Constant Spring Support/Hanger

These supports are gaining popularity and are often used instead of variable spring supports. They are modeled as rigid rod hangers hung over a rotating block with a P value load hung on the end (fig. 1). During vertical displacement, supporting force P remains constant. However, this structure is not used in practice due to its large size.

Modern constant spring support structures usually use a spring-lever mechanism (fig. 2), which uses pre-stretch adjustments to ensure nearly constant supporting force in a fixed range of vertical displacement (fig. 3).

This support does not use any external restraints. Supporting force is applied to the support's node, which is input as three projects on the global coordinate axes Fx, Fy, Fz. See "custom restraints"

Properties

Property	Description
Name	Element name. If checked then it shown in 3D view
Series	KHD - horizontal constant force brace with double ears for restraints to the upper support structure KHS - horizontal constant force brace with double ears for installation on the lower support structure KVD - vertical constant force hanger with double ears for restraints to the upper support structure KVS - vertical constant force hanger with double ears for installation on the lower support structure KSP - constant spring support with a supporting stand KSR - roller constant spring support
Rod number	Parallel installed hanger rod numbers (1 or 2)
Support number	Parallel installed support numbers (1 or 2)
Rod length	Rod length, used for considering the pendulum effect
Test state mode	In some cases, springs may be temporarily locked during testing, which must be taking into account in the analysis
Friction factor	Friction factor
Force along the X axis	Support force project along the global X axis. Automatic rod selection is not done
Force along the Y axis	Support force project along the global Y axis. Automatic rod selection is not done
Force along the Z axis	Support force project along the global Z axis. If 0, automatic constant spring support selection is performed.

Menu and Toolbar Access

To insert an element, select the desired node and use: Insert > Insert Restraint > Constant Spring Support / Insert > Insert Restraint > Constant Spring Hanger