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Very Technical [clear filter]
Thursday, October 18
 

4:25pm

Repair of Micrometeroid Orbital Debris on the canadarm2 Structure
Thermoplastic composite materials (TPC) have been used for a number of years in the space industry. One of the most famous applications of TPCs is on the Canadarm2, a robotic arm used on the International Space Station, which has been in service since 2001. The initial planned lifespan for Canadarm2 was of 10 years, however, because Canadarm2 is still very useful in current missions, the plan is now to extend its service life until 2028. The low Earth orbit is now littered with millions of manmade debris resulting from decades of space
exploration. Space structures are now more likely to be impacted by debris than ever before.

This paper presents the development of a repair method for hypervelocity impact damage on the Canadarm2 structure. Since the thermoplastic composites have the advantage of being re-processable, we use induction welding to repair the damaged laminates. An induction welding process that allows the repair of large areas was developed. This method allows thewelding of patches over a damaged area in a continuous fashion by moving the part to be repaired under an induction coil.

Laminates that were damaged via a hypervelocity impact show a residual flexural rigidity of 75% and 45% compared to intact laminates for the entry and secondary exit damage respectively. After repair using a quasi isotropic 8 ply patch [0, 90, ±45]s, the secondary exit damage shows a flexural rigidity of 300% compared to an intact laminate and a maximum flexural strength of 130% compared to intact laminates.

Finally, a finite element model of a laminate and patch was developed. The finite element model of an intact laminate converges to a rigidity within 3% of the experimental results. The finite element model of an intact laminate and patch shows a rigidity within 2% of the experimental results. Due to the high increase in rigidity of the repaired laminates, different patch stackups can be simulated. This allows to determine an ideal patch that would allow repaired laminates to have closer mechanical properties to that of intact laminates.

Keywords: repair, composite materials, welding, induction, thermoplastic 

Speakers
NC

Nicolas Côté

Master graduate / Research assistant, ÉTS
I have recently finished my masters in mechanical engineering. My research project was on the repair of micrometeroid orbital debris on the canadarm2 structure. I am now a research assistant at ÉTS working primarily on welding and assembly procedures for thermoplastic composite... Read More →


Thursday October 18, 2018 4:25pm - 4:45pm
Room AB Concordia Conference Center, MB Building 9th floor, 1450 Guy St, Montreal, QC H3H 0A1
 
Friday, October 19
 

2:35pm

PERWAVES combustion experiment performed on the Maxus 9 sounding rocket

The combustion of metal suspensions occupies an important place in modern technology, such as propulsion or chemical safety. Metals have even been proposed as a possible carbon-free energy carrier as well as a propellant for in-situ production on the Moon or on Mars. It has been discovered that for a given field of parameters, the heterogeneous flames exhibit an unusual behavior. The flame cease to propagate as continuous fronts and become dominated by discrete effects, leading to low-velocity percolation-like propagation. This phenomenon has been reported in other areas of science such as in self-propagating high-temperature synthesis (SHS), chemical kinetics, or biology; the study of discrete flames in metal suspensions may therefore be crucial in understanding front propagation in many of these systems. Due to particle settling and buoyancy-driven disruptions of the flame, both caused by gravity, a clear parametric study of discrete flames can only be realized in microgravity environments. This lead to the PERWAVES experiment, performed in a microgravity environment aboard the European Space Agency sounding rocket Maxus 9, launched on April 7th, 2017. The tests involved the propagation of flames of iron suspensions dispersed in oxygen/xenon gas. The particle concentration was varied and two different oxygen/xenon proportions, 20%/80% and 40%/60% respectively, were used. It was found that flames propagate at low average speed (~1 cm/s), insensitive to combustion time of individual particles, in agreement with discrete regime predictions.


Speakers
avatar for Jan Palecka

Jan Palecka

PhD student, McGill University
PhD student in Mechanical Engineering, working in the area of Combustion and Reactive Materials. My main specialization is heterogeneous combustion in metal suspensions. During my PhD, I have been tasked with the preaparation and analysis of the PERWAVES project, which has been performed... Read More →


Friday October 19, 2018 2:35pm - 2:55pm
Room CD Concordia Conference Center, MB Building 9th floor, 1450 Guy St, Montreal, QC H3H 0A1