Orcina news

It’s been over a year since OrcaFlex 10.1 was released, which means it is time for the 2017 major release, version 10.2. The software was finalised and built on 24^th November. All clients with up-to-date MUS contracts should receive the new version by early December.

We have been blogging regularly through the development process and these posts give a good overview of the more significant enhancements in 10.2. For convenience, here are links to each of those posts:

• Line feeding
• New line clearance results
• Coupled object modal analysis
• Vessels and 3D buoys can be slave objects
• Line statics policy
• Support and constraint release
• Vessel calculation mode
• Text labels on 3D views
• Undo
• Compound properties report
• Documentation

These are the most important developments, in our opinion. As always there are a great many more enhancements which are documented in the What’s New topic for 10.2. Any known bugs will be listed at the support page for the 10.2 release.

For the final post in our series on upcoming developments for version 10.2, we look at line feeding. Line feeding allows line to be dynamically fed into, or out of, the active model.

OrcaFlex 10.2 is very nearly ready to be released and we expect this to happen in the next fortnight. In the meantime, we hope that this article whets your appetite!

Continue reading “Upcoming in OrcaFlex 10.2: Line feeding”

It’s been a little while since we posted in our series on upcoming developments for version 10.2. We’ve been busy finishing off development for the release, and hosting our annual series of user group meetings.

OrcaFlex 10.2 is very nearly ready to be released and we expect this to happen in the next fortnight. In the meantime this post introduces two new features that enable text labels to be displayed in 3D views.

Continue reading “Upcoming in OrcaFlex 10.2: Text labels on 3D views”

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.

A patch to upgrade from earlier releases of 10.1 is available. If you would prefer to receive version 10.1e on CD please contact us.

Continuing our series of posts on upcoming developments for version 10.2, we consider a number of enhancements to the line clearance results.

Historically, OrcaFlex has offered results reporting the clearance between lines. These results report the shortest distance, in 3D space, between lines. Results are available for clearance between centrelines or between contact surfaces. Some OrcaFlex applications, for example riser / pipeline crossing analysis, call for clearance distances measured horizontally or vertically. A number of new results variables have been introduced in 10.2 to address these requirements.

Continue reading “Upcoming in OrcaFlex 10.2: New line clearance results”

Continuing our series of posts on upcoming developments for version 10.2, we consider a couple of enhancements to the support and constraint objects.

OrcaFlex objects can be connected to each other, so that the connected objects move together. In addition, certain types of connections can be released at defined points in the simulation. For example, line, link and winch connections can all be configured to release at the beginning of a specified stage in the simulation. Version 10.2 introduces the same capability for supports and constraints.

Continue reading “Upcoming in OrcaFlex 10.2: Support and constraint release”

Continuing our series of posts on upcoming developments for version 10.2, let’s now look at a further relaxation of the rules relating to object connectivity.

In version 10.0 we made it possible to connect lines to lines and to form chains of connections, e.g. 6D buoy1 is connected to 6D buoy2, which in turn is connected to 6D buoy3 etc. In version 10.1 the constraint object was introduced, and mid-line connections were enabled.

In version 10.2 it will be possible to connect both vessels and 3D buoy objects as slaves of other objects.

Continue reading “Upcoming in OrcaFlex 10.2: Vessels and 3D buoys can be slave objects”

Continuing our series of posts on upcoming developments for version 10.2, we now move to an important enhancement to modal analysis. This development has aspects in common with another new feature, line statics policy, which we have discussed in an earlier post.

OrcaFlex modal analysis calculates modes for individual lines or for the entire system. The individual line option is commonly used to generate mode shapes for use in an external VIV analysis program like SHEAR7 or VIVA. Modal analysis for an individual line is based on the assumption that the line end nodes are fixed, and the remaining nodes in the line have freedom. For many riser or umbilical configurations it is perfectly reasonable to use these modes in a VIV analysis. However, there are some systems for which this approach is not appropriate, and the new coupled object modal analysis feature is intended to addresses this limitation.

Continue reading “Upcoming in OrcaFlex 10.2: Coupled object modal analysis”

We have somewhat neglected our series of posts on upcoming developments for version 10.2 of late, mostly because we have been working flat out on some new features. In this post we will cover multi-level undo and redo in the user interface.

Continue reading “Upcoming in OrcaFlex 10.2: Undo”

Continuing our series of posts on upcoming developments for version 10.2, we look at some enhancements to static analysis.

Version 10.0 relaxed the rules for connecting objects together, one aspect of which was allowing lines to be connected to other lines. This new flexibility had a number of consequences for static analysis of lines. In version 10.0, these consequences were dealt with in a very simple manner and in many situations that approach worked perfectly adequately. However, some models that took advantage of more general connectivity proved difficult to handle in static analysis. In version 10.2 we have introduced some new functionality to address these issues.

Continue reading “Upcoming in OrcaFlex 10.2: Line statics policy”