Rhodia launches new, advanced MMI* design support to improve reliability of plastic part simulation and accelerate customer innovation

Düsseldorf, Germany – October 24, 2007 – At K 2007 Rhodia launches its MMI* new generation of computer aided engineering (CAE) service for parts moulded in polyamide. This tailored approach excels particularly in impact resistance calculations, and puts Rhodia’s polyamides TECHNYL® and TECHNYL® STAR™ in the spotlight. This innovative calculation package rests on quality material data, including high-speed properties, and on multi-scale modelling software Digimat-MF, developed by e-Xstream Engineering.

This new generation of calculation has made the mechanical behaviour of moulded plastic parts more predictive, allowing development schedules to be compressed and the number of prototypes needed reduced.

MMI, towards excellence in impact simulation

MMI exhibits its full potential when used in testing the impact resistance of parts made of polyamide. Indeed, in the calculation process, the advanced mechanical properties of the polymer matrix stored in the new MMI database are combined with the glass fibre orientation defined by injection simulation software. This map of mechanical properties is then transmitted to usual mechanical simulation software, like ANSYS and LS-Dyna, in order to evaluate stresses affecting the part. It does this with a unique quality of predictability.

Using MMI, the first studies on parts have shown excellent correlation between impact simulations and actual experimental tests (Figure 2). To achieve this with traditional methods of calculation, reverse engineering using prototypes would have been needed to correct the model.

Moreover, if the part is moulded differently (Figure 3), MMI enables the anticipation, very early in the design phase, of the change in mechanical resistance caused by the modification of glass fibre orientation distribution thereby avoiding the repetition of a complete testing phase with prototypes.

MMI, a dedicated database

In order to provide engineers with high quality calculation data on materials, Rhodia Polyamide has invested in a research project and the latest generation of characterisation tools to analyse its materials.

• Analysis of the material microstructure by microtomography X so that the influence of glass fibre orientation on mechanical properties is mastered

• Material damage evaluation under multiple conditions

• Creep measurement

Most notable is the investment made by Rhodia Polyamide in the field of high-speed characterisation for crash testing. This has generated a MMI performance database dedicated to TECHNYL®, TECHNYL STAR™ and TECHNYL® FORCE. Benefiting from these advanced material data allows Rhodia to offer predictability at a new, higher level of accuracy.

MMI, an innovative technology

Providing the cornerstone of the calculation chain is Digimat-MF, a product of e-Xstream Engineering. Based on the theory of semi-analytical, non-linear, mean-field homogenisation, this software allows engineers to accurately calculate the material behaviour of TECHNYL® products at every location point in a part. It combines the advanced behaviour models of the polyamide matrix developed by Rhodia Polyamide, with the glass fibre orientation distribution determined by injection simulation software such as Moldflow.

This all-new approach takes into consideration the relationship between the state of the thermoplastic polymer reinforced with glass fibre, after injection moulding, and the mechanical properties of the processed part.

While calculating the mechanical behaviour of the part, the multi-scale calculation software Digimat-MF is in continuous exchange with a mechanical calculation software - ANSYS or LS-Dyna. This dynamic communication allows identification of the microstructure changes arising from the effects of stress during a test, so that the complex non-linear behaviour of the material is accurately described.

In summary, MMI allows the effect of injection on the mechanical behaviour of a part to be captured and, at the same time, benefit from the behaviour models specifically adapted to TECHNYL® materials so that reliable design is achieved in respect of impact simulation.

MMI, stimulating innovation in the field of technical plastics

The simulation software presently available to engineers does not easily allow the influence of processing on mechanical properties to be taken into consideration. Moreover, the specific behaviour laws for plastic materials (elasto-viscoplasticity, anisotropy as a function of orientation of the reinforcements, creep, etc) from experimental databases are still very rarely used. Therefore, part dimensioning is rarely optimal because of the use of security coefficients or of costly reverse engineering methods.

This is particularly true in the field of impact resistance predictions. From a complete system of simulations, MMI improves the mechanical behaviour reliability of polyamide parts, accelerates the development period and will potentially lead to new applications for plastic materials.

Due to MMI, Rhodia Polyamide allows customers to demand a higher level of predictability in the behaviour of their applications, thus opening the way for innovations in the field of plastic parts.

* MMI: Multi-scale modelling, Mechanical calculation, Injection moulding simulation

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+33 4 72 89 29 24

jerome.pisani@​eu.rhodia.com

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