HyCEML - Hybrid CFRP/ elastomer/ metal laminates containing elastomeric interfaces for deliberate dissipation

点击翻译按钮获取中文摘要

The main objective of the project is to identify and to investigate the advantages and disadvantages of hybrid laminates made of carbon fiber reinforced polymers (CFRP), elastomers and metals (HyCEML) in terms of ist calm, smooth and smart behavior. In contrary to conventional fiber-metal laminates, the elastomer forms the interface between metal and CFRP and establishes the generally very good damping (calm) behavior of HyCEML. Beyond damping, the elastomer covers a series of further (smart) aspects that are crucial in hybrid systems. It acts as adhesive and thus facilitates the joining of the dissimilar materials. It compensates internal stresses caused by a mismatch of the coefficients of thermal expansion (CTE mismatch) and acts as an insulating layer that counteracts contact corrosion. Furthermore it improves the impact tolerance of the hybrid laminate significantly due to energy absorption in the elastomer layer in combination with superior delamination resistance. A jerk-free (smooth) operation of the system can be assured. Therefore, comprehensive experimental and numerical investigations are needed, which require new methods or method adjustments. Since the damping characteristics of the hybrid laminate are highly anisotropic, one of the objectives of this project is the experimental characterization of the anisotropic behavior as well as their underlying mechanisms. In addition to anisotropy, investigating the calm properties aims for the analysis of the laminates damping characteristics. In addition to the characterization of the calm properties, a further objective represents the analysis of smart aspects such as the compensation of the CTE mismatch and the corrosion behavior. Based on the experimental results, suitable finite element (FE) modeling techniques need to be developed to describe the laminate damping behavior numerically. The first modelling objective is to build up and validate detailed multi-layer FE models to be used to investigate the effect of varying layup and loading constitutions on the damping behavior. For verification and validation purposes, analytical closed-form solutions (e.g. for simply supported plates) and experimental tests are needed. Furthermore, specific laminate configurations need to be investigated to deliberately increase the damping capability of the laminate. Since multi-layer shell elements are computationally more efficient than detailed multi-layer FE models, a suitable shell theory is needed to model the hybrid laminates on structural level. Based on the state of the art in multi-layer modelling and based on the experimental results to be obtained, an essential objective of the proposed project is the development of a multi-layer shell formulation. A further aim of the project is to investigate the influence of different geometric aspects onto the resulting damping behavior of the structure. To do this, different generic parts with varying geometrical complexity will be modelled.