This publication deals with finite element based modelling and the experimental validation of the flow characteristics of glass mat reinforced thermoplastic composite (GMT). Furthermore, the interaction of GMT and UD-Tape inserts is examined. The simulation model is set up in LS-Dyna. In order to model the high degree of deformation of the GMT the smooth particle hydrodynamics (SPH) method is used. A viscoplastic material model is applied in order to take into account the strain rate as well as strain hardening flow behavior. For the experimental validation of the numerical investigations, a heated plate tool with a surface area of 300 x 300 mm was built. This tool contains two internal pressure sensors as well as a temperature sensor. With the help of this test setup, it is possible to investigate the pressure build-up, pressure differences and surface temperatures of the GMT as well as the time-dependent position of the flow front. In addition, to pressure differences over the contact area between tool and GMT, there are differences in wall thickness, fiber orientation and fiber matrix separation depending on the flow path. The forming tests were carried out at a tool temperature of 115 °C. After the validation of the simulation model the fiber displacement of UD-Tapes insert is discussed.