Thermoplastic-compatible Piezoceramic Modules Research Articles

Experimental Investigation of the Frequency‐Dependent Performance of Thermoplastic‐Compatible Piezoceramic Modules (TPM)

Especially due the background of highly automated processes within the processing of fiber‐reinforced polymer (FRP) structures with thermoplastic matrix systems, a wide field of functionally integrative lightweight construction solutions ready for mass production is developed. Furthermore, the layered texture in combination with the specific heating processes of the semi‐finished products enable a material‐homogeneous integration of flat sensors, respectively, actuators into such structures. Due to this, the development of functional elements which are tailored to process is of increasingly importance to generate a significant additional benefit for this material class. The developed thermoplastic‐compatible piezoceramic modules (TPM) are applicable for adhesive‐free integration into fiber‐reinforced thermoplastic structures within the forming process, which is realized by hot‐stamping or thermoforming. On the one hand such active composite parts is used for material integrated sensorial tasks, for example, for condition or structural health monitoring. On the other hand, actuator applications such as natural frequency manipulation or structural morphing are conceivable as application fields. The paper reports on the manufacturing process of TPM and the major‐signal behavior driven by the use of different functional layers using piezoactive fiber composites, respectively, piezoelectrical wafer material. In addition, the frequency‐dependent performance of the defined TPM is compared to commercially available flat transducers like Macro Fiber Composites (MFC, Smart Material GmbH) and DuraAct (PI Ceramic GmbH) actuators by means of voltage‐strain behavior driven by high‐voltage excitation at frequencies of 5, 50, and 500 Hz. Therefore, the use of an adapted high‐speed digital image correlation method is been applied. The aims of the investigations are to proof the functionality of novel TPM and to demonstrate the performance compared to common flat piezo transducers.

Numerical and Experimental Characterization of Fiber-Reinforced Thermoplastic Composite Structures with Embedded Piezoelectric Sensor-Actuator Arrays for Ultrasonic Applications

The paper presents preliminary numerical and experimental studies of active textile-reinforced thermoplastic composites with embedded sensor-actuator arrays. The goal of the investigations was the assessment of directional sound wave generation capability using embedded sensor-actuator arrays and developed a wave excitation procedure for ultrasound measurement tasks. The feasibility of the proposed approach was initially confirmed in numerical investigations assuming idealized mechanical and geometrical conditions. The findings were validated in real-life conditions on specimens of elementary geometry. Herein, the technological aspects of unique automated assembly of thermoplastic films containing adapted thermoplastic-compatible piezoceramic modules and conducting paths were described.

Experimental and Numerical Studies on Integration Thermoplastic Composite Compatible Piezoelectric Ceramics for Actuatory Application of Cylindrical Hollow Structures

Regarding the economical use of fiber-reinforced plastics (FRP) as a construction material for structural components whose additional value caused not only in their high specific mechanical properties. Due to the layerwise structure definition of continuous fiber reinforced composites the corresponding production technologies offers a high potential for integration of additional functional elements. Past efforts to the integration of functions in fiber-reinforced composites usual provide in front of a passive use of the piezoelectric effect (eg. structural-health monitoring). Through efficient and structurally defined using of piezoceramic actuators, the planar structure topology of cylindrical hollow FRP profiles can be actively influenced. Based on experimental studies on the definition of basic concepts for the integration of thermoplastic compatible piezoceramic modules (TPM) in fiber composite tubular segments, this paper deals with the understanding and performance capabilities of such actuarical hollow frp structures. The selective excitation and manipulation of the vibration behavior of such rotationally symmetric structures serves for generation of wave effects with radial translational characteristic. The performed experimental studies on the structural behavior of active piezo integral pipe segments are abstracted and compared by means of numerical simulations using multi-physical elements.

Online Poling of Thermoplastic-Compatible Piezoceramic Modules during the Manufacturing Process of Active Fiber-Reinforced Composites

Due to high specific properties and the ability for the realisation of short cycle times within the production process, the use of fiber-reinforced thermoplastic composites offers a high potential for high volume applications. Furthermore, the layered built-up and the according manufacturing processes of these materials give the possibility to integrate functional elements, like electronic components or piezoelectric sensor/actuator modules. Within the collaborative research center CRC/TRR 39 “Production Technologies for light metal and fiber-reinforced composite-based components with integrated piezoceramic Sensors and Actuators”, the integration of piezoceramic modules into lightweight structures ready for series production is investigated. This paper presents the manufacturing process of active fiber-reinforced thermoplastic composites. Here, the focus is on experimental investigations covering the process-integrated poling of novel piezoceramic modules during the manufacturing of active fiber-reinforced thermoplastic components. Therefore, laboratory and process-oriented tests are performed for the determination of appropriate parameters for the pressing and poling process. The functionality of the embedded and poled TPM is validated by the excitation of an active component structure and the optical measurement of the vibration behaviour using a laser scanning vibrometer.

