Overview
The following write up illustrates the practical use of the CathCAD® Modelling software to develop the proximal end of a catheter design. In this example, the proximal end of a catheter (being developed) was determined to have the following required performance attributes:
- ID: 0.070″ – 0.080″
- OD: 0.089″ Maximum
- Kink radius <= 2 inches
- The proximal end cannot elongate more than 0.1 percent when subjected to an axial force of 5 N (note that 5 N = 1.124 lb).
Stress strain equation (Hooke’s Law)
Substituting (F/A) for stress
We rearrange equation (2) so that we get the quantity EA which is computed by CathCAD®
In this design case, the quantity EA is a minimum and anything larger works for the customer. We also have to convert from Newtons to pounds as the software works in English units.
The CathCAD® software may now be used to model/design a tube to meet the following complete set of constraints
- ID: 0.070″ – 0.080″ (the input range)
- OD: 0.089″ maximum
- Design: As determined by the user. You might get away with a uniform material and/or you might have to design a braid reinforced tube. There are potentially an infinite number of solutions to the problem.
- EA >= 1,124 lb. If the computed EA of the design is greater than 1,124 lbs then the design will meet the maximum elongation requirement of 0.1 percent
- Kink radius <= 2 inches
If you have any particular design example you wish to formulated in order to be solved by the software, please email us at sales@cathcad.com.
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