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.

A micromechanical model of carbon fiber-reinforced plastic and steel hybrid laminate composites

2021 ◽  
pp. 002199832110075
Author(s):  
Minchang Sung ◽  
Hyunchul Ahn ◽  
Jinhyeok Jang ◽  
Dongil Kwon ◽  
Woong-Ryeol Yu
Keyword(s):  
Carbon Fiber ◽  
Compressive Stress ◽  
Fracture Strain ◽  
Matrix Material ◽  
Micromechanical Model ◽  
Fiber Reinforced ◽  
Laminate Composites ◽  
Reinforced Plastics ◽  
Carbon Fiber Reinforced ◽  
Hybrid Laminate

The fracture strain of carbon fiber-reinforced plastics (CFRPs) within CFRP/steel hybrid laminate composites is reportedly higher than that of CFRPs due to transverse compressive stress induced by the steel lamina. A micromechanical model was developed to explain this phenomenon and also to predict the mechanical behavior of CFRP/steel hybrid laminate composites. First, the shear lag theory was extended to calculate stress distributions on fibers and matrix material in a CFRP under multiaxial stress condition, considering three deformation states of matrix (elastic and plastic deformation and fracture) and the transverse compressive stress. Then, the deformation behavior of CFRP was predicted using average stress in the ineffective region and the Weibull distribution of carbon fibers. Finally, the mechanical properties of CFRP/steel hybrid laminate composites were predicted by considering the thermal residual stress generated during the manufacturing process. The micromechanical model revealed that increased transverse compressive stress decreases the ineffective lengths of partially broken fibers in the CFRP and results in increased fracture strain of the CFRP, demonstrating the validity of the current micromechanical model.

INCREASING SENSITIVITY OF EDDY CURRENT NON-DESTRUCTIVE TESTING OF DELAMINATION IN CARBON-FIBER REINFORCED PLASTICS

2021 ◽  
pp. 28-37
Author(s):  
P. N. Shkatov ◽  
G. A. Didin ◽  
A. A. Ermolaev
Keyword(s):  
Carbon Fiber ◽  
Eddy Current ◽  
Calculation Model ◽  
Fiber Reinforced ◽  
Destructive Testing ◽  
Carbon Fiber Reinforced Plastics ◽  
Reinforced Plastics ◽  
Fiber Reinforced Plastics ◽  
Carbon Fiber Reinforced ◽  
The Difference

The paper is concerned with increasing sensitivity of eddy current nondestructive testing of most dangerous delamination in carbon-fiber reinforced plastics (CFRP). Increased sensitivity is achieved by separate registration and comparison of eddy current signals obtained from a set of stratifications of carbon fibers with the same orientation. The separation of eddy current signals is possible due to pronounced anisotropy of the electrical conductivity of the layers dominant in the direction of the fibers of the corresponding layer. Eddy-current signals are registered by eddy current probes with maximum sensitivity in a given angular direction. Prior to the scan eddy current signals of the probe are leveled on a defect-free area. The influence of the working gap on the difference between the eddy current signals of the probe is suppressed by normalizing it according to one of the signals. The analysis of the registered signals from delamination has been performed using an approximate calculation model. The reliability of the obtained results has been confirmed by comparison with experimental results and calculations using the finite element method.

Rotary Ultrasonic Machining: Effects of Tool End Angle on Delamination of CFRP Drilling

2017 ◽  
Author(s):  
Palamandadige K. S. C. Fernando ◽  
Meng (Peter) Zhang ◽  
Zhijian Pei ◽  
Weilong Cong
Keyword(s):  
Carbon Fiber ◽  
Material Removal ◽  
Ultrasonic Machining ◽  
Fiber Reinforced ◽  
Rotary Ultrasonic Machining ◽  
Carbon Fiber Reinforced Plastics ◽  
Reinforced Plastics ◽  
Hole Making ◽  
Fiber Reinforced Plastics ◽  
Carbon Fiber Reinforced

Aerospace, automotive and sporting goods manufacturing industries have more interest on carbon fiber reinforced plastics due to its superior properties, such as lower density than aluminum; higher strength than high-strength metals; higher stiffness than titanium etc. Rotary ultrasonic machining is a hybrid machining process that combines the material removal mechanisms of diamond abrasive grinding and ultrasonic machining. Hole-making is the most common machining operation done on carbon fiber reinforced plastics, where delamination is a major issue. Delamination reduces structural integrity and increases assembly tolerance, which leads to rejection of a part or a component. Comparatively, rotary ultrasonic machining has been successfully applied to hole-making in carbon fiber reinforced plastics. As reported in the literature, rotary ultrasonic machining is superior to twist drilling of carbon fiber reinforced plastics in six aspects: cutting force, torque, surface roughness, delamination, tool life, and material removal rate. This paper investigates the effects of tool end angle on delamination in rotary ultrasonic machining of carbon fiber reinforced plastics. Several investigators have cited thrust force as a major cause for delamination. Eventhogh, it is found on this investigation, tool end angle has more significant influence on the delamination in rotary ultrasonic machining of carbon fiber reinforced plastics comparing to cutting force and torque.

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