Meccanica

Stress Analysis of a Vacuum Vessel

About Meccanica

Robert Boz holds an engineering degree in Mechatronics with honors. He started the company Meccanica 8 years ago in Australia, with an initial focus on the optical industry.

Meccanica is a joint venture with Marco Engineering that provides responsive solutions to unique customer requirements. This collaboration merges the unique strengths of each entity to provide a unified solution partner with capabilities in engineering design and analysis, multiphysics simulation, testing and validation, and more.

Meccanica maintains a specialised but agile professional base with proven experience and ongoing commitments to commercial, defence, scientific and aerospace industries.

A philosophy of continuous improvement to each of our research and development, prototyping, product development and high-value manufacturing processes, is applied to the company and is reflected in 50 years of continuous engineering excellence on behalf of Marco Engineering.

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 Challenge

Evaluating the Performance of a Cryogenic Vacuum Vessel

During Robert’s previous research work, he has noticed many shortcomings of on-premises simulation software. One big issue is the limitation of computing power. The local workstation is basically useless during a simulation run, which can take up to 16 hours per calculation.

When Robert was searching for a solution, he first came to know Onshape and soon adopted it as his preferred CAD design tool.

The collaborations between his team and clients went very smoothly on the Onshape platform; hence Robert became very satisfied with cloud-based platforms. Through the partnership program of Onshape, he learned about SimScale and started performing diverse simulations with it. From structural analysis to fluid dynamics, he has managed to impress his clients by elaborating the SimScale platform along with the post-processing images he obtained.

The integration of high-end numerical tools also allowed him to move away from hand calculations. Although the analytical formulation of any problem gives a fast general overview of a problem, it cannot provide detailed information about the system’s performance.

Furthermore, numerical simulations allow highlighting interesting areas in the design, which might need dedicated investigation in order to ensure the performance of the whole system.

Solution

Stress Analysis of a Vacuum Chamber

One of the first analyses that Meccanica realized using the SimScale platform was the stress analysis of a (cryogenic) vacuum vessel. The task aimed to present the behavior of the assembly exposed to atmospheric pressure while keeping the inside of the part in the vacuum.

Since no significant deformations were expected, the static finite element analysis simulation type was selected. The nonlinearities of the problem were limited to physical contacts. Further modeling improvements were achieved by removing hyperelastic o-ring gaskets.

In order to acquire the best leverage of time and accuracy, the geometry was first tested on a coarse mesh. This way, the simulation setup could be tested, and modifications of the settings could be applied in a fast manner.

After the coarse mesh produced a reasonable and stable simulation, the geometry was discretized with much bigger precision. Thanks to that, the obtained results were accurate and reliable.

Results

Data Analysis has Shown Displacements of the Plates

The results have demonstrated the capability of the platform to tackle complex systems of vacuum vessels. Data analysis has shown the displacements of the top and bottom plates with respect to the casing. Most importantly, they have demonstrated that contacts are engaged in limited areas, which might result in poor closing. A comparison of the results of simulations with and without gaskets have shown that, as assumed, the part had little effect on the precision of simulation.

The performed analysis provided valuable insights into the behavior of the cryogenic vessel and was a great starting point for further, more detailed investigation. The screenshots and images were also used during a successful project pitch. This demonstrated the strategic advantage of incorporating numerical simulations into consultancy process.