Analyses of criticality for multiple-site delaminations in the flap spar of Finnish F/A-18 aircraft

2020 ◽  
pp. 1-22
Author(s):  
J. Jokinen ◽  
M. Kanerva ◽  
M. Wallin ◽  
O. Saarela
Keyword(s):  
Interaction Parameter ◽  
Important Variable ◽  
Experimental Program ◽  
Metal Composite ◽  
Control Parameters ◽  
Reinforced Plastic ◽  
Trailing Edge Flap ◽  
Carbon Fibre Reinforced Plastic ◽  
Material Values ◽  
Delamination Propagation

Abstract Metal-composite airframes will suffer various defects during their lifetime. One category of defects is composite laminate delamination. This study evaluates the criticality of delaminations existing around adjacent fastener holes in the carbon-fibre-reinforced plastic spar web of the F/A-18 aircraft’s trailing-edge flap. The evaluation is based on experiments and analyses. First, an intensive experimental program for determining necessary material values of F/A-18 is described. Multiple delaminations of the flap spar web are then modelled by varying the set of delaminated hole edges and the interface of delamination. The interaction of defects at the start of delamination propagation is studied via the developed interaction parameter. The results suggest that the interaction parameter can show significant differences in the interaction per delamination case and that the interface of delamination is an important variable. Finally, operator-dependent control parameters are studied, and it is found that the criticality of a delamination case is merely dependent on true material parameters.

scholarly journals BENDING BEHAVIOUR OF GLULAM BEAMS REINFORCED WITH CARBON FRP PLATES

2015 ◽  
Vol 21 (7) ◽  
pp. 923-932 ◽  
Author(s):  
Ivan Glišović ◽  
Boško Stevanović ◽  
Miloš Petrović
Keyword(s):  
Mechanical Properties ◽  
Load Capacity ◽  
Experimental Program ◽  
Structural Elements ◽  
Ultimate Load Capacity ◽  
Four Point Bending ◽  
Reinforced Beams ◽  
Reinforced Plastic ◽  
Glued Laminated Timber ◽  
Carbon Fibre Reinforced Plastic

The idea of reinforcing glued laminated timber (glulam) beams came in response to the need to improve the mechanical properties, as well as to ensure higher reliability of this type of structural elements. This paper describes an experimental program which examines the reinforcement in flexure of glulam beams with carbon fibre reinforced plastic (CFRP) plates. Fifteen beams reinforced with CFRP at the tension side and five unreinforced control beams were instrumented and tested to failure in a four-point bending configuration. The mechanical properties of reinforced beams are compared to those of unreinforced beams with regard to the load-deflection behaviour, failure mode, ultimate load capacity, stiffness and strain distribution. The experimental results demonstrated the beneficial effect of the proposed reinforcing solution in terms of strength, stiffness and ductility.

Equivalent capacity and efficiency of reinforced concrete beams strengthened with carbon fibre reinforced plastic sheets

1996 ◽  
Vol 23 (1) ◽  
pp. 21-29 ◽  
Author(s):  
P. J. Heffernan ◽  
M. A. Erki
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fibre ◽  
Concrete Beams ◽  
Maximum Load ◽  
Reinforced Concrete Beams ◽  
Experimental Program ◽  
Cfrp Sheets ◽  
Reinforced Plastic ◽  
Carbon Fibre Reinforced Plastic ◽  
Equivalent Capacity

Fibre reinforced plastic sheets have recently been used in Switzerland and Japan as an alternative to steel plates for the external strengthening of structural components. This paper presents the results of an experimental program that examines the behaviour of reinforced concrete beams strengthened using carbon fibre reinforced plastic (CFRP) sheets. The concept of equivalent strength is introduced for comparative purposes, and its applicability to design is discussed. The results and analysis of three 2 m reinforced concrete beams and two 5 m reinforced concrete beams of various tensile reinforcement configurations are presented. The CFRP sheets are shown to enhance the stiffness of the beams, the load at which the tensile steel yields, the stiffness of the beams after yielding of the tensile steel, and the maximum load of the beam. The behaviour of the rehabilitated beam is compared to the understrength beam and the equivalent all steel reinforced beam. An equivalent capacity based on the load at which the tensile steel yields is proposed to ensure adequate stiffness within the working stress range. The concept is equally applicable to strengthening as it is to rehabilitation. Key words: reinforced concrete, CFRP, rehabilitation, poststrengthening.

scholarly journals Analysis and Design of a Leading Edge with Morphing Capabilities for the Wing of a Regional Aircraft—Gapless Chord- and Camber-Increase for High-Lift Performance

2021 ◽  
Vol 11 (6) ◽  
pp. 2752
Author(s):  
Conchin Contell Asins ◽  
Volker Landersheim ◽  
Dominik Laveuve ◽  
Seiji Adachi ◽  
Michael May ◽  
...  
Keyword(s):  
Leading Edge ◽  
Bird Strike ◽  
High Lift ◽  
Analysis And Design ◽  
Actuation System ◽  
Aerodynamic Properties ◽  
Reinforced Plastic ◽  
Stall Angle ◽  
Carbon Fibre Reinforced Plastic ◽  
Electromechanical Actuation

In order to contribute to achieving noise and emission reduction goals, Fraunhofer and Airbus deal with the development of a morphing leading edge (MLE) as a high lift device for aircraft. Within the European research program “Clean Sky 2”, a morphing leading edge with gapless chord- and camber-increase for high-lift performance was developed. The MLE is able to morph into two different aerofoils—one for cruise and one for take-off/landing, the latter increasing lift and stall angle over the former. The shape flexibility is realised by a carbon fibre reinforced plastic (CFRP) skin optimised for bending and a sliding contact at the bottom. The material is selected in terms of type, thickness, and lay-up including ply-wise fibre orientation based on numerical simulation and material tests. The MLE is driven by an internal electromechanical actuation system. Load introduction into the skin is realised by span-wise stringers, which require specific stiffness and thermal expansion properties for this task. To avoid the penetration of a bird into the front spar of the wing in case of bird strike, a bird strike protection structure is proposed and analysed. In this paper, the designed MLE including aerodynamic properties, composite skin structure, actuation system, and bird strike behaviour is described and analysed.

Impact and Damage Localisation of Carbon-Fibre-Reinforced Plastic Plates

PAMM ◽  
2011 ◽  
Vol 11 (1) ◽  
pp. 639-640 ◽  
Author(s):  
Andy Ungethuem ◽  
Rolf Lammering
Keyword(s):  
Carbon Fibre ◽  
Reinforced Plastic ◽  
Carbon Fibre Reinforced Plastic

Systematic Process Chain Creation for CFRP Structures in Early Product Development Stages

2016 ◽  
Vol 1140 ◽  
pp. 328-334
Author(s):  
Matthias Behr ◽  
Carsten Schmidt
Keyword(s):  
Composite Structures ◽  
Production Costs ◽  
Preliminary Design ◽  
Process Chain ◽  
Whole Process ◽  
Reinforced Plastic ◽  
Building Process ◽  
Process Chains ◽  
Carbon Fibre Reinforced Plastic ◽  
Specific Sequences

A planning method is presented which allows to systematically building process chains based on a preliminary design of composite structures. The method utilises the specific sequences of procedural steps that occur in the production of carbon fibre reinforced plastic (CFRP) structures, to build sub process chains for each component of the structure. Process restrictions are considered to evaluate the suitability of different production processes. To obtain the whole process chain of the structure, different joining methods are applied in addition to combine the components and its sub process chains. The results of the presented method are used in an overarching development procedure to investigate resulting impacts on the solution. Possible impacts could be the production costs or the material characteristics.

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