DNV Software is releasing new versions of Framework, Postresp, Stofat and Xtract, including updated features for the ISSC spectrum, the wind fatigue model, unit conversions and export model & result for external presentation.

New features
The new features and improvements in Framework 3.5-01, Postresp 6.2-04, Stofat 3.3-01 and Xtract 2.1-00, are described in the respective User Manuals. Alternatively, you may find a description from the program download site by selecting "Reasons for update". The new features may be summarized as follows (in addition there are other modifications as well as error corrections, for details please consult the Sesam Status List.)

Framework 3.5-01 (general part)

• Implemented the ISSC wave spectrum. Recommended sea spectrum from ISSC (International Ship and Offshore Structure Congress) has been implemented and called the ISSC wave spectrum. The spectrum is recommended for open sea conditions and fully developed sea by the 15th ITTC (International Towing Tank Conference). The parameters of the wave spectrum are significant wave height (Hs) and mean wave period (T1). The wave spectrum is associated with scatter diagram of type 'ISSC-SCATTER-DIAGRAM'. Hence new options have been added to the commands below: CREATE WAVE-STATISTICS, new select option: ISSC-SCATTER-DIAGRAM and ASSIGN WAVE-SPECTRUM-SHAPE, new select option: ISSC.
• Define reference Young's modulus for code check. Both AISC and Eurocode refer to modulus of elasticity defined in ksi and MPa respectively. In previous versions these built in reference values have been set to 30458 ksi and 2.1E5 MPa. For models using Young's modulus equal to 29000 ksi (corresponding to 2.0E5 MPa) some deviations in results could occur in code checks according to Eurocode and AISC. The user should define these two values consistent with actual modulus of elasticity used in the model. E.g. if using E = 2.0E11 Pa (N/m2) in the model; set E = 29000 ksi and 2.0E5 Mpa.
• Print effective modal mass. Now possible to print effective modal mass for selected mode shapes. The printed values equal the modal load factors for X, Y and Z-directions squared. The sum of the effective modal mass (for the selected mode shapes) is also printed.

Framework 3.5-01 (wind fatigue module)

• Assignment of coherence model. The user may select between three coherence models: GENERAL, GUSTO and NPD. The GENERAL coherence model is new model implemented and may be assigned to all wind spectra except the NPD spectrum. The GUSTO coherence model is the original model of the program. The NPD coherence model may now be assigned to all wind spectra. The NPD coherence model is always applied together with the NPD wind spectrum even if the GENERAL or GUSTO model is selected.
• Modifying the section dimensions for use in wind fatigue. A new command CHANGE WIND-FATIGUE SECTION-DIMENSIONS is implemented. The command makes it possible to change diameters and thicknesses of tubular members applied in the wind fatigue analysis. The modifications apply only to the wind fatigue module and may e.g be used to select the chord element of a joint where all members have the same cross section

Postresp 6.2-04

• Implemented the ISSC wave spectrum. Recommended sea spectrum from ISSC (International Ship and Offshore Structure Congress) has been implemented and called the ISSC wave spectrum. The spectrum is recommended for open sea conditions and fully developed sea by the 15th ITTC (International Towing Tank Conference). The parameters of the wave spectrum are significant wave height (Hs) and mean wave period (T1). The wave spectrum is associated with scatter diagram of type 'ISSC-SCATTER-DIAGRAM'. Hence new options have been added to the commands below: CREATE WAVE-STATISTICS, new select option: ISSC-SCATTER-DIAGRAM and ASSIGN WAVE-SPECTRUM-SHAPE, new select option: ISSC.

