The primary unknowns (nodal degrees of freedom) calculated in a structural analysis are displacements.
Other quantities such as strains, stresses, and reaction forces are then derived from the nodal displace-
ments.
Structural analyses are available in the ANSYS Multiphysics, ANSYS Mechanical, ANSYS Structural, and
ANSYS Professional products only.
1.2. Elements Used in Structural Analyses
Most element types are structural elements, ranging from simple spars and beams to more complex
layered shells and large strain solids. Most types of structural analyses can use any of these elements.
For more information, see Selecting Elements for Your Analysis in the Element Reference.
1.3. Material Model Interface
For analyses described in this guide, if you are using the GUI, you must specify the material that you
intend to simulate using an intuitive material model interface. The interface uses a hierarchical tree
structure of material categories, intended to assist you in choosing the appropriate model for your
analysis.
See Material Model Interface in the Basic Analysis Guide for information about the material model interface.
1.4. Damping
Damping is present in most systems and should be specified in a dynamic analysis. The following forms
of damping are available:
- Global Alpha and Beta Damping (Rayleigh Damping) (ALPHAD,BETAD)
- Material-Dependent Alpha and Beta Damping (Rayleigh Damping) (MP,ALPD,MP,BETD)
- Constant Global Damping Ratio (DMPRAT)
- Constant Material-Dependent Damping Ratio (MP,DMPR)
- Mode-Dependent Damping Ratio (MDAMP)
- Constant Global Structural Damping Coefficient (DMPSTR)
- Material-Dependent Structural Damping Coefficient (MP,DMPR,TB,SDAMP)
- Viscoelastic Material Damping (TB,PRONY )
- Element Damping (e.g.,COMBIN14,COMBIN40,MATRIX27,MPC184)
Only the constant global damping ratio and mode-dependent damping ratio are available in the ANSYS
Professional program.
The structural damping coefficients lead to damping forces which are proportional to the displacements
(strains). Also known as hysteretic damping, this type of damping represents the damping that may be
due to internal friction of the material or in the structural connections. The other damping forms lead
to damping forces which are proportional to the velocity (or frequency of vibration). Also known as
viscous damping, this type of damping represents a system immersed in a fluid.
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