Tape Wound Research Articles

Surface matching design of carbon fiber composite honeycomb

Applying carbon fiber composite honeycomb in curved sandwich shells faces challenges due to the saddle-shaped bending surface in hexagon configurations and potential damage during the shape-forming process. This study analyzes the bending deformation of honeycombs by developing large deformation theoretical model for their bending surfaces. The study introduces two novel honeycomb configurations—Boomerang-shaped with a positive Poisson's ratio and Jellyfish-shaped with a negative Poisson's ratio—achieved through curved-wall design and fabrication using a modified carbon fiber composite tape winding molding process. Experimental tests, including bending deformation and shape-forming tests, measure the three-dimensional bending surfaces and mechanical responses of carbon fiber composite honeycombs. Additionally, a developed finite element model analyzes the damage states of various carbon fiber composite honeycombs during shape-forming processes. The results reveal the bending deformation of carbon fiber composite honeycombs and present damage state cloud maps to facilitate the optimal matching of objective sandwich shells with minimal scathe.

The Effects of Laser-Assisted Winding Process Parameters on the Tensile Properties of Carbon Fiber/Polyphenylene Sulfide Composites.

Currently, there is limited research on the in situ forming process of thermoplastic prepreg tape winding, and the unclear impact of process parameters on mechanical properties during manufacturing is becoming increasingly prominent. The study aimed to investigate the influence of process parameters on the mechanical properties of thermoplastic composite materials (CFRP) using laser-assisted CF/PPS winding forming technology. The melting point and decomposition temperature of CF/PPS materials were determined using DSC and TGA instruments, and based on the operating parameters of the laser-assisted winding equipment, the process parameter range for this fabrication technology was designed. A numerical model for the temperature of laser-heated CF/PPS prepreg was established, and based on the filament winding process setup, the heating temperature and tensile strength were simulated and tested. The effects of process parameters on the heating temperature of the prepreg and the tensile strength of NOL rings were then analyzed. The non-dominated sorting genetic algorithm (NSGA-II) was employed to globally optimize the process parameters, aiming to maximize winding rate and tensile strength. The results indicated that core mold temperature, winding rate, laser power, and their interactions significantly affected mechanical properties. The optimal settings were 90 °C, 418.6 mm/s, and 525 W, achieving a maximum tensile strength of 2571.51 MPa. This study provides valuable insights into enhancing the forming efficiency of CF/PPS-reinforced high-performance engineering thermoplastic composites.

Three-Dimensional Numerical Field Analysis in Transformers to Identify Losses in Tape Wound Cores.

To find the total core losses in 1-phase medium-frequency transformers, a 3D numerical field analysis was carried out. The proposed numerical modeling was based on the extended iterative homogenization method (IHM) developed by the authors. The achieved calculation results were validated by the corresponding values obtained experimentally, and a reasonably close agreement was obtained.

Influence of HTS tape arrangement on the transverse compression performance of copper former CORC cables

CORC cables are subject to large transverse compression electromagnetic forces in fusion projects. Unfortunately, the electromagnetic force exceeding its critical transverse compression load will cause an irreversible decrease in its critical current. Therefore, it is particularly important to enhance the critical transverse compression load to ensure that the critical current does not decrease during operation. The winding method of high temperature superconducting (HTS) tape on the central former is variable. So the experimental study on how to increase the critical transverse compression load of CORC cable by changing the winding method of HTS tape is carried out in this paper. Firstly, the influence law of parameters of the number of HTS tapes per layer and the number of HTS tape layers on their transverse compression performance are analysed independently. The results indicate that increasing the number of HTS tapes per layer and the number of HTS tape layers can both improve the transverse compression performance of CORC cables. Whereas, in the case of a cable with a certain critical current demand (the same total number of HTS tapes), increasing the number of HTS tape layers necessarily reduces the number of HTS tapes per layer. Therefore, in order to compare the degree of influence of the above two parameters, we conducted transverse compression experiments on multiple groups of CORC cables with different winding methods (more layers with few tapes per layer or few layers with more tapes per layer) under the same critical current demand. The results show that under the same critical current demand, choosing the winding method that reduces the number of HTS tape layers and increases the number HTS tapes per layer can effectively improve the transverse compression performance of CORC cables. A 3D multilayer CORC cable transverse compression finite element model is also established to explain the inherent reasons for the differences in transverse compression performance of CORC cables under different HTS tape winding methods.

