Grégoire Lepoittevin, Markus Zogg and Paolo Ermanni COMPTEST 2011 TESTING OF MULTIFUNCTIONAL STRUCTURAL COMPOSITE COMPONENTS WITH INTEGRATED DAMPING TREATMENTS Grégoire Lepoittevin, Markus Zogg and Paolo Ermanni

Contents Multifunctional structures Demonstrator Mechanical tests ETH ZÜRICH 07.11.2018 Contents Multifunctional structures Demonstrator Mechanical tests Vibro-acoustic tests Conclusion CENTRE OF STRUCTURE TECHNOLOGIES WWW.STRUCTURES.ETHZ.CH

Contents Multifunctional structures Demonstrator Mechanical tests ETH ZÜRICH 07.11.2018 Contents Multifunctional structures Demonstrator Mechanical tests Vibro-acoustic tests Conclusion CENTRE OF STRUCTURE TECHNOLOGIES WWW.STRUCTURES.ETHZ.CH

Multifunctional structures A structure can be defined as follows [1] In addition to this primarily function, a structure can also fulfil others Thermal management Vibration damping Sound insulation Power distribution networks Energy harvesting … ‘‘The fundamental function of a structure is to maintain a specified configuration, appropriately constraining and supporting other elements, typically transferring mechanical loads between the parts.’’ [1] G. S. Aglietti, C. W. Schwingshackl, and S. C. Roberts. Multifunctional structure technologies for satellite applications. The Shock and Vibration Digest, 39:381–391, 2007.

Multifunctional structures This concept is commonly apply for spacecraft design

Multifunctional structures With the use of composite materials, it is possible to add a soft layer in the laminate lay-up to increase the vibration damping performance of the structure. The challenge is to propose a design guideline where the structure has both very good mechanical and vibration damping performances. Damping layer Composite laminates

Multifunctional structures Design approach The goal of this study to asses the effect of the damping layer on the mechanical and vibro-acoustic behaviour of a structural component.

Contents Multifunctional structures Demonstrator Mechanical tests ETH ZÜRICH 07.11.2018 Contents Multifunctional structures Demonstrator Mechanical tests Vibro-acoustic tests Conclusion CENTRE OF STRUCTURE TECHNOLOGIES WWW.STRUCTURES.ETHZ.CH

Demonstrator ETH ZÜRICH 07.11.2018 CENTRE OF STRUCTURE TECHNOLOGIES WWW.STRUCTURES.ETHZ.CH

Demonstrator Manufacturing - RTM Process ETH ZÜRICH 07.11.2018 Demonstrator Manufacturing - RTM Process CENTRE OF STRUCTURE TECHNOLOGIES WWW.STRUCTURES.ETHZ.CH

Demonstrator Manufacturing - RTM Process ETH ZÜRICH 07.11.2018 Demonstrator Manufacturing - RTM Process Process characteristics Resin degasing under vacuum at 80 ºC for 30 min Mold temperature during injection: 125 ºC Injection under vacuum at 4 bar pressure Curing at 180 ºC for 180 minutes under 3 bar pressure CENTRE OF STRUCTURE TECHNOLOGIES WWW.STRUCTURES.ETHZ.CH

Contents Multifunctional structures Demonstrator Mechanical tests ETH ZÜRICH 07.11.2018 Contents Multifunctional structures Demonstrator Mechanical tests Vibro-acoustic tests Conclusion CENTRE OF STRUCTURE TECHNOLOGIES WWW.STRUCTURES.ETHZ.CH

Four-Point Bending Test Set-Up ETH ZÜRICH 07.11.2018 Mechanical tests Four-Point Bending Test Set-Up CENTRE OF STRUCTURE TECHNOLOGIES WWW.STRUCTURES.ETHZ.CH

Mechanical tests 4-point bending test results ETH ZÜRICH 07.11.2018 Mechanical tests 4-point bending test results 4180N 4622N 21.1mm 20.5mm 2520N 2420N 29.3mm 826N/mm 831N/mm 28.6mm 5442N 5344N 21.7mm 20.2mm 2466N 46.9mm 2954N 50.1mm 888N/mm 849N/mm Higher torsional stiffness of the web and higher bending strength for the C-frame with damping treatment CENTRE OF STRUCTURE TECHNOLOGIES WWW.STRUCTURES.ETHZ.CH

Mechanical tests ‘Step’ Test Set-Up ETH ZÜRICH 07.11.2018 CENTRE OF STRUCTURE TECHNOLOGIES WWW.STRUCTURES.ETHZ.CH

Mechanical tests Step test results - C-frame without damping layer ETH ZÜRICH 07.11.2018 Mechanical tests Step test results - C-frame without damping layer CENTRE OF STRUCTURE TECHNOLOGIES WWW.STRUCTURES.ETHZ.CH

Mechanical tests Step test results - C-frame with damping layer ETH ZÜRICH 07.11.2018 Mechanical tests Step test results - C-frame with damping layer Lower strength and stiffness for the C-frame with damping treatment CENTRE OF STRUCTURE TECHNOLOGIES WWW.STRUCTURES.ETHZ.CH

Contents Multifunctional structures Demonstrator Mechanical tests ETH ZÜRICH 07.11.2018 Contents Multifunctional structures Demonstrator Mechanical tests Vibro-acoustic tests Conclusion CENTRE OF STRUCTURE TECHNOLOGIES WWW.STRUCTURES.ETHZ.CH

Mechanical tests Vibro-acoustic test step-up ETH ZÜRICH 07.11.2018 Mechanical tests Vibro-acoustic test step-up CENTRE OF STRUCTURE TECHNOLOGIES WWW.STRUCTURES.ETHZ.CH

Mechanical tests Vibro-acoustic test results ETH ZÜRICH 07.11.2018 Mechanical tests Vibro-acoustic test results FRF C-frame without damping FRF C-frame with damping CENTRE OF STRUCTURE TECHNOLOGIES WWW.STRUCTURES.ETHZ.CH

Contents Multifunctional structures Demonstrator Mechanical tests ETH ZÜRICH 07.11.2018 Contents Multifunctional structures Demonstrator Mechanical tests Vibro-acoustic tests Conclusion CENTRE OF STRUCTURE TECHNOLOGIES WWW.STRUCTURES.ETHZ.CH

Conclusion The mechanical tests in 4-point bending reveal that the C-frame with damping as a higher stiffness and strength than the one without. The ‘step’ tests shows that the C-frame without damping treatment has a higher stiffness and strength The vibro-acoustic measurement campaign shows that the resonance frequencies of the C-frame with damping are higher than for the structure without damping. Future works will aim at demonstrating the efficiency of multifuncional composites in comparison with a composite structure having a classical damping treatment.

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