Tensile Test: The cable is wound in the machine over appropriately sized sheaves. The cable ends extend to reach the measuring instruments. A pre-determined number of fibres within the cable are concatenated by fusion splicing. Typically, two sets of fibres are used, one will serve to measure attenuation change and the other serves for elongation monitoring.
After all initial measurements and calibration are carried out; the cable is pulled at a specified rate until a pre-determined tension is applied. The cable is laid to rest under tension as per detail specifications, and then the attenuation and fiber length are measured. This process may involve several tensile levels in order to characterize the entire tensile behaviour of the cable, or be carried out only at the defined maximum allowed tension level.
Crush Test: The cable sample is mounted between the plates so that lateral movement is prevented, and a pre-determined force is applied gradually. The maximum applied force is typically maintained for 10 minutes.
Two types of measurements may be defined:
The fiber attenuation is measured at the end of the 10-minute period while the cable is still under pressure. The fiber attenuation is measured 5 minutes after pressure. This requirement is usually carried out at higher compressive loads than the previously described measurement.
These machines offer force, displacement or deformation closed loop testing. The load frames are rigid constructed, providing superior axial and lateral stiffness.
Method E1: Tensile performance
This measuring method applies to optical fiber cables which are tested at a particular tensile strength in order to examine the behaviour of the attenuation and/or the fiber elongation strain as a function of the load on a cable which may occur during installation. This method is intended to be non-destructive (the tension applied shall be within the operational values).
Method E3: Crush
The purpose of this test is to determine the ability of an optical fiber cable to withstand crushing.