Modeling and Programming of a Spiral Winding Cycle Using a Robotic Arm

This article is devoted to solving the problem of manufacturing products from carbon fiber composite materials, which are obtained as a result of layer-by-layer laying of carbon fiber with impregnation of their binder components. This paper presents a description of the process of spiral winding of products on a cylindrical mandrel and the mathematical model, which takes into account the coefficient of friction and the necessary reverse zones in which the tape will not slip. The model is implemented as a Python program and is capable of simulating and visualizing the step-by-step winding of a carbon tape on a cylindrical surface. It is possible to optimize the friction coefficient to ensure the tightest winding of subsequent passes. The program takes into account reverse zones, which are calculated taking into account the friction coefficient of the cylindrical mandrel. Based on the simulated winding process, a control program for the robotic arm is generated. The performance of the proposed model and its implementation was tested on a test bench with a robot.

A rapid heat treatment for nanocrystallization of amorphous Fe75.1Cu1Nb1.5Si15.5B6.9 and Fe83Cu1Nb4B12 tape wound cores

A rapid annealing technique for soft magnetic Fe75.1Cu1Nb1.5Si15.5B6.9 and Fe83Cu1Nb4B12 tape wound cores is presented. Its effectiveness for creating a fine-grained nanocrystalline structure is demonstrated by measurements of the magnetic hysteresis loops as well as by structural investigations done by X-ray diffraction. The results show that the technique reduces the average crystallite sizes from about 27 nm to 17 nm for Fe75.1Cu1Nb1.5Si15.5B6.9, and from about 52 nm to 15 nm for Fe83Cu1Nb4B12. The coercivity after the rapid annealing is about three times lower for the Fe75.1Cu1Nb1.5Si15.5B6.9 alloy and up to one order of magnitude lower for the Fe83Cu1Nb4B12 alloy compared to the coercivity after the standardized long-time heat treatment. The improved heat treatment is outstanding in the way that it produces better soft magnetic properties in high-performance alloy cores within much shorter time than the standard core heat treatments.

Stiffness and loss characteristics of superconducting magnetic bearings using layered HTS tapes and a permanent magnet

This paper discusses some mechanical results from experiments on Superconducting Magnetic Bearings (SMBs) consisting of HTS tapes wound in a ring and a permanent magnet as could be applied to larger rotating machines and ultra-low temperature submerged motors. The wound-ring superconductors are made of 12 mm-width HTS tapes. The authors estimated the spring constant, k, after measuring the thrust force, as 3.85 × 103 N/m, for three-layered wound HTS tapes, and 2.44 × 103 N/m, for the single-wound HTS tape, respectively. The rotating losses for speeds of 500–4500 rpm in the constructed SMB system were also estimated and they were less than 10 W in the constructed measurement system.

Measurement and analysis of winding stresses in dry-wound pancake coils considering nonlinear compressive behaviors

Considering coil stress management, conductor thermal stability, and susceptibility to delamination, the dry-winding approach has been gradually applied and tested in high-temperature-superconducting coils wound with REBa2Cu3O (REBCO) coated conductors (CCs). In dry-wound coils, the winding tension can be a useful tool for managing the mechanical stresses and maintaining the structural stability. It is also related to the contact resistivity characteristics of no-insulation and metal-as-insulation coils. In this paper, we present a study on the winding stresses in dry-wound pancake coils considering nonlinear compressive behaviors in the radial direction. Coils wound with stainless-steel (SS) tapes and REBCO CCs were prepared, respectively, with various sizes (90–140 turns) and winding tensions (26–61 MPa). The radial pressure was obtained by applying the pressure measurement films, which cover a pressure range up to 50 MPa. A relatively moderate radial pressure buildup was observed in coils wound with SS tapes, indicating that the effective radial modulus of the coil as an entity is considerably lower compared to the tensile modulus in the azimuthal direction. This is consistent with the nonlinear stress–strain relationship of stacked thin sheets under transverse compression, which can be further explained by the contact behaviors between two rough surfaces. The average radial pressure in CC coils shared similar characteristics as that in SS coils, whereas the radial stress along the conductor edges were significantly higher compared to the middle. Cross-sectional microscopy of the CCs suggests that this can be primarily attributed to the thickness variations across the conductor width. These results suggest that the microscopic rough-surface contact and thickness variation of the wound tape play a critical role in the coil stiffness as well as the winding stress distributions.

