Final Report Summary - QUALIFY (Qualification of insulation materials to engine oils)
Executive Summary:
Aircraft components are subject to in-service damage from a variety of threats, including impact, chemicals, high temperatures and ultraviolet light. To calculate the probability of failure (represented by knock-down factor (KDF)), empirical data is collected from numerous experiments. Currently, KDFs are determined individually for each threat rather than in combination, increasing the number of tests and simultaneously cost and time. In addition, such procedures do not adequately represent real in-flight conditions.
EU-funded scientists working on the QUALIFY (Qualification of insulation materials to engine oils) project have developed an innovative test set-up. It enables simultaneous exposure of insulation materials to thermal and cyclic mechanical loading as well as aggressive engine oils and temperature changes. The technology allows quantifying global interactions of parameters to realistically predict failure in manufactured parts. In turn, better understanding of materials and components behaviours will foster development of lighter higher-performance parts for important reductions in fuel consumption and emissions.
Thermoplastic organic polymers have been used in the insulation materials due to their good mechanical properties and chemical and temperature resistance. Engine oils for conditioning of specimens have been taken from those in service for two years and in good condition. The team has also designed the test set-up to enable testing of two specimens simultaneously in different environments. As result of the project, an optimized qualification plan for insulator materials to engine oils in “near reality” conditions has been obtained.
Project results will be widely disseminated to end users within the aircraft industry, including manufacturers, suppliers, industrial bodies and related associations. They are expected to be instrumental in the development of new standards of qualification during manufacturing. The novel testing methodologies will also be included in the portfolio of services offered by one of the world's testing, inspection and certification leaders. Finally, partners will share results with materials and components manufacturers in the plastics and composites industries.
Improved testing procedures will decrease production costs and time-to-market while enhancing product quality. Better design of aircraft components for lower weight and higher performance will help reduce the environmental impact of flight.
Project Context and Objectives:
Nowadays, in-service damages such as impacts during overhaul or external influences, such as exposure to severe environments with chemical agents, thermal loadings or ultraviolet light have to be taken into account for the design of the elements. Therefore, knock-down factors have to be determined. This knock-down factors take into account an extensive number of conditions such as loads –both static and cyclic-, temperatures, impact damages or the exposure to aggressive mediums such as engine oils. Due to the costs and complexity of performing full scale tests including factors such as temperature and exposure to a variety of aggressive atmospheres, during the qualifications, lots of tests are necessary in order to certify the integrity of the component material.
The actual state of the art is to determine this knock-down factors independently and not in combination of them, meaning that composite samples are for example immersed during a determined time in a fluid and afterwards tested statically at a given temperature.
The innovative idea to develop during this project is to develop a test set-up permitting to expose on the same time the specimen to not only thermal and cyclic mechanical loading, but also to synthetic engine oils atmospheres in order to be afterwards able to quantify how the global interaction of these parameters is and be able to predict failure of real manufactured parts subjected to “near reality” loading (in terms of loading, temperature and oil exposure) scenarios.
The project deals with the qualification of insulating materials in front of engine oils. The investigation will be done using four different types of materials (reinforced plastics) and different engine oils - in a new state, and after two year usage in an engine.
A “conventional” qualification plan of the materials under study will be drawn, the manufacturing plan for the “to be tested” specimens will be detailed and the specimens will be manufactured. A report detailing the manufacturing details such as materials, lay-up, dimensions and the quality reports of the specimens will be prepared.
Simultaneously, an “innovative” test set up for material specimen tests will be developed mimicking the “real life” conditions, meaning a tooling capable of introducing on the same time to the specimen mechanical, thermal and chemical loads. The idea for the tooling is that there is one area subjected to the exposure to fluid at high temperature, whereas another is not subjected to the exposure. The aim therefore is to analyse the impact of the “oil and temperature loading”. This tooling will be used in order to develop an innovative qualification plan. For this “innovative” qualification plan as well as for the “conventional” qualification plan, the number and type of necessary specimens and tests will be detailed in a qualification plan, the manufacturing plan will be detailed and the specimens will be manufactured.
