Bending Situations Research Articles

A Four Port Flexible UWB MIMO Antenna with Enhanced Isolation for Wearable Applications

This article presents a four-port multiple-input-multiple-output (MIMO) flexible antenna design for Ultrawideband (UWB) application using Polydimethylsiloxanes substrate. The single UWB antenna structure consists of modified circular radiator with elliptical slot and partial ground plane. To achieve high isolation among antenna element, a Defective Ground Structure (DGS) is adopted to decouple the low frequency band. DGS comprises a centrally placed square shape slotted structure connected by horizontal and vertical lines, achieving isolation below -20 dB. The proposed antenna has a dimension of , bandwidth of 3.4–11.8 GHz (110.5%) and 4.3 dBi peak gain. Simulation and measurement findings show that the antenna performs well under bending situations with different curvature radius. At 4 GHz and 8.1 GHz, W/kg specific absorption rate (SAR) for 1/10 g tissue is examined. A low value of SAR is obtained at both the resonating frequencies. Additionally, an analysis is conducted on the diversity parameters, and the antenna demonstrates comparatively good results having mean effective gain (MEG) ratio < -3 dB envelope correlation coefficient (ECC) < 0.02, total active reflection coefficient (TARC) < − 10 dB, channel capacity loss (CCL) < 0.3 bps/Hz, and diversity gain (DG) > 9.99 dB, implying that it's appropriate for wearable MIMO applications.

Damage and fracture investigation of self-compacting concrete in the filling layer of CRTS-III using three-point bending tests

Literature about filling layer self-compacting concrete (FLSCC) has indicated that FLSCC plays a crucial role in its application to Chinese railway track system III (CRTS-III). It is apparent that the damage characteristics of FLSCC have not been clearly investigated, as the actual working conditions are not considered enough. There exists a remaining gap about the mechanical properties and fracture behaviors of FLSCC under bending loads. In order to fill this gap, in this study, three-point bending (TPB) tests on the FLSCC beams with precast notches were performed based on the real bending situation of FLSCC in CRTS-III. Acoustic emission (AE), strain gauges and a digital camera were utilized to monitor the fresh evolutionary laws of micro- and macro-cracks as well as the corresponding damage morphology. The study presents that the monitored load-crack mouth opening displacement (P-CMPD) curves, load-strain (P-ε) curves and AE activity curves all exhibited similar distributions, including four stages with increasing bending loads. In term of the AE activities, the first apparent crack in the interior and warning point of failure can be detected by analyzing the captured AE activities of the FLSCC beams. In addition, the dominant failure mode of the specimens was determined as tensile cracks according to the rising angle-average frequency (RA-AF) criterion for potential FLSCC application in terms of the limiting ratios. This failure mode indicates that under pure bending loads, the mid-span section is subjected to the maximum bending moment, and the specimen experiences tensile damage. Therefore, for future practical application, the structural health state of FLSCC in CRTS-III could be nondestructively real-time monitored by the AE technique. Meanwhile, the calculated fracture parameters of the FLSCC specimen can reflect the cracks stability of the specimen. This study can also present experimental and theoretical references for further studies on FLSCC in CRTS-Ⅲ under other types of loads.

A numerical study on bending behavior of sandwich beam with novel auxetic honeycomb core

To further improve the load-bearing capability and anti-impact properties of the auxetic structure, a novel enhanced auxetic honeycomb core (NEH) was introduced, and the bending resistance and crashworthiness of this sandwich beam (NEH-SWB) were analyzed through numerical simulation. First, bending tests on sandwich beams under different loading situations revealed that NEH-SWB was more susceptible to impact damage in three-point bending situations than those under four-point bending, and the influence of structural parameters were more pronounced. In addition, the impact of load position and structural parameters on the bending response and deformation pattern of NEH-SWB were investigated. NEH-SWB exhibited superior bending resistance when the punch was located in the S position. Furthermore, increasing the panel thickness and altering the panel thickness configuration both contributed to improving the flexural resistance of NEH-SWBs. At a certain mass, the configuration with T f / T b > 1 exhibited better bending resistance. Meanwhile, increasing both the cell angle (θ) and wall thickness-to-length ratio (t/l) enhanced load-carrying capability and energy absorption of NEH-SWB. Subsequently, further analysis showed that NEH had better bending performance compared to cell structures with reentrant (RH), star-shaped (SSH), and reentrant-star (RSH) honeycombs. Finally, the complex proportion assessment method was employed to examine the significance of structural parameters regarding the flexural behavior of the NEH-SWB. It was concluded