Measurement and analysis of residual stress in a metal/FRP hybrid structureTuesday (28.04.2020) 10:40 - 11:00 Room 2
Lightweight materials contribute to an efficient decrease of fuel consumptions in automotive and aircraft industries. Hybrid structures made up by metal and fibre reinforced plastics (FRP) have a high potential in lightweight applications due to their high specific strength and stiffness. For cost and time effective processing of hybrid materials, new processes such as the prepreg-press-technology have been developed, in which the bonding between a metallic material and a fibre compound is exclusively realized by adhesive forces. However, upon processing of these hybrid structures at high temperature, the free or restricted warpage of the component induced by cooling leads to the formation of residual stresses. It is well known that these residual stresses are relevant for the mechanical performance of the material and have a significant impact on the durability of the hybrid structure.
The objective of this work is to present a reliable experimental approach to accurately determine and analyze the residual stresses in the hybrid material. The work tries to cover distribution of residual stresses across the thickness of the hybrid structure with focus on the transition zone between metal and FRP. Furthermore, optimization of process parameters for obtaining the minimal residual stresses is considered. With the goal of having a comprehensive understanding on the relation between process parameters and residual stresses, numerical simulations of manufacturing hybrid materials through prepreg-press-technology are carried out. Based on the approach detailed above, numerical simulations are validated by experiments. Thereby, methods used for measuring the residual stress, i.e. nondestructive and destructive methods, are compared in terms of applicability and reliability.