Stress-strain synchronization for high strain rate tests on brittle composites

Nowadays, many researchers develop rate-dependent composite material models for application in dynamic simulations. Ideally, full stress-strain curves at a wide range of strain rates are available for identification of the different parameters of these models. Dynamic tensile tests are needed to produce the experimental input data. However, especially for brittle materials, data acquisition during these tests becomes critical. The effect of synchronization on the test results was investigated by conducting a series of dynamic tensile tests on three different brittle continuous-fibre composite laminates. It is demonstrated that synchronization errors of the order of 1 microsecond already have a significant effect on the test outcome at high rates. With the aid of a finite-element model, the limiting factors on the maximum attainable strain rate are quantified.