scholarly journals Structure-Integrated Loudspeaker Using Fiber-Reinforced Plastics and Piezoelectric Transducers—Design, Manufacturing and Validation

2020 ◽  
Vol 10 (10) ◽  
pp. 3438
Author(s):  
Benjamin Zenker ◽  
Martin Dannemann ◽  
Sirko Geller ◽  
Klaudiusz Holeczek ◽  
Oliver Weißenborn ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Sound Radiation ◽  
Fiber Reinforced ◽  
Side Panel ◽  
Lightweight Structures ◽  
Reinforced Plastics ◽  
Design Variables ◽  
Element Simulation ◽  
Radiation Behavior ◽  
The Given

In the present study, it could be shown that by integration of a piezoceramic transducer in a fiber-reinforced door side panel, a flat loudspeaker can be realized. Taking into account the given restrictions, the integration position has been identified, where the geometry decouples the vibrating membrane from the supporting surface. With the help of an acoustic finite-element simulation, the main design variables of the integration position were found and the relevant effects for sound radiation were made visible. The manufacturing of the test specimen with piezoceramic transducers was performed using vacuum-assisted resin infusion and the long fiber injection procedure. The effect on the real sound radiation behavior of the door side panel with a material-immanent loudspeaker was experimentally determined using laser scanning vibrometry and sound pressure measurements. The presented work shows, for the first time, the high potential of acoustic functionalization of lightweight structures during the manufacturing process for the realization of lightweight and space-saving loudspeakers in a production-ready process.

Aerodynamic and Mechanical Optimization of CF/PEEK Blades of a Counter Rotating Fan

2012 ◽  
Author(s):  
Daniel Goerke ◽  
Anne-Laure Le Denmat ◽  
Thomas Schmidt ◽  
Frank Kocian ◽  
Eberhard Nicke
Keyword(s):  
Carbon Fiber ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Material Behavior ◽  
Fiber Reinforced ◽  
Reinforced Plastics ◽  
Mechanical Constraints ◽  
Design Variables ◽  
Carbon Fiber Reinforced ◽  
Mechanical Optimization

Since the development of the CRISP [1–3], a counter rotating integrated shrouded propfan, within a MTU-DLR program between 1985 and 2000, huge improvements in fan technologies have been made. In 2010 DLR launched an initiative to redesign the existing fan blades, taking advantage the latest developments in the field of material and manufacturing technology as well as numerical methods. The new fan blades will be made of a carbon fiber reinforced PEEK material. Compared to the so called “onion skin configuration” of CRISP-1m, the layers of the CRISP2 lamina setups are parallel to each other. In contrast to metals, carbon fiber reinforced plastics have an orthotropic material behavior and a higher stiffness mass ratio, which have to be taken into account. The existing shaft and bearing system of the CRISP-1m-model [1–3] will be reused. The blades are mounted in titanium clevises by bolting. To achieve an optimal design, it is necessary to optimize the aerodynamic performance together with the mechanical behavior within a multidisciplinary automated optimization process. The optimization featured approximately one hundred free design variables, two objective functions (maximal displacement for respectively Rotor 1 and Rotor 2), as well as a high number of aerodynamic and mechanical constraints (efficiency, total pressure ratio, axial Mach number, stress, strain, eigenfrequencies, etc.). This work shows how the challenge to integrate the modeling of CF/PEEK blades in a multidisciplinary design process were met in terms of the methods and optimization strategies involved. The major results of this optimization will be presented. This design approach will give a new CRISP blade design ready for a planned rig test in the axial compressor test rig at the DLR in Cologne.

Development and mechanical properties of adaptive fiber-reinforced plastics

2018 ◽  
Vol 48 (6) ◽  
pp. 1081-1096 ◽  
Author(s):  
Moniruddoza Ashir ◽  
Andreas Nocke ◽  
Chokri Cherif
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Mechanical Characterization ◽  
Mechanical Load ◽  
Load Capacity ◽  
Fiber Reinforced ◽  
Lightweight Structures ◽  
Reinforced Plastics ◽  
Hybrid Yarn ◽  
Fiber Reinforced Plastics

Textile-based lightweight structures offer various possibilities for the design of tailored structures by the selective choice of materials and their processing into textile semi-finished products and fiber-reinforced plastics. Lightweight structures with a high mechanical load capacity are feasible by developing fiber-reinforced plastics with adaptive properties that are able to adapt their characteristics, e.g. geometry or stiffness, to external influences. Thus, the application potential of fiber-reinforced plastics can be further expanded. In this paper, we present novel adaptive fiber-reinforced plastics based on textile semi-finished products with integrated shape memory alloys and their mechanical characterization. The shape memory alloy is textile technically integrated and converted into friction spun hybrid yarn. Next, the produced hybrid yarn is integrated with plain, twill and satin woven reinforcement fabric in the weft direction during the shedding operation in weaving. Adaptive fiber-reinforced plastics are developed by infusing textile semi-finished products. Subsequently, the mechanical characterization of the adaptive fiber-reinforced plastics is carried out. Results show that, by integrating shape memory alloys into adaptive reinforced fabrics, the mechanical performance of fiber-reinforced plastics can be tailored.

Effect of long climatic ageing on the microstructure of the surface of сarbon-fiber-reinforced plastics on base epoxy matrix

2019 ◽  
pp. 157-169 ◽  
Author(s):  
I. S. Deev ◽  
E. V. Kurshev ◽  
S. L. Lonsky
Keyword(s):  
Climatic Factors ◽  
Temperate Climate ◽  
Fiber Reinforced ◽  
Humid Climate ◽  
Climatic Zones ◽  
Reinforced Plastics ◽  
Carbon Plastics ◽  
Fiber Reinforced Plastics ◽  
Determining Factor

Studies and experimental data on the microstructure of the surface of samples of epoxy сarbon-fiber-reinforced plastics that have undergone long-term (up to 5 years) climatic aging in different climatic zones of Russia have been conducted: under conditions of the industrial zone of temperate climate (Moscow, MTsKI); temperate warm climate (Gelendzhik, GTsKI); a warm humid climate (Sochi, GNIP RAS). It is established that the determining factor for aging of carbon plastics is the duration of the complex effect of climatic factors: the longer the period of climatic aging, the more significant changes occur in the microstructure of the surface of the materials. The intensity of the aging process and the degree of microstructural changes in the surface of carbon plastics are affected by the features of the climatic zone. general regularities and features of the destruction of the surface of carbon plastics after a long-term exposure to climatic factors have been established on the basis of the analysis and systematization of the results of microstructural studies.

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