The mechanical behavior of textile composites (qualitative analysis) Yasser Gowayed Department of Textile Engineering Auburn University

Textile Composites Steady Improvements in weaving technology has increased the availability of textile preforms Advantages include ease of handling, ability to conform to complex shape and improved residual strength after impact Successful application requires accurate prediction of thermo-mechanical properties and the rate of damage accumulation to allow design engineers to predict when components should be removed from service (relationship between micro damage and mechanical properties)

Textile vs. Laminated Composites Laminated Composites Textile Composites High fiber vol. fraction High in-plane properties Low out-of-plane properties Low resistance to crack initiation and propagation Low fiber vol. fraction Low in-plane properties High out-of-plane properties Low resistance to crack initiation and high resistance to crack propagation

Mechanical behavior: The Effect of Yarn Crimp Intro to composites, Hull & Clyne Plain weave

T. Norman et al. FiberTex 92 Mechanical behavior: The Effect of Yarn Crimp Angle Interlock weave

Mechanical behavior: The Effect of Yarn Crimp XYZ orthogonal weave

Mechanical behavior: The Effect of Yarn Crimp 3D braids

Mechanical behavior: The Effect of Yarn Crimp Knits Univ. of Leuven, Belgium

Stitched Composites Mechanical behavior: The Effect of Yarn Crimp

Laminated Composites Textile Composite Mechanical behavior: The Effect of Yarn Crimp

Layup 0/90 +/- 45 WovenLaminate Woven Laminate Thickness (mm) Strength (MPa) Failure strain Modulus (GPa) Poissons ratio Tensile properties of carbon/epoxy composites: Bishop et al., Composites 84 Mechanical behavior: The Effect of Yarn Crimp

Layup Tensile Compressive WovenLaminate Woven Laminate 0/90 (Curtis, ICCM 85) /- 45 (Bishop, AGARC 83) /- 45 (Curtis, ICCM 85) Tensile and Compressive strength (MPa) of carbon/epoxy composites: Mechanical behavior: The Effect of Yarn Crimp

Kollegal et al. Tensile behavior of AS4/epoxy plain weave with on and off-axis loads Mechanical behavior: The Effect of Yarn Crimp

Chian-Fong Yen et al. Tensile behavior of CVI SiC/SiC plain weave Mechanical behavior: The Effect of Yarn Crimp

Kollegal et al. Shear behavior of AS4/epoxy plain weave with on and off-axis loads Mechanical behavior: The Effect of Yarn Crimp

Mechanical behavior: The Effect of Yarn Crimp Local Fiber Failure Mechanisms Resulting from Compression of Kevlar/Epoxy Composites

Property3-D braidUnidirectional Tape Fiber Vol. Fraction Total Energy Absorbed (ft.lbs) Crack initiation energy (ft.lbs) Crack propagation energy (ft.lbs) Maximum impact load (lbs) Impact Behavior Impact properties of Alumina/Al-Li composites Ko, et al. ASTM STP 964

Impact Behavior Bishop, Textile Structural Composites X-ray radiograph of fatigue damage at notches Micrographic images of fatigue damage at notches

Fatigue Behavior Bishop, Textile Structural Composites

Fatigue Behavior Bishop, Textile Structural Composites

Crack Initiation: The Effect of Yarn Crimp Laminated Composites Textile Composite (3D XYZ woven)

Laminated Composites Textile Composite (3D XYZ woven) Crack Growth: The Effect of Yarn Crimp

Crack Growth: Micrographic images Failure of plain weaves Univ. of Leuven, Belgium

Crack Growth: Micrographic images Failure of Angle Interlock weaves T. Norman et al. FiberTex 92

Crack Growth: Micrographic images Pretest condition of Angle Interlock weaves with stuffers

Crack Growth: Micrographic images Failure of Angle Interlock weaves with stuffers T. Norman et al. FiberTex 92

Textile Composites Imperfections - voids