Reduced Stiffness Constants
The application of
fibre-reinforced composite materials in the aerospace industry extends from
commercial to military aircraft, such as the Boeing F18, B2 Stealth Bomber,
AV-8B Harrier (Jones, 1998). The attractiveness of composites lies in their
mechanical properties; such as weight, strength, stiffness, corrosion
resistance, fatigue life. Composites are widely used for control surfaces
such as ailerons, flaps, stabilizers, rudders, as well as rotary and fixed
wings. That is why the analysis of composite structures is imperative for
aerospace industry. The main advantage of composites is their flexibility in
design. Mechanical properties of the laminate can be altered simply by
changing the stacking sequence, fibre lay-up and thickness of each ply which
leads to optimization in a design process. reference
Assumptions
The composite beam
is modeled based on the chord-wise bending moment (about the z-axis)
being small compared to the span-wise moment (about the y axis, see
Figure 2). The chord-wise moment is then neglected. The composite material
pertaining to this research is a unidirectional fibre reinforced composite
material. The given information of any unidirectional composite material is
the elastic modulus in both the longitudinal and transverse axis (see
Figures 1 and 2), Poison's ratio and the shear modulus in the principle
directions. The reduced stiffness constants in the
material principle directions are defined as follows.
The reduced transformed stiffness constant are defined above.
Part 2 Defines the effective rigidities using this reduce stiffness
See http://www.aeroway.ca/Laminatetheory.html
http://www.compositecalculator.com/
Editor's Note: Click here for Part 2 of this series.
| 
