Reversal bending fatigue testing
AssigneeUT-Battelle, LLC
InventorsJy-An John Wang, Hong Wang, Ting Tan
Life of this patent
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Abstract
Embodiments for apparatuses for testing reversal bending fatigue in an elongated beam are disclosed. Embodiments are configured to be coupled to first and second end portions of the beam and to apply a bending moment to the beam and create a pure bending condition in an intermediate portion of the beam. Embodiments are further configured to cyclically alternate the direction of the bending moment applied to the beam such that the intermediate portion of the beam cyclically bends in opposite directions in a pure bending condition.
Claims15
An apparatus for testing reversal bending fatigue in an elongated beam, the beam having opposing first and second end portions and an intermediate portion between the first and second end portions, the beam having a longitudinal axis extending between the first and second end portions, the apparatus comprising:
- a first rigid arm having a load end portion, a linkage end portion, and a first opening for receiving the first end portion of the beam;
- a second rigid arm comprising a load end portion, a linkage end portion, and a second opening for receiving the second end portion of the beam;
- a linkage having a first end portion coupled to the linkage end portion of the first rigid arm and a second end portion coupled to the linkage end portion of the second rigid arm;
- a first bearing positioned within the first opening for allowing the beam to translate in the longitudinal direction of the beam relative to the first rigid arm;
- a second bearing positioned within the second opening for allowing the beam to translate in the longitudinal direction of the beam relative to the second rigid arm, the first and second bearings restricting translation of the beam perpendicular to the longitudinal direction of the beam when the beam is installed;
- and
- wherein pivoting the load ends portions of the first and second rigid arms in opposite directions causes the first bearing to exert a first bending moment on the first end portion of the beam and causes the second bearing to exert a second bending moment on the second end portion of the beam, resulting in a pure bending condition in the intermediate portion of the beam;
- and
- wherein cyclically alternating the direction of the first and second bending moments cause the intermediate portion of the beam to cyclically bend back and forth in opposite directions while remaining in a pure bending condition.
A method of testing reversal bending fatigue in an elongated beam, the method comprising:
- a) positioning a beam in a testing apparatus, the testing apparatus comprising a first rigid arm coupled to a first end portion of the beam and a second rigid arm coupled to a second end portion of the beam;
- b) applying a first bending moment to the beam to create a first pure bending condition in an intermediate portion of the beam, wherein applying the first bending moment to the beam includes applying opposing compressive forces on the first and second rigid arms, the compressive forces being generally parallel with a longitudinal axis of the beam;
- and
- c) applying a second bending moment to the beam, the second bending moment being substantially equal in magnitude and substantially opposite in direction relative to the first bending moment, to create a second pure bending condition in the intermediate portion of the beam, the second bending condition being substantially equal in magnitude and substantially opposite in direction relative to the first bending condition, wherein applying the second bending moment to the beam includes applying opposing separation forces on the first and second rigid arms, the separation forces being generally parallel with the longitudinal axis of the beam and opposite the compressive forces;
- wherein applying the first and second bending moments to the beam are performed without changing the rotational orientation of the beam relative to the testing apparatus.
Dependencies are inferred from the claim text.