JEC COMPOSITES MAGAZINE - Issue #65 - May/June 2011 - 42

software

Composite manufacturing simulation to drive process and design innovation
This article goes through the development process supported by Finite Element (FE) manufacturing simulation applied to two industrial composites parts: an innovative thermoformed clip design developed by Letov and a Resin Transfer Moulded (RTM) rotor blade developed by VZLÚ. These two concrete examples show how simulation can provide time and cost savings, boost process innovation and optimize part quality.

MATHILDE CHABIN COMPOSITES BUSINESS DEVELOPMENT AND PRODUCT
MARKETING MANAGER

ESI GROUP

etov Letecka Vyroba Ltd. is the oldest aircraft manufacturer in the Czech Republic. Established in 1918 as the country’s first aircraft manufacturing facility, they mostly develop and manufacture parts and subassemblies for civil and military aircraft. In 2000, Letov joined the French Groupe Latecoere. Letov has a dedicated composite production centre, which was created to develop and manufacture composite parts for civil aircraft.

optimise the forming process of the integrated composite clip, that has a complex shape. PAM-FORM was also used to optimise tool design.

Standard shape versus integrated shape
To produce such components, engineers generally use flat composite plates which are preheated and then formed into the corresponding shape by press. A carbon fibre fabric is used for reinforcement in a very different process mechanism compared to sheet metal forming, the methodology usually applied for developable shapes. Although the shape corresponded to the usual sheet metal design, composite materials gave Letov engineers the chance to use new shapes. “Only a new design philosophy with high integration of

structural requirements can make the best of composite potential,” said Josef Krena, Development Manager at Letov Letecka Vyroba, Ltd., Groupe Latecoere. “We wanted to develop a forming tool shape that would enable us to produce a clip in one shot,” he continued. The engineers were faced with three levels of complexity: the geometry of the integrated clip itself, the composite material used, and the part’s rigorous mechanical requirements. In addition, there were very high risks of folding and other defects appearing during the forming process. Many trials and considerable development time would be required to define optimum tooling and process parameters and reach the initial targets. In order to shorten development time, Letov used PAM-

In a recent project, the company produced clips for a major aircraft manufacturer. Clips are small joining parts used in the fuselage structure of an airplane. A standard clip consists of two components. To lower production costs and save weight, Letov engineers sought to develop an integrated part in a single shot, without impacting the mechanical properties of the clip. To do so, they used ESI’s composite forming simulation software PAMFORM to analyse and Standard shape and Integrated shape

jec composites magazine / No65 May –June 2011

JEC COMPOSITES MAGAZINE - Issue #65 - May/June 2011

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #65 - May/June 2011