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Carbon fiber reinforced plastics (CFRPs) are widely used in the aerospace, automotive, and construction industries. CFRP prepregs (intermediate products) are generally used in CFRP production, with a large number of prepreg cut‐offs being discarded during cutting processes. There is strong demand for a method for recycling carbon fiber prepreg cut‐offs. This paper proposes a method for recycling such material, which is characterized by low cost and high added value, in order to foster the development of a recycling‐oriented society. We prepare carbon tapes (CTs) by cutting discarded cut‐offs according to their size so as to maximize fiber length. Using a simple water CT dispersion method, we fabricate uniform CT sheets and mold a recycled CT‐reinforced composite (R‐CT‐RC). Sample prototyping and mechanical characteristic testing indicate that this R‐CT‐RC is characterized by low recycling cost and desirable mechanical properties. Recycled CT‐reinforced composite with thermoplastic (R‐CT‐RC/TP), which is prepared by adding thermoplastic resin between CTs, can be re‐molded and therefore readily re‐recycled. [ABSTRACT FROM AUTHOR]

Carbon fiber is an ideal candidate for preparing electrode of structural supercapacitors, while its low specific surface area is a vital factor which restricts energy storage performance. In this study, MnOOH nanowires (MnOOH‐NWs) are in‐situ deposited onto the woven carbon fiber fabric (WCF) surface through an effective one‐step hydrothermal treatment to prepare MnOOH‐NWs modified WCF (MnOOH‐NWs@WCF) structural supercapacitor with appreciable electrochemical performance. The areal capacitance of MnOOH‐NWs@WCF structural supercapacitor reaches 77.1 mF/cm2, which is two orders of magnitude higher than that made from neat WCF electrode. The increase in areal capacitance is primarily due to the presence of conductive networks and abundant ion storage sites constructed by the MnOOH‐NWs. Meanwhile, flexural strength and modulus of the MnOOH‐NWs@WCF structural supercapacitor are 30.3 MPa and 1.8 GPa, respectively. Interestingly, the resultant structural supercapacitor also enables electromagnetic interference (EMI) shielding based on the conductive networks constructed by the WCF and MnOOH‐NWs, and the maximum EMI‐shielding effectiveness (EMI‐SE) is 59.1 dB. Consequently, a highly integrated multi‐functional structural supercapacitor is developed, which cannot only be applied as energy storage module and load bearing component but can also be adopted to protect electronic devices from the electromagnetic pollution. [ABSTRACT FROM AUTHOR]

Delamination in carbon fiber reinforced polymer (CFRP) composite structures plays a significant role in reducing the stiffness and strength of the structure, thus downgrading the integrity and reliability of the system. Aiming at the problem that traditional linear Lamb wave technology is not sensitive to the layered defects of composite materials and the existing nonlinear Lamb wave method is difficult to locate and detect damage, this paper proposes an ultrasonic tomography method based on Lamb waves to detect and reconstruct the delamination defects in CFRP plate. The dynamic finite element analysis method is used to simulate the propagation process of A0 mode Lamb waves in the 14-layer cross-layer CFRP defect plate. Sixty-four sensors perform fan-beam scanning on the composite plate in an equal-angle arrangement to obtain time-of-flight data corresponding to the sensing path. The layered defects of the composite material are imaged and evaluated by the filtered back-projection method. The experimental results show that this method can obtain high-quality reconstructed images of layered defects. [ABSTRACT FROM AUTHOR]

