JEC COMPOSITES MAGAZINE - Issue #116 - October 2017 - 64

TECHNOLOGY efficiency

Fig. 2: Production of locally-reinforced woven fabrics via the ORW technology [3, 4]

Fig. 3: Comparison of the designed ORW preform concept with conventional
preform concepts

special thread guides arranged between the reed and weaving shafts. Electronically-controlled linear drives shift the
thread guides horizontally on a profile depending on the
specified pattern. This allows flexible reinforcement designs
optimized for the load path requirements. The modular integration of the ORW unit retains the full productivity and
unrestricted application spectrum of the weaving machine.
Investigations at ITA showed that the technology is best
suited for the local reinforcement of inserts and holes or for
the integration of unidirectional load tapes. The production
of locally-reinforced woven fabrics via the ORW technology
is shown in Figure 2.
The chosen application was an automotive convertible hardtop, which was already used as a demonstrator part in the
AutoPreforms AiF-funded project [5]. The hardtop features
a number of typical characteristics, such as:
- Three-dimensional surface with average complexity
- Local reinforcements
- Thickness variations

the determination of the exact reinforcement thread paths as
well as the development of the corresponding weave design
and further process adjustments. The resulting concept consists of four layers of carbon fibre woven fabrics with different local carbon fibre reinforcements:
- Layer 1: Woven fabric with integrated multiaxial window
reinforcements
- Layer 2: Woven fabric with integrated unidirectional reinforcements
- Layer 3: Woven fabric with integrated multiaxial insert reinforcements
- Layer 4: Unreinforced basic woven fabric
To illustrate the capabilities of the ORW technology, a comparable preform concept with a slightly higher complexity
was designed and produced. The demonstrator is shown
in Figure 4. To enhance the visibility of the tailored reinforcements, the woven fabrics for the demonstrator were
produced using glass fibre rovings while the integrated reinforcements were made from carbon fibre rovings.

Metallic inserts for load introduction

Conclusions

Based on the preliminary design, load paths and production
scenario, the TailoredPreform tool identified approximately
150,000 different part concepts suitable for ORW production. The different concepts were automatically evaluated
by comparing their projected production costs with the estimated costs of a part produced by means of conventional
preforming. The concept with the highest cost saving potential was subsequently selected for further customization.
The specific cost saving potential is shown in Figure 3.

ITA developed and validated an adapted design process to
determine the optimal application of tailored textiles in the
development process of composite parts. The cost reduction

Following the selection of the best fitting part concept, the
local reinforcements were designed in detail. This included

Fig. 4: Assembled preform demonstrator with local reinforcements

jec composites magazine / N°116 October 2017

Focus
The Institut für Textiltechnik (ITA) of RWTH Aachen University
conducts research projects to find answers to today's questions
regarding cutting-edge composite applications. About 100 researchers work in the field of materials, textile production processes and products for technical applications. The Institute has
a fully equipped technology centre and various laboratories with
about 250 textile machines and test benches covering almost all
textile processing stages.

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #116 - October 2017