Development of Composite Ablative Liners for Solid Rocket Motor Flex Nozzles

Solid Rocket Motor generates high thrust by accelerating high pressure gases to supersonic velocities in convergent divergent nozzle, thus converting pressure energy to kinetic energy of propulsion. As exhaust gas from chamber is of high temperature, the structural steel members of nozzle should be protected from hot gases by highly erosion resistant thermal liners. For this purpose, ablative composite liners made up of Phenolic resin matrix based combined with reinforcement material like carbon fabric is extensively used [1]. Divergent being largest component and contributes more to nozzle weight, the thickness of liner should be as least as possible at the same time; it should be more erosion resistant. The erosion resistant due to hot gases can be increased by fabricating the liner in such a way that the flame only touches the edge of the composite ply of liner and liner has more density. This can be achieved by tape winding of composite prepreg tapes at Zero degrees on tapered metal mandrel using tape winding machine followed by Autoclave curing [2]. This paper gives the details of prepreg, Tape winding, Autoclave Curing and NDT of ablative liner.

Practical Forecasting of AC Losses in Multi-Layer 2G-HTS Cold Dielectric Conductors

With the recent progresses on the designing and manufacturing of lightweight superconducting cables with high engineering current density, the need for a reliable, fast, and accurate computational model forecasting the alternating current (AC) losses of cold-dielectric conductors is pivotal for power grid investors and operators. However, validating such models is not an easy task. This is due to the low availability of experimental data for large scale power cables, and likewise, because of the large computational burden which underlies the total number of second generational high temperature superconducting (2G-HTS) tapes in the modelling of realistic power cables. Thus, aiming to overcome these challenges, we present a detailed two-dimensional H-model capable to reproduce the experimentally measured AC-losses of multi-layer power cables made of tens of 2G-HTS tapes. Two cable designs with very high critical currents ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{1.7}~kA$</tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{3.2}~kA$</tex-math></inline-formula> ) have been considered. These are composed of five and six concentric layers wound over a cylindrical former consisting of 50 and 67 2G-HTS tapes, respectively. In both situations a remarkable resemblance between the simulations and experiments has been found, offering a unique view of the local electrodynamics of the wound tapes where the mechanisms of shielding, magnetization, and transport currents coexist within the hysteretic process.

Surface Defect Detection for Automated Tape Laying and Winding Based on Improved YOLOv5.

To address the issues of low detection accuracy, slow detection speed, high missed detection rate, and high false detection rate in the detection of surface defects on pre-impregnated composite materials during the automated tape laying and winding process, an improved YOLOv5 (You Only Look Once version 5) algorithm model was proposed to achieve the high-precision, real-time detection of surface defects. By leveraging this improvement, the necessity for frequent manual interventions, inspection interventions, and subsequent rework during the automated lay-up process of composite materials can be significantly reduced. Firstly, to improve the detection accuracy, an attention mechanism called "CA (coordinate attention)" was introduced to enhance the feature extraction ability, and a Separate CA structure was used to improve the detection speed. Secondly, we used an improved loss function "SIoU (SCYLLA-Intersection over Union) loss" to replace the original "CIoU (Complete-Intersection over Union) loss", which introduced an angle loss as a penalty term to consider the directional factor and improve the stability of the target box regression. Finally, Soft-SIoU-NMS was used to replace the original NMS (non-maximum suppression) of YOLOv5 to improve the detection of overlapping defects. The results showed that the improved model had a good detection performance for surface defects on pre-impregnated composite materials during the automated tape laying and winding process. The FPS (frames per second) increased from 66.7 to 72.1, and the mAP (mean average precision) of the test set increased from 92.6% to 97.2%. These improvements ensured that the detection accuracy, as measured by the mAP, surpassed 95%, while maintaining a detection speed of over 70 FPS, thereby meeting the requirements for real-time online detection.

Theoptical‐thermalmodeling of carbon black filled glass fiber reinforced poly‐ether‐ether‐ketone in laser assisted tape winding

