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Is there any methodology for FEA analysis of Sheet Moulded Compound (SMC) with Glass Fiber in OPtiStruct?

I request support on FEA Analysis method on Menzolit SMC 0400 (https://menzolit.com/wp-content/uploads/2020/11/Menzolit-S-PI-SMC-0400-en.pdf).

Glass Fiber Content is 27%.

Menzolit SMC 0400 is a sheet moulding compound based on unsaturated polyester resin. The product is glass fibre reinforced and contains mineral fillers.

The material is compression moulded in heated steel moulds.

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v2021.1

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Adriano_Koga

i don't think we have a complete solution for the SMC process.

But depending on what you are trying, it might be simplified with an equivalent anisotropic property, or quasi-isotropic, depending on your fibers orientation.

If it was injection molding, Inspire Mold would help to get the final orientation tensors.

But for SMC i don't know how to properly calculate the orientations.

If you consider some random orientation or some specific orientation tensor, you could go to MultiScale Designer and feed it with yor glassfiber and matrix, and calculate an equivalent material property to use in OptiStruct, with MAT9ORT for instance.

But you would need to somehow provide a basic orientation tensor through thickness.

PSiedlaczek

If SMC was deviled without information on fiber directivity as in many cases is (in industrial reality all) fiber control in SMC product will not be possible. There will be no big difference in using SMC and BMC for many products.

The analysis based on weakest link principle can give good estimation of SMC part weak points, however if You have resources it is best when You test physically your product up to failure. This will give You real safety factor that can be applied on FEA results of this single part type and failure mode as in test.

I mean SMC is cruel material, it behaves nonlinear when loaded, creeps when hold under load, have not predictive friction, hets-up internally subjected to vibration cycles, cracks badly if especially when used with to thin walls, and have nonuniform properties which depends on stamping process, have short shelf life and it cheap to name few its great properties.

Matt Kedgley

SMC is tricky to analyse, agreed - a problem that cannot be tackled using your regular techniques. I find it's because the strength can vary from resin strength to UD tape and it's all too easy to think of the worst case scenario of having resin strength in a stress concentration which doesn't inspire confidence! However, it turns out, that scenario is quite unlikely.

I've been working on an analysis method which uses a customisation of hypermesh called FiRMA (Failure in Random Material Architectures). It aims to answer the question of the range of performances you will get from a population of parts and does so using a different analysis technique to normal.

We even have a development of FiRMA (which assumed random fibre orientations everywhere) called FiRMA-flow which accounts for compression mould fibre orientation bias.

Feel free to get in touch if you want to explore more!