The test results from the “conventional” and “innovative” test plan will be summarized in one report, the advantages and disadvantages of both methods will be analysed and the best materials according to the qualification plans will be selected. Using the testing results from the “conventional” and the “innovative” qualification plan independently the expected life and failure load of a real part under “next to reality loading conditions” will be predicted.
Finally, from the analysis of the results of the different tests plans, an optimized qualification plan will be defined.
Project Results:
In periods 1 and 2 the work has focused mainly in the documentation and definition of specifications for tests and material, which is necessary to start the test campaigns and subsequent studies. We have defined the testing and manufacturing plans for both the conventional and the innovative plan.
We have established the necessary materials for the qualification studies, and the types of oils that we will use for conditioning of the specimens. Two sets of tests have been defined, both for the conventional and innovative plans, as well as the number of specimens and dimensions, according to the applicable standards.
In the selection of materials it has been taken into account the breaking loads of these as a reference to an actual piece. Different thermoplastic organic polymers with different degrees of fibre reinforcement have been selected offering high mechanical properties, enhanced resistance to temperature and good chemical resistance. Engine oils selected are those used in a real environment, in perfect condition and after two years of usage.
For the innovative plan, it is necessary to design a test fixture that will allow testing two specimens simultaneously in different environments. The design has been performed.
The manufacturing of the specimens for both the conventional and the innovative test plans have been performed, and the oils (new and used) have been collected.
During Period 3, the tests foreseen in the conventional and the innovative qualification plan have been developed and reported. After analysing the results of the conventional qualification plan, performed over the specimens of 4 materials with and without pre-conditioning in the different oils at 160ºC, some additional tests have been performed in order to better characterize the behaviour of the materials under temperature and under dynamic loading, before executing the innovative test plan. Thanks to the information obtained, the test conditions have been precisely defined, and the design of the tooling for innovative plan has been revised. The tooling, which allows the testing of 2 samples, one of them immersed in oil at high temperature and the other one at room temperature in air, has been manufactured and set-up.
The innovative tests over specimens of four materials have been performed and the results have been analysed. Test results of both qualification plans have been compared in order to analyze the capabilities of both methodologies and their benefits and disadvantages, regarding technical and economic aspects and quality of results obtained for the different materials.
The materials with best performance are different according to each qualification plan. This fact has been analysed taking into account the characteristics of both materials, which are reinforced plastics with different fibre content, so they behave very different under static or dynamic loadings.
A thermoplastic material with 40% glass fiber is the most suitable material according to the conventional test plan as it has better resistance at oils and mechanical properties than the other three materials. However it does not correspond with the results from innovative test plan, because thermoplastic materials without fiber have a better behavior under fatigue loads than fibre reinforced materials. Then the best material from innovative plan is the one without reinforcement.
The fatigue properties in fibre - reinforced plastics are mainly dominated by the fibre support. Because the low fibre failure strain limits the resin failure strain, fatigue-sensitive resin does not influence the fatigue performance of the materials tested under cyclic loads. This explains that thermoplastic material without glass fibers have had the best fatigue performance.
So, as said above, a thermoplastic with 40% glass fiber is the material selected according the results of convectional qualification test plan, while a thermoplastic without reinforcement is the material selected according the results of innovative qualification test plan.
Fatigue behaviour of the plastic materials is not studied and quantified on the majority of qualification test plans. However based on these test results, we find that this “new concept” of testing materials under cyclic loads and simulated real conditions of service or usage, could be an interesting methodology to be developed in the field of testing plastic materials.
Two main advantages of the innovative test method are, by one side, that with the in-serie two-specimen test set-up, two specimens are exposed to a different conditioning ambient (RT / dry and 160ºC / oil), and the data evaluation could conduct a reliable conclusions regarding the material selection, and on the other hand, the reduction of testing time as it is not necessary conditioning of the samples in oil and temperature and consequently reduction of direct costs.
According to the results of both plans and best performance materials, a prediction of the behaviour of a real part according to conventional and innovative qualification plan have been done.
