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Disbond-Stopping Concepts for Bonded Composite Joints

Löbel, Thomas and Holzhüter, Dirk and Hühne, Christian (2016) Disbond-Stopping Concepts for Bonded Composite Joints. In: INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES. SAMPE Long Beach, 23.-26. Mai 2016, Long Beach, USA.

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Official URL: http://www.sampelongbeach.org/

Abstract

Bonded composite joints have many advantages in comparison to conventional fasteners. However, adhesive bonding of primary aircraft structures is still a certification issue. One promising way to achieve airworthiness of bonded CFRP joints in accordance with FAA and EASA requirements is the establishment of disbond-constraining design features. Consequently, two novel design features are developed. On the one hand, small pin elements are used as through-thickness reinforcements that reduce stresses in the vicinity of the crack tip and thereby stop crack growth. Preliminary studies showed that small diameter elements are beneficial as disturbance and weakening of adherent parts is reduced and the overall bearing capacity is increased. In contrast to conventional chicken rivets, the elements are not supposed to transfer full operational load. On the other hand, a combination of two different adhesives is explored in a novel concept called hybrid bondline. A thermoplastic phase as second adhesive constrains cracks by posing a distinct physical barrier through a sharp change of materials. Furthermore, the material allows thermoplastic welding instead of adhesive bonding by use of a sophisticated manufacturing technology. Enhanced manufacturing concepts are developed for both features and their mechanical performance is evaluated by means of static and fatigue tests.

Item URL in elib:https://elib.dlr.de/106535/
Document Type:Conference or Workshop Item (Speech)
Title:Disbond-Stopping Concepts for Bonded Composite Joints
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Löbel, ThomasThomas.Loebel (at) dlr.deUNSPECIFIED
Holzhüter, Dirkdirk.holzhueter (at) dlr.deUNSPECIFIED
Hühne, Christianchristian.huehne (at) dlr.deUNSPECIFIED
Date:May 2016
Journal or Publication Title:INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:Yes
Status:Published
Keywords:Adhesive Bonding; Crack Stoppers; Crack Growth
Event Title:SAMPE Long Beach
Event Location:Long Beach, USA
Event Type:international Conference
Event Dates:23.-26. Mai 2016
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:fixed-wing aircraft
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Structures and Materials
Location: Braunschweig
Institutes and Institutions:Institute of Composite Structures and Adaptive Systems > Functional Lightweight Structures
Deposited By: Löbel, Thomas
Deposited On:16 Oct 2016 10:21
Last Modified:09 Feb 2017 19:22

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