The complex geometry and material behavior of stents result in highly nonlinear and challenging analyses.This course focuses on the use of Abaqus for modeling and analyzing stents.
However, its content can also be useful when modeling other types of medical devices. The course is targeted at engineers responsible for the design of medical devices who are looking to accelerate their understanding of the highly complex mechanical behavior associated with performance of such devices. Some understanding of AbaqusCAE is helpful but is not required. Please note that the actual course agenda may vary depending on location. Download the course overview Schedule and Registration North America. Thus, any slave node that penetrates the master surface by less than the allowable interference will be reported as being open. Abaqus Modeling Free Adjustments AndABAQUSStandard offers alternative methods to resolve initial overclosures with strain-free adjustments and to model specific overclosures or clearances different from those calculated from the initial configuration. These methods are discussed in Adjusting initial surface positions and specifying initial clearances in ABAQUSStandard contact pairs, Section 29.2.5. Resolving excessive initial overclosures If there are large overclosures in the initial configuration of model, ABAQUSStandard may not be able to resolve the interference fit in a single increment. ABAQUSStandard provides alternative methods that allow overclosures to be resolved gradually over multiple increments. The default contact constraint imposed at each constraint location is that the current penetration is. To alter this constraint, you can specify an allowable interference,, that will be ramped down over the course of a step. The specified allowable interference modifies the contact constraint as follows: Thus, specifying a positive value for causes ABAQUSStandard to ignore penetrations up to that magnitude. Figure 29.2.41 illustrates a typical interference fit problem. Figure 29.2.41 Interference fit with contact surfaces. If the penetration in the model is, you may declare or request an automatic shrink fit. In either case ABAQUSStandard will consider the two bodies to be just in contact at the start of the simulation. As the allowable interference,, is decreased during the step, ABAQUSStandard pushes the surfaces apart until there is no more allowable penetration. There are three different ways in which to specify the allowable interference. ![]() It is recommended that you specify allowable interferences in a step separate from the rest of the analysis; additional loads may adversely affect the resolution of the interference fit and the response to loading with partially-resolved interferences may be non-physical. Once the overclosures are resolved, you can continue the analysis in a new step. When the contact interference is specified, output variable COPEN does not reflect the actual overclosure value during the step; it reflects the actual value only at the end of the step. ![]() Input File Usage: Use the following option to define an allowable interference for contact pairs: CONTACT INTERFERENCE, TYPE CONTACT PAIR. Using a nondefault amplitude curve for the allowable interference You can define a time-varying allowable contact interference by creating an amplitude curve (see Amplitude curves, Section 27.1.2, for details) and then referring to this curve from the contact interference definition. The amplitude will be ignored, however, if the Riks method (see Unstable collapse and postbuckling analysis, Section 6.2.4 ) is used. Input File Usage: CONTACT INTERFERENCE, AMPLITUDE amplitudecurvename ABAQUSCAE Usage: Interaction module: interaction editor: Interference Fit: Gradually remove slave node overclosure during the step, Uniform allowable interference, Amplitude: amplitudecurvename Removing or modifying the allowable contact interferences By default, only the allowable contact interferences defined or redefined by a particular contact interference definition will be modified. Alternatively, you can specify that all previously defined allowable contact interferences should be removed from the model and only those defined with this definition will remain. Input File Usage: Use the following option to add or modify an allowable contact interference definition: CONTACT INTERFERENCE, OP MOD Use the following option to remove all previously defined allowable contact interferences: CONTACT INTERFERENCE, OP NEW ABAQUSCAE Usage: Contact interferences in ABAQUSCAE propagate along with the interaction for which they are defined. You cannot remove all previously defined contact interferences at once in ABAQUSCAE. Specifying the same allowable contact interference for an entire surface A single allowable interference can be specified for every node on the slave surface or every slave node in the specified set of contact elements. The concepts of slave nodes for the various families of contact elements are discussed in their respective sections. The specified allowable contact interferences are included in the current penetrations of the slave nodes reported in the message file when you request detailed contact printout.
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