Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Service Life Simulation on Plastics under the Influence of Aggressive Fluids

01.04.2008
Components in the vehicle engine compartment must withstand high temperatures, mechanical vibration and the effect of aggressive substances such as fuel, brake fluid or engine oil.

Until now, the durability of plastic components has been extremely difficult to assess, considering the variety of influencing factors. This is particularly important for critical safety components, whose failure involves a significant danger potential and subsequent liability risks.

At the "JEC" trade show held from 1 to 4 April in Paris, at its stand U74, hall 1.3, Fraunhofer LBF will present solutions for simulating the service life of components made from plastic and other composite materials.

The number and usage of components made from plastic and composite materials has been growing steadily throughout the last few years. Until now, reliable, material-specific testing methods and rating concepts for these plastic components, enabling an assessment of their expected service life, have not been available. Within the framework of a Wing Project of the German Federal Ministry for Education and Research lead by Robert Bosch GmbH, engineers are currently working on new material technologies. Research scientists at the Fraunhofer Institute for Durability and System Reliability LBF in Darmstadt are developing a simulation method which will enable the reliable assessment of fatigue and ageing of plastic components under various ambient influences. Using specimens made from thermoplastic materials and resembling the actual components, researchers have investigated the behaviour of the materials in laboratory tests, as a function of material, geometry, manufacturing process and various environmental factors (such as temperature, fuel, or oil). These parameters are critical to strength, load-carrying capability and service life of the materials.

The effect of these combined parameters on material fatigue can subsequently be shown in a numerical simulation of the components. "First of all we analyse the vibratory strength of plastic specimens immersed in an oil bath, by introducing cyclic loads", explains Andreas Büter, Head of Department at Fraunhofer LBF. "Depending on the load at which specimen fatigue or fracture occurs, the fatigue strength, i.e. the relationship between the cyclic load applied and the maximum permitted number of vibrations can be calculated." On the basis of the results obtained, a diagram called Wöhler curve is determined by the engineers, which enables a statistical assessment of the fatigue life of a component.

How a fuel rail, for example, will withstand engine vibrations under simultaneous contact with fuel, is simulated on the basis of the results obtained by means of a numerical model of the component. "We calculate the stress and strain occurring in the material at various loads", explains Büter. "We know from experiments the stresses the material can withstand without damage, and at which strains damage occurs. Hence we can assess the service life of plastic components with maximum reliability".

The purpose of the simulation models, which are adapted to the specific material in hand, is to enable designers to take into account ageing processes and the effects of various ambient factors on plastic components at an early stage in the development phase - similar to metal components. This will reduce the cost and time involved in design modifications and adaptation of shape.

Scientific contact at the show:
Dr. Andreas Büter, Julia Hartmann
mobile +49 172 6184202
julia.hartmann@lbf.fraunhofer.de

Anke Zeidler-Finsel | Fraunhofer Gesellschaft
Further information:
http://www.lbf.fhg.de/

More articles from Process Engineering:

nachricht Fraunhofer researchers develop measuring system for ZF factory in Saarbrücken
21.11.2017 | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP

nachricht New manufacturing process for SiC power devices opens market to more competition
14.09.2017 | North Carolina State University

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Plasmonic biosensors enable development of new easy-to-use health tests

14.12.2017 | Health and Medicine

New type of smart windows use liquid to switch from clear to reflective

14.12.2017 | Physics and Astronomy

BigH1 -- The key histone for male fertility

14.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>