Stofat 3.3-01

• Table print of worst sea state part of damage fatigue results. A new option for table print of worst sea state fatigue results has been implemented in Stofat, see command PRINT FATIGUE-CHECK-RESULTS. The worst sea state is the sea state with largest fatigue damage and is printed for individual elements and hotspots. Printed results of worst sea state: Sea state number and wave direction, wave height and wave period, fatigue damage and fatigue life, names of applied wave spectrum, wave statistics and wave spreading.
• Implementation of ISSC wave spectrum. Recommended sea spectrum from ISSC (International Ship and Offshore Structure Congress) has been implemented in Stofat and called the ISSC wave spectrum. The spectrum is recommended for open sea conditions and fully developed sea by the 15th ITTC (International Towing Tank Conference). The parameters of the wave spectrum are significant wave height (Hs) and mean wave period (T1).The wave spectrum is associated with scatter diagram of type 'ISSC-SCATTER-DIAGRAM' in Stofat.
• Long term stress range calculation for defined probabilities. Long term stress ranges may be calculated for user defined probabilities. A maximum of 5 probabilities may be specified. Table print of stress ranges, return periods, exceedances and Weibull parameter for the defined probabilities is possible as well as print to the vtf file for graphic presentation in Xtract.
• Selection of element stress points for the fatigue analysis. Stress points of the +z side, -z side or both sides of a shell element may be selected for the element fatigue check.
• Deassignment of assigned wave spreading functions. Wave spreading assigned to a wave statistics model is removed by performing a new assignment with the NONE wave spreading.
• Check of cosine wave spreading for non-symmetric spreading. Use of symmetric cosine wave spreading may result in non-symmetric wave energy spreading if spacing of the wave directions in the integration range of the cosine function (90 deg. to both side of main direction) is not constant. Each wave direction with assigned cosine wave spreading is checked and information printed if symmetric spreading does not take place.
• Print of element material data. Print of material data assigned to current selection of elements is made possible by the command PRINT RUN-OVERVIEW ELEMENT-MATERIAL-DATA.

Xtract 2.1-00

• Export model & results to VTF for external presentation. The command 'File > Export to VTF' allows exporting a display scene, i.e. a model with results, to a VTF-file. This file may be opened in two Ceetron freeware software products: GLview 3D Plugin and GLview Express. The former is through installation embedded into PowerPoint and allows 3D manipulation of model with results inside a PowerPoint slideshow. The latter works similarly but as a separate program. This new feature allows distribution of a 3D model with results to anyone installing the freeware from Ceetron.
• Unit conversion. The command 'Model > Unit conversion' allows user specification of length and force units. Both units on results file and desired new units are specified. The new units are given in the Info box. 'Display > Information' allows switching information on units in Info box on and off
• Principal stress based on membrane stress components only. A new result attribute named PM-STRESS (available in positions Nodes, Elements and Element average) is available. It contains the components P1 and P2 that are principal stresses based on the membrane stresses. I.e. only D-STRESS components SIGMX, SIGMY and TAUMXY contribute.
• After replacing the previous Xtract and Siftooldll versions and installing the freeware from Ceetron save the enclosed PowerPoint file and two VTF-files somewhere (to same directory) and run the PowerPoint file in slideshow mode to learn about the new features
  

Modified input format
Please notice that existing Stofat input files should be modified in order to run using Stofat version 3.3-01 (for more details, please consult the updated user manual):

• CREATE FATIGUE-CHECK-POINTS ELEMENT-CHECK. Old command will not run
• DEFINE FATIGUE-RESULTS-VTF-FILE. Some old options will not run
• DEFINE FATIGUE-RESULTS-DUMP. New toggle button added
• PRINT FATIGUE-RESULTS-VTF-FILE. Some old options will not run

How to install
When upgrading existing result files as well as journal files can be used, except for Stofat where new features have made it necessary to modify some of the input format (see above).
You can install the programs by downloading the new program modules (zip-files) here.

Each program module should now be copied to your Sesam installation directory - or an alternative directory if you want to keep the old program versions. Notice that the Xtract installation zip-file also includes a new version of Siftool and a utility tool for installing a plug-in component from Ceetron to view VTF files in either GLview Express or as a plug-in to MS PowerPoint. The User Manuals are found here.

Please make sure you copy the updated manuals to your default installation directory; they can then automatically be found also when browsing the Sesam user documentation from Brix Explorer - Sesam Configuration.