mode shapes.
When to Use
- Slender columns and beams under compressive loads
- Thin-walled shells and plates
- Determining the safety factor against buckling
- Identifying the buckling mode shape
Configuration
analysisType
buckling
Analysis type selector
bucklingNumModes
3
Number of buckling modes to compute
Interpreting Results
The buckling analysis returns load factors. A load factor of 2.5 means the structure buckles at 2.5 times the applied load. The critical (lowest) buckling factor determines the design safety margin.
- Factor > 1.0: Structure is safe under the applied load
- Factor < 1.0: Structure will buckle before reaching the applied load
- Design codes typically require factors of 2.0–3.0 for safety
Prestress Analysis
Apply initial stress states for bolted connections, pre-tensioned cables, or shrink-fit assemblies using Code_Aster's CREA_CHAMP command.
Configuration
analysisType
prestress
Analysis type selector
prestressType
bolt
Type: bolt or cable
prestressForce
50000
Prestress force in Newtons
prestressDirectionX
0
Direction vector X component
prestressDirectionY
0
Direction vector Y component
prestressDirectionZ
1
Direction vector Z component
Safety Factor
confBuild automatically calculates the safety factor from your simulation results.
Calculation
Safety Factor = Yield Strength / Max Von Mises Stress Yield Utilization = (Max Stress / Yield Strength) × 100%
- SF > 2.0: Safe — comfortable margin (shown in green)
- SF 1.0–2.0: Warning — low margin, review design (shown in orange)
- SF < 1.0: Critical — material will yield, redesign needed (shown in red)
Best Practices
Tips for accurate structural analysis.
Recommendations
- Always start with linear static analysis before moving to nonlinear
- Check that displacements are small (less than ~10% of part size) for linear analysis validity
- Verify boundary conditions: under-constrained models won't solve, over-constrained ones give artificially low stresses
- Refine mesh in areas of high stress gradients (near holes, notches, fillets)
- Compare results against analytical solutions when available