Development Path

SHEAR7 undergoes constant development to meet the needs of the industry. This development is a result of the industry driven requirements, the implementation of results of experiments and research being conducted around the world, in particular that of the SHEAR7 JIP.

Shear7 Technology

SHEAR7 is the offshore industry’s leading software tool for the prediction of Vortex-Induced Vibration (VIV) with close to twenty years of industry use and continuous development. The program’s forte is the VIV response prediction of offshore structures subjected to spatially varying currents; realistic of ocean environments. The program enables users to estimate structural responses, drag force amplification factors and predict fatigue damage. SHEAR7 couples to other offshore system modelling tools such as Orcaflex and Flexcom enabling VIV assessment through the front end of these packages. It is simple and fast to run with all the results summarized in a convenient standard output file.

SHEAR7 is used throughout the world by engineers in Australia, Brazil, China, Denmark, France, India, Japan, Korea, Malaysia, Norway, Spain, UK and USA.

SHEAR7 v4.12a was released in July 2023. Program enhancements included:

Theoretical Improvements

  • A new lift table for high Reynold’s number has been developed for High Reynolds numbers and included in the new Lift Table file.
  • The Order that Power Zone Amplitude Limit (PZAL) And Power Cutoff are applied by SHEAR7 have been reversed (details for this change are provided in the User Guide).

Processing Enhancements

  • Inclusion of optional displacement time history output file *.s7dth

Bug Fixes

  • The stress range within the stress time history (.s7sth) output file was twice that within the other SHEAR7 output files (.s7out section 15.1 and 15.4, .s7plt, and .s7str).
  • Diameter units incorrectly converted for the c* calculation when using English Units.
  • When specifying the calculation option (block 5 line 1) in an input .s7dat file, a filename should only be required for calculation option 3, a unique-name.mds. The SHEAR7 input file parser incorrectly requires a filename to be provided after the calculation option number and causes an input error to be raised if not provided.

Academic License

  • The academic licence contains all changes above,  subject to the restrictions detailed in the User Guide. Please contact the SHEAR7 Support Team for additional information on the Academic License, including license terms.

Refer to the updated SHEAR7 User Guide for more information on updates included in the v4.12 release.

SHEAR7 v4.11 was released in July 2021. Program enhancements included:

Theoretical Improvements

  • Addition of a Varying Structural Damping “Stick-Slip” module for BETA testing. Refer to Appendix I for further information on this new module introduced in SHEAR7 v4.11.
  • Distributed amplitude iterations for more accurate hydrodynamic lift and damping (previously known as “Beta iterations”)
  • Inclusion of other VIV suppression default lift table values (Longitudinally Grooved Suppression – (LGS®)) post-critical Re number parameters
  • Inclusion of optional stress time history output file
  • Program added new input and output files for this module

Processing Enhancements

  • Adding SHEAR7 to the Windows Add/Remove Programs list
  • Allowing SHEAR7 to be installed and uninstalled in silent mode so that it does not generate any dialog boxes
  • Remove upper mode limit of 1000
  • File name changes
    • Changing all the S7 file extensions to avoid conflicts with other programs that produce .dat files. All files now use “.s7xxx” format. E.g. .dat -> .s7dat, .str -> .s7str
    • Users may now specify a unique name for the CL file (<unique-name>.CL) for improved quality control purposes or maintain as common.s7cL
    • Users may now specify a unique name for the .s7cat file (<unique-name>.cat) for improved quality control purposes or maintain as common.s7cat

Bug Fixes

  • An under relaxation factor has been adjusted to provide a more accurate convergence of the amplitude iterations.

Academic License

  • The academic licence contains all changes above which includes the new Varying Structural Damping “Stick-Slip” module for BETA testing. Subject to the restrictions detailed in the User Guide. Please contact the SHEAR7 Support Team for additional information on the Academic License, including license terms.

Refer to the SHEAR7 User Guide for more information on updates included in the v4.11 release.

SHEAR7 v4.10b was released in February 2019. Program enhancements included the following bug fixes:

Bug Fixes

  • A scenario was uncovered where the first mode was marked as potentially excited even though it was outside the shedding frequency range. For this particular scenario the bandwidth factor was being double counted to further extend the shedding frequency range, which captured the first mode as potentially excited.
  • Due to a minor inconsistency in the equations used for determining the potentially excited modes, and power-in and power-out regions, a scenario existed where the largest potentially excited mode (number) may not have been marked as potentially excited.
  • The highest and lowest Strouhal frequencies reported in Section 7 of the .out file do not have reduced velocity bandwidth factors applied, which returns the output to its v4.9 state.
  • Allow the power-in region of an excited mode to be comprised of a single node.

