Investigation of adhesion properties in load coupling applications for flexible composites

Viscoelastic Behavior of Glass-Fiber-Reinforced Silicone Composites Exposed to Cyclic Loading

“…As recommended by the manufacturer, the matrix material was then cured in an air circulating drying oven at 70 °C for 60 min. Regarding the mechanical properties of the individual components (i.e., fibers and matrix) and the flexible composite, corresponding tensile tests were carried out as in previous studies [ 51 ]. The mechanical properties of the fibers were tested in tensile tests according to ASTM D2256 [ 52 ], the elastomeric matrix with ISO 37 [ 53 ], while the composite material was investigated based on ISO 527-4 [ 54 ].…”

“…Compared to this, the pure fiber material showed an elongation at break value of approximately 2.3%, with a force at break value of about 119.8 N. Subsequently, the mechanical properties of the tailor-made fiber-reinforced elastomers were analyzed regarding the influence of the fiber orientation and adhesion properties. Representative for the flexible composite, the ±45° orientation revealed a determined elongation at break value of about 38.2%, with a corresponding stress at break value of approximately 34.3 MPa [ 51 ].…”

“…The step cycle tests were also performed under tensile loading, using rectangular samples with a defined length/width ratio of 90:30 (l is the specimen gauge length, between the clamping fixture), ensuring smooth data recording without any effects caused by the clamping area due to affected deformation or hindered fiber reorientation. This sample geometry was already applied in a previous study [ 51 ], where the influence of the sample geometry on structural properties, the effects of fiber orientation on shear stresses, and the tensile properties of flexible composites were investigated. For all tests, a defined fiber volume content of about 50% was set, which was verified through thermogravimetric analysis (TGA).…”

“…This is mainly related to the multiaxial stresses caused by large necking and deformation due to the sharp transition in the material between clamping and testing areas. The effects of these local stress concentrations, including their prevention by rubber pads, were already analyzed in previous research studies [ 51 ].…”

Comparison and Impact of Different Fiber Debond Techniques on Fiber Reinforced Flexible Composites

“…The test setup for the fiber pull-out testing represents a combination of the standardized testing method for pure yarn tension testing, according to the ASTM D2256 enhanced with the specimen holder for the modified FBPO test, shown in Figure 1d. This test setup represents the fiber-loaded measuring device, where the upper clamping device fixes the fiber bundles and represents the movable part [28]. The tests were performed with a constant displacement rate v pull out.…”