Category: News

SDT 7.5 is compatible with MATLAB 9.4 (2018b) to 24.1 (2024a). In the base and FEMLink modules, key changes of this release are

• To answer customer requests on making numerical and test processes accessible through GUI, revision and extension work has continued. In particular
  • for the tabs Ident identification of modal tests, MAC shape correlation, MDRE expansion, Report automated report generation.
  • This is enabled by the continued rewrite of the SDT handle and sdtm allowed implementation of generic utilities transversely used in SDT. urn resolutions for object search urnObj. Callback and string formatting urn_fmt are now more explicitly documented. User readability of parameters is better supported using vhandle.uo objects. Integration of graphical tables is now uniformly supported by vhandle.tab.
  • code was made compatible with the deployment of GUI using the MATLAB Compiler and Runtime license.
• Parametric superelement/reduced model handling continues to be a key capability that differentiates SDT from other software. The latest developments are
  • uniformisation efforts to render SDT a FEM code neutral import form the major software (NASTRAN, ANSYS, Abaqus, …). This has driven recent FEMLink developments of nasread, ans2sdt, abaqus, and documentation efforts SeImport.
  • to answer the need to efficiently animate models in tens of million of DOF and deal with confidentiality issues, new level-set based model selections for display as plane cuts combinations for feplot, see selcut.
  • GUI interactions between state-space building fe2ss  frequency response computations qbode, and state-animation have been notably extended.
  • ability to use superelements in test-analysis correlation processes
  • parametric superelements deal with reduced models with stiffness, complex modulus, mass, thickness, … aggregated in element groups zCoef or distributed in non-linearities NLdata.
  • Integration of parameter inputs in abaqus for SDT compatible types.
  • for large FEM, DOE, JobH applications, out-of-core functionalities have been thoroughly revised and extended. Revision of sdthdfmethods for HDF5 support with optimized read/write capabilities and improved robustness. Implementation of omat object for out-of-core numerical data handling, supporting several underlying file strategies (extended v6, low level HDF5 or high level MATLAB builtin commands HDF5).
  • job generation and monitoring for abaqus, combined with module SDT/JobH
  • cases reduced using nominal periodicity and extendend to variable properties  [2, 3, 4, 5]
• In relation to the experimental vibration applications
  • ufread and fe_sens support better channel label translation
  • on the experimental modal analysis side, the handling of parametric tests (dependence on temperature, loading, amplitude, …)
• To support of the development of efficient custom solvers
  • low level optimization associated with time integration continued with performance optimization in vhandle.matrix, viscoelastic transient models, …
  • Contact support for ans2sdt and abaqus, combined with SDT/Contact, or translated as MPC.
  • Moving contact of surfaces was notably extended for the simulation of rail-wheel contact problems.
• Piezo capabilities for active control and SHM applications, were continued and the associated documentation (https://www.sdtools.com/help/piezo.pdf) will be updated soon.

The major revision 7.2 was only made available as a beta version, with the stable version skipped due COVID related constraints.

SDT 7.3 is the only version fully compatible with MATLAB 9.4 (2018b) to 9.8 (2020a) mostly due to changes in the representation of complex numbers in MATLAB. Key changes of this release are

• a major rewrite of the SDT handle object with major impact on GUI performance and compatibility with expect future changes in MATLAB GUI. sdth.urn provides a general mechanism for Uniform Resource Names which can now be used to designate and select many GUI or model components.
• the introduction of the +vhandle package of classes to upgrade earlier functionality implemented in v_handle. In particular, vhandle.matrix provides a user readable access point to C libraries linked into the mkl_utils mex file corresponding to matrix like operators, but with possible parallel or initialization/repeated call (called inspector/executor by INTEL) optimization. This has provided speedup factors between 2 and 100 for a range of high performance time computations using both implicit or explicit time schemes. The SDT/nlsim token may be required for calls to the nl_solve diagNewmark solver (non-linear time domain transients in modal coordinates) and to the nl_solve expNewmark (explicit time solver). The vhandle.chandle object is used to provide init/call separation for non matrix like objects.
• on the experimental modal analysis side, the handling of parametric tests (dependence on temperature, loading, amplitude, …)

For femlink the main changes were related to GUI and superelement import. For MATLAB compatibility see section 1.10.2.

SDT 7.4 is the only version fully compatible with MATLAB 9.4 (2018b) to 9.12 (2022a) mostly due to changes in the representation of complex numbers in MATLAB. Key changes of this release are

• the introduction of the +vhandle package of classes to upgrade earlier functionality implemented in v_handle. In particular, vhandle.matrix provides a user readable access point to C libraries linked into the mkl_utils mex file corresponding to matrix like operators, but with possible parallel or initialization/repeated call (called inspector/executor by INTEL) optimization. This has provided speedup factors between 2 and 100 for a range of high performance time computations using both implicit or explicit time schemes. The SDT/nlsim token may be required for calls to the nl_solve diagNewmark solver (non-linear time domain transients in modal coordinates) and to the nl_solve expNewmark (explicit time solver). The vhandle.chandle object is used to provide init/call separation for non matrix like objects.
• on the experimental modal analysis side, the handling of parametric tests (dependence on temperature, loading, amplitude, …)
• full rewrite of fluid structure interaction implementation in fsc. Added Transmission Loss and Rayleigh integral computation capabilities.

Etienne Balmès, CEO of SDTools was invited as a keynote speaker at the ISMA (International Symposium on Modal Analysis) conference in Leuven, Belgium on September 17, 2018.

ISMA 2018 is the 28th international conference in a series of annual courses and biennial conferences on structural dynamics, modal testing and noise and vibration engineering, organised by the Department of Mechanical Engineering of the KU Leuven., and is a reference in the field of structural dynamics and vibro-acoustics.

Shapes & DOF: on the use of modal concepts in the context of parametric non-linear studies

copy of the slides (pdf)

Abstract:
Physical responses tend to lie within restricted subspaces even for parametric problems. For a given subspace, the choice of a basis defines Degree Of Freedom (DOF) and this choice may give interesting meaning to the associated amplitudes. Classical modal analysis builds subspaces combining modeshapes and static responses. Parametric loads for non-linear, damped, variable, … structures are discussed to extend the theory and illustrated for test and simulation cases. Challenges in shape extraction and basis generation techniques are then detailed. Introducing the ability to manipulate models with variable junction properties, component material and geometry, load and operating conditions, … opens new questions on the quantification and tracking of changes and objectives throughout design exploration. The definition of a reference linear system and the use of global and/or local modal DOF are shown to provide an interesting perspective.