Bending Fatigue Strength Test for Metallic Bone Staples
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Bending Fatigue Strength Test for Metallic Bone Staples
Metallic bone staples are tested under bending loads until the specimen fails or a predetermined number of samples has been completed. The test objective is to determine the fatigue resistance of metallic bone staples when subjected to repetitive loads over large cycle periods. This test method is intended to aid in characterising the fatigue behaviour of metallic bone staples used for fixation of bone-to-bone or soft tissue to bone. The results are used to assist in determining material behaviour in either an ambient condition or in an aqueous or physiological solution. A four-point bending fixture is used such that the loading point and support rollers contact the staple extensions on either side of the staple. A starting load is applied equal to approximately 50% of the static bend strength. Cyclic loads are applied at a distance so as not to cause a deformation in the staple. Since stress verification is required, it is generally common practice to employ high accuracy extensometers to measure the bending strain induced on the specimen.
tandards for determining bending fatigue strength of metallic bone staples