• Tribology and Lubricants
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• 제15권3호
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• pp.278-286
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• 1999

To predict the behavior of the intravascular micro active endoscope in the real human vascular system, a human mock circulation system was developed. The intravascular micro active endoscope which consists of micro active bending catheter and micro drug infusion catheter was driven in the velocity, Re number and temperature controlled flow. The three SMA (Shape Memory Alloy) zigzag type spring in the micro active bending catheter was heated by the electric current generated by PWM controller, and the shape memory effect made the actuator bend to any direction. The micro drug infusion catheter was driven through the inner hole of the micro active bending catheter. A mock circulation system is shaped from Ascending Arota to Femoral artery according to a human data (the data contains many vascular sizes and hydrographs of many control points). We developed a vascular model with glass and silicone tubes, and set the flow system with circulation parts, flow settling parts, and lots of valves. The heater and heat-controller was added to the How system to centre! the temperature of the How at 36.5$^{\circ}C$. The result showed that the developed intravascular micro active endoscope could be induced to any point in the vascular model.

• Tribology and Lubricants
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• 제15권3호
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• pp.272-277
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• 1999

The objective of this investigation is to examine the influence of the micro catheters, which mimic the intravascular micro active endoscopes, on local pressure changes and flow rate in an arterial branch model similar to the femoral artery of human. The effects of branch to main lumen flow rate ratios and the locations of a catheter tip were found to be significant on the local pressure changes. Relatively large pressure drops and an increase in shear stress due to the obstruction effects may induce an endothelial cell damage and a change in arterial wall permeability, which have been reported to be the primary cause of the initiation of the atherosclerosis and other major vascular diseases.