ASTM F1541 Classification of external fixation devices

We offer you various test methods for the characterization of the mechanical functionality of external fixation devices according to the test standard ASTM F1541. We help you to select the appropriate test methods for your individual implant from the following offer:

• Test method for connector elements of external fixation devices
  The connector elements, which serve for the connection of bridge and anchoring elements of the external fixation devices, are fixed to the test device and loaded with an axial load and a moment. Force-displacement and torque-angle curves are recorded and the stiffness and strength are determined.
  
  
• Determination of the in-plane compressive properties of circular ring or ring segment bridge elements
  Circular rings or ring segments are firmly clamped into the test device and are loaded with an increasing force. A force-displacement curve is recorded and the stiffness and strength under compression in a plane are determined.
  
  
• Test method for joints of external fixation devices
  A joint consisting of a connector element and a bridge or anchoring element is fixed to the test device. An axial load and a moment are applied via the bridge or anchoring element. Force-displacement and torque-angle curves are recorded and the stiffness and strength are determined. In addition, the range of movement of the joint is determined by loosening the connection of the joint and applying a continuous displacement via the bridge or anchoring element. A sudden increase in force defines the limit of the range of movement.
  
  
• Test method for pin anchorage elements of external fixation devices
  A pin is clamped into the test device and subjected to a constant speed in a four-point bending test. A force-displacement curve is recorded and analyzed with regard to bending stiffness and flexural strength. In addition, a torsion test is performed. For this purpose one side of the pin is clamped and a torque is applied over the other side. The torsional stiffness and strength are determined by means of a torque-angle curve.
  
  
• Test method for subassemblies of external fixation devices
  An assembly, consisting of a bridge and two connecting elements, is clamped into the test device. Subsequently, different loads (axial force, medial-lateral shear and anterior-posterior shear) or moments (torsion, medial-lateral bending and anterior-posterior bending) are applied to determine the stiffness and strength.
  
  
• Test method complete external fixation devices
  A complete external fixation device is connected to a bone analogue simulating a fracture. The connected construct is clamped into the test device and subjected to various loads (axial force, medial-lateral shear and anterior-posterior shear) or moments (torsion, medial-lateral bending and anterior-posterior bending) to determine the stiffness and strength.
  

The test methods indicated can also be carried out dynamically, in order to determine the fatigue behavior of the constructs.