Academic License

SHEAR7 is now available under an Academic License. The Academic License, which is consistent with v4.10b, requires a separate license dongle and executable. This license was released in April 2019.

 The Academic License is provided with the following input limitations:

  • Overall Length limited to 800m (or 2624ft)
  • Limited to one S-N Curve
  • Limited to one S-N curve segment
  • Limited to one Local SCF

To Download: If your license is current you should have received an email with passwords and instructions on downloading this latest version. If you believe your license is up to date and you have not received this information or would like more information on SHEAR7 please contact us.

SHEAR7 v4.10a was released in February 2018 and included significant improvement to the modelling of spatially varying damping, resulting in a more accurate response prediction, particularly in regions outside of the excitation zone.

This release also resolved bugs relating to the reduced velocity bandwidth parameter and the required number of spatial segments.

For more information on these theoretical improvements, bug fixes, error handling, I/O handling, improved input validation, and command line options, please contact the SHEAR7 team.


SHEAR7 v4.9b was released in April 2016. Program enhancements included:

Theoretical Improvements

  • The definition of Uf have been revised based on recent research findings. Uf is defined as the RMS of the of the current speeds in the power-in region for the excited mode.
  • Note that Uf is used in the calculation of cf*
  • Please note, the parameters Af*, cf* and Uf are part of ongoing research. These parameters are intended to be interpreted in the context of being an ongoing Research and Development activity. Af* and cf* are calculated using the reference diameter which is specified by the end user in Block 5.

Bug Fixes

  • Refinement of the convergence criteria applied to the beta iterations to resolve a bug causing the beta iteration for particular cases to cease after one iteration when convergence has not been reached. The beta iteration convergence tolerance was also decreased from 0.05 to 0.01
  • Fixed a bug in Section 11 of the .out file where the Uf values were reported as Uf2
  • Resolution of a memory allocation bug where the number of modes was greater than the number of nodes

Processing Enhancements

  • SHEAR7 now supports the three Windows versions of Windows 7, Windows 8, and Windows 10
  • SHEAR7 is now compiled as a 64 bit program to improve memory allocation and overall performance
  • A 32 bit version of the program is included as part of the standard installation to provide compatibility for users with 32 bit versions of Windows

SHEAR7 v4.9a was released in December 2015. Program enhancements included:

Theoretical Improvements

  • Integration of Higher Harmonics correction to take into account observations from some experimental and field data. The user also has the option of running the program without activating the Higher Harmonics correction factor.

  • Implementation of the non-dimensional parameters Af*and cf*:

    1. cf* is defined as the flexible cylinder equivalent damping parameter and improves on the previous c* parameter by capturing the role of damping in the determination of the VIV of flexible cylinders in sheared flow.

    2. Af* is defined as the flexible cylinder equivalent dimensionless response amplitude. The goal of Af* is to provide a single number that characterizes the responses for the entire flexible cylinder by using the average of the RMS response in the power-in region.

    3. Both Af* and cf*are calculated based on a reference diameter specified by the user in the input .dat file.

    4. Based on new theory developed that represents a flexible cylinder by an equivalent spring-mounted rigid cylinder, the product of Af* and cf* equates to an equivalent flexible cylinder lift coefficient.

  • Refinement of the beta calculation to represent the ratio of the spatial average RMS modal displacement for all modes (resonant and associated) to the spatial average RMS resonant mode displacement.

Bug Fixes

  • Resolved bug when using beta iteration where the .fat file would be written during each iteration. The .fat file will now only contain the results after the final beta iteration.

  • Resolved bug for situation where SHEAR7 would fail to exit for particular cases when no VIV response was predicted.

  • Resolved bug in the structural damping term used to calculate the model power in some cases.

Processing Enhancements

  • Development of a more robust regression testing program for verifying the SHEAR7 installation for use on multilingual Windows OS installations.

  • Further code refactoring leading to decreased runtime and improved maintainability.

I/O Data Handling

  • Warning messages have been improved and are included in the.out file for all outputs.

  • Reporting of the Af*, cf* and Uf values in the .out file.

Regression Tests

  • The regression test suite has been expanded both in breadth and quantity, in order to extend the verification checklist to include the newly added features and fixes to the bugs.

Other Versions

SHEAR7 Development Path History Table

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