In order to meet the hydrogen storage requirements of fuel cell vehicles, and improve the storage density of hydrogen, a cryo-compressed hydrogen storage method was proposed. The performance of cryo-compressed hydrogen storage vessel was analyzed in this paper. Based on the classical laminate theory and heat transfer solution, the stress and displacement of carbon fiber were precisely calculated to guarantee the cryo-compressed vessel severing in the cryogenic condition. Subsequently, the Tsai-Wu failure criterion was used to judge the failure of carbon fiber reinforced plastics layers. The stacking sequence, winding angle, comparison of the vessel's performance at room temperature and low temperature were conducted. The numerical results showed that the properties of storage vessel decreased at cryogenic condition, and the thickness of carbon fiber at cryogenic temperature at least increased by 47.06% than that at the room temperature. Mainly influence of low temperature on the cryo-compressed vessel were concentrated on the hoop stress of helical winding and the axial stress of hoop winding. For the vessel design, it is achievable to increase these two parts by using higher strength resin materials. • A method to design CcH 2 storage vessel was developed for vehicle applications. • Distributions of stress, strain and deformation of CcH 2 vessel were calculated. • Normal compressed vessel failed under cryogenic situation unless thickening. • Influence of low temperature can also be reduced by higher strength resin materials. [ABSTRACT FROM AUTHOR]

The mode-I and mode-II interlaminar fracture properties of high modulus pitch-based carbon fiber reinforced polymers (CFRPs) (fiber: K13C; resin: EX-1515 cyanate ester) modified with 20–30 nm β-SiC nanoparticles or multiwalled-carbon nanotubes (MWCNTs) were investigated. Different volume fractions of both the β-SiC nanoparticles (1, 2, 5, and 10 vol%) and MWCNTs (1, 3, 5, and 7 vol%) were tested. The values of the mode-I and mode-II interlaminar fracture toughness of the CFRPs containing the lowest volume fractions of these nanostructures were larger compared with the unfilled composite but decreased with increasing the volume fraction of the inclusions. No differences in mechanical properties were observed among the different nanostructure types. [ABSTRACT FROM AUTHOR]

The influence of technologies of preliminary treatment of carbon fibers by various electromagnetic methods, namely, cold plasma and ultraviolet radiation, on their mechanical characteristics is considered. The purpose of this treatment is to increase the adhesive strength of a metal coating with a fiber to produce carbon fiber plastics with a high interlayer shear strength. The use of plasma treatment is experimentally found to be most effective. The interlayer shear strengths are presented for the manufacture of carbon fiber plastics from carbon fabrics and tapes after their preliminary treatment and the subsequent deposition of a copper coating onto their surface. [ABSTRACT FROM AUTHOR]

A new strategy of recycling and reusing abandoned carbon fiber reinforced plastics (CFRP) is proposed: CFRPs are first fully carbonized to CF reinforced carbon (C/C) preforms, and then are manufactured into high value-added C/C composites. The results showed that the carbon residue rate of epoxy-resin (EP) matrix was fully recovered as the decomposition route of EP matrix was changed by charring agent. The recycled CF (rCF) was not markedly oxidized or thermally damaged, and possessed comparable properties with those of the virgin CF (vCF) after pyrolysis. The pyrolytic char had no obvious negative effect on the densification efficiency of the rCF reinforced carbon (rCF/C) composites. Both of the rCF/C and vCF reinforced carbon (vCF/C) composite bodies were quite dense, and exhibited almost no difference in their microstructures. The rCF/C and vCF/C composites therefore had quite close interface bonding strength (12.6 MPa and 13.0 MPa, respectively), and bending strength (106.4 MPa and 111.5 MPa, respectively). Furthermore, the rCF/C composites possessed comparable ablative rate with that of the vCF/C composites. The rCF/C composites derived from abandoned CF/EP composites present a great potential to be used as substitutes for vCF/C composites owing to their indistinguishable properties. [ABSTRACT FROM AUTHOR]

