ASTM F2346 | Spinal Artificial Discs | Static and Dynamic Testing
ASTM F2346 describes a variety of axial and bi-axial test methods to evaluate and compare the static and dynamic mechanical performance of orthopedic intervertebral discs specific to cervical, thoracic, and lumbar areas of the human spine. The outlined static test methods utilize steel blocks, and enable manufactures to evaluate the static axial and torsion stiffness behavior of their intervertebral discs via position-controlled compression/torque until functional failure is obtained. The outlined dynamic test methods utilize polyacetal blocks, and enable manufacturers to evaluate the dynamic fatigue behavior of their intervertebral discs via load-controlled compression/torque to a specified cycle count. Maximum runout load is to be reported as the maximum load at which the sample successfully endured the specified cycle count. In principle, fatigue tests should be conducted within an environmental bath.
Before conducting testing per ASTM F2346, it is important to read the entire specification in the relevant ASTM publication.
ASTM F2346 | Spinal Artificial Discs | Static and Dynamic Testing
Static Test Procedures
- Ensure the correct fixtures are utilized for axial compression, compression shear, and torsion testing.
- Prepare a minimum of 5 test samples as described in the sampling section of the standard.
- Insert a solid steel metal sample with identical dimensions to that of the intervertebral disc within metal blocks with geometries that mate geometrically with the disc.
- Perform desired position-controlled test method (axial compression, compression shear, torsion) until functional failure to generate stiffness data of the fixtures.
- Remove the steel sample and insert intervertebral disc within metal blocks.
- Repeat test procedure from Step 4 to obtain stiffness data of both the fixtures and your test sample
- MTESTQuattro will automatically perform stiffness compensation to obtain a stiffness value solely for the test sample.
Calculations:
- Axial and torsional stiffness
- Yield displacement
- Yield Load or Moment
- Ultimate Displacement
- Ultimate Load or Moment
Dynamic (Fatigue) Test Procedures
- Ensure the correct fixtures and saline bath are utilized for axial compression, compression shear, and torsion testing.
- Prepare samples as described in the sampling section of ASTM F2346
- Insert intervertebral disc sample within polyacetal blocks with geometries that mate geometrically with the disc
- Perform desired load-controlled test method (axial compression, compression shear, torsion) to the specified cycle-count to generate fatigue data of your specimens.
Calculation:
- Maximum runout load
ASTM F2346 | Spinal Artificial Discs | Static and Dynamic Testing
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