Flexure endurance
BS EN 3475-512:2021 pdf free.Aerospace series一Cables, electrical, aircraft use – Test methods Part 512: Flexure endurance.
This document specifies a method of testing ulexure endurance of the cable when it is subjected to alternating flexing.
It is used together with EN 3475-100.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
EN 3475-100, Aerospace series — Cables, electrical, aircraft use — Test methods — Part 100: General
EN 3475-302, Aerospace series — Cables, electrical, aircraft use — Test methods — Part 302: Voltage proof test
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• ISO Online browsing platform: available at http://www.iso.org/obp
• IEC Electropedia: available at http://www.electropedia.org/ 4 Preparation of specimens and principle of test
Take specimens of adequate length from a finished cable and install them on apparatus described hereafter.
This test makes it possible to determine the resistance of the cable to cycles of repeated flexing.
With the cable vertical, a cycle is defined by a rotation 01900 left, return to the vertical, rotation of 90° right and return to the vertical.
The damage is detected by conductor breakage and thus an interruption of electrical continuity between the two ends of the tested specimen.
The test is normally performed on gauge 20 cables.
It is carried out at ambient temperature.
S Apparatus and Installation of specimens
The apparatus Is described by FIgure 1.
It Is fitted with a counter and an automatic stop device controlled by InterruptIon of electrical continuity.
The rotation s shall be a uniform rate of(18 *2) cydes/mln.
The space between mandrels Is equal to the maximum diameter oldie tested cable.
The mandrel diameter D and weight Mare specified In the product standard.
The test setup shall be designed to avoid any swing motion/displacement of the cable between the mandrels.
The length should be sufficient to ensure that the weight shall not influence the bending motion.
After installing a specimen and before commencing the full test, perform a preliminary run and,if necessary, adjust the distance, the mandrels and the attached weight such that possible resonance effects are avoided. For the actual test, actuate the detection circuit, reset the counter and run the machine until auto shut down takes place.
7 Requirement
Method A: flexure endurance test of the conductor.
This test shall be performed on a minimum of 3 (three) specimens.
The mean value of this test shall be greater than the value specified in the product standard.
The number of cycles between the beginning of the test and the ending triggered by the detection system shall be greater than the value specified in the product standard.
Method B: flexure endurance of the cable insulation.
Three additional specimens shall be submitted to the number of cycles requested in the specification.
These specimens shall pass the voltage proof test EN 3475-302 (immersion test).
Unless otherwise specified, only method A is required.BS EN 3475-512 pdf free download.Flexure endurance