Presentation on Aircraft Structural Integrity Following Bird Strike

This presentation delves into the critical aspects of aircraft structural integrity, focusing on a case involving damage caused by a bird strike. It emphasizes the importance of aircraft safety and airworthiness, tracing performance from initial flight to retirement. The presentation establishes design criteria and reviews manufacturer's performance declarations, considering prevailing conditions for structural integrity maintenance. It examines material selection for structural components, highlighting the use of metallic and composite materials, including advanced options like GLARE. The analysis covers the impact of bird strikes on vulnerable areas such as the nose, fuselage, and engine cowlings, quantitatively determining fatigue behavior using methods applicable to fiber-reinforced matrix composites. It explores design preclusion methods for damaged parts, including adhesively bonded repairs, and discusses the properties of fiber matrix composite materials. The presentation further addresses structural integrity of adhesively bonded repairs, requirements for joint design, and methods for adhesive bonding. It concludes by emphasizing the importance of care and maintenance programs, adherence to international air safety protocols, and damage assessment methods for ensuring airworthiness and air safety, noting the anisotropic behavior of fiber-reinforced matrix composites and their superior performance under impact loading stresses, ultimately affirming that bird strikes can significantly affect aircraft structural integrity, necessitating the use of high-integrity materials.

AIRCRAFT 757546
Presentation on the Aircraft structural Body
integrity: a case for bird striking

INTRODUCTION
Aircraft safety and airworthiness are among
the most critical factors in the design,
manufacture, operation and maintenance of
aircraft and its associated systems.
Performance of aircraft is often tracked from
the time it undertakes its debut flight until it
is retired.

Scenario details
Consider the technical details on the damage
caused by the aircraft accidentally hitting a
flock of birds.
It was suspected that the aircraft structural
components could have been seriously
affected by the impact

Establishing the Design criteria
It is believed that the impact could have
damaged some parts of the aircraft body.
However, prior to acceptance of liability
resulting from the damage, it is crucial to
undertake a rigorous inspection on the
structural integrity of the components after
the accident
Review manufacturer’s performance
declaration and the prevailing conditions for
structural integrity maintenance.

Effects on design for the selected parts
Based on the conditions for performance,
material selection for structural components
of aircraft is designated.
This is based on the environment and the
type of loading and stresses likely to be
encountered.

Selection of different applicant materials
it is clear that the predominant materials making
up the body of this aircraft are metallic and
composites. More advanced materials have been
used to replace some materials due to their
increased strength to weight ratio and the fact that
they can easily be repaired using certain
specialized techniques
The high strength aluminum developed micro-
cracks as a result of fatigue from several impacts.
Hence the GLARE (Glass laminate aluminum and
reinforced epoxy) were used to make the upper
fuselage and the stabilizers

Case for selection
An assessment on the choices made between
different candidate materials is presented.
The most critical portions of the aircraft body
as far as bird striking is concerned are the
nose, fuselage and the engine cowlings as
they are more exposed to the impact.

Determining the structural fatigue for a selected material
Nature of aircraft fatigue
 The airbus plane could have hit the birds
with one of the following parts: nose,
fuselage, flight deck, jet engine, wing, aileron
or stabilizers.
 Each of these aircraft body parts has unique
features that could affect the structural
behavior of the materials making up the
selected part

Quantitative methods for fatigue behavior prediction
The following methods were used to
quantitatively determine the likely fatigue
behavior of the selected parts material, that
is, the nose and the front side of flight deck
Are mainly built of fibre reinforced matrix
composites rather than aluminum as was the
case with previous airbus models

Design preclusion methods for the damaged parts
From the fiber reinforced matrix point of
view, the adhesively bonded repairs are often
undertaken. The bird strike impact is likely to
have caused the material surface develop a
micro scale-based cracking

Properties of fiber matrix composite materials
Great resistance to corrosion
Great impact strength per unit surface of
material
Exhibit greater surface hardness than the
aluminum alloy materials
Can be fabricated using the common
aluminum fabrication techniques.
Are dimensionally stable
Great fracture toughness against impact
loading cycles

Structural integrity of adhesively bonded
repairs
The cracks are often sealed by applying the
film adhesives within the cracks. They are
supposed to blend suitably with the parent
material such that homogeneity in material
properties is achieved..
The structural bonding of material is often
dictated by the degree of toughness and
choice of resins.