Structural Analysis

SEAM uses finite element analysis (FEA) to conduct stress analysis, and to evaluate strain, displacements and vibration within structures. For a given structure and type of loading, SEAM can develop an analysis strategy to investigate all possible modes of failure. We have experience in the analysis of all types and sizes of structures from electronic components to large structural frames, as well as in the simulation and analysis of metals, plastics, elastomers and composites. We conduct structural analysis to comply with industry codes and standards as required by inspectors and regulatory bodies.

Static Structural Analysis

Most structures experience loads which are applied slowly and do not vary much with time. The response of the structure can be investigated using a static structural analysis, as the dynamic response of the structure is small and can be ignored. Typical loads a structure may be exposed to include gravity, pressure, temperature, current, and environmental loads.

The range of structures and components that are typically assessed using static structural analysis is broad, and ranges across many industries. Some examples are: 

  • Structural framework
  • Machined parts
  • Pressure retaining components such as piping, vessels, and associated equipment, see also Pressure Equipment Design by Analysis
  • Bolted connections
  • Electronic components
  • Composite structures

Static structural analysis is typically used to assess the safety of the design against the following failure modes:

  • Plastic collapse
  • Cyclic strain accumulation
  • Fatigue and fracture
  • Buckling
  • Creep
  • Delamination

Sleeve stress thrird crimping cycle dies closed 300 dpi.pngcable stresses 300 dpi.png

Cable Crimping FEA Stress Contour Plot (Images courtesy of ESB International)

 
 

Dynamic Structural Analysis

Structures are often exposed to loading which varies over time, exciting the structure and causing it to resonate and vibrate. Depending on the level vibration and the nature of the structure, failure may occur by collapse or by fatigue. Some examples of conditions that may cause a structure to exhibit a dynamic response are:

  • Structures exposed to earthquake loading
  • Piping exposed to loading resulting from internal flow, such as flow induced vibration, acoustic pulsation, or slug loading
  • Equipment or structures attached to rotating machinery
  • Vortices shed when fluid or air flows past a structure can cause it to vibrate. This is typically considered in the design of chimney stacks, piping or bridge cables.
In order to ensure that the structure does not vibrate excessively, resonance must be avoided by ensuring that the load excitation frequencies do not coincide with the structural natural frequencies. SEAM performs random vibration, modal analysis, response spectrum, and time history simulations to assess the response of structures to various dynamic loading scenarios and to determine cyclic stresses and strains. This enables the optimisation or modification of structural designs in order to avoid vibration issues, and the calculation of the remaining life of structures subject to vibration.

Stresses in a Vibrating Pipe under Loading due to Internal Flow