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TRIMIS

Study on the Processing and the Performance of Cyanate Ester Composites Towards the Optimization for Harsh Service Environments

PROJECTS
Funding
European
European Union
Duration
-
Status
Complete with results
Geo-spatial type
Other
Total project cost
€380 252
EU Contribution
€285 189
Project Acronym
SPECIMEN
STRIA Roadmaps
Vehicle design and manufacturing (VDM)
Transport mode
Airborne icon
Transport policies
Societal/Economic issues,
Safety/Security
Transport sectors
Passenger transport,
Freight transport

Overview

Call for proposal
SP1-JTI-CS-2010-05
Link to CORDIS
Objectives

Cyanate esters are a relatively new generation of thermosetting resins that exhibit considerable tolerance in high service temperatures where the effects of moisture and micro-cracking due to thermal cycling loading are important. They exhibit low moisture absorbency, whilst retaining useful processing characteristics, e.g. cure temperatures, handling and composite processing by pre-pregging or by resin transfer moulding. In particular, the improvements over epoxies are good toughness, lower moisture absorption, higher glass transition temperatures at lower cure temperatures and increased resistance to micro-cracking. Consequently, cyanate ester based composites are exceptional candidate materials for parts used in aircraft or rotorcraft components that are subjected to a complex history of temperature, moisture and other environmental conditions. Nevertheless, the long-term exposure of cyanate ester-based composite materials to those harsh environmental conditions and the respective degradation of their properties defined as material ageing process is not yet fully studied and understood. This aspect limits the further utilization of such materials in aeronautical applications.

SPECIMEN project aims to fill this missing knowledge gap and create specific technical guidelines. Taking into account the technical requirements provided by the topic manager, SPECIMEN project will provide CSJU a complete study that will include a Material Screening Procedure, a Manufacturing Process Plan, the methodologies for studying ageing process using accelerated testing protocols, the durability performance characteristics of selected materials and a Compliance and Optimization Study for selected materials. The deeper understanding of the degradation in harsh environments using advanced material screening/testing procedures, accompanied with optimized manufacturing protocols will clarify issues concerning the inputs, outputs and nuisances during all three phases of aircraft life. Both participants that form the SPECIMEN consortium have strong background on processing-characterization of cyanate ester based materials and have extensive experience and infrastructure on ageing studies, which originates from their participation in various EC, ESA and national projects.

Funding

Parent Programmes
Institution Type
Public institution
Institution Name
European Commission
Type of funding
Public (EU)
Specific funding programme
JTI-CS - Joint Technology Initiatives - Clean Sky
Other Programme
JTI-CS-2010-5-ECO-01-010 Study of cyanate ester based composites in a high service temperature environment

Results

Executive Summary:

SPECIMEN project aimed to fill this missing knowledge gap and create specific technical guidelines for the use of cyanate ester composite material systems in long-term harsh environmental conditions. Taking into account the technical requirements provided by the topic manager, SPECIMEN project was designed to provide CSJU a complete study that will include a Material Screening Procedure, a Manufacturing Process Plan, the methodologies for studying ageing process using accelerated testing protocols, the durability performance characteristics of selected materials and a Compliance and Optimization Study for selected materials. SPECIMEN team was Applied Mechanics Laboratory of University of Patras (GR) and TECNALIA R&D center in San Sebastian (ES).

At the beginning the Technical Requirements from partners were gathered from the ITD members. Requirements were categorised in terms of material performance, manufacturing processes and other parameters (e.g. cost). Also envisioned applications were communicated. The search of materials has been based on requirements specified by the ITD members. After analysing the technical requirements, material properties and recommendations from suppliers, the materials were selected for further screening. Afterwards a test plan has been elaborated in order to define an initial ageing procedure and a test campaign, which will allow the verification of the compliance of the selected material systems with the given technical requirements and the specifications by both ITD members. Since screening testing decided to be performed in FRP level, considerable effort was given on manufacturing process investigations towards the production of materials required for specimens. Work involved process optimization of 3 different GFRP pre-pregg material systems and 2 different RTM bulk resin material systems. When the manufacturing processes were conclusively defined, specimens were provided for the finalization of the testing of all different materials. The analysis and the review of the results provided the background for the selection of one material per route.

The process optimization work was continued on the selected materials in order to produce specimens needed for the degradation studies envisioned. Under this framework for the case of RTM route, SPECIMEN team worked heavily to optimize the cure cycle succeeding 51% reduction of the curing time and a 33% of energy saving. Also, with the new proposed optimised cure cycle, a higher degree of cure is obtained in the post-curing and consequently a higher final Tg. Moreover, in the first dwell, the reaction rate is lower than in the baseline one, reducing the risk of exo-therm. For the case of PREPREG route, the optimisation of the process was kept limited focused on cure cycle and degree of curing control.

In parallel to the process optimization work, SPECIMEN team established a comprehensive methodology for Degradation Behaviour Study using the data from screening testing. The comprehensive methodology for an ageing study was based on the accelerated methods principles in order to investigate and understand the various degradation mechanisms of the Cyanate ester matrix composites that occur at high service temperature environments. Two (2) different protocols, for long-term exposure study were elaborated one for elevated temperatures for CFRP materials produced by RTM technique and one for elevated temperatures in humid atmosphere for GFRP materials produced by PREPREG/AUTOCLAVE technique. The actual ageing and respective testing & analysis performed provided significant information on the activation and operation of all applicable degradation mechanisms. Finally, for RTM process a manufacturing of optimized fibre reinforced composites was performed in order to perform a Life Cycle Analysis.

Taking into account the work performed during early screening stage, the main Degradation behaviour study and the given technical requirements by the topic manager last part of the SPECIMEN activity was focused on defining and addressing application specific critical parameters (e.g. severity categorization of Degradation Mechanisms, classification of operational conditions per criticality etc.). Moreover, Time Temperature Superposition (TTS) was used in order to try to estimate the lifetime under specific conditions. Additionally, three (3) simple & sort test protocols based on accelerated testing principles were produced for future use. SPECIMEN activity ended by providing a deeper understanding of the degradation in harsh environments using advanced material screening/testing procedures, accompanied with optimized manufacturing protocols.

Partners

Lead Organisation
Organisation
Panepistimio Patron
Address
University Campus- Rio, 26500 Patras, Greece
Organisation website
EU Contribution
€143 550
Partner Organisations
Organisation
Fundacion Tecnalia Research & Innovation
Address
PARQUE CIENTIFICO Y TECNOLOGICO DE GIPUZKOA PASEO MIKELETEGI 2, 20009 DONOSTIA/SAN SEBASTIAN (GIPUZKOA), Spain
Organisation website
EU Contribution
€141 639

Technologies

Technology Theme
Composite materials
Technology
Composite materials for structural purposes in the aircraft
Development phase
Validation

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