We have just released a minor upgrade to OrcaFlex, version 10.1e. This minor upgrade fixes the following bugs:
- In earlier OrcaFlex versions, when importing vessel type data from AQWA, both difference frequency QTFs and sum frequency QTFs were conjugated upon import. After feedback from users, we now have a more complete understanding of the AQWA QTF output conventions and load calculation. With this release, OrcaFlex no longer conjugates the sum frequency QTF values. We believe that this change ensures that the QTF load calculations performed by OrcaFlex match those performed by AQWA. If existing simulations need to be run again because of this issue, note that OrcaFlex sum frequency QTF load will only change if the AQWA QTF data are first re-imported into OrcaFlex.
- For frequency domain analysis, the ZZ Stress process reported through the API, could be 180° out of phase. The error only arises when using a nonlinear Young’s modulus, and for sections of line in mean compressive stress.
- The Line Type Wizard for Umbilicals calculated EA and EI incorrectly if the model force units were not set to kN.
- Previously, when conducting a frequency domain solve, at low or combined solution frequencies, the analysis could fail and present an Argument out of range error message. This affected models containing vessel types with no wave drift QTF data present.
- The bulk modulus data for 3D buoys, 6D buoys and lines specifies the compressibility of the object. When the fluid pressure exceeds the bulk modulus, the formula for compressed volume breaks down and OrcaFlex uses a value of zero. Unfortunately, the related code that calculates variation of compressed volume with depth does not handle this case correctly which in turn leads to statics and dynamics calculations failing. This problem affected line objects from 9.1a, and buoy objects from 10.0a.
- For frequency domain analysis, the external load on 6D lumped buoys associated with a dynamic change in the proportion wet was 180° out of phase. This only affected 6D lumped buoys that were partially submerged, i.e. surface piercing, in the static state.
- Fatigue analysis based on frequency domain simulations did not take account of stress loading factors.
- The extreme statistics results diagnostic quantile plots were not being drawn correctly for the Weibull distribution. Specifically, the fitted model quantiles (along the x-axis) were calculated incorrectly. These plots are intended to provide support (or otherwise) for your choice of fitted distribution, so this bug might have influenced your interpretation of the validity of this choice.