CommonLab

A full service for FEM material input decks

Finite element analyses with nonlinear material behaviour, e.g. forming or crash simulation, require a good description of the material behaviour. Obtaining reliable material parameters is not trivial. MATFEM can test your materials and derive material input data for your FEM analyses.

We cover a wide range of material models for various commercial explicit simulation codes.

We characterize your individual material and do not offer data from a general material database.

The service is fully transparent to our customers. We provide all lab data, lab reports, a theoretical report on the parameter identifi­cation process and a comparison of the identified model data with the original lab data at the end of the project.

The customer holds the rights to all lab data and identified parameters.

Reliable material data in six steps

❶ Discuss the simulation problem

The first step is to assess the simulation problem at hand and to identify the important physical effects that should be considered in the material model.

failure plastic behaviour elastic behaviour fracture instability plastic hardening yield criterion physical properties thermal expansion mass density linear hyper- elastic aniso- tropic asym- metric ductile normal fracture ductile shear fracture isotropic isotropic trans- versely isotropic kine- matic ortho- tropic tensile

Material modelling comprises a vast range of aspects. For a single application, only a subset of this range is important. We can help you to find out which aspects of the material behaviour are worth modelling in detail and which aspects can be neglected.

❷ Select the proper material model

The commercial finite element codes provide various material models. Depending on the problem, we can help you to choose an appropriate model, for which we will prepare the data. We also provide material data for MATFEM’s material model MF GenYld + CrachFEM.

❸ Define an experimental programme

We define a cost-effective test programme which takes into account the special properties of your material and the application field of the simulation.

For example, fracture tests are carried out only for materials with low ductility. Tests with load reversal may not be needed for some simulations, but recommended for others.

The experimental programme is discussed with the customer. The project’s time frame, data available from customer facilities and the required quality are taken into account.

The programme is modular. Costs are assigned to each module such that individual modules may be skipped or postponed.

❹ Carry out experiments

MATFEM has a network of specialized partner labs at universities, research institutes and private companies from Germany and other countries. In cooperation with our partner labs, new tests and specimens are developed.

We select the most appropriate partner labs for each project. If the customer can provide their own test results, those results can be included in the process.

❺ Identify material data

We use in-house software to derive all material parameters for a theoretical phenomenological material model from basic tests. This theoretical model is indepen­dent of the finite-element solver.

By fitting clearly described basic load cases well, the material model should be able to describe the material behaviour for arbitrary loads. Inverse iterative procedures usually yield parameters that are valid only for limited load cases. Therefore, such procedures are kept to a minimum.

❻ Prepare and test material cards

After parameter identification we create the material input for the chosen models. We also simulate test cases with the selected FEM software to validate the material card.