Method of monitoring the needling of fiber structures in real time, and needling apparatus for implementing the method

摘要

A needled fiber structure is made by stacking fiber plies on a platen, by needling the plies as the stack of plies is built up by means of needles driven with reciprocating motion in a direction that extends transversely relative to the plies, and by varying the distance between the platen and an end-of-stroke position of the needles while building up the stack so as to obtain a desired distribution of needling characteristics through the thickness of the fiber structure. The instantaneous force exerted during needle penetration is measured (sensors) and a magnitude representative of needling force or penetration energy is evaluated on the basis of the instantaneous force, and the evaluated magnitude is verified for compliance with at least one predetermined condition to monitor proper operation of the process or to act on the way the distance between the platen and the end-of-stroke position of the needles is varied.