Production process adapted design of thermoplastic-compatible piezoceramic modules

Fibre-reinforced polymers with thermoplastic matrix systems are suitable for a wide range of applications in the field of function-integrative lightweight structures ready for series production. The development of functional elements which are tailored to processes is therefore of increasingly significant importance. The thermoplastic-compatible piezoceramic modules under development are suitable for adhesive-free integration into fibre-reinforced thermoplastic structures using a welding process which is intrinsic to the manufacturing process. The continuous refinement of the novel module design and the corresponding manufacturing process (which is based on hot-pressing technology) is supported by the development of tailored coupled and physical nonlinear simulation models which facilitate module design and the analysis of functionality in terms of interactions between technical and technological parameters. Special attention is given to the definition of precise, function-specific manufacturing tolerances as well as the residual stresses caused by the various thermal expansion coefficients of the module components and the use thereof as a means of enhancing module performance.

Sensitivity Analysis for the Manufacturing of Thermoplastic e-Preforms for Active Textile Reinforced Thermoplastic Composites

Active fibre-reinforced thermoplastic composites offer a high application potential for lightweight structures capable for series production. By the integration of functional components like material-embedded piezoceramic actuators or sensors the structural behaviour becomes actively controllable and manipulable. Currently, a wide application of such adaptive structures is mainly restricted by the lack of robust manufacture technologies. Therefore, these investigations are performed to develop and realise a novel robust and efficient manufacture process capable for series production. This process bases on a material and actuator adapted hot pressing technique. In this context, special regard is given to the sub process e-preforming. There a thermoplastic film is assembled with thermoplastic compatible piezoceramic modules and the necessary conductive paths. By the development of a special e-preforming unit and the corresponding parameter investigations an adapted manufacture of so called e-preforms can be realised.

Consolidation behaviour during manufacture of adapted piezoceramic modules for functional integrated thermoplastic composite structures

Abstract For the series production of adaptive fibre-reinforced thermoplastic structures, the development of process-adapted piezoceramic modules is gaining central importance. Thermoplastic-compatible piezoceramic modules are being developed which are suitable for a matrix-homogeneous adhesive-free integration of the modules in fibre-reinforced thermoplastic structures during a simultaneous welding process. Aiming at the continuous improvement of the novel module design and its manufacturing technology based on a hot-pressing technology, an adapted physical nonlinear simulation model was developed in order to analyze the material and process dependent function and consolidation behaviour. Special regard is given to residual stresses caused by different coefficients of thermal expansion of the component materials and their specific use to enhance the module performance.

Embedding versus adhesive bonding of adapted piezoceramic modules for function-integrative thermoplastic composite structures

Against the background of an integration of piezoceramic modules into thermoplastic composite structures the development of thermoplastic-compatible piezoceramic modules (TPM) requires the consideration of the type of module-structure-connection and module position for an optimal strain transmission. While commercially available low profile transducers are applied predominantly by adhesive bonding, TPM with thermoplastic carrier films identical to the thermoplastic matrix of the composite structure offer the possibility for a material-homogeneous integration by a hot-pressing process. The aim of the presented work is to examine the influence of an adhesive layer as well as the comparison of adhesive bonding and module integration by a hot-pressing process. Therefore a common analytic model and the finite element method (FEM) is used. Particular regard is given to a maximum strain transmission between the functional module and the composite structure. For pure bending as well as for pure linear expansion the studies show the advantages of a material-homogeneous integration of function modules.

Sensitivity analysis for the process integrated online polarization of piezoceramic modulesin thermoplastic composites

The use of active composite structures in high-volume applications requires novelrobust manufacturing processes as well as specially adapted functional modules.The paper presents actual research results with regard to the process-immanentpolarization of novel thermoplastic-compatible piezoceramic modules (TPM)during the consolidation process of active fibre-reinforced thermoplastic compositestructures. In particular the influence of varying manufacture process parameters of ahot-press process on the polarization behaviour is investigated. The main principalobjective is the purposeful utilization of process parameters for polarization support.

Development of novel piezoceramic modules for adaptive thermoplastic composite structures capable for series production

The use of adaptive composite structures in series applications requires novel actuators and related manufacture processes capable for serial production. The paper shows latest research results with regard to the continuous development of novel thermoplastic-compatible piezoceramic modules (TPM). These modules are predestined for the material homogeneous actuator integration in fibre-reinforced thermoplastic composites by means of a welding process. The research focuses on numerical and experimental studies in order to design efficient modules capable for a continuous production process. Especially studies with regard to geometrical parameters and their influences on the actuator performance as well as studies with respect to the manufacture process are accomplished.

Design and testing of novel piezoceramic modules for adaptive thermoplastic compositestructures

For the series production of adaptive fibre-reinforced thermoplastic structures, thedevelopment of process-adapted piezoceramic modules is gaining central importance.Therefore, thermoplastic-compatible piezoceramic modules (TPMs) are being developedwhich are suitable for a matrix-homogeneous adhesive-free integration of the modules infibre-reinforced thermoplastic structures during a sequential hot-pressing process.Extensive numerical and experimental studies are available on the systematicdevelopment of the TPMs, whose thermoplastic carrier film, made, respectively, ofpolyetheretherketone (PEEK) or polyamide (PA), is already adapted to the matrixmaterial of a thermoplastic composite structure and thus can be joined in a welding processwithout additional adhesives. The studies carried out indicate the influence of geometricaland technological parameters on the efficiency of consolidated and polarized TPMs and canthus be used to adapt the design specifications and process parameters of theTPMs. Besides these studies, a numerically based residual stress analysis shows thepotential for a defined inducing of residual stresses in the TPM components.