• Glass and carbon fiber reinforced plastic waste masses within the European Union. • Material specific weight functions in dependence on rotor blade length. • Realistic projection of masses by normally distributed lifetimes of rotor baldes. • Simulation study to account for uncertainties within the estimation. The European Union is aiming at a circular economy and increased resource efficiency, which requires a waste management at the end-of-life of products. This is especially challenging for new and innovative products for which no recycling infrastructure exists so far. Wind power plants are such a product, for which large amounts of waste are expected within the next years as more and more plants reach their end-of-life. Especially the end-of-life rotor blades of wind power plants pose challenges with regard to waste management, since treatment options for the installed glass and carbon fiber reinforced plastics are still in a development stage. Moreover, material specific characteristics and technical aspects require separate treatment of these materials. To plan efficient treatment infrastructure, detailed knowledge on future waste streams is required. Against this background, this paper aims at estimating the mass of glass and carbon fiber reinforced plastic waste from rotor blades. To do so, we derive material specific weight functions and material specific shares to calculate the amount of installed glass and carbon fiber reinforced plastics in rotor blades. We apply normally distributed life times to project the calculated installed masses into the future and account for uncertainties within a simulation study. The estimation model is applied to a dataset of wind power plants within the European Union. Based on the considered dataset, we estimate that 570 [Mt] of fiber reinforced plastic waste will occur between 2020 and 2030 in the European Union of which 18 [Mt] are carbon fiber reinforced plastic waste. [ABSTRACT FROM AUTHOR]

The formulation for time- and temperature-dependent statistical static and fatigue strengths for carbon fiber reinforced plastics laminates is newly proposed based on the physically serious role of resin viscoelasticity as the matrix of carbon fiber reinforced plastics. In this study, this formulation is applied to the tensile strength along the longitudinal direction of unidirectional carbon fiber reinforced plastics constituting the most important data for the reliable design of carbon fiber reinforced plastics structures which are exposed to elevated temperatures for a significant period of their operative life. The statistical distribution of the static and fatigue strengths under tension loading along the longitudinal direction of unidirectional carbon fiber reinforced plastics were measured at various temperatures by using resin-impregnated carbon fiber reinforced plastics strands as specimens. The master curves for the fatigue strength as well as the static strength of carbon fiber reinforced plastics strand were constructed based on the time–temperature superposition principle for the matrix resin viscoelasticity. The long-term fatigue strength of carbon fiber reinforced plastics strand can be predicted by using the master curve of fatigue strength. [ABSTRACT FROM AUTHOR]

The results of studies on the recovery of carbon fibers by the method of low-temperature solvolysis from prepreg and reinforced plastics based on it are reported. The surface of carbon fibers extracted from prepreg and carbon fiber reinforced plastics (CFRPs) was characterized using scanning electron microscopy, thermal analysis, Fourier transform infrared spectroscopy, and Raman spectroscopy to understand their thermal stability characteristics, possible surface chemical composition, and the presence of functional groups. It was shown that in the case of solvolysis of a single-layer carbon fiber, the recoverable carbon fibers contain a smaller amount of undecomposed polymer matrix than in the case of prepreg solvolysis. [ABSTRACT FROM AUTHOR]

The comminution of carbon fiber reinforced plastics (CFRP) is a central process step for almost all recycling processes. Size reduction creates a specific surface that serves as a measure in particular of the size reduction success of fines. The article shows the comminution from 1 m edge length in the feed material down to a target product size of less than 100 µm by means of three‐stage comminution. The challenges of granulometric characterization of the comminution products and the associated evaluation of the comminution success are specifically addressed. [ABSTRACT FROM AUTHOR]

Due to the continuing trend towards lightweight construction, more and more carbon fiber reinforced plastics (CFRP)‐containing waste is generated, particularly in the areas of transportation, energy technology as well as in the mechanical engineering or leisure sector. For CFRP‐containing waste with thermoplastic matrix, a closed‐loop recycling by regranulation could be demonstrated. Under multi‐stage mechanical stress, the CFRP material was comminuted to a defined granule size. This granulate from secondary material was converted by means of a special process in an injection molding complex into new components. [ABSTRACT FROM AUTHOR]

As a kind of typical structure, the hat-shaped structure (HSS) is widely used in carbon fiber reinforced plastics (CFRP) aircraft parts. In this work, a scheme of filling fillers and adding reinforcing plies in R-regions was proposed to strengthen the R-regions of HSS. Moreover, the force analysis of R-region with or without strengthening in R-region under pull-off load was presented. A finite element model was developed to study the failure behavior of R-regions. A series of HSS samples were fabricated by co-curing process. The pull-off tests of HSS were conducted to validate the model, and the failure mechanism of R-regions was further studied by characterizing the macro-micro structure of R-regions in HSS under pull-off load. Results showed that the structural bearing capacity of HSS can be improved by strengthening in R-regions. After strengthening in R-regions, the pull-off load was borne by multiple interfaces, and the interlaminar interface pull-off strength can increase by 38.8 %. [ABSTRACT FROM AUTHOR]

