Sensor Networks for Integration into Textile-Reinforced Composites
The integration of sensor networks into textile-reinforced composites enables monitoring of different physical values like strain, acceleration and temperature in a component. This paper presents a system concept of a modular sensor network supporting different sensor types and the wireless transmission of stored measurements. Sensor and transponder ASICs have been developed for realizing first demonstration examples. The feasibility of integration of discrete components and silicon chips was successfully verified in experiments with a composite made of glass fibers and polypropylene. Two demonstrators with fully functional integrated modules were fabricated in order to show the possibility of integrated strain monitoring and recording of impact events with wireless data transmission.
Multidisciplinary Analysis Concept for the Development of a Composite Adaptive Leaf Spring
Textile-reinforced plastics are of continuously rising interest for industrial applications due to their tailo rable properties and large-scale production capability. The utilisation of this novel material group as components in mult i-material structures for complex lightweight applications with a high degree of function integration is focussed within the research of the collaborative research centre (SFB) 639. Lightweight design and function integration potentials of these novel structures are examined using an adaptive, self-diagnosing leaf spring within the framework o f a demonstrator vehicle. In this article, a concept for the leaf spring design and the actuation mechanism based on an internal pressure cavity fo r the realisation of a stiffness adaptation are presented. A mult idisciplinary analysis concept was established including three sub-models an analytical based Fast Design Tool, a Finite Element Model and a Multi-body simulation model. The investigations include the simulation of the leaf spring characteristics for different internal pressures and the influence on the static and dynamic behaviour of the demonstrator vehicle.
Damage localization in composite plates using wavelet transform processing on Lamb wave signals
The wavelet transform signal processing applied to Lamb wave signals is a potential technique allowing to detect the possible presence of defects such as delamination and fiber fracture, in layered Carbon/epoxy structures. After a short recall on continuous and discrete wavelet transforms and description of the experimental set-up, this paper presents the main results obtained by this method. Time-frequency diagrams are shown and discussed, an interpretation of phenomena is given and a method of defect localization is presented. This paper shows that it is perfectly possible to detect and localize the defects included in a Carbon/epoxy structure, by using continuous and discrete wavelet transforms applied to Lamb wave signals resulting from an integrated network of piezoelectric transducers working sequentially as emitters and receivers.