Glue and bolts. A new approach to “wet” assembly has been proposed in Russia

MOSCOW, June 3. A new approach to analyzing the “wet” assembly of large structures using glue and fasteners was developed by SPbPU scientists. According to the authors, their approach has no analogues in the world and will allow engineers to design assembly processes not by trial and error, but using numerical modeling, which is much faster, cheaper and more reliable. The results were published in The International Journal of Advanced Manufacturing Technology.
The technology of the so-called hybrid or “wet” assembly consists of simultaneously installing bolts and applying a layer of glue when connecting parts. Today, such technologies are widely used in the automotive industry, shipbuilding, and the construction of engineering structures, for example, bridges, said scientists from Peter the Great St. Petersburg Polytechnic University (SPbPU).

Researchers have created a complex mathematical model and wrote computer code that, in their opinion, makes it possible to correctly reproduce the process of assembling flexible parts, between which a layer of viscous sealant or glue is applied, with fasteners (for example, bolts).

The new approach will allow engineers to design assembly processes using numerical modeling, and not at random, noted Sergei Lupulyak, head of the Virtual Simulation Modeling Laboratory of the Institute of Physics and Mechanics of St. Petersburg Polytechnic University.
«We've all glued something. And every time we asked ourselves the questions: how much glue and how to spread it? How hard to press? How long to wait until it dries? The same questions face engineers who develop assembly processes using glue. But before Until now, there have been no software packages that would help engineers answer these questions,” he said.

According to the scientist, the reason for this was the mathematical and computational difficulties that arise when modeling these processes. For this reason, for example, in the «wet» assembly of the upper wing panel and fuselage of an airliner, an extremely complex and large-scale structure, numerical modeling has not yet been used.

Today, this field has comparable capabilities. the technology does not exist, the study authors said. The model they built allows them to analyze the assembly process of parts of almost any size and complexity.
“It’s impossible to give exact figures now, but the commercialization of this technology can bring an economic effect of billions of dollars around the world,” said Artem Eliseev, a research engineer at the SPbPU Virtual Simulation Laboratory.

The novelty of the approach, according to him, is that it arose at the junction of several various scientific and technological fields: structural analysis, theory of modeling assembly processes, theory of hydrodynamic lubrication, computational mathematics. The SPbPU scientific group brings together specialists from all these areas. The authors note that the development of their development will make it possible to use it to simulate the production of composite structures and in many other areas.
The research is supported by the Russian Science Foundation (project 22-19-00062).