# Structural Nonlinearities

Major sources of structural nonlinearities encountered in practical applications are as follows:

## Geometric Nonlinearities

In nonlinear finite element analysis, a major source of nonlinearities is due to the effect of large displacements on the overall geometric configuration of structures. Structures undergoing large displacements can have significant changes in their geometry due to load-induced deformations which can cause the structure to respond nonlinearily in a stiffening and/or a softening manner.

For example, cable-like structures generally display a stiffening behavior on increasing the applied loads while arches may first experience softening followed by stiffening, a behavior widely-known as the snap-through buckling .

 Cable-like structures Snap - through buckling

## Material Nonlinearities

Another important source of nonlinearities stems from the nonlinear relationship between the stress and strain which has been recognized in several structural behaviors. Several factors can cause the material behavior to be nonlinear. The dependency of the material stress-strain relation on the load history (as in plasticity problems), load duration (as in creep analysis), and temperature (as in thermo-plasticity) are some of these factors.

This class of nonlinearities, known as material nonlinearities, can be idealized to simulate such effects which are pertinent to different applications through the use of constitutive relations.

Yielding of beam-column connections during earthquakes is one of the applications in which material nonlinearities are plausible.

 Beam-column connections

## Contact Nonlinearities

A special class of nonlinear problems is concerned with the changing nature of the boundary conditions of the structures involved in the analysis during motion. This situation is encountered in the analysis of contact problems.

Pounding of structures, gear-tooth contacts, fitting problems, threaded connections, and impact bodies are several examples requiring the evaluation of the contact boundaries. The evaluation of contact boundaries (nodes, lines, or surfaces) can be achieved by using gap (contact) elements between nodes on the adjacent boundaries.

 Pounding of structures

Provide feedback on this topic

* Required

 *Email: Subject: Feedback on Help Topics Page: Structural Nonlinearities *Comment: * I acknowledge I have read and I hereby accept the privacy policy under which my Personal Data will be used by Dassault Systèmes

Print Topic

Select the scope of content to print:

x

We have detected you are using a browser version older than Internet Explorer 7. For optimized display, we suggest upgrading your browser to Internet Explorer 7 or newer.

Never show this message again
x

Web Help Content Version: SOLIDWORKS 2016 SP05

To disable Web help from within SOLIDWORKS and use local help instead, click Help > Use SOLIDWORKS Web Help.

To report problems encountered with the Web help interface and search, contact your local support representative. To provide feedback on individual help topics, use the “Feedback on this topic” link on the individual topic page.