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1.8  Release notes for SDT and FEMLink 7.6

• Key features
• Notes by MATLAB release
• Detail by function
• Developer notes

1.8.1  Key features

SDT 7.6 is compatible with MATLAB 9.4 (2018b) to 24.2 (2024b).

In the base and FEMLink modules, key changes of this release are

• A major update of the piezo/pzrel76.html documentation (see also piezo.pdf). Access points are piezo/p_piezo.html and piezo/d_piezo.html. In particular, many new tutorials have been written to help with sensor and actuator defintion, meshing methods, and state-space models with reduced systems.
• Parametric Experimental Modal Analysis: GUI integration. Video showcase is available in this post here.
• As of MATLAB 2025a, the MathWorks discontinued support for javaframe. This requires profound changes to the SDT graphical interfaces, which we have started addressing (thus limiting GUI work for this release). We expect to resume compatibility with MATLAB >= 2025a with the next SDT release. For the current release, this is only visible in the revised sdtweb _taglist.

SDTools also produces modules that are mostly integrated in custom industrial developments.

The associated developments are now listed here to ease tracking of our development efforts.

• visc viscoelastic vibration simulation and test analysis
  • state-space representations are now supported in the linear case. Temperature root locus in state-space form provided a more robust strategy for very heavily damped cases with multiple interacting modes.
  • work on handling unidirectional composites for constrained layer patches has progressed and topology optimization tools start to be functional.
  • direct FRF and state-space computations using pagemldivide, pageeig, ... have provided large speedup for specific cases. This affects parametric studies associated to reduced multi-models [2, 3] (distributed with visc or the ZParam module).
• Squeal module for squeal studies to enable deployment of SDT squeal analysis expertise
  • experimental work on the Harmonic Balance Vector model https://popups.uliege.be/2684-6500/index.php?id=260
  • numerical work has focused on reduced basis transients using SDT-nlsim.

1.8.2  Notes by MATLAB release

• This release is not compatible with MATLAB 2025a (in terms of SDT graphical interfaces) due to discontinued support for javaframe by the MathWorks. We expect to resume compatibility with the next SDT release, but this requires a profound rewriting of SDT GUI.
• MATLAB 9.4 (2018a) to 24.01 (R2024a). SDT & FEMLink 7.6 are developed for these versions of MATLAB and are fully compatible with them.
• Earlier MATLAB are no longer supported although significant aspects may still work.
• Earlier MATLAB releases are no longer supported.

1.8.3  Detail by function

SDT-base/SDT-FEMLink

• ans2sdt: notable speed improvements and extended superelement support
• cdm: is the new curve display model object. It will gradually group methods implemented in a less general setting in iiplot, so the currently documented uses are limited.
• d_imw: extended colorbar Cb styles, added tool-tips (descriptions of styles) to a number of cases. Extended automated report styles.
• fe2ss: was notably extended to implement interactions between feplot and iiplot figures : animate on frequency click, cursor on display, ... this is expected to still change notably for the next release and will be further documented.
• fe_exp: new command NumCheck to perform efficient FEM to FEM comparisons using expansion concepts.
• fe_quality: extended capability of degenerate elements handling with command CleanDegenRecast, now handling quadband hexa20elements.
• fe_range: multiple robustness issues as a transition to the parallel coordinate framework expected for the next release.
• fe_reduc: low level modifications associated with state-space generation phases. Examples are documented in in the new piezo/p_piezo.html.
• fe_sens: is converging towards a fully equivalent handling of sensors in both testing and simulation processes. The next steps are to revise the documentation to fully reflect the capabilities. ICP algorithm optimization to superpose to FEMs and generate distance map has been developed.
• fe_simul: was made more robust in the handling of sensors and various damping model handling strategies.
• fecom: improved the handling of selcut and material orientation maps.
• fegui: support of energy at nodes rather than elements was extended. Fast toggling of element visibility has progressed and will be further revised/documented with the new interface. A first GUI was developed to interact with surface matching results (fluid/structure interaction and contact problems).
• FEMLink: integration of systematic file type detection has continued.
• feplot: continued improvements linked to interactivity and on the fly restitution optimization
• fesuper: improved handling of superelement form transformations MacNeal to Craig Bampton, ... Optimized restriction of restitution shapes to partial display meshes selcut for large cases (shapes in the 100 GB range). First iteration on allowing transformations and checks as part of a loop doCheck subfunction.
• feutilb: new constraint control utility FixMultiSlave to resolve multiple slave issues. Capability to transform a load to an elastic superelement with associated non-linearity CaseLoad2SE-nlc to help handling loads induced by non-modeled actuators. Implementation of quality indicators for the MatchSurf procedure.
• fsc: improved handling of reduction processes
• idcom: Optimization and tracking methods are now available for automatic optimization of parametric EMA
• ii_mac: MDRE tab has been refined with a cleaner generation of analysis views (Exp+Test, Error fields,...) and the integration of automatic reporting. Messaging was improved and computation of FDAC (correlation of frequency responses with a large number of points) is now supported.
• nlutil: work on viewModel handling has progressed. Extensions linked to SDT-contact and SDT-visc are also reflected here.
• nor2ss: The ss2struct command has improved compatibility with the MATLAB ss object.
• polytec: improved support for the TimeScan mode where a few milliseconds of a limit cycle are measured thus providing a more accurate to the FastScan mode provided by https://www.polytec.com/.
• qbode: continued optimization and compatibility with MATLAB ss objects.
• sdtm: continues to be the place where methods of general interest are stored. Database handling (node, data, dtype, ...)
• sdtsys: continued extensions of experiments launched using sdtm.range.
• sdtweb: notable rewriting associated with the new help index and ability to search code with _mtag,_textag, ...
• ss2res: improved compatibility with fe2ss for interactivity on frequency responses.
• ufread: Import of transfers and geometry from https://www.optomet.com/ .mat output format

