Application of Eco-Efficiency Analysis to Assess Three Different Recycling Technologies for Carbon Fiber Reinforced Plastics (CFRPs)

2017 ◽  
Vol 742 ◽  
pp. 593-601
Author(s):  
Michael Dieterle ◽  
Elisa Seiler ◽  
Tobias Viere

The purpose of this paper is to evaluate the eco-efficiency of three different recycling technologies for carbon fiber reinforced plastic (CFRP) waste, and to identify the preferable and most efficient solution. Recycling via mechanical shredding, microwave pyrolysis and subcritical solvolysis is compared and comprehensive primary data on energy demand and process throughput are examined. Following an ecological and economic assessment, the results are normalized and summarized into three single-score indicators. To decide which solution is most efficient, economic and ecological data are plotted on an eco-efficiency portfolio. The achieved results demonstrate that the eco-efficiency of the recycling technologies investigated is entirely positive on an industrial scale, and that the efficient use of CFRPs across the entire life cycle is possible. The material recycling of CFRP waste is consequently a promising topic for future development. The use of recycled material as conductivity additives in secondary applications can be considered as a valuable option for all three technologies, although the benefits of recycling are strongly dependent on the quality and quantity of the recycled material. Depending on the resources substituted in a secondary application, different recycling technologies offer considerable advantages. To ensure a consistently high quality of output materials on an industrial scale, specific process parameters have to be identified, for which, further research is necessary.

2021 ◽  
pp. 002199832110075
Author(s):  
Minchang Sung ◽  
Hyunchul Ahn ◽  
Jinhyeok Jang ◽  
Dongil Kwon ◽  
Woong-Ryeol Yu

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.


2021 ◽  
pp. 28-37
Author(s):  
P. N. Shkatov ◽  
G. A. Didin ◽  
A. A. Ermolaev

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.


Author(s):  
Palamandadige K. S. C. Fernando ◽  
Meng (Peter) Zhang ◽  
Zhijian Pei ◽  
Weilong Cong

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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