Transient analysis of structures


Investmech offers the structural integrity assessment and certification of structures subject to transient loads and consequential responses.  Where the transient inputs are not known, responses van be measured on existing structures and inputs inferred using autoregressive calculations.  Transient analysis of non-linear contact bodies and coupled systems are time consuming and may take a long time to complete.

System response with a known transient inputs

The process:

  1. Generate a finite element model of the structure.
  2. Define the transient structural inputs and apply to the model.
  3. Finite element analysis based transient modelling.
  4. Use results for structural mechanics, vibration severity, etc

Structures under steady-state vibrating conditions

According to the lumped mass theory, the dynamic response of a super structure is the sum of the responses of the individual natural modes at their respective natural frequencies.  Resonance is in most cases the cause of excessive structural responses, even a distance away from the source.  Investmech ensures that vibrating sources in structures are positioned such to minimize excitation of structural natural modes (resonance).  A harmonic modal analysis is sufficient for this purpose.

System response with unknown transient inputs

This is the case with existing structures giving high vibrations and unpredicted failures.  The responses can be easily measured, but, the structural inputs are unknown and need to be determined for design purposes.  The process:

  1. Responses are measured (strain, acceleration, pressure, flow, temperature, etc.)
  2. Mathematical model.
  3. Characterize the mathematical model
  4. ARX or NARX to iterate structural inputs
  5. Design modifications to ensure compliance with mission profile and standards driven requirements.