Structural Analysis: Multiple-Body Contact and Interaction

Multiple-Body Contact and Interaction

Extensive, easy-to-use capabilities are available for simulating contact and interaction between multiple bodies in a structural analysis. These capabilities include both linear and nonlinear contact scenarios. The general classes of contact that can be simulated include:

Point to ground
Point to point
Point to surface
Surface to ground
Surface to surface

Contact technology provides the ability to model contact between parts of an assembly. Often in assemblies, some parts are not in perfect contact with the other parts. Some common examples include:

parts that are bolted together are connected only at the bolt holes
a shaft in a hole may contact on only one side of the hole
interference fits, which occur when one part undergoes an expansion within another part

Linear Contact Scenarios

Five types of linear contact scenarios are supported:

Bonded
Welded
Free/no contact
Surface contact
Edge contact

This linear contact technology is ideal for use on models created in the wide range of leading CAD solid modelers that ALGOR supports including Alibre Design, Autodesk Inventor, CADKEY, Mechanical Desktop, Pro/ENGINEER, Rhinoceros, Solid Edge and SolidWorks.

The surface contact option is used to simulate contact between the surface area where parts touch and the edge contact option is used to simulate contact between edges and where those edges touch other parts. For both contact options, the software automatically calculates the necessary contact parameters so that no additional data input is required.

The surface and edge contact capabilities also allow for the consideration of static friction effects by simply specifying a static friction coefficient or by using the default.

These linear contact capabilities are made possible by mesh matching technology and right-click menus and dialogs in ALGOR's FEMPRO interface. The user simply sets the default contact type for the entire assembly through the contact branch of the tree view. Optional contact pairs between specific parts and/or surfaces can be interactively specified through the graphics window or tree view. The user then decides whether to include friction effects. After an analysis, FEMPRO's Superview IV Results environment provides the capability to inquire on the total force transmitted between the contacting surfaces and/or edges.

Nonlinear Contact Scenarios

Mechanical Event Simulation (MES) provides additional capabilities for nonlinear contact scenarios. MES provides nonlinear, multi-body dynamics with large-scale motion, large deformation and large strain with body-to-body contact, which allows engineers to see motion and its results, such as impact, buckling and permanent deformation. MES' nonlinear contact capabilities include additional types of contact elements and surface-to-surface contact:

General contact elements are line elements that have different properties when in tension and compression to simulate contact conditions. Coupling, contact and dashpot elements are variations of general contact elements.

Surface-to-surface contact allows you to specify the surfaces and parts that may come into contact with each other throughout the duration of an event. When objects come within a certain distance of each other, a local stiffness will be automatically applied to simulate the two bodies contacting each other. Static and dynamic friction can also be applied. Options for surface-to-surface contact methods include:
- Frictionless contact - allows parts to experience large relative motion at the contact surfaces without frictional resistance.
- Frictional contact - static and sliding friction coefficients can be defined to resist motion between the surfaces.
- Slide / No Bounce Contact - normal and tangential motion can be constrained such that, once contact is initiated, the nodes will not separate even under tension.
- Tied Contact - initial distance and tolerance values can bond two parts even if the nodes are not matched.

With MES, there is no need to estimate dynamic or contact forces because the software calculates these forces automatically. Additionally, MES provides automatic calculation of contact points and orientations.

For analyzing large models involving contact, fast sparse solvers that support parallel processing on multi-processor systems are available for all analysis types, including static stress with linear material models and MES. These solvers provide significantly faster processing times through sparse solver technology that utilizes the power of all available system processors to perform parallel solutions and reduce solution time.

For more information on our multiple-body contact and interaction capabilities, see the ALGOR User's Guide.

See multiple-body contact capabilities featured in the following software in action replays:

TYPICAL APPLICATIONS

Crash test simulation
Drop tests
Forging simulation
Impact analysis
Interference analysis
Material forming
Mechanical linkages
Press-fit
Rolling, extruding and forming
Snap-fit
Stamping
Tolerance testing
Vehicle rollover
Wear analysis