MARS release notes

MARS 1.3.0 release notes

Bolt Static Analysis v1.2.0 – Comprehensive analysis

  • Various changes to parameters notation, both in the user interface and in the report, to improve consistency between them

 

  • Eliminated the bolt group parameters for Minimum distance of bolt hole to flange edge and Minimum distance of bolt hole to counterpart edge. This information was moved to become an individual parameter for each plate. When loading a BSA file generated with a previous version, it will automatically be updated as follows:

    • The Minimum distance of bolt hole to flange edge will be assigned as Bolt hole to plate edge for all plates except the bottom one
    • The Minimum distance of bolt hole to counterpart edge will be assigned as Bolt hole to plate edge for the last plate in the stack (the bottom plate)

bolt hole to flange edge ui

 

  • Updated the report to include the new parameter for Bolt hole to plate edge, for every plate

bolt hole to flange edge report

 

  • Added a control to enable the user to override the number of contact areas between the plates. When set to 0 (default) the number of contact areas is automatically calculated as the number of plates - 1

num contact areas

 

  • Added the possibility to specify the bolt preload either as:
    • the fraction of bolt tensile yield stress to be reached when the bolt is loaded (also known as coefficient of utility) or
    • the nominal installation torque at reference temperature

bolt preload options

 

  • Updated the pop-up message shown when the user loads a BSA file created with an older version. Now the message displays a detailed list of the changes made (if any) in order to update the file to the latest version

pop up message

 

  • Corrected the calculation of margin of safety for thread pull-out (mosth) to use maximum preload including thermal load instead of maximum preload without thermal load

Previous calculation : mosth-formula-previous

Current calculation : mosth-formula-current

where

fult

Critical fastener load for failure of thread (minimum between male and female thread)

fpmax

Maximum preload without thermal load

fvmax

Maximum preload including thermal load

phi n

Joint stiffness ratio which accounts for bolt loading plane factor

faupd

Derived maximum external axial bolt load, when moments loads are considered

sfult

Ultimate safety factor

 

  • Corrected the calculation of necessary length of the engaged thread (lengreq)

Previous calculation : lengreq formula previous

Current calculation : lengreq formula current

where

fult

Critical fastener load for failure of thread (minimum between male and female thread)

fth

Axial load transmitted by the thread

p

Bolt thread pitch

d

Bolt major diameter

d2

Bolt pitch diameter

beta

Bolt thread angle

d1

Minor diameter of the female thread

c1

Empirical coefficient accounting for the depth of supporting material behind the female thread

c2

Empirical coefficient accounting for the strength ratio of the two threads

tauultb

Shear ultimate strength of the bolt material

tauultn

Shear ultimate strength of the material forming the female thread. Equal to:

Shear ultimate strength of nut material if counterpart is a nut

Shear ultimate strength of last plate material if counterpart is threaded insert

Shear yield strength of helicoil material if counterpart is threaded insert with helicoil

 

  • Corrected the calculation of margin of safety on fastener failure for combined loads, yield (moscomby)

Previous calculation : moscomby formula previous

Current calculation : moscomby formula current

where

ray

Fastener strength utilization ratio (axial, yield)

rqy

Fastener strength utilization ratio (shear, yield)

 

  • Corrected the calculation of margin of safety on fastener failure for combined loads, ultimate (moscombult)

Previous calculation : moscombult formula previous

Current calculation : moscombult formula current

where

rault

Fastener strength utilization ratio (axial, ultimate)

rqult

Fastener strength utilization ratio (shear, ultimate)

 

  • Corrected the calculation of margin of safety on plate hole bearing stress, yield (mosbry) for every plate (i = plate index)

Previous calculation : mosbry formula previous

Current calculation : mosbry formula current

where

sigmabryp

Bearing yield of plate i, linearly interpolated between sigmabr15yp and sigmabr20yp

dhi

Nominal bolt hole diameter of plate i

d

Bolt major diameter

ti

Thickness of plate i

fqupd

Derived maximum radial bolt load, when moments loads are considered

sfy

Yield safety factor

sffit

Joint fitting safety factor

 

  • Corrected the calculation of margin of safety on plate hole bearing stress, ultimate (mosbrult) for every plate (i = plate index)

Previous calculation : mosbrult formula previous

Current calculation : mosbrult formula current

where

sigmabrultp Bearing ultimate of plate i, linearly interpolated between sigmabr15ultp and sigmabr20ultp
dhi

Nominal bolt hole diameter of plate i

d

Bolt major diameter

ti

Thickness of plate i

fqupd

Derived maximum radial bolt load, when moments loads are considered

sfult

Ultimate safety factor

sffit

Joint fitting safety factor

 

  • Corrected a bug in the representation of the compression zone, in the bolted joint drawing, whereby when this was a full sleeve the compression zone would extend beyond the counterpart or nut. This bug only affected the visual representation of the compression zone and not the calculations.

MARS 1.2.0 release notes

Bolt Static Analysis v1.1.0 – Comprehensive analysis

  • Introduced the possibility to visualize a drawing of the bolted joint together with the calculated compression cone, by right-clicking on a bolt group and selecting View joint drawing. This helps to double-check the setup before the analysis and more easily spot possible mistakes in the inputs.

view joint drawing menu

joint drawing full cone

joint drawing partial cone

joint drawing full sleeve

  • Corrected the calculation of the compression cone when the counterpart is a plate with threaded insert (with or without helicoil) and is narrow enough to be considered as a nut, to consider the possible presence of a washer with external diameter bigger than that of the bolt head.
  • Corrected the calculation of the compression cone parameters such that if a partially developed cone is obtained but the cone does not actually sit outside any of the plates, then it is switched to a fully developed cone. Due to this change the compression cone half angle is sometimes calculated based on the plate with the maximum diameter.

compression cone correction

  • Other minor corrections to the calculation of the compression cone.
  • Corrected the calculation of the plates’ compliance to consider the bottom plate in all situations. Previously the bottom plate was not considered in certain situations.
  • Corrected a bug whereby if Both was selected for washer setup and then the counterpart type was changed from nut to threaded insert, the washer setup selection was adjusted in the MARS window without also updating the analysis data.

MARS 1.1.0 release notes

  • Introduced the possibility to specify a custom path to the MARS components and materials database, accessible by going to Options -> Configuration.

config window

 

Bolt Static Analysis v1.0.0

  • Corrected a problem whereby the default safety factors where not being loaded correctly when starting a new analysis.
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