In this study, X-ray computed tomography (X-ray CT) was used to investigate internal defects generated on machine milled carbon fiber reinforced plastics (CFRP). Internal defects such as cracks, fractures, and deformation of the carbon fibers, which are invisible from the surface, were observed using the X-ray CT method. Defects were generated based on the machining method and direction of the fibers. A large number of defects were generated when using the conventional cut method along 45°, 90°, and the climb cut method along 90°. Few internal defects were observed when using the climb cut method along 45°; however, the machined surface was very rough. The mechanism for these phenomena was investigated by studying surface observations and cutting force, in addition to X-ray CT imaging. These results indicate that X-ray CT is a powerful tool for visualizing internal defects in CFRP, which differ significantly based on the direction of the fiber and machining method used. • Internal defects generated on machined CFRP was observed by X-ray CT method. • The species of internal defect differed by the fiber direction and machining method. • The mechanism for defect generation was studied by surface shape and cutting force. [ABSTRACT FROM AUTHOR]

Composite lightweight components of carbon fiber reinforced plastics (CFRP) provide great potential for the automotive industry. Yet, due to their complexity, there is a high amount of quality defects in their production processes. Thus, this article deals with an approach for in-process metrology of CFRP components by means of an eddy-current sensor array. First, the development of the sensor design and its in-process integration is introduced. Second, a method for the quantitative evaluation of the measurement data as well as the measurement uncertainty is elaborated. Finally, a machine learning approach for the classification of crucial defects is shown. [ABSTRACT FROM AUTHOR]

Multifunctional composites combine structural and other physicochemical properties, with major applications in aeronautical, space, telecommunication, automotive, and medical areas. This research evaluates electromagnetic properties of multifunctional composites based on glass fiber woven fabric pre-impregnated with epoxy resin laminated together carbon fiber non-woven veil metalized with Ni. In this way, searching for possible application as radar absorbing structures or electromagnetic interference shielding structures. The scattering parameters, in the frequency range of 8.2 to 12.4 GHz, show that the epoxy resin/glass fiber prepreg allows the transmission of the electromagnetic waves through its microstructure, independently of the glass fiber reinforcement orientation (98% transmission, S24 = -0.09 dB). However, the carbon fiber/Ni veil shows highly reflector behavior (91% reflection, S22 = -0.43 dB). Energy dispersive spectroscopy of the veil, before and after nitric acid attacks, confirmed the Ni coating removal from the carbon fiber surface. Still, the scattering parameters show reflector behavior (77% reflection, S22 = -1.13 dB), attributed to the electrical conductivity of carbon fibers. Multifunctional composites based on glass fiber/epoxy/carbon fiber/Ni veil laminates were processed by hot compression molding. The scattering parameters show that the laminates do not behave as good radar absorbing structures. Nevertheless, the laminates present promising results for application as light weight and low thickness structural composites with electromagnetic interference shielding effectiveness (91.4% reflection for 0.36 mm thickness and 100% for ~ 1.1 mm) for buildings, aircraft, and space components. [ABSTRACT FROM AUTHOR]

In this study, a new cutting model for the machining of unidirectional CFRP laminates was developed to examine the mechanism for changes in the cutting forces with tool wear. This model is based on Zhang's model and divides the cutting zone into two characteristic deformation regions; chipping and pressing. Furthermore, CFRP milling tests were performed using two kinds of cutting tools: tungsten carbide (WC–Co) and polycrystalline diamond (PCD). Based on the experimental results with the developed cutting model, the net cutting forces to make a cut chip and press CFRP laminates under the flank surface of the tool were quantitatively evaluated. Consequently, it was found that the former does not depend on the progress of the tool wear, but the later increases with tool wear. Additionally, based on the results in this study, a new technique for reducing cutting forces during CFRP machining, which is based on the use of two layer tool that has a wear resistance distribution at around the tool edge was introduced. [ABSTRACT FROM AUTHOR]

