2021-12-152021-12-152011-03Karahan, M. (2011). "Investigation of damage initiation and propagation in 2x2 twill woven carbon/epoxy multi-layer composites". Textile Research Journal, 81(4), 412-428.0040-51751746-7748https://doi.org/10.1177/0040517510395996https://journals.sagepub.com/doi/10.1177/0040517510395996http://hdl.handle.net/11452/23272Damage and mechanical properties in textile composites are closely connected with the textile reinforcement's internal structure. This paper reports and discusses a study of the mechanical behavior and damage of a 2 x 2 twill woven carbon/ epoxy composite resulting from uniaxial tension in the warp and bias directions. A damage investigation was performed by using acoustic emission and full-field strain optical measurements, as well as X-ray and optical microscopy. As a result of the tests, the mechanical properties and strain values of the composite's damage threshold were determined. Damage initiation when loaded in the warp and bias directions occurred between 0.2% and 0.3% and 0.88% and 1.71% of the applied strain, respectively. Microscopic examination showed that damage or cracks initiated where the yarn was crimped and at interactions between the warp and filling yarns. Full-field strain measurements highlighted the relation between the strain concentrations that are linked with the damage initiation and the reinforcement structure.eninfo:eu-repo/semantics/closedAccessMaterials science2x2 twill woven compositesAcoustic emissionDamageFull-field strain measurementMechanical propertiesBraided textile composites3d orthogonal weaveTensile propertiesPart 1Failure analysisBehaviorAcoustic emission testingAcoustic emissionsComposite materialsFibersMechanical propertiesOptical data processingOptical microscopyReinforcementStrainStrain gagesStrain measurementTextilesApplied strainCarbon/epoxyDamageDamage initiationDamage investigationDamage thresholdEpoxy compositeFull-fieldFull-field strain measurementInternal structureMechanical behaviorMultilayer compositeOptical measurementReinforcement structuresStrain concentrationStrain valuesTextile compositeTextile reinforcementUniaxial tensionsWoven compositeWeavingArticle0002891617000082-s2.0-79953243790412428814Materials science, textilesBraided Composites; Braiding; Three Dimensional Composites