Experimental Characterization of Composite Materials

COURSE CONTENT

Experimental characterization of thermomechanical properties of orthotropic layer of fibrous composites (Basics of anisotropic theory of elasticity).
Engineering elastic constants, Effect of the shear interaction components, SXS, SYS, on the deformation behavior of generally orthotropic layers.
The principal stress and strain systems in orthotropic materials,

Measurement of shear deformations using strain gauges,
Errors of experimental measurements in tests of fibrous composites. Measurement of fiber volume fraction,
Tests based on EN & ISO standards to characterize mechanical properties at the layer level.
Hydrothermal behavior. Measurement of thermal and hygroscopic expansion coefficients.
Interlaminar fracture toughness under mode I and Mode II loading conditions.
Interlaminar Shear Strength (ILSS).
Fatigue behavior of fibrous composites (Mechanisms of failure, Degradation of mechanical properties (strength and stiffness), Tests based on standards for characterization of fatigue behavior, SN curves, Constant life diagrams, Generalized Goodman law, Statistical evaluation of experimental fatigue data, Damage accumulation laws.

LEARNING OUTCOMES

Understanding the Anisotropic nature of Composite Materials and consolidating the necessary tests methods for their full characterization in relation to their Mechanical and Hydro-Thermal behavior.
In particular, students learn and understand the necessary tools/techniques for the characterization and measurement of a set of critical properties of materials required for the design and analysis of composite structures. Analysis and Measurements of:
• Engineering elastic constants,
• The Effect of Shear Interaction Components, SXS, SYS, on the deformation behavior of generally orthotropic layers,
• The principal stress and strain systems in orthotropic materials,
• Measurement of shear deformations using strain gauges,
• Errors of experimental measurements in testing of fibrous composites, Measurement of fiber volume fraction,
• Tests based on EN standards for the characterization of the layer mechanical properties,
• Interlaminar fracture toughness (mode I, mode II) and ILSS,
• Hydro-thermal behavior of composites,
• Measurement of the thermal and hygroscopic expansion coefficients.
• Fatigue behavior of fibrous composites (Mechanisms of failure, Degradation of mechanical properties strength/stiffness),
• Standard Tests for the characterization of fatigue behavior of composites, S-N curves, Constant life diagrams.