Novel Approach on Material characterization Testing of various Wiring Harness

The automotive wiring harness (length of 4-5 km) is a very important and complex system in the development of a modern car due to a lot of new electric & electronic components and sensors. It is a very sensitive material unlike metals and is considered as a composite which is highly anisotropic in nature, as it consists of several different layers of copper/aluminum strands and insulation. Because of insulation, wiring harness exhibits viscous plastic behavior which is crucial in determining the durability and long-term performance of the cables. Material properties play an important role in determining the behavior of wiring harness after assembly into the car. Wiring harness may undergo Bending, Torsion and Tension loads, causing the stress and strain in the individual electrical wires. The lack of CAE validation of the wiring harness routing may lead to extra costs for the automotive OEMs over a period. This paper describes the novel method of Testing the Cables and Bundles used in a car to get the material properties of it. The procedural description is applicable to single core, multi core and Bundles containing various combinations of cables. Initial trial tests have been carried out before confirming the methodology for this testing, to ensure the repeatability of test results among various Test samples. The findings from this Testing are Bending stiffness, Torsional stiffness and Axial (Tensile) stiffness for calculating the length-independent stiffness of the wiring harness material. The result plots from this Testing contain flow curves to determine the modulus of elasticity, ultimate strength etc., and cyclic curves to determine the Visco-plastic properties of the wiring harness. Material properties from this Testing will be used in the digital development of wiring harness CAE during Car development.