Twin fibers pull out tests have been designed and carried out to obtain load-displacement curves. Simultaneously

such tests have been simulated by setting a 3D numerical model

which adopts material heterogeneity. Mechanical properties of twin fibers pull out test can

therefore

be studied by changing embedment depth. The results include tensile stress distribution

load-displacement curves

load-AE-step curves and AE evolution

and these results show that the change of twin fibers embedment has great influence on stress distribution. With an increasing embedment depth

peak load and toughness increase either. In addition

similar trend of load-displacement curve of twin fibers pull out test could be observed in both laboratory experiment and numerical simulation.