Analyzing all the work and results obtained with the different qualification plans and the different materials, it has been possible understand the differences in the behavior of the materials, the importance of testing them in near-reality conditions to understand well the performance of these kind of plastic reinforced materials when used in oil at high temperature, and the need to perform additional dynamic tests to completely characterize the materials, due to their special nature (polymer + reinforcement with fibres).
With all this information, we have been able to define an optimized qualification plan for this kind of insulation materials to engine oils, using the innovative testing system developed in the present project.
The result of the Project is not patentable since it is a methodology for a qualification plan for materials.
Potential Impact:
The final result of the project is a set of qualifications plans, the “innovative” one and the “optimized” one. These new testing methodologies have been included in Applus+ services portfolio, allowing the company to offer a more complete and innovative service for characterization of composite materials under combination of different external factors, which will help material suppliers and product developers to improve the performance of their products.
The project results and new services will be disseminated not only in the aeronautical field (Airbus Group and suppliers), but also to material and component manufacturers like Hexcel, Dupont, BASF, Cytec, composite industries). Also the automotive sector will be a potential customer for these new services.
The main objective in the dissemination is to publicize the results of the project and conclusions to industry and focusing on the final end-users, therefore, the dissemination activities are addressed to all stakeholders of the aircraft industry in the form of industrial bodies, and related associations. It is expected that the results and conclusions will be interesting to these bodies for developing new internal standards or to implement the necessary measures for qualifying the manufacturing processes.
Regarding impact in the Clean Sky objectives, the project will contribute to the improvements in the area of electrical energy generation and conversion. The project will have strong impact on the necessary knowledge for the introduction of new materials in the systems for electrical energy generation. The obtention of systems with better performances while maintaining or reducing the weight of the aircraft, will have a direct consequence on the better energy efficiency of the aircraft and the decreasing of fuel consumption.
At this moment, the project has been presented to several aeronautic equipment suppliers. Also, the project has been publicized in the web page of Applus+ Laboratories.
List of Websites:
The Project has been publicized in the Applus+ Laboratories web (http://www.appluslaboratories.com/en/innovation/QUALIFY-1340235486875(si apre in una nuova finestra)). Also, an internal new has been shown in the Applus+ Group intranet.
Aircraft components are subject to in-service damage from a variety of threats, including impact, chemicals, high temperatures and ultraviolet light. To calculate the probability of failure (represented by knock-down factor (KDF)), empirical data is collected from numerous experiments. Currently, KDFs are determined individually for each threat rather than in combination, increasing the number of tests and simultaneously cost and time. In addition, such procedures do not adequately represent real in-flight conditions.
EU-funded scientists working on the QUALIFY (Qualification of insulation materials to engine oils) project have developed an innovative test set-up. It enables simultaneous exposure of insulation materials to thermal and cyclic mechanical loading as well as aggressive engine oils and temperature changes. The technology allows quantifying global interactions of parameters to realistically predict failure in manufactured parts. In turn, better understanding of materials and components behaviours will foster development of lighter higher-performance parts for important reductions in fuel consumption and emissions.
Thermoplastic organic polymers have been used in the insulation materials due to their good mechanical properties and chemical and temperature resistance. Engine oils for conditioning of specimens have been taken from those in service for two years and in good condition. The team has also designed the test set-up to enable testing of two specimens simultaneously in different environments. As result of the project, an optimized qualification plan for insulator materials to engine oils in “near reality” conditions has been obtained.
Project results will be widely disseminated to end users within the aircraft industry, including manufacturers, suppliers, industrial bodies and related associations. They are expected to be instrumental in the development of new standards of qualification during manufacturing. The novel testing methodologies will also be included in the portfolio of services offered by one of the world's testing, inspection and certification leaders. Finally, partners will share results with materials and components manufacturers in the plastics and composites industries.
Improved testing procedures will decrease production costs and time-to-market while enhancing product quality. Better design of aircraft components for lower weight and higher performance will help reduce the environmental impact of flight.
