This paper presents a thermal investigation of lightweight on-board receiver modules of wireless power transfer systems for electric vehicles. The studied modules are capable of receiving up to 11 kW at a resonance frequency of 85 kHz over a distance of 110–160 mm. The receiver modules were built as sandwich and space–frame concept to design stiff and lightweight structures. The high transmission power of automotive wireless power transfer systems combined with the multi-part assembly of receiver modules led to challenges in heat management. To address this, the physical behaviour of the proposed lightweight concepts were studied on component and system level using a hardware-in-the-loop testing facility for wireless power transfer systems. Special emphasis was laid on the validation of a thermal simulation model, which uses analytical calculated power losses taking into account their temperature dependency. The proposed simulation model is consistent with the experimental validation of the critical active components. The performed systematic studies build the basis for a more sophisticated thermal dimensioning of various constructions for wireless power transfer modules.
Function‐integrative lightweight engineering represents an essential element in modern design methods. Currently, there is a great need for the incorporation of sensors, actuators and electronics in novel, demand‐oriented components. In contrast to a subsequent, mostly adhesive bonding, structural integration offers numerous advantages, for example in terms of space requirements and robustness. This paper demonstrates the potential of integrated sensors for various industrial sectors based on selected examples from mechanical engineering, aviation, mobility, sports, and medical technology.
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.
2 August 2019 in Journal of Applied Polymer Science
Fiber reinforced composites combine low density with high specific mechanical properties and thus became indispensable for today’s lightweight applications. In particular, carbon fibre reinforced plastic (CFRP) is broadly used for aerospace components. However, damage and failure behaviour, especially for complex fibre reinforcement set-ups and under impact loading conditions, are still not fully understood yet. Therefore, relatively large margins of safety are currently used for designing high-performance materials and structures. Technologies to functionalise the materials enabling the monitoring of the structures and thus avoiding critical conditions are considered to be key to overcoming these drawbacks. For this, sensors and actuators are bonded to the surface of the composite structures or are integrated into the composite lay-up. In case of integration, the impact on the mechanical properties of the composite materials needs to be understood in detail. Additional elements may disturb the composite structure, impeding the direct connection of the composite layers and implying the risk of reducing the interlaminar integrity by means of a lower delamination resistance. In the presented study, the possibility of adjusting the interface between the integrated actuator and sensor layers to the composite layers is investigated. Different polymer layer combinations integrated into carbon fibre reinforced composite layups are compared with respect to their interlaminar critical energy release rates and . A standard aerospace unidirectionally reinforced (UD) CFRP prepreg material was used as reference material configuration. The investigations show that it is possible to enhance the mechanical properties, especially the interlaminar energy release rate by using multilayered sensor–actuator layers with Polyimide (PI) outer layers and layers with low shear stiffness in between.
The dimensioning of wireless power transfer systems requires compliance with safety standards for human exposure and electromagnetic compatibility. For this reason, shielding is conventionally carried out with heavy and costly plates. In order to evaluate a lightweight and low-cost alternative, this paper presents a comprehensive investigation of the shielding effectiveness of metal meshes in magnetic fields of wireless power transfer systems, including analytical modeling and experimental validation. Special emphasis is laid on the validation of novel analytical approximation approaches to model the anisotropic electrical conductivity of metal meshes. The proposed approaches show good consistency of the mean value taking into account warp and weft direction, whereas the modeling of the anisotropic behavior is not sufficiently accurately represented. Using the calculated electrical conductivity, the analytical modeling of the maximum shielding effectiveness based on a literature-known approach is very consistent for the experimental validation. Thus, the performed studies provide a significant contribution to the dimensioning of metal meshes as shielding for wireless power transfer systems.