Customer

Materials

Our client, the Centre Technique des Industries Mécaniques, aims to provide mechanical engineering companies with the means and skills to increase their competitiveness, participate in standardisation and act as a link between scientific research and industry.


Tested product

Carbon composite

Carbon composite is made up largely of carbon fibres and is a very light but strong material. Carbon composite can be used to build rocket engines, aircraft brakes or various parts for industry. Some parts are made by winding and gluing a ribbon of carbon fibres.

 

Carbone composite sample
Carbone composite roll

Objective

This machine is designed to perform peel tests on carbon fibres, bonded together by a bonding system whose effectiveness must be evaluated.


Problematic issues

To carry out a continuous peel test of a sample (composite coil) in order to test and optimise the bonding process.

Solution and result

In partnership with CETIM, LF Technologies has developed a new principle of continuous peel testing (patented).

The system consists of evaluating the unwinding force of a web by pulling on it with a speed-controlled drum, while the reel itself is held in rotation by another drum whose holding torque is controlled. The angle of detachment, measured by a roller, is kept constant in relation to a set point, by the control of the holding torque.

The phenomenon used is similar to the one observed when a roll of tape is unwound, by braking the rotation more or less. The more the roll is braked, the more the peeling is tangential. If the roll is completely free, the peel is almost radial. Because of the bending fragility of carbon fibres, the angle of disbonding is kept rather tangential.

A suitable software program developed under LabVIEW permanently receives the information on the rotational position of each of the servomotors, the value of each of the measured torques, and the angular position of the disbonding angle measuring roller. The program allows the desired test parameters to be set and the curves and test results to be displayed, viewed and saved.

The realized continuous peeling bench was presented at JEC Americas in 2016 and won the award in the category "Testing".

 

 

French Fab