Design of a composite tube to analyze the compressive behavior of CFRP

A dumbbell-shaped tube is designed in order to study the compression of composites in the direction of the fibers. Three conditions are defined that ensure the validity of the experimental procedure: the cracks appear in the middle of the specimen, the strain field is homogeneous in the gauge area, and buckling must be avoided. Several tubes are manufactured and then analyzed to verify that they satisfy these three conditions. It turns out that a [0°]11 woven carbon/epoxy (G939/M18) tube reinforced with [90°] unbalanced woven glass/epoxy tabs (1055/ES18) is suitable for compression tests. The non linear elastic behavior of the material is then identified. The values of the parameters are close to those identified in a pure bending test.