OpenFEM

The openfem folder contains a copy of the open source https://github.com/SDTools-support/openfem project which contains the FEM development by SDTools and others (INRIA initially, ...)

• fe_case: introduced urn to specify rigid motion of a face. Will be further documented with the description of numerical experiments.
• fe_mat: started support of Map:MatName and worked on unit system transformations.
• fe_mpc: increased robustness for RBE3: handling in alternative input formats, and bug correction in non-unit master weight handling.
• lsutil: significant extensions of EdgeSelLevelLines and cuts. That is only partially documented as the procedures are still being made more general.

SDT-visc

• d_visco: notable extensions of composite support for uni-axial constraining layers. Transition of the examples to sdtm.range experiment format. Initial work on topology optimization strategies. Extensions of fe_shapeoptim for material map orientation visualization.
• fe2xf: improved support of clustering strategies, work on interactivity (on the fly computation and animation of shapes on click in temperature/frequency/parameter maps).
• fevisco: MehPlies introduces support of ply meshing capabilities for laminated blades represented using volume elements.

SDT-nlsim, SDT-contact

• ctc_utils: revision of display procedures, conforming to nlsim performance evolution.
• vhandle.chandle: low level improvements linked to SDT-nlsim. These are associated to work on contact laws in mkl_utils used for reduced basis squeal computations.

support

The support folder contains a copy of the open source https://github.com/SDTools-support/support used for faster interactions on documentation/help developments.

• d_doe: Etienne Balmes (1)
• d_mesh: Improved support of meshes used in numerical experiments.

1.8.4  Developer notes

This section lists developments that can be of interest but are not sufficiently documented, robust or stable enough to be considered as supported.

• fe_caseg: improved handling of cuts and strain energy computations associated with topology optimization applications.
• sdtu: groups generic utilities implemented in the form of methods.
  • sdtu.f: file handling. Use methods sdtu.f to get a list.
  • sdtu.grep: equivalent of Unix grep.
  • sdtu.idx: supports indexing of source code, html documentation, tex and markdown documentation source files, some pdf files.
  • sdtu.ivec: implicit vector utilities.
  • sdtu.log: background support of logging capabilities
  • sdtu.pref: preference handling
  • sdtu.ui: user interface.
• omat: now supports element-by-element operations, corrected behavior associated to numel overload.
• vhandle.matrix: continued improvements of matrix handles for performance issues in time integration and large model handling.
• vhandle.nmap: generalization of the use of maps in many aspects of SDT.
• vhandle.tab: development work that will become visible with the future java script interface (expected for MATLAB 2025b)
• vhandle.uo: extended support of this object as a replacement of the java EditJ as part of the transition to java script MATLAB controls.
• vhandle.graph: Database handling tools (loading, saving, displaying...) and procedure to load main dock (Id, CoTopo, CoShape) from database