JEC COMPOSITES MAGAZINE - Issue #58 - June - July 2010 - 30

FEATURE

“Aeronautics”

The quest for lighter and stronger aircraft with realistic simulation
The aluminium age in new aircraft design is all but over. Aircraft manufacturers in every market are increasingly looking to composite materials to create vehicles that are lighter, stronger and easier to maintain. Lighter weight aircraft means increased range, which in turn means lower fuel costs – a critical factor in a petroleumdependent world, especially in commercial jet design.
To fully understand the performance of these composite components, as well as assembly and maintenance challenges, a Grupo TAM structural analysis engineering team conducted a series of in-depth analyses of components including a curved, stiffened composite panel typical of a fuselage or fan cowls (see Figure 1). The panel and stiffeners are made of uniaxial and biaxial carbon fibres that are bonded with adhesive. The team focused on the composite manufacturing variables and tolerances for the panel, including material properties, geometric tolerances, thicknesses and lay-up alignment axes, as well as the delamination and disbonding that can occur during the manufacture, assembly and service life of the composite structure. The objective of these analyses was to identify the influence Fig. 1: Cylindrical stiffened compoof deviations, defects and site panel with two stiffeners for the Airbus 380 damage and to consider it during the initial design phase. In this way, non-conforming parts would be minimized, with associated cost savings.

ABEL PARDO, JOSE CARLOS FERNANDEZ STRUCTURAL ANALYSIS ENGINEERING GRUPO TAM

he Boeing 787 Dreamliner will be the first commercial jet to be more than 50% composite by weight. The Airbus A380, with deliveries that started in 2008, is also increasing its reliance on composites. With the material paradigm shifting in aerospace, it was predicted at the CompositesWorld 2008 conference that demand for composites would grow 30% in the general aviation market over the next three years. Carbon-fibre-reinforced polymer (CFRP) is the most common composite used in the aerospace industry. Carbon fibres have a micro-graphite crystalline structure and a pattern similar to chicken wire; they derive their strength from layering, or sandwiching, multiple sheets in a polymer matrix. With their attractive strength-to-weight ratio and other attractive material properties such as high tensile strength, high elastic modulus, heat resistance, low thermal expansion and chemical stability, CFRP composites are highly desirable in high-performance aerospace and automotive applications. They are also used widely in sailboats, canoes, bicycles, tennis rackets and golf clubs, as well as consumer goods such as laptops and stringed instrument bodies. Like any material, composites have their own set of manufacturing, assembly and lifespan challenges that must be fully understood to make their use in critical applications, such as commercial flying, acceptable and safe.

Abaqus FEA creates baseline for composite analysis
For the intact panel analysis, the Grupo TAM engineers chose Abaqus FEA from SIMULIA, the Dassault Systèmes brand for realistic simulation, largely for its ability to handle both implicit and explicit non-linear analysis. The team needed more than their in-house tools for their analysis. They chose Abaqus for its extensive composite capabilities and to meet the high quality standards required by customers. They also chose Isight from SIMULIA for its Monte Carlo and Stochastic Design Improvement

jec composites magazine / No58 June - July 2010

JEC COMPOSITES MAGAZINE - Issue #58 - June - July 2010

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #58 - June - July 2010