Wydawnictwa Uczelniane / TUL Press
Stały URI zbioruhttp://hdl.handle.net/11652/17
Przeglądaj
4 wyniki
Wyniki wyszukiwania
Pozycja Innovative thermally stablized low twist hybrid yarns from recycled carbon fibre for thermosplastic composites(Wydawnictwo Politechniki Łódzkiej, 2022) Hasan, Mir Mohammad Badrul; Khurshid, Muhammad Furqan; Abdkader, Anwar; Cherif, ChokriHybrid yarns consisting of rCF and thermoplastic fibre offer a good potentials to improve mechanical properties of carbon fibre reinforced composites due to high fiber length, homogeneous mixing and high rCF content [1]. However, the twisting of the yarn in conventional spinning processes leads on one hand to the damage in rCF during spinning because of its high brittleness and sensitivity to shear forces. On the other hand, mechanical properties e.g. tensile and flexural strengths of composites decrease significantly with the increase of twist as a result of low fibre orientation [2]. On the contrary, the yarn strength and the stability of the spinning process are strongly dependent on the level of yarn twist. In our previous paper [3], the development of low twist hybrid yarns (75-30 T/m) consisting of rCF and polyamide 6 (PA6) fibre for high performance thermoplastic composites has been reported. However, hybrid yarns with low twist levels suffer from low spinning stability and poor yarn strength, which limits their further processablity in weaving or knitting processes. Therefore, the focus of this work is the development of a method to reduce yarn twist but still ensuring a stable spinning process, high yarn and composite strengths.Pozycja Micromechanical models for fabrics and composites made of hybrid yarns from recycled carbon fibers(Wydawnictwo Politechniki Łódzkiej, 2022) Lang, Tobias; Hasan, Mir Mohammad Badrul; Huynh, Thy Anh My; Gereke, Thomas; Abdkader, Anwar; Cherif, ChokriAlthough the great potential of carbon fibers for use in lightweight applications has been demonstrated in the past, their cost and environmental impact remain a barrier to their widespread use [1]. Recycling of carbon fibers from end-of-life components and combining them with thermoplastic fibers to form hybrid yarns addresses both issues. Due to the stochastic nature of hybrid yarns in terms of recycled carbon fiber (rCF) length and orientation [2], their influence on drapability and performance of rCF composites needs to be investigated. In this paper, a micromechanical model for analysing the dry and composite properties of yarns made from rCF is presented. By using a self-developed framework for generating representative volume elements (RVE) based on parameters such as fiber length, orientation, waviness, and fiber volume content, a variety of idealised random yarn geometries is created. A subsequent simulation step of the compaction of the RVE assures a more realistic RVE geometry. The models are validated by carrying out virtual tests and comparing the results with real tensile tests. The modelling approach can be used for further analyses.Pozycja Non-stationary effects of ring rail movement in the high-speed ring spinning process with a superconducting magnetic bearing twisting system: problem and its solution(Wydawnictwo Politechniki Łódzkiej, 2022) Hossain, Mahmud; Abdkader, Anwar; Cherif, Chokri; Sparing, Maria; Hühne, Ruben; Maximilian, Krentzien; Beitelschmidt, MichaelCurrently, a major challenge in conventional ring spinning is to increase productivity. This is essentially due to friction between the twisting elements. An innovative approach to the solution is the use of frictionless twisting system based on superconducting magnetic bearing (SMB) system. However, previous studies with the SMB system were mainly restricted to an angular spindle speed of up to 30.000 rpm because of: instabilities caused by the non-stationary process forces originating from the nonuniform ring rail movement, complex interactions between the yarn dynamics and the bearing properties of the SMB, aerodynamical subsonic flow regimes of the rotating yarn balloon etc. The ring-rail movement must be taken into account especially at higher angular spindle speed, as a ring-rail cycle occurs every few rotations of the spindle and results in fast-periodic variation of the balloon form, which in turn leads to extreme yarn tension peaks. In this study, metrological investigations were conducted considering the ring rail movement at different angular spindle speeds with the SMB twisting system to understand the influence of the ring rail movement on the spinning stability, dynamic yarn path during spinning process, balloon form etc. Moreover, a concept using servo motor driven lifting mechanism is presented to solve the problem of non-uniform ring rail movement.Pozycja Friction spun yarns with high RCF content for thermoset composites(Wydawnictwo Politechniki Łódzkiej, 2022) Hasan, Mir Mohammad Badrul; Huỳnh, Thị Anh Mỹ; Abdkader, Anwar; Cherif, ChokriThermoplastic composites based on hybrid yarn structures consisting of recycled carbon fibre (rCF) and thermoplastic fibres (rCF content approx. 50 weight percentage) achieve high mechanical properties because of a long fiber length, homogeneous mixing and even yarn structure [1]. However, manufacturing of yarns with high rCF content (>90%) required for thermoset composites is still not realizable. Because of the special properties of rCF such as low shear strength, smooth fibre surface and high brittleness, high shortening (≥ 70%) in fibre length of rCF occurs during different processing steps of spinning [2]. The wide distribution of rCF fibre length arising especially during carding of pure rCF is regarded as very critical. In addition to this, lack of crimp in rCF leads to drafting error during drawing and spinning process. As a result, the quality of a yarn with high rCF content is still not acceptable. For this purpose, investigations are carried out in this work to enable gentle processing of rCF to produce slivers consisting solely of rCF. Furthermore, different core sheath yarn structures with rCF content (>90%) have been developed on a DREF-3000 friction spin machine for thermoset composites.