AbstractTo facilitate the application of carbon black filled glass fiber reinforced poly‐ether‐ether‐ketone (CB‐GF/PEEK) prepreg in laser assisted tape winding (LATW), a finite element method is used to analyze the optical‐thermal characteristics of the following three prepregs with distinct laser absorption properties: (i) 0.5%CB (incomplete absorption), (ii) 2.74%CB (complete, single‐layer absorption), (iii) 4%CB (complete, near‐surface absorption). Thus, the energy distribution, temperature distribution and thermal accumulation are revealed, and the heating strategy is customized according to the laser absorption characteristics of each prerpeg. Then the feasibility of CB filled GF/PEEK prepreg in LATW is verified by manufacturing and testing NOL rings. Finally, the nip‐point irradiation scheme is optimized. The simulation results reveal a significant difference between the optical‐thermal characteristics of the 0.5%CB and those of the other two prerpegs. Benefited from the energy leakage, the 0.5%CB facilitated twice melting by thermal accumulation, along with a higher nip‐point temperature. Meanwhile, the mechanical performance tests of the NOL rings indicate a similar tensile strength of ~1300 MPa for the 0.5%CB and 4%CB, while the interlaminar strength of the 0.5%CB is slightly higher than that of the 4%CB. The latter result may be due to the higher nip‐point temperature of the 0.5%CB, which promotes resin diffusion and enhances the bonding strength. Finally, an optimized heating strategy with short laser length, vertical irradiation of the nip‐point is proposed, and is shown to reduce the ineffective thermal accumulation and ensured the suitability of Tape and Laminate temperature.

Development of a Tape Winding Mechanism for HTS Power Cables

Manufacturing of HTS power cables requires winding the HTS tapes helically around a former. These HTS tapes are costly, and delicate and require sophisticated winding machinery which is expensive. In this paper, an in-house economic mechanism for converting a conventional lathe machine to a Tape Winding Mechanism (TWM) is discussed in detail. In addition to the developed prototype, the technical issues and challenges encountered during the development of TWM are listed. The developed TWM was instrumental in successfully winding 10 HTS tapes simultaneously around a tin-coated braided copper former of 19 mm diameter with a pitch length of 210 mm for a continuous length of 5 m HTS cable. The recommendation of modifying any existing cable winding machine to TWM is also discussed.

Carbon Fiber Prepreg Composites Failure Mechanism Based on Electrical Resistance Method during Hight-Strain Rate Loading.

In this study, a unidirectional and plain weave carbon fiber/epoxy prepreg was used as the raw material, and the prepreg tape winding process was used to prepare carbon fiber/epoxy prepreg composites with 65% and 75% carbon fiber volume content, respectively. Based on traditional damage experiments and mechanical measurements, electrical measurements are introduced to study the damage to carbon fiber prepreg composites. The damage behavior of the carbon fiber prepreg composite under a high-speed impact load was monitored using the resistance method. By arranging electrodes on the sample and tracking the change in resistance during the entire process of high-speed impact of the material, the relationship between the damage and the change in resistance parameters of the carbon fiber prepreg composite winding products under high-speed impact was determined. The stress-strain curve and the final failure mode of the sample and the microstructure mechanics of carbon fiber prepreg winding products under different strain rates were analyzed. These results indicate that, as the change in resistance over time was almost stable from 0 to 200 μs. From 200 to 250 μs, the resistance decreases sharply; from 250 to 400 μs, the resistance approximates a plateau. From 400 to 500 μs, the resistance value increases again; at this time, the resistance value decreases to 3.2% of the initial resistance value.

Thermoplastic composite connecting rods

Engineering carbon fiber thermoplastics have been used in the development and optimization of composite connecting rod(s) with design requirement of bearing 14,000 N and 1 mm maximum deflection. The studies featured engineering thermoplastics- 30 wt percent carbon fiber poly ether ether ketone (C-PEEK) long fiber thermoplastics (LFT) injection over molded in conjunction with 70 wt percent carbon/polyphenylene sulfide (C-PPS) and carbon/poly ether imide (C-PEI) tapes. Over molding of thermoplastic tapes has been investigated in terms of number of tape winding around the small and big end, and different winding patterns within the connecting rod geometry. The design was progressively optimized for the geometry of the connecting rod, i.e., increasing the wall thickness of the small end and width of the center section. The effect of over molded metal bushing with C/PEEK LFT at the bearing surfaces was also investigated. The material and geometry optimization successfully met 14,000 N while several design iterations were necessary to meet the 1 mm deflection limit constraint. Finite element analysis (FEA) was adopted to optimize the increase of the width of the center section width and wall thickness of the small end. The optimized composite connecting rod was estimated to be 78% lighter than the steel incumbent.

