Looking for guidelines for strength assessments

Hello everyone,

This question is only indirectly related to CalculiX, so I hope it is still allowed to ask it here.

Determining stresses under load is only half the way to finding out whether a component can withstand the assumed loads. The stresses must be compared with the stress states that can be withstood, which are usually specified by guidelines / regulations / codes or determined according to the same.

Which verification methods or sets of rules for static and cyclic verifications do you use? In order to expand my horizon, I am looking for codes that are unknown to me, maybe they account phenomena that are unknown to me. In particular, I am looking for “generally valid” guidelines, i.e. not those that deal with specific component types such as bearings, bolts, etc… The verification should allow FEA.

In German-speaking countries, the FKM guideline (Analytical Strength Assessment 7th. Ed. 2020 EN | FKM-Richtlinien | VDMA Verlag Shop) is often used as a common guideline for mechanical components if no other explicit rules are mandatory. However, the FKM guideline seems to be relatively unknown internationally. I would therefore like to know if you know of any standards / guidelines / rules that are internationally well-known / accepted and applicable for a wide range of applications.

Thank you very much for the hopefully upcoming inspirations!

Edit:
I am mainly interested in the verification of metallic materials.

I guess is different in each industry, however same principles: Tresca, Von Mises or Rankine failure theories in the end plus stability analysis. Not very familiar with fatigue/damage tolerance analysis. As a reference in Aerospace even if old consider this manual: AD0759199.pdf

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for steel material, there is a method widely accepted to predict strength, named Stress Modified Critical Strain (SMCS). It seems FreeCAD has been implemented this feature in their internal solver, but some parameter fixed.

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Thanks for the tips! I will have a look at both.

I forgot to mention that I am mainly interested in the verification of metallic materials. I have edited this to the question above.

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Although it is very specific DNV are also good references.

DNVGL-CG-0127
DNV-RP-C208 Non-linear FE analysis Methods.

The design-by-analysis manual form the european comision can provide guidance too.

When reading any paper take a look at the references.

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For steel constructions you could look at Eurocode 3 (EN 1993).

And often I resort to the manufacturer’s documentation, especially for specialty materials or heat treatable alloys.

The influence of the manufacturing method on the material strength is sometimes underappreciated, IMO. A good example would be wrought versus machined parts.

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For aerospace this is thoroughly accounted for in MMPDS (formerly MIL-HDBK-5), the last free edition is available here: Metallic Materials Properties Development and Standardization (MMPDS). | National Technical Reports Library - NTIS

since then available here ($): https://www.mmpds.org/

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Many thanks for the suggestions, I will have a look at all of them.

The Eurocode 3 seems to me to be the most generally valid in terms of application (Buildings, Bridges, Towers, Silos, Pipelines … ) as long as it is made from steel (no Aluminum, no Cast Iron, …).

DNV and MMPDS seem to be very specific for ships and airplanes respectively, so not very general. Nevertheless, there are some interesting approaches that are worth pursuing.

I can’t really judge “The Design by Analysys” from a rough skimming. In the introduction it looks as if this manual is intended for vessels, but the examples look very general again. I’ll have to investigate this further.

EN 1999 Eurocode 9 is dedicated to aluminium, and there is another for sandwich

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it seems Eurocode limit 5% plastic strain is not yet widely used and accepted in US/CA, also inconsistent with another criteria of 25 to 50 times yield strain in static and cyclic. DNV did not follow these criteria also, using average curve fitting instead of peaks. However, SMCS seem to be consistent and general approach to predict strength or failure, but it’s required convergence mesh study even some reported not too sensitive. Alloy type of metallic of materials also seem to be possible by changing the toughness and void growth parameters, need more calibration before.

another reference cited look like semi-analytical approach which probably can be specific, not general FEM based numerical solutions.

While cast iron definitely has its uses, I don’t think it is much used for new structures of the types that fall under Eurocode.

And the subtypes of cast iron are different enough that e.g. strength and failure behavior will differ significantly between them.
Finally there are processes like austempering that can be applied to both gray cast iron and ductile cast iron and modify properties.
So cast iron is not as much a material but a category of related materials, sometimes only differentiated by processing conditions.