• residual strength
• impact damage
• compressive strength
• composite materials

This report outlines the work performed during the five months internship carried out at Structural,Thermal and Material department of the Launchers Directorate of the French Space Agency (CNES) in Evry (Paris) - France for the achievement of the Master's Degree in Mechanical Engineering.
The aim of the work was the developing of a simplified procedure for the prediction of the residual compressive strength of impact-damaged composite structures.
This need started from the will to simplify the qualification process of composite structures reducing costs and times needed for the determination of the residual properties of a damaged material, overtaking the disadvantages of the principal approaches nowadays used. The subject is characterized by phenomenons often very difficult and sometimes impossible to model and by a high complexity of the whole problem.
The work started from a deep and wide literature's review and from a long study
of the experimental data. That brought to the determination of some experimental laws that are able, respecting the phisics of the problem, to make good prevision of many aspects.
Afterwards it has been developed a mechanical model able to simulate the behaviour of the damaged material subjected to a compression load and to calculate the residual resistance; this model has been implemented in Matlab code, validated and applicated to some structures of the new small european launcher Vega.