Root Cause Analysis

SnRD Post-Processing proposes two modules: Modal Contribution and Modal Sensitivity.

Modal Contribution

The E-Line method is a time domain analysis approach, using Modal Transient Analysis, also known as the Modal Superposition Method. This enables a transition to the frequency domain.

(1)

U (t) = \sum_{i = 1}^{N} m_{i} \times Ψ_{i} (t)

Where:

$U (t)$ is the time domain displacement.
$N$ is the number of modes extracted.
$m_{i}$ is the Modal displacement for a mode $i$ .
$Ψ_{i}$ is the Participation factor for mode $i$ .

With all the above responses available in the standard outputs from OptiStruct Analysis, the Relative Modal Contribution [%] values can be calculated. These will describe the participation of a mode or modes on a peak of the time domain response.

Modal Sensitivity

Use modal sensitivity to live perform what-if studies by altering the time domain response of an E-Point or complete E-Line. This is achieved by decomposition of the Modal Superposition response, applying a factor (between 0 and 1) on selected modes, damping, and canceling or isolating them.