Project Context and Objectives:
Nowadays, in-service damages such as impacts during overhaul or external influences, such as exposure to severe environments with chemical agents, thermal loadings or ultraviolet light have to be taken into account for the design of the elements. Therefore, knock-down factors have to be determined. This knock-down factors take into account an extensive number of conditions such as loads –both static and cyclic-, temperatures, impact damages or the exposure to aggressive mediums such as engine oils. Due to the costs and complexity of performing full scale tests including factors such as temperature and exposure to a variety of aggressive atmospheres, during the qualifications, lots of tests are necessary in order to certify the integrity of the component material.
The actual state of the art is to determine this knock-down factors independently and not in combination of them, meaning that composite samples are for example immersed during a determined time in a fluid and afterwards tested statically at a given temperature.
The innovative idea to develop during this project is to develop a test set-up permitting to expose on the same time the specimen to not only thermal and cyclic mechanical loading, but also to synthetic engine oils atmospheres in order to be afterwards able to quantify how the global interaction of these parameters is and be able to predict failure of real manufactured parts subjected to “near reality” loading (in terms of loading, temperature and oil exposure) scenarios.
The project deals with the qualification of insulating materials in front of engine oils. The investigation will be done using four different types of materials (reinforced plastics) and different engine oils - in a new state, and after two year usage in an engine.
A “conventional” qualification plan of the materials under study will be drawn, the manufacturing plan for the “to be tested” specimens will be detailed and the specimens will be manufactured. A report detailing the manufacturing details such as materials, lay-up, dimensions and the quality reports of the specimens will be prepared.
Simultaneously, an “innovative” test set up for material specimen tests will be developed mimicking the “real life” conditions, meaning a tooling capable of introducing on the same time to the specimen mechanical, thermal and chemical loads. The idea for the tooling is that there is one area subjected to the exposure to fluid at high temperature, whereas another is not subjected to the exposure. The aim therefore is to analyse the impact of the “oil and temperature loading”. This tooling will be used in order to develop an innovative qualification plan. For this “innovative” qualification plan as well as for the “conventional” qualification plan, the number and type of necessary specimens and tests will be detailed in a qualification plan, the manufacturing plan will be detailed and the specimens will be manufactured.
The test results from the “conventional” and “innovative” test plan will be summarized in one report, the advantages and disadvantages of both methods will be analysed and the best materials according to the qualification plans will be selected. Using the testing results from the “conventional” and the “innovative” qualification plan independently the expected life and failure load of a real part under “next to reality loading conditions” will be predicted.
Finally, from the analysis of the results of the different tests plans, an optimized qualification plan will be defined.
Project Results:
In periods 1 and 2 the work has focused mainly in the documentation and definition of specifications for tests and material, which is necessary to start the test campaigns and subsequent studies. We have defined the testing and manufacturing plans for both the conventional and the innovative plan.
We have established the necessary materials for the qualification studies, and the types of oils that we will use for conditioning of the specimens. Two sets of tests have been defined, both for the conventional and innovative plans, as well as the number of specimens and dimensions, according to the applicable standards.
In the selection of materials it has been taken into account the breaking loads of these as a reference to an actual piece. Different thermoplastic organic polymers with different degrees of fibre reinforcement have been selected offering high mechanical properties, enhanced resistance to temperature and good chemical resistance. Engine oils selected are those used in a real environment, in perfect condition and after two years of usage.
For the innovative plan, it is necessary to design a test fixture that will allow testing two specimens simultaneously in different environments. The design has been performed.
The manufacturing of the specimens for both the conventional and the innovative test plans have been performed, and the oils (new and used) have been collected.
During Period 3, the tests foreseen in the conventional and the innovative qualification plan have been developed and reported. After analysing the results of the conventional qualification plan, performed over the specimens of 4 materials with and without pre-conditioning in the different oils at 160ºC, some additional tests have been performed in order to better characterize the behaviour of the materials under temperature and under dynamic loading, before executing the innovative test plan. Thanks to the information obtained, the test conditions have been precisely defined, and the design of the tooling for innovative plan has been revised. The tooling, which allows the testing of 2 samples, one of them immersed in oil at high temperature and the other one at room temperature in air, has been manufactured and set-up.
The innovative tests over specimens of four materials have been performed and the results have been analysed. Test results of both qualification plans have been compared in order to analyze the capabilities of both methodologies and their benefits and disadvantages, regarding technical and economic aspects and quality of results obtained for the different materials.
