NIET DESTRUCTIEF ONDERZOEK VASTE STUWSTOF RAKETMOTOREN – TNO RIJSWIJK

Company description

De Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek (TNO) heeft als een van haar taken het ondersteunen van de Nederlandse Defensie met hoogwaardige kennis van o.a. militaire operaties en inzet en instandhouding van Defensie materieel. Deze opdracht kan worden uitgevoerd bij de vestiging in Rijswijk.

Introduction to the subject

The monitoring and ageing of solid propellant for rocket engines is mainly based on destructive testing. Mechanical and chemical analyses on samples of the propellant are now executed to monitor the ageing process and associated degradation of the structural properties. One of the main mechanisms is oxidation, which increases the stiffness and reduces the ductility of the propellant. These effects increase the probability that cracks develop in the propellant.

 

Transient model 3D

Figuur 1: Typische stuwstof grain: metalen casing van enkele millimeters dik. Lengte stuwstof grain is typisch 1 a 2 meter. Buitendiameter motor is orde grootte enkele tientallen centimeters. Tijdens werking brandt de grain van binnen naar buiten op. De stuwstof bestaat typisch uit een rubberachtig materiaal als binder (en brandstof) waarin zoutkristallen zijn gegoten die de zuurstof voor de verbranding leveren. De gewichtsverhouding tussen binder en zoutkristallen is typisch ¼.

Destructive testing is not very cost-effective, since every test requires to sacrifice one of the missiles. Non-destructive methods might therefore be an interesting alternative to monitor the degradation.

Research objectives

TNO wants to get insight in the feasibility of Non-Destructive Testing (NDT) as alternative for (or addition to) the present destructive tests. A feasibility study must thus be performed, consisting of a literature study, simulations and experiments. At the start of the project, a wide range of methods will have to be compared (e.g. X-Ray, thermographic methods, dynamic method, e.g. ultrasonic / structural vibrations). After a trade-off, the most promising techniques can be studied in more detail.

In this second phase, experiments can be performed at the TNO laboratories, data can be collected and appropriate analysis techniques must be developed. To aid the interpretation of the obtained signals, numerical models can be developed to simulate the tests and compare the results.

Student profile

Mechanical engineering

More information

R. Loendersloot / T. Tinga