Conversion of Chemically-Derived Polymeric Precursors to High performance Ceramic Fibers

1986 ◽  
Vol 73 ◽  
Author(s):  
M. Ishaq Haider ◽  
Terence J. Clark

ABSTRACTIn recent years, there has been steadily increasing research activity directed towards preparation of ceramic materials via polymer pyrolysis. Among the most thermomechanically stable structural ceramics are SiC, Si3N4, and their solid solutions. These materials are widely used as ceramic fiber reinforcements in composites owing to their high mechanical strength, stiffness, and oxidative stability. Processes have now been developed to make these fibers by utilizing melt spinning. Fine diameter continuous filaments are formed, and further processing involves the steps of mild reactive cure and high-temperature pyrolysis. The approach in this review is to summarize the fiber making process with emphasis on improving fired properties by utilizing known mechanisms of fiber failure and process modification procedures. Fiber characteristics, applications of high performance fiber, and perceived trends will also be discussed.

2021 ◽  
pp. 004051752110362
Author(s):  
Xiaoming Chen ◽  
Tianlei Yao ◽  
Chenyang Li ◽  
Yuying Wei ◽  
Jiao Li ◽  
...  

I-fiber implantation is a new stitching technology that can effectively enhance the interlayer performance of laminated composites. This paper presents and evaluates the design and implementation of the I-fiber robot implantation system integrated for producing high-performance fiber preforms for advanced composites. The system was constructed and validated through I-fiber robot implantation experimentation. It was demonstrated that automated I-fiber implantation could be achieved by use of an industrial robot. The programming method and computer-aided manufacturing software of the I-fiber implantation robot were feasible and effective. The double-cantilever-beam (DCB) experiments showed that the implantation of I-fiber significantly improved the interlaminar fracture toughness of the laminated composite, where the maximum load value increased by up to 106%. The DCB load–displacement curve presented a zigzag shape, where the peaks and valleys were the location points of the I-fiber break. It was also found that for the reinforced laminated composite without an I-fiber head, the delamination failure was manifested as resin cracking and I-fiber pullout, while for the I-fiber with a certain head length, the I-fiber failure mechanism was brittle fracture. I-fiber with a certain head length could significantly improve the interlayer performance of the composite. In addition, DCB experiments also revealed that the implantation matrix had little effect on the interlayer performance of I-fiber reinforced composites, and the failure load value and the I-fiber implantation volume showed an obvious proportional relationship.


Author(s):  
Igor Chilin ◽  

Приведены результаты исследований и выполнена оценка влияния технологических факторов на реологические свойства самоуплотняющихся сталефибробетонных смесей, определены кратковременные и длительные физико-механические и деформативные характеристики сверхвысокопрочного сталефибробетона, включая определение его фактической морозостойкости.


2021 ◽  
Vol 2 (3) ◽  
pp. 501-515
Author(s):  
Rajib Kumar Biswas ◽  
Farabi Bin Ahmed ◽  
Md. Ehsanul Haque ◽  
Afra Anam Provasha ◽  
Zahid Hasan ◽  
...  

Steel fibers and their aspect ratios are important parameters that have significant influence on the mechanical properties of ultrahigh-performance fiber-reinforced concrete (UHPFRC). Steel fiber dosage also significantly contributes to the initial manufacturing cost of UHPFRC. This study presents a comprehensive literature review of the effects of steel fiber percentages and aspect ratios on the setting time, workability, and mechanical properties of UHPFRC. It was evident that (1) an increase in steel fiber dosage and aspect ratio negatively impacted workability, owing to the interlocking between fibers; (2) compressive strength was positively influenced by the steel fiber dosage and aspect ratio; and (3) a faster loading rate significantly improved the mechanical properties. There were also some shortcomings in the measurement method for setting time. Lastly, this research highlights current issues for future research. The findings of the study are useful for practicing engineers to understand the distinctive characteristics of UHPFRC.


2020 ◽  
Vol 92 (5) ◽  
pp. 767-772
Author(s):  
Ye Zhang

AbstractThis short review summarizes our recent progress in fiber-shaped lithium-ion batteries and lithium-air batteries based on carbon nanotube hybrid fiber electrodes. The fiber architecture allows batteries to be deformable in all dimensions and bear various deformations such as bending, tying, twisting and even stretching. They are scaled up and further woven into breathable, flexible, stretchable and shape-memory textiles to effectively meet the requirements of modern electronics such as wearable products.


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