During the process of drilling carbon fiber reinforced plastics (CFRP), it tends to effectively reduce or eliminate manufacturing deficiency, such as burr and delamination using electroplated diamond step-core drill whose service life mainly depends on the service life of electroplated diamond abrasive. Therefore, systematic statistical observation was carried Out on the abrasive wear patterns of electroplated diamond. Investigations show that using the electroplated diamond step-core drill, three unique stages of diamond abrasive wear can be observed during the process of drilling T300 CFRP, which involves initial instable wear stage, mixed-wear stage and normal wear stage. The wear patterns of diamond abrasive and drilling thrust force have a significant linear relationship. With the growing of hole numbers, the thrust force gradually increases, but diameter tolerances of the holes are still stabilized in a range of 0. 024 mm after the initial instable wear stage. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced plastics (CFRP) have high strength in comparison with dimensional stability, invariability of material property, high strength and rigidity, corrosion resistance. Therefore, CFRP is widely used in various fields including space and aviation industries, sports and leisure industries, and general structural members and parts. To achieve structural members of CFRP with high strength and rigidity, theoretical approaches are limited to isotropic material, and empirical studies have been conducted. As with other composite materials, CFRP shows different rigidity and strength due to differences in properties in fiber and matrix material. In this study, a CFRP specimen with changing stack orientation angle was manufactured as general structural application, and bending strength and rigidity of the corresponding composite was measured. In addition, square aluminium tube reinforcement is applied to prevent the shortcoming of CFRP. Vacuum compressed CFRP via autoclave with square aluminium tube reinforcement material (Hybrid) was evaluated by changing the orientation angle. [ABSTRACT FROM AUTHOR]

Drilling laminates composites materials are significantly affected by delamination tendency of these materials under action of cutting forces (thrust force and torque). On the other hand, drilling is an operation frequently used in industry due to the need for component assembly in mechanical pieces and structures. So the aim of this paper is the study of the cutting parameters (cutting velocity and feed rate) on power (Pc), specific cutting pressure (Ks), and delamination in carbon fiber reinforced plastics (CFRPs). A plan of experiments, based on the techniques of Taguchi, was established considering drilling with prefixed cutting parameters in an autoclave CFRP composite laminate. The analysis of variance was preformed to investigate the cutting characteristics of CFRPs using cemented carbide (K10) drills with appropriate geometries. The objective was to establish a correlation between cutting velocity and feed rate with the power (Pc) specific cutting pressure (Ks) and delamination factor (Fd) in a CFRP material. Finally, this correlation was obtained by multiple linear regression. [Copyright &y& Elsevier]

In this paper is presented a new comprehensive approach to select cutting parameters for damage-free drilling in carbon fiber reinforced epoxy composite material. The approach is based on a combination of Taguchi’s techniques and on the analysis of variance (ANOVA). A plan of experiments, based on the techniques of Taguchi, was performed drilling with cutting parameters prefixed in an autoclave carbon fiber reinforced plastic (CFRP) laminate. The ANOVA is employed to investigate the cutting characteristics of CFRP’s using high speed steel (HSS) and Cemented Carbide (K10) drills. The objective was to establish a correlation between cutting velocity and feed rate with the delamination in a CFRP laminate. The correlation was obtained by multiple linear regression. Finally, confirmation tests were performed to make a comparison between the results foreseen from the mentioned correlation. [Copyright &y& Elsevier]

