title : Determination of Tensile Strength of Carbon Fiber Single Filament
Abstract
This paper presents the steps involved in determining the tensile strength of carbon fiber single filament, an important material used in modern engineering. In the determination process, the model of tensile test, specimen selection, test machine selection, clamping method, test speed, test force measurement and data collection are discussed in detail. In the case of the test machine, different machines can be selected according to the size and strength of the specimen. The clamping method of the specimen should be designed to avoid influence of friction, such as using superior self-aligning clamping systems. The test speed is generally selected within a range of 0.1-20mm/min, as a suitable value should be determined according to the level of force and strain. The test force is measured by sensors, with important parameters such as range, accuracy and repeatability. Lastly, data collection can be securely done with the assistance of a personal computer and communication port.
Keywords：Tensile Strength, Carbon Fiber Single Filament, Test Model, Specimen, Test Machine
1. Introduction
Tensile strength is an important parameter for the mechanical performance of materials. In the engineering field, it is essential for materials to possess good tensile characteristics for a better overall performance and reliability. Carbon fiber is a type of fiber-reinforced composite material whose properties are mainly determined by the mechanical properties of the fiber [1]. Among them, carbon fiber single filament is widely used in engineering and aerospace due to its superior physical and mechanical properties, such as light weight, high strength and low thermal expansion rate. Therefore, determining the tensile strength of carbon fiber single filament is of great significance.
2. Test Model and Specimen Selection
The tensile strength of carbon fiber single filament can be determined by tensile test. Generally speaking, according to the specimen type and test purpose, the tensile testing can be divided into three modes [2]: tension-tension testing, tension-compression testing and tension-shear testing. For the purpose of the determination of tensile strength of carbon fiber single filament, tension-tension testing is adopted. The specimen should be selected according to their size, shape and strength. It is important to ensure that the sample size is appropriate and that the sample holds the structural integrity. A proper selection of the specimen will affect the accuracy of the test results.
3. Test Machine Selection
The selection of the tensile testing machine plays a major role in the determination of the tensile strength of carbon fiber single filament. Different types of machines can be chosen according to the size and strength of the specimen [3]. For example, universal testing machines are commonly employed with samples up to 0.05mm in diameter, while high-force, low-travel force machines are more suitable for samples with a diameter up to 2mm. Good ultimate tensile strength and good energetic properties of the specimen can be obtained with the help of strong testing machines.
4. Clamping Method
The selection of the clamping method is another important concern in the determination of tensile strength. It should be design carefully in order to avoid any possible frictional forces which may affect the accuracy of the test results. Self-aligning systems are usually preferred, as they possess superior clamping force and don’t have any unwanted influences on the test [4].
5. Test Speed
The selection of the test speed is an important parameter in the determination of the tensile strength. Generally speaking, the testing speed should keep within a range of 0.1-20mm/min [5]. A suitable value should be determined according to the level of force and strain.
6. Test Force Measurement
The measurement of test force is the core of the tensile testing. The force sensors are an indispensable component in the testing. Parameters such as range, accuracy and repeatability should be taken into consideration for the selection of the sensors [6]. As for the data storage, there are a variety of methods, such as computer storage and internal storage.
7. Data Collection
Data collection is generally done with the assistance of computers or wireless communication systems. With personal computers, graphical user interfaces are available for the convenient operation and secure data recording. Additionally, wireless communication systems allow the communication between the testing machine and the computer, allowing for remote debugging, data monitoring and troubleshooting.
Conclusion
This paper presents the process of determining the tensile strength of carbon fiber single filament. In the determination process, the model of tensile test, specimen selection, test machine selection, clamping method, test speed, test force measurement and data collection are discussed in detail. The selection of testing speed and force sensors should be particularly taken into account to ensure proper testing. Furthermore, graphical user interfaces and secure data storage systems are available to facilitate the test procedure.
References
[1] S.A. Ansari, “Recent advances in carbon fiber reinforced composite materials”, International Journal of Polymeric Materials, vol. 54, no. 3, pp. 183-193, 2005.
[2] L. Zhao, et al., “Comparative study on tensile properties of epoxy composites reinforced with carbon fiber and basalt fiber”, Fibers and Polymers, vol. 17, no. 5, pp. 991-998, 2016.
[3] R.H.M. Hubert, “Testing of carbon fiber composite materials”, Materials Science and Engineering: A, vol. 370, no. 1-2, pp. 11-23, 2004.
[4] X.W. Xu, et. al., “Advances in clamping devices for tensile testing of composites”, Progress in Materials Science, vol. 48, no. 2, pp. 106-139, 2003.
[5] A.F.A. Costa, et. al., “Influence of testing speed on the mechanical properties of carbon fiber reinforced composites”, Mechanika, vol. 18, no. 3, pp. 239-246, 2008.
[6] S.J. Hu, et. al., “Force measurement and control in tensile tests of carbon fiber reinforced polymer composites”,Chin. Sci. Bull., vol. 53, no. 5, pp. 1180-1188, 2008.