The materials with best performance are different according to each qualification plan. This fact has been analysed taking into account the characteristics of both materials, which are reinforced plastics with different fibre content, so they behave very different under static or dynamic loadings.
A thermoplastic material with 40% glass fiber is the most suitable material according to the conventional test plan as it has better resistance at oils and mechanical properties than the other three materials. However it does not correspond with the results from innovative test plan, because thermoplastic materials without fiber have a better behavior under fatigue loads than fibre reinforced materials. Then the best material from innovative plan is the one without reinforcement.
The fatigue properties in fibre - reinforced plastics are mainly dominated by the fibre support. Because the low fibre failure strain limits the resin failure strain, fatigue-sensitive resin does not influence the fatigue performance of the materials tested under cyclic loads. This explains that thermoplastic material without glass fibers have had the best fatigue performance.
So, as said above, a thermoplastic with 40% glass fiber is the material selected according the results of convectional qualification test plan, while a thermoplastic without reinforcement is the material selected according the results of innovative qualification test plan.
Fatigue behaviour of the plastic materials is not studied and quantified on the majority of qualification test plans. However based on these test results, we find that this “new concept” of testing materials under cyclic loads and simulated real conditions of service or usage, could be an interesting methodology to be developed in the field of testing plastic materials.
Two main advantages of the innovative test method are, by one side, that with the in-serie two-specimen test set-up, two specimens are exposed to a different conditioning ambient (RT / dry and 160ºC / oil), and the data evaluation could conduct a reliable conclusions regarding the material selection, and on the other hand, the reduction of testing time as it is not necessary conditioning of the samples in oil and temperature and consequently reduction of direct costs.
According to the results of both plans and best performance materials, a prediction of the behaviour of a real part according to conventional and innovative qualification plan have been done.
Analyzing all the work and results obtained with the different qualification plans and the different materials, it has been possible understand the differences in the behavior of the materials, the importance of testing them in near-reality conditions to understand well the performance of these kind of plastic reinforced materials when used in oil at high temperature, and the need to perform additional dynamic tests to completely characterize the materials, due to their special nature (polymer + reinforcement with fibres).
With all this information, we have been able to define an optimized qualification plan for this kind of insulation materials to engine oils, using the innovative testing system developed in the present project.
The result of the Project is not patentable since it is a methodology for a qualification plan for materials.
Potential Impact:
The final result of the project is a set of qualifications plans, the “innovative” one and the “optimized” one. These new testing methodologies have been included in Applus+ services portfolio, allowing the company to offer a more complete and innovative service for characterization of composite materials under combination of different external factors, which will help material suppliers and product developers to improve the performance of their products.
The project results and new services will be disseminated not only in the aeronautical field (Airbus Group and suppliers), but also to material and component manufacturers like Hexcel, Dupont, BASF, Cytec, composite industries). Also the automotive sector will be a potential customer for these new services.
The main objective in the dissemination is to publicize the results of the project and conclusions to industry and focusing on the final end-users, therefore, the dissemination activities are addressed to all stakeholders of the aircraft industry in the form of industrial bodies, and related associations. It is expected that the results and conclusions will be interesting to these bodies for developing new internal standards or to implement the necessary measures for qualifying the manufacturing processes.
Regarding impact in the Clean Sky objectives, the project will contribute to the improvements in the area of electrical energy generation and conversion. The project will have strong impact on the necessary knowledge for the introduction of new materials in the systems for electrical energy generation. The obtention of systems with better performances while maintaining or reducing the weight of the aircraft, will have a direct consequence on the better energy efficiency of the aircraft and the decreasing of fuel consumption.
At this moment, the project has been presented to several aeronautic equipment suppliers. Also, the project has been publicized in the web page of Applus+ Laboratories.
List of Websites:
The Project has been publicized in the Applus+ Laboratories web (http://www.appluslaboratories.com/en/innovation/QUALIFY-1340235486875(si apre in una nuova finestra)). Also, an internal new has been shown in the Applus+ Group intranet.