Eddy-current testing (ECT) is relatively mature and has gradually become one of the main non-destructive testing technologies of carbon fiber reinforced plastics (CFRP). From the perspective of low conductivity of CFRP, high-frequency ECT technology is considered to be more suitable for such materials with less conductivity. However, high-frequency ECT method is more susceptible to various interference factors and has higher background noise, which will cause great inconvenience to practical applications. Concerning this issue, a self-resonance ECT method in noncontact detection of CFRP was proposed in this paper, and the corresponding ECT system that can detect the defects of CFRP at a low-frequency and keep a relatively high signal-to-noise ratio was developed. The system is mainly composed of a resonant eddy-current probe, a special excitation circuit, and an ECT signal pickup module. Three CFRP samples (orthogonal woven laminate, cross-ply laminate, four-directional angle-ply laminate) were scanned by using the self-resonance ETC system developed in this paper. The scanning results show that the detection effect of the self-resonant ECT system at 500 kHz is similar to that of the traditional ECT system at 10 MHz, and 500KHz is enough to provide good detection results for the above CFRP samples. Therefore, the proposed research is a valuable ECT technology, which has played a guiding role in the application of low-frequency ECT method in CFRP. [ABSTRACT FROM AUTHOR]

Fiber reinforced plastics can absorb energy, in the unlikely event of a crash, on the other hand, foam improves the structural integrity of the device being filled with. Therefore, foam-filled carbon fiber reinforced plastic (CFRP) composites are extensively used as an energy absorber for safety enhancement. Current study aims to characterize the impact response of CFRP composite tubes filled with polyurethane foam with five different combinations. The CFRP tubes were internally stiffened with sheets, tubes and hats made of CFRP composite. In addition, the internally stiffened tubes were filled with polyurethane (PU) foam for structural integrity. Specimens were then tested under dynamic crushing using a drop weight impactor with an impact energy of 75 J. During the tests, the behaviors of specimens were recorded by high speed camera. Visual inspections and micrographs of the specimens were also investigated. The results revealed that the peak force, threshold force, and energy absorbed were increased by using the PU foam inside the CFRP composite tubes. The energy absorption did not show significant improvement by adding the internal CFRP reinforcements, whereas, the peak load improvement was considerable. The specimen filled with only PU foam yielded the best specific energy absorption among all the specimens. [ABSTRACT FROM AUTHOR]

A comparative life cycle assessment analysis among pressure bag molding and bag molding with autoclave for the manufacturing of car components in carbon fiber reinforced plastic (CFRP) was carried out. Four scenarios were analyzed: i) autoclave bag molding with aluminum mold, ii) autoclave bag molding with CFRP mold and plastic master, iii) autoclave bag molding with CFRP mold and medium density fiberboard master, and iv) pressure bag molding with aluminum mold. The collected data for life cycle inventory derives from an Italian manufacturer of CFRP car components, scientific references and Ecoinvent database. Cumulative energy demand, global warming potential, ReCiPe midpoint and endpoint methods were used as impact and damage categories for quantifying the environmental impacts of the different manufacturing processes investigated. The results showed that the pre-impregnated composite fibers with thermoset polymer matrix, used as input material for the four investigated scenarios, represents the main source of total environmental impact, due to the use of polyacrylonitrile as a precursor for carbon fibers. The comparison among the environmental assessments of the different scenarios demonstrated that the most impacting process is the autoclave bag molding with composite mold and polyurethane master, whilst the most sustainable process is the autoclave bag molding with aluminum mold. • Comparative LCA between two different manufacturing methods for CFRP components. • Autoclave curing with aluminum mold is the less impacting process. • Autoclave curing with polyurethane master is the most impacting process. • Higher impacts of PBM are related to the high mass of the aluminum mold. • Main differences among scenarios is material and manufacturing of molds and masters. [ABSTRACT FROM AUTHOR]

The tensile deformation process of carbon fiber reinforced plastics (CFRPs) was in situ observed by high-resolution transmission electron microscopy (TEM). CFRPs were prepared with sizing and unsizing treatment on the fiber surfaces. The microstructural evolution of crack propagation along fiber/resin interfaces and inside resin matrices was examined. Fine resin fragments remained on the fiber surfaces after fracture. From the differences in the shape of the residual resin fragments between the two types of CFRPs, the influence of the sizing treatment on fracture was quantitatively evaluated. We demonstrated a new method on the basis of in situ TEM to evaluate the microstructural fracture dynamics and the influence of the sizing treatment on fracture. Image 1 [ABSTRACT FROM AUTHOR]

