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Student paper

Crash-proof design of components – Analysis of the strength and stiffness of thermoplastics after impact

Bachelorarbeit oder Masterarbeit

Während deiner Abschlussarbeit wirst du mithilfe von Crashversuchen am Fallturm unterschiedliche Vorschädigungen in Kunststoffproben einbringen. Du erlernst neben der Prüfung im hochdynamischen Bereich auch wie man die Deformationen im Millisekundenbereich mithilfe von Highspeedkameras auswertet.

Topic of the work:

Engineering thermoplastics are predominantly processed using the injection molding process, as this method enables the economical, high-quality and automatic production of components. By reinforcing the material with short or long fibers, the mechanical properties can be increased to such an extent that structural applications in vehicle or appliance construction are also possible. Crash events can cause sudden loads on the components, which must be taken into account during the design process.

Stuwi-Crashsichere-Auslegung© Evonik
Batterieabdeckungen welche sich im Unterbodenbereich von Elektrofahrzeugen befinden werden durch Steinschläge einer Impaktbeanspruchung ausgesetzt

The work is related to this research project:

During your final thesis, you will use crash tests on the drop tower to introduce different types of pre-damage into plastic samples. In addition to testing in the highly dynamic range, you will also learn how to evaluate deformations in the millisecond range using high-speed cameras. In addition, you will determine the residual stiffness and residual strength after the impact as a function of the energy applied and the realised strain rate. You will carry out preliminary tests on the high-speed tearing machine at high elongation rates in order to independently derive a test plan. Based on your analyses, a dimensioning method for components is derived which makes it possible to take dynamic pre-damage into account.

Objective:

The damage mechanisms at high loading speeds in fiber-reinforced plastics are not yet fully understood. For this reason, components fail prematurely, are replaced early or have to be over-dimensioned with high material input so that the component function can be guaranteed despite impact events. As part of the working group, you will contribute to research into material damage and thus support IKV in developing methods for safe dimensioning, taking sustainability into account.

Your task:

Production of test specimens from short- and long-fiber-reinforced thermoplastics by injection molding Production of test specimens from short- and long-fiber-reinforced thermoplastics by injection molding
Crash tests on the drop tower and the rapid tear test Crash tests on the drop tower and the rapid tear test
Test evaluation using the images from the high-speed camera Test evaluation using the images from the high-speed camera
Analysis of microdamage as a function of strain rate

Your profile:

  • Degree in natural sciences or engineering
  • Independent and quality-conscious way of working
  • Interest in experimental work and scientific data analysis
  • Ideally initial experience in the field of mechanical testing