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This device is intended for use in hospitals to shut off the flow of intravenous solutions to the patient. In addition to determining the stress/strain levels in the component, the following is also determined from the finite element analysis:

  1. The force required to shut off the hose;
  2. The state of shut-off retention after the deflection boundary condition at the hinge is relaxed;
  3. The state of stress/strain in the hose at shut-off;
  4. The amount of deflection of the link needed to fully close off the hose.

The analysis model is shown below.

The center nodes on both cylinders of the link were restrained in the "Y" direction to prevent vertical movement. The center nodes on the left cylinder were restrained in the "X" direction to prevent rigid body motion. The surfaces of the model in the X-Y plane were restrained in the "Z" direction to prevent rigid body motion. A deflection was applied to the hinge simultaneously in the "X" and "Y" direction using tables to define the path. The bow, link and hose were defined as deformable bodies in the MARC contact table, with each of them defined as touching each other. The hose and the link were further defined as touching themselves. For the initial step, the hose was restrained using a link defined with very low spring rate properties to prevent hose rigid body motion. There were no gap elements or rigid contact surfaces defined in this model. Note the portion of the link that applies the pressure to the hose to shut off the flow. Note the stiffener and the boss detail in the bow.

The following video shows results from the analysis.

Video of Analysis Results

Note: the ZIP files download faster than the AVI file. After downloading, you must unzip the file with a program, such as WinZip or PKzip. Then choose "File | Open" from your web browser's menu. Find the unzipped file and open it with the web browser. Click on the image to see the video.

 

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