EN 3745-402:2005

Overview

EN 3745-402:2005 is a European standard developed by the European Committee for Standardization (CEN) under the Aerospace series focused on fibres and cables, specifically optical cables designed for aircraft use. This standard outlines a test method for temperature cycling to evaluate the durability and reliability of optical cables under varying thermal conditions typical of aerospace environments. The objective is to simulate temperature fluctuations that aircraft cables endure during operation, ensuring product quality and performance.

Key Topics

• Scope and Purpose
  EN 3745-402:2005 specifies a detailed method for temperature cycling of optical cables used in aircraft, helping manufacturers and testing labs verify cable resilience against thermal stresses. The test simulates extreme temperature variations affecting optical fibre integrity.

• Specimen Preparation
  Test specimens must be prepared following product-specific standards and stabilized at standard test conditions for 24 hours prior to testing. Specimens are to be loosely coiled with bend radius not less than the specified storage radius, reflecting real usage scenarios.

• Apparatus Requirements
  A climatic chamber with precise temperature control (±2 °C) is essential for performing the test. This equipment must be capable of cycling temperatures between defined high and low extremes according to the product specification.

• Test Methodology
  The temperature cycling procedure includes seven phases:

  1. Initial placement at ambient temperature.
  2. Heating from ambient to high temperature (rate ~5 °C/min).
  3. Holding at high temperature for 30 minutes.
  4. Cooling to low temperature.
  5. Holding at low temperature for 30 minutes.
  6. Returning temperature to ambient.
  7. Holding at ambient before next cycle.

  These phases constitute one cycle, repeated as per product requirements. The cycling stresses the cable materials and construction to reveal potential thermal fatigue or failure points.

Applications

• Aerospace Industry
  Manufacturers of aircraft-grade optical fibres and cables rely on EN 3745-402:2005 to certify their products meet the stringent temperature durability requirements essential for flight safety and performance.

• Quality Assurance and Testing Laboratories
  Aerospace testing facilities use this standard to perform acceptance testing, product qualification, and routine quality checks on optical cables intended for aircraft systems.

• Design and Development
  Engineering teams integrate findings from temperature cycling tests into design improvements, ensuring cables can withstand harsh thermal environments encountered during flight cycles, ground operations, and varying atmospheric conditions.

Related Standards

• EN 3745-100: Aerospace series - Fibres and cables, optical, aircraft use - Test methods - Part 100: General
  Provides foundational guidelines on specimen preparation and conditioning necessary for conducting test methods including temperature cycling.

• Other parts within the EN 3745 series addressing various mechanical, environmental, and electrical test methods pertinent to aerospace optical cables.

Keywords: EN 3745-402:2005, temperature cycling, optical cable testing, aerospace optical fibres, aircraft optical cables, thermal durability test, climatic chamber testing, aerospace standards, CEN aerospace cable tests, fibre optic cable reliability