A SIX-NODE PRISMATIC SOLID FINITE ELEMENT FOR LAMINATED COMPOSITES

Anti-symmetrically laminated composites have coupling effects between tensile stress and twisting deformation, and are very attractive as fan blade materials of aircraft engines. Blades fabricated by anti-symmetrically laminated composites can automatically adjust the stagger angle to better aerodynamic conditions with change of axial force or rotational speed owing to the coupling effects. Thus, the anti-symmetrically laminated composite blades are expected to improve aerodynamic efficiency and the stability of aircraft engines. In this paper, the mechanical behavior of anti-symmetrically laminated composite blades is evaluated by spin tests and finite element analyses. Three kinds of blades fabricated by carbon/epoxy laminated composites in different anti-symmetrical stacking sequences were tested. A non-contact measurement technique using a multi-channel optical fiber sensor was used for measurements of blade deformations at high-speed rotating conditions, up to 10,000 rpm. The twisted angle change at the blade tip could be successfully measured. The twisted angle change increased in proportion to the second power of rotational speed, and the maximum angle change was about 4 degree at 10,000 rpm. The finite element analysis results agreed well with the spin test results. Furthermore, the three-dimensional deformation of the test blades was evaluated based on finite element analyses.

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Finite element analysis of vibration and damping of laminated composites

Composite Structures ◽

10.1016/0263-8223(93)90213-a ◽

1993 ◽

Vol 24 (3) ◽

pp. 193-204 ◽

Cited By ~ 33

Author(s):

Rolands Rikards

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Laminated Composites ◽

Element Analysis

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Progressive Fatigue Damage Simulation in Laminated Composites Based on Explicit Finite Element Formulation

Journal of the American Helicopter Society ◽

10.4050/jahs.64.022004 ◽

2019 ◽

Vol 64 (2) ◽

pp. 1-12

Author(s):

Yuri Nikishkov ◽

Guillaume Seon ◽

Andrew Makeev

Keyword(s):

Finite Element ◽

Laminated Composites ◽

Test Methods ◽

Remaining Useful Life ◽

Image Correlation ◽

Progressive Damage ◽

Damage Analysis ◽

Explicit Finite Element ◽

Analysis Methods ◽

Open Hole

Advanced polymeric composites are playing a major role in designing high-performance and lightweight vertical lift structures. However, uncertain residual strength and remaining useful life of the composite rotor and airframe structures due to complexity of failure mechanisms and susceptibility to manufacturing irregularities, which may be precursors to structural damage, impose risks that cannot be mitigated exclusively by time-consuming and costly experimental iterations. Validated analysis techniques accelerating design, certification, and qualification of composite structures are needed. Our team has been taking essential steps toward improving confidence in material qualification for laminated composites. The first step started with our reduced lamina test methods, short-beam shear, and small-plate twist based on digital image correlation measuring as a subset the standard material properties and, in addition, key properties that cannot be currently measured using any standard test methods. The lamina properties provide essential material input data for laminate analysis. The laminate analysis was the second step increasing confidence in material qualification. A known weakness of the existing progressive damage analysis methods is the lack of effective techniques to predict ultimate failure. The newly developed methodology relies on explicit finite element modeling and eliminates convergence issues in the ply-level progressive damage analysis methods due to severe nonlinear discontinuities after propagation of damage beyond detectable size. This work shows results of applying this methodology to nanosilica-toughened IM7/PMT-F3GHT open-hole tension strength/fatigue, open-hole compression strength/fatigue, and bearing strength multidirectional laminate configurations. The ability to predict progression of damage from initiation to ultimate strength and fatigue for advanced material systems including IM7/PMT-F3GHT carbon/epoxy reinforced by nanosilica has been demonstrated for the first time.

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