Fiber and bundle orientations, matrix rich regions, and mechanical properties of fiber reinforced composites using thermal digital image correlation

A method for assessing fiber orientation in a composite material or a joint between two materials, the method comprising:

• exposing a cross-section of the composite material or the joint to a light source;
• obtaining multiple magnified optical images of the cross-section of the composite material or the joint;
• detecting differences in grey-scale intensity values from the multiple images;
• and
• assessing the fiber orientation for the cross-section of the composite material or the joint based on the differences in grey-scale intensity values in the cross-section of the composite material or the joint.

A method of manufacturing a composite material, the method comprising:

• during manufacturing of the composite material, applying indicia to a surface of the composite material and exposing the composite material to a temperature change;
• imaging the composite material comprising the indicia using one or more optical cameras to measure strain and a thermal camera to measure spatially resolved temperature at a plurality of time points before, during and/or after the temperature change, thereby monitoring a surface mechanical strain tensor while the composite material is undergoing the temperature change;
• and
• assessing a characteristic of the composite material based on the imaging.