A liquid nitrogen cooling system was developed to ensure the successful ultrasonic testing of composite materials to characterize the very High Cycle Fatigue (VHCF) of carbon fiber reinforced plastics (CFRP). The fatigue failure of CFRP occurs even in the very high cycle range and there is no traditional fatigue limit. The S–N curve of the CFRP presents a step whose characteristics appear in the transition between high cycle and very high cycle fatigue. The damage evolution of CFRP in the same field of view is investigated. The morphology of damaged CFRP composites under ultrasonic loading is described by three characteristics: matrix damage at the intersection of fiber bundles, near fiber bundle parallel section matrix cavity and matrix penetration. With the increasing of cycles, the damage process is also presented in turn according to these three characteristics. The post-fatigue bending modulus changed significantly from the pre-fatigue values, indicating that the VHCF had a considerable impact on the mechanical properties of the composite. An evolution threshold was introduced from the S–N curve to determine the fatigue evolution law from the high cycle regime to the very high cycle regime. [ABSTRACT FROM AUTHOR]

• Environmental impacts induced by innovative recycling processes applied to epoxy / carbon fiber composites. • Supercritical hydrolysis and electrodynamic fragmentation versus pyrolysis, incineration and landfilling. • Reduction of the supercritical hydrolysis and electrodynamic fragmentation environmental impact through optimization. Global consumption of carbon fibers reinforced polymer (CFRP) is rising and the management of waste is an issue of high concern. In order to implement a sustainable carbon fiber recycling sector, there is a need to evaluate the potential environmental impacts of recycling processes. In this context, we compared current end-of-life scenarios (landfilling and incineration) with recycling technologies: pyrolysis, supercritical solvolysis and electrodynamic fragmentation using life cycle assessment. We conducted two analyses: a comparison between the CFRP end-of-life processes and a comparison including the substituted products from the recycled carbon fibers. When only considering the end-of-life processes, recycling processes have a higher environmental impact as they require higher energy demand than incineration or landfilling. When considering product substitution, recycling is environmentally beneficial since they replace the production of virgin products. Results are variable depending on the technology readiness level and the quality of fibers recovered from the recycling processes. [ABSTRACT FROM AUTHOR]

In high-speed precision machining, thermal deformation caused by temperature rise affects the accuracy stability of the machine tool to a significant extent. In order to reduce the thermal deformation of ball screws and improve the accuracy, a new adaptive method based on carbon fiber reinforced plastics (CFRP) was proposed in this study and the thermal deformation of ball screws was determined. By using the sequential coupling method, the thermal–structural coupling analysis of a ball screw was conducted based on the finite element method (FEM). The analysis results were verified through a comparison with the experimental results. Based on the verification, an FE model of the improved ball screw was established to study its thermal characteristics. The key design parameters of the improved ball screw were optimized based on the Kriging model and genetic algorithm (GA). The thermal reduction effect of the improved ball screw was validated through the experimental results. The results indicate that the adaptive method proposed in this research is effective in reducing the thermal deformation of ball screws. [ABSTRACT FROM AUTHOR]

Standard Compression-After-Impact test devices show a weakening effect on thin-walled specimens due to a free panel edge that is required for compression. As a result, thin-walled undamaged samples do not break in the free measuring area but near the free edge and along the supports. They also show a strength reduction due to the free edge which can become potentially relevant for very weakly damaged panels. In order to reduce the free edge influence on the measured strength, a modified Compression-After-Impact test device has been developed. In an experimental investigation with carbon fiber reinforced plastics, the modified device is compared with a standard device. It is shown that thin-walled undamaged specimens investigated with the modified device now mainly break within the free measuring area and no longer at the free edge and along the bearings as it is the case for standard test devices. The modified device does not cause a free edge weakening effect in comparison to standard devices. The modified device is therefore more suitable for determining the compression strengths of undamaged thin-walled composite plates. [ABSTRACT FROM AUTHOR]