December
04
2015
Written by  Erika
Published in PhD Thesis

New Doctoral Thesis partly supported by Hippocamp Project

Our colleague Qilin Fu (Plasmatrix) has just published his PhD tittled ”High dynamic stiffness nano-structured composites for vibration control: A Study of applications in joint interfaces and machining systems”. The defense was hold on 1st December 2015, in Royal Institute of Technology, Stockholm (Sweden). Part of his research is related to the HIPPOCAMP project. Congratulations Dr. Fu!

High dynamic stiffness nano-structured composites for vibration control: A Study of applications in joint interfaces and machining systems

Fu, Qilin

KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology. Plasmatrix Materials AB.(Manufacturing and Metrology Systems)ORCID iD: 0000-0002-4677-7005

2015 (English)Doctoral thesis, comprehensive summary (Other academic)

Abstract [en]

Vibration control requires high dynamic stiffness in mechanical structures for a reliable performance under extreme conditions. Dynamic stiffness composes the parameters of stiffness (K) and damping (η) that are usually in a trade-off relationship. This thesis study aims to break the trade-off relationship.

After identifying the underlying mechanism of damping in composite materials and joint interfaces, this thesis studies the deposition technique and physical characteristics of nano-structured HDS (high dynamic stiffness) composite thick-layer coatings. The HDS composite were created by enlarging the internal grain boundary surface area through reduced grain size in nano scale (≤ 40 nm). The deposition process utilizes a PECVD (Plasma Enhanced Chemical Vapour Deposition) method combined with the HiPIMS (High Power Impulse Magnetron Sputtering) technology. The HDS composite exhibited significantly higher surface hardness and higher elastic modulus compared to Poly(methyl methacrylate) (PMMA), yet similar damping property. The HDS composites successfully realized vibration control of cutting tools while applied in their clamping interfaces.

Compression preload at essential joint interfaces was found to play a major role in stability of cutting processes and a method was provided for characterizing joint interface properties directly on assembled structures. The detailed analysis of a build-up structure showed that the vibrational mode energy is shifted by varying the joint interface’s compression preload. In a build-up structure, the location shift of vibration mode’s strain energy affects the dynamic responses together with the stiffness and damping properties of joint interfaces.

The thesis demonstrates that it is possible to achieve high stiffness and high damping simultaneously in materials and structures. Analysis of the vibrational strain energy distribution was found essential for the success of vibration control.

Place, publisher, year, edition, pages

Stockholm: KTH Royal Institute of Technology, 2015. , ix, 71 p.

Series

TRITA-IIP, ISSN 1650-1888

Keyword [en]

Vibration control, High dynamic stiffness, Metal matrix composite, Nano structures, Plasma enhanced chemical vapour deposition (PECVD), High power impulse magnetron sputtering (HiPIMS), Adiabatic, Machining, Regenerative tool chatter

National Category

Nano Technology Production Engineering, Human Work Science and Ergonomics Composite Science and Engineering Fusion, Plasma and Space Physics Chemical Sciences Manufacturing, Surface and Joining Technology Applied Mechanics

Research subject

Production Engineering

Identifiers

URN: urn:nbn:se:kth:diva-176869ISBN: 978-91-7595-740-1OAI: oai:DiVA.org:kth-176869DiVA: diva2:868453

Public defence

2015-12-01, M311, Brinellvägen 68, KTH, Stockholm, 10:00 (English)

Opponent

Nylén, Per, Professor

Supervisors

Nicolescu, Cornel-Mihai, Professor

Funder

EU, FP7, Seventh Framework ProgrammeEU, FP7, Seventh Framework ProgrammeVINNOVAVINNOVA

Available from: 2015-11-11 Created: 2015-11-10 Last updated: 2015-11-11Bibliographically approved

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Last modified on Friday, 17 June 2016 08:33
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