Electro-Thermal Behavior of Layer-Wound BSCCO Coils With and Without Insulation

In this work, the electro-thermal behavior of two layer-wound High Temperature Superconducting (HTS) coils, realized with and without electrical insulation, is compared. Both coils are wound from the same BSCCO tape, and have a very similar geometry, with the same number of turns and layers. A heat input is applied to both coils, by tuning the current supplied to resistive heaters realized through stainless steel tapes wound on the mandrel at the inner surface of both coils. The heaters are in contact with one full inner turn of the winding. The coils are cooled in a liquid nitrogen bath, and the heaters are supplied with a constant current. Then, the windings are charged until the tape critical current is exceeded, and the tests are repeated for different heat loads. The signals acquired through voltage taps, suitably soldered at the same locations in both windings, are compared at the same testing conditions. Finally, the electrical characteristic of the different layers of the coils is related to the temperature of the heater and of the various turns of the coil by means of a 1-D thermal model.

Fabrication and Test of HTS Magnet for Induction Heating Device in Aluminum Extrusion Processing

This paper reported the fabrication and the test results of the high temperature superconducting (HTS) magnet developed for the aluminum billet heater for aluminum extrusion processing. In this magnet, the HTS coils were combined with iron cores, because the required magnetic field in the working region was about 1T. Two HTS coils wound directly on the convex shape iron cores were fabricated. The HTS coils were made by the no-insulation winding of REBCO tape with the YOROI-coil technique. Each of them was separately installed in an individual cryostat. Two HTS coils with iron cores were disposed oppositely to each other and were magnetically connected by a C-shape yoke placed in room temperature. The HTS coil was cooled down to about 15 K by the GM cryocooler in the initial cooling. The magnetic field of 1.06 T at the center of the heating region was stably generated with the rated current of 200 A. It was also demonstrated that the HTS magnet could be charged up to 300 A without quench. According to the observation of the electromagnetic force direction from the outside of the cryostat, it was confirmed the validity of the force balance design of the magnet.

Determination of No-Insulation HTS Coil Parameters

A procedure for measuring the parameters of superconducting coils with non-insulated tape windings is described. The results of measurements of inductance, radial resistance, static current-voltage, and magnetic characteristics of two superconducting coils, one of which has a soldered connection, are presented.

Comparative study on HTS magnet coil design approach for 1.0 T @ 65 K with 10 ppm field homogeneity at 80 mm DSV

A comparative study is carried out between two distinct coil design approaches (Multi-coil and Compensated solenoid) for the development of 1.0 T REBCO main magnet coil suitable for Extremity Magnetic Resonance Imaging (E-MRI). The design includes a operating temperature of 65 K, for the enhancement of Ic with field anisotropy of REBCO tape. Each magnet design consists of HTS tape wound in the form of double pancake coils, having the inner winding diameter as 200 mm, whereas both outer diameter and magnet length are restricted to less than 400 mm. The two coils configurations are compared by keeping the bore inner diameter, outer diameter, length and fixed HTS tape length constant. Thereafter the parameters such as peak flux density, maximum radial field, stray field distribution, coil stress and field homogeneity for 80 mm diameter of spherical volume (DSV) are analyzed. Multi-coil design gives a better field homogeneity (315 ppm) as compared to Compensated solenoid.

Enhanced critical axial tensile strain limit of CORC® wires: FEM and analytical modeling

Conductor on Round Core (CORC®) cables and wires are composed of spiraled high-temperature superconducting (HTS) rare-earth barium copper oxide (REBCO) tapes, wound in multiple layers, and can carry very high currents in background magnetic fields of more than 20 T. They combine isotropic flexibility and high resilience to electromagnetic and thermal loads. The brittle nature of HTS tapes limits the maximum allowable axial tensile strain in superconducting cables. An intrinsic tensile strain above about 0.45% will introduce cracks in the REBCO layer of straight HTS tapes resulting in irreversible damage. The helical fashion at which the REBCO tapes are wound around the central core allows tapes to experience only a fraction of the total axial tensile strain applied to the CORC® wire. As a result, the critical strain limit of CORC® wires can be increased by a factor of more than 10 that of REBCO tapes. Finite element (FE) and analytical models are developed to predict the performance of CORC® wires under axial tensile strain. A parametric analysis is carried out by varying the winding angle, the Poisson’s ratio of the CORC® wire core, the core diameter, and the tape width. The results show that a small variation in winding angle can have a significant impact on the cable’s axial tensile strain tolerance. While the radial contraction of the helically wound tapes in a CORC® wire under axial tensile strain depends on its winding angle, it is mostly driven by the Poisson’s ratio of the central core, affecting the tape strain state and thus its performance. Contact pressure from multiple layers within the CORC® wire also affects the CORC® wire performance. The FE model can be used to optimize the cable design for specific application conditions, resulting in an irreversible strain limit of CORC® cables and wires as high as 7%.