CheFEM - Chemical interaction driven FEM simulation of advanced composites

What is CheFEM?

CheFEM is used for analysis of chemical resistance, diffusion and forthcoming mechanical retention of polymer based materials. As such, the software enables lifetime prediction of composites, coatings, laminates and seals during exposure to any chemical or chemical mixture in any state: liquid, gas or supercritical. CheFEM is also used for failure and permeation assessments, for example in packaging.

CheFEM predictions show high degree of correlation to - properly carried out accelerated and long term - laboratory test results.

The software can be used in addition to other existing mechanically oriented FEM software.

How does CheFEM work?

CheFEM quantifies external surface interactions (surface corrosion rates, solubility thermodynamics, blister formation, etc.) as well as internal phenomena (diffusion/chemical potential driven corrosion of internal materials, interfacial swelling shears, plasticizing of the matrix, effects of insufficient wetting, stress driven void formation, etc.) and relates this to long term mechanical retention and permeation properties. CheFEM consists of the following four modules:

100  FEM/FD Sequencer
101  Lattice Based Thermodynamics & Diffusion
102  Surface & Chemical Activity Driven Corrosion
103  Gibbs Free Restraint

Click respective tabs to learn more about the different modules.

CheFEM_intro

100 FEM/FD Sequencer

The FEM/FD sequencer is used for the mathematical modeling of the application/equipment dimensions in terms of Finite Elements (FEM) and Finite Differences (FD). The spatial domain ranges from nano (e.g. carbon nano particles), to micro (e.g. a glass fibre), to macroscopic (e.g. a coating on top of metal) distance. In next three modules the chemical-physical parameters are defined in function of this spatial domain and the time domain of interest (stationary and instationary solutions). The module is compatible with all modern CAD formats.

Module 101

101 Lattice Based Thermodynamics & Diffusion

The lattice based thermodynamics & diffusion module deals with (multicomponent) chemical potential and solubility in different material layers as function of temperature, system pressure and stress on the element under consideration. The module also seamlessly calculates (multicomponent) diffusion rates. On this basis, permeation rates, time lag, degree of plasticizing and swelling stresses are determined. Effects of (anomalous) ageing are included.

101-1

102 Surface & Chemical Activity Driven Corrosion

Polymers can exhibit high surface corrosion resistance, but chemical reactivity of internal interfaces can drive loss of interfacial strength. The long term strength of advanced materials is largely dependent on the interfacial robustness. This module uses chemical potential data from the lattice based thermodynamics & diffusion module in combination with chemical reaction kinetics in the specific element under consideration.
102

103 Gibbs Free Restraint

The Gibbs Free restraint module is based on a thermodynamical-mechanical fracture based analysis of composite components and interfaces between components. The module predicts whether surfaces restrain the effects of an internal pressure potential and/or of chemical degradation. If not, it predicts the extent of fracture as function of place and time.
103

Only a production version of CheFEM is currently available.

For more information, we invite you to contact us or to use the form below.

For applied industrial examples of CheFEM also visit the case stories section.


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