FATIGUE TESTING OF A TEST SPECIMEN

摘要

The invention pertains to a combination of a test rig and test specimen for performing a fatigue test, wherein the test specimen is non-axisymmetric and comprises:—a central element,—a first branch element, which has a longitudinal axis that extends at an angle to the longitudinal axis of the central element,—a joint connecting the first branch element to the central element, which has an in plane bending resonance frequency with an associated in plane bending mode shape, and an out of plane bending resonance frequency with an associated out of plane bending mode shape, wherein the in plane bending resonance frequency and the out of plane bending frequency are substantially the same, wherein the first node of the in plane bending mode shape and the first node of the out of plane bending mode shape are substantially at the same position at the first branch element and wherein the test rig comprises:—a support for supporting the test specimen,—an excitator for subjecting the test specimen to forced vibration at an excitation frequency.

主权项

1. A combination of a test rig and a test specimen for performing a fatigue test of said test specimen,
wherein the test specimen is non-axisymmetric and comprises:
a central element, said central element having a longitudinal axis,a first branch element, said first branch element having a longitudinal axis that extends at an angle to the longitudinal axis of the central element, anda joint connecting the first branch element to the central element, wherein the non-axisymmetric test specimen has a plurality of resonance frequencies with associated mode shapes, which plurality of resonance frequencies comprises an in-plane bending resonance frequency with an associated in-plane bending mode shape, and an out-of-plane bending resonance frequency with an associated out-of-plane bending mode shape, wherein the in-plane bending resonance frequency and the out-of-plane bending frequency are substantially the same, and wherein the in-plane bending mode shape comprises a first node, which first node is located at the first branch element, and wherein the out-of-plane bending mode shape comprises a first node, which first node is located at the first branch element, wherein the first node of the in-plane bending mode shape and the first node of the out-of-plane bending mode shape are substantially at the same position at the first branch element, and wherein the test rig comprises:
a first support for supporting the test specimen, which first support supports the test specimen at or adjacent to the node of the in-plane bending mode shape and the out-of-plane bending mode shape,an excitator for subjecting the test specimen to forced vibration at an excitation frequency.