Latest posts by Ben Meyer (see all)
- Are you in a ‘materials authority’ role and supporting simulation? - 26th January 2017
Simulation engineers are often desperate for sophisticated material properties to support their temperature dependent and/or non-linear material models, enabling more accurate simulation and validation of product performance.
If you are in the ‘material authority’ role in your company, either as a materials specialist or a member of the simulation team who has acquired this responsibility, you will need to respond! I’ve worked with many people in this role who are dedicating a lot of time to queries from design and simulation engineers about how materials will perform under various conditions, or which is the best material to use in certain operating conditions and environments.
Unfortunately, the material data to support these models can be very hard to come by. It is expensive to produce and validate. If someone has gone to all that effort, it’s unlikely they will make that data public and allow it to fall into the hands of competitors!
Materials authorities often have to take the plunge and commission test programs. In this case, it is vital to make sure that the maximum value is obtained from this effort and expense. The resulting test data must be accurately captured, with full supporting information for future reference:
- What test machines were used?
- How many specimens were used?
- What load cycles and conditions were the tests carried out under?
- What raw material batches were used, who was the supplier and what were the secondary processing and surface treatments used?
- What were the failure modes and what do the failed specimens look like?
Tests may be carried out in-house, at universities, or at subcontracted commercial test facilities. No matter what the source, this information must be captured easily, efficiently, and comprehensively, so that it can be easily retrieved and understood. Raw test data is often noisy, incomplete, and scattered, needing several clean-up and statistical analysis stages before it can be used to build simulation material models. It is important that this process is also carried out in a clear, repeatable, and transparent way.
The actual fitting of a simulation material model to the underlying test data is sometimes done by material authorities. But, often, key individuals within the simulation teams do this work. The tools to fit these models may be their own bespoke spreadsheets, macros, or scripts. Often, there are slight variations in methodologies or the application of ‘fudge factors’ between team members and this can be a source of concern for consistency and repeatability.
For simulation engineers, there is often a conflict between wanting to use approved, validated material data, and ‘getting the job done’ in time. Materials authorities need to provide both easy access to approved data and also a robust process to enable simulation engineers to:
- Make traceable modifications to existing material models to best approximate the behaviour of other, similar materials until better data is available.
- Request the material tests to generate the required material data.
Do these issues sound familiar? Part of the answer is to develop a systematic approach to managing materials data for simulation – and we would love to discuss that with you!