Project IMVAL (completed 04.2007)

Project content and results

The aim of the joint project was to develop, manufacture, analyze, characterize and apply a new lightweight composite material. The composite material consists of geometrically well-defined small and specifically very light mineral foam spheres (inserts), which are shaped into a macroscopically geometrically defined form and infiltrated with a liquid plastic or metal (matrix) via a casting process. The resulting creation of many interfaces and cavities and the possibility of integrating force introduction and fastening elements lead to significantly reduced weight with simultaneously defined adjustable deformation properties. Due to the low specific weight, the uniform and easily reproducible foam structure, the good shaping possibilities and the favorable energy absorption capacity, this cellular composite material offers particular advantages for lightweight construction, for example in automotive engineering. In particular, the composite can be used as a core material for sandwich constructions, thus providing good stiffness and strength properties.

The favorable energy absorption capacity of closed-cell foams also promises functionally highly modulable solutions for crash problems (e.g. energy-absorbing structural components for head impact on the hood, defo elements in a skewed crash or lightweight stiffening elements for side impact). Another advantage is the relatively low material costs resulting from the use of recycled products (e.g. bottle glass or filter dust from power plants) for the inserts.

Within the research project, the mineral foam granules were optimized and manufacturing technologies for the composite were developed. In order to open up the wide range of applications within lightweight construction, suitable material models with experimentally determined material parameters have been set up for the computer simulation of the material and component behavior with regard to deformations and internal stresses using the finite element method (FEM). The knowledge of the material properties including the damage behavior, as well as the availability of suitable material laws for FEM applications in the viscoelastic and elastoplastic range and at high strain rates as they occur in crash applications, should enable the use of the new composite material in the automotive industry as well as in other industries in which lightweight construction technologies play a major role.

In addition, design guidelines were drawn up for designing with this lightweight material in a way that is suitable for materials, production and testing. These were developed on the basis of specific design tasks in the field of thin-walled frame and shell structures.

Material parameterization was carried out by means of microcomputer tomography (µCT) and 3d image processing in order to verify the specific setting of material parameters in samples and in the component and thus to open up quality assurance for component manufacture.

The development process and the production of molded parts were set up in order to cover the entire process chain from material production to the finished product and to demonstrate the economic manufacturability for series production. The final objective of this research project was the production of a prototype of a lightweight molded part which is to be developed, manufactured, machined and tested under operating conditions using all the technologies described.

Cooperation Partners

 

Research partner:

 

Competence Center of Lightweight Design at the University of Applied Sciences in Landshut

Subproject: Material laws for cellular composites in the time-free elasto-plastic range

Ingolstadt University of Applied Sciences

Subproject: Material laws for cellular materials at higher strain rates

Fraunhofer Institute for Industrial Mathematics (ITWM)

Subproject: Analysis of the structure of mineral foam composites

Foundry Institute

Technical University Bergakademie Freiberg

Subproject: Cellular materials with zinc matrix

 

Industrial partner:

 

BMW AG Landshut plant

Development of design guidelines for the different materials

Determination, design and production of a prototype

Investigation of material application in energy-absorbing profiles (so-called crash absorbers) in the bumper beam

Dennert Poraver GmbH

Optimization of mineral foam granules

Production of component prototype

DST Dräxlmaier Systemtechnik GmbH

Investigation of material behavior at high strain rates (drop tower tests)/li>

Development of design guidelines for the different materials/li>

Determination, design and manufacturing of a prototype

CADFEM GmbH

Implementation of the material laws in FEM software

FEM consulting & support

Grillo Werke AG

Main focus on content:

Development & optimization of zinc foam

Production of test specimens

HZD Havelländische zinc die casting GmbH & Co.KG

Optimization zinc foam

Production of component prototype

HÖRMANN Engineering GmbH

Development & design of component prototype

Development of design guidelines for composite material

Quadrant EPP Nederland B.V.

Production of solid specimens of the matrix material, specimens of the filler-matrix composite (with the support of Poraver) as well as simple structural components (sandwich panels, filled hollow sections, etc.)

Material data for plastic matrix

ZoE Center of Exellance GmbH & Co.KG

Production of solid specimens of the matrix material, specimens of the filler-matrix composite (with the support of Poraver) as well as simple structural components (sandwich panels, filled hollow sections, etc.)

Production of component prototype

Material data for duromer matrix

Data & Facts

Project name IMVAL – Innovative mineral foam composite applications for lightweight construction
Technology fieldLightweight materials, lightweight mechanics, lightweight design, design methodology, mechanics of materials, numerical simulation
Project duration 01. August 2003 until 30. April 2007
Project volume1,5 Mio. EUR
Funding 0,8 Mio. EUR
Support Program InnoNet, Federal Ministry of Economics and Technology (BMWi)
Project PromoterVDI / VDE Innovation + Technik GmbH