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act distributed mass ansys
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© 2014 ANSYS, Inc. 1 Release 15.0
15.0 Release
Distributed Mass Extension Version 3
Anthony Dawson [email protected]
© 2014 ANSYS, Inc. 2 Release 15.0
Introduction
• Standard Workbench functionality allows for the addition of a point mass
• However, the MAPDL solver’s ESURF command can be used to create distributed mass on a surface
• This is done by placing SURF154 elements on a desired surface/surfaces and assigning them a mass through real constants
• Distributed mass can be useful for several applications, most notably modal and other dynamic analyses
© 2014 ANSYS, Inc. 3 Release 15.0
Distributed Mass Object
• The ACT ‘Distributed Mass’ extension creates a load object which will fully automate this process
• The object can be loaded by clicking the ‘Distributed Mass’ button that appears in Workbench Mechanical upon loading the extension
• Distributed mass loads can be added to ‘Static Structural’, ‘Transient Structural’, ‘Modal’ or ‘Harmonic Response’ analyses
• This object can be scoped to any face/faces via geometry selection or named selection
• Mass can be assigned as total mass or mass per unit area
© 2014 ANSYS, Inc. 4 Release 15.0
Conversion to APDL
• Information input into the details box will be converted to APDL script and placed in the problem’s input file just before the solve
• Total mass values will be converted to mass per unit area
© 2014 ANSYS, Inc. 5 Release 15.0
Version 3 Release Notes
• Corrected a defect which caused the distributed mass to be added in each step of a multi-step static or transient analysis
• Corrected a defect which caused solves to fail if the Distributed Mass object was scoped to a ‘Named Selection’ containing spaces in its name
• Allowed for use in regions of the world where commas are generally used for decimal points
© 2014 ANSYS, Inc. 6 Release 15.0
Limitations
• A ‘Distributed Mass’ object cannot be added directly under a harmonic analysis that uses the “Mode Superposition” solution method • Note, however, that a ‘Distributed Mass’ object CAN be added to the modal analysis
that precedes a linked MSUP harmonic analysis without issue
• If an extremely large number of ETs or Real Constants are created in any subsequent linked analyses, this could cause issues • This issue is only relevant if linking analyses to the ‘Solution’ cell of your original
distributed mass analysis
• The potential to encounter this limitation is vary rare, even in extremely large models
