Hourglass (LS-DYNA)

Modeling Object
Name	Specifies the name of the load curve definition.
Label	Specifies a unique numerical identifier for the load curve definition.
*HOURGLASS
Control Type (IHQ)	Specifies the type of hourglass control to apply.(0) NoneThe software does not apply any hourglass control.(1) Standard LS-DYNA viscous formThe software uses the load curve in stress initialization but not in transient analyses.(2) Flanagan-Belytschko viscous form(3) Flanagan-Belytschko viscous form with exact volume integration(4) Flanagan-Belytschko stiffness form(5) Flanagan-Belytschko stiffness form with exact volume integration(6) Belytschko-Bindeman assumed strain co-rotational form for solids(7) Linear total strain form of type 6 hourglass control(8) Applicable to type 16 fully integrated shellActivates the full projection warping stiffness for accurate solutions with type 16 fully integrated shell elements. A speed penalty of 25% is common with this option.(9) Puso enhanced assumed full strain form for hexahedral elementsSee *HOURGLASS in the LS-DYNA Keyword User's Manual for more information.
Coefficient (QM)	Specifies the hourglass coefficient.
Bulk Velocity Type (IBQ)	Specifies the type of bulk velocity to use.
Quadratic Bulk Viscosity Coefficient (Q1)	Specifies the quadratic bulk viscosity coefficient.
Linear Bulk Viscosity Coefficient (Q2)	Specifies the linear bulk viscosity coefficient.
Coefficient for Shell Bending (QB)	Specifies the hourglass coefficient for shell bending.
Viscous Damping Coefficient (VDC)	If Control Type (IHQ) is set to (6) Belytschko-Bindeman assumed strain co-rotational form for solids or (7) Linear total strain form of type 6 hourglass control, specifies the coefficient for viscous damping.
Coefficient for Shell Warping (QW)	Specifies the hourglass coefficient for shell warping.

Additional coefficient options

You can define the coefficient values with a constant value, expression, or field. You can:

• Type a constant value directly in the box.

• Type an expression directly in the box. As you begin to type the expression, tooltips provide hints about valid parameter names. If you type an invalid or incomplete expression, the icon appears next to the box.

• Click and select from these options: Expression opens the Expressions dialog box, where you can select an existing expression or create a new one.For more information about expressions, see Expressions.Select Existing Field opens the Fields dialog box, where you can select a field. A field can define a magnitude that varies with independent variables such as frequency, temperature, or time. For more information about fields, see Fields.New Field→Formula opens the Formula Field dialog box, where you can define a formula to construct a field.For more information, see Define a boundary condition using a formula field.New Field→Table opens the Table Field dialog box, where you can define tabular data to construct a field.For more information, see Define a boundary condition using a table field and Define a material property using a table field.New Field→Link opens the Linked Field dialog box, where you can construct a linked field from an existing spatial field. For more information, see Linked Field dialog box.Plot (XY) plots the field as an XY graph. For more information, see: Graph overview.Overlay(XY) overlays a plot on an existing plot. You can overlay up to 50 plots. For more information, see Overlay plots.

For more information about other options in the list, see Additional magnitude options.

Quick links

Command reference

Pre/Post video examples

Bulk Entry Descriptions

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Hourglass (LS-DYNA), Simcenter 3D 2021.1 Series

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