In search of perfect industrial parts



Manufacturers of aeronautical and aerospace parts are having a gas problem! Gas bubbles found in composite materials are causing them headaches: they reduce the mechanical properties of structures, which can prevent them from passing rigorous industry certification processes.

Pupin proposes to build mathematical models to describe the optimal manufacturing conditions of high-performance composite materials.

Many parts—and company profits—end up in the trash. Cédric Pupin, a research student in the Department of Mechanical Engineering at École Polytechnique de Montréal, is hoping to come to the aid of manufacturers by modelling the formation of these pores according to various manufacturing parameters.

The problem occurs during moulding, and more precisely when resin is injected into carbon fiber reinforcements. This viscous substance does not always perfectly fill the space, and micro air pockets can be formed. In addition, the chemical reactions that cause the resin to harden on curing create more gas bubbles. For the time being, manufacturers attempt to reduce porosity rates by adjusting injection and curing parameters by trial and error. As this method increases production time and costs, Pupin proposes to build mathematical models to describe the optimal manufacturing conditions of high-performance composite materials.

The PhD student is currently carrying out a series of analyses designed to determine the loss of mass associated with different curing conditions and to define the chemical nature of the elements that cause the formation of pores. This work is being carried out at ERFT Composites, a Québec manufacturer of composite parts for the aerospace industry.

On the long term, Pupin would like his model to be integrated into digital simulation programs and—why not?—to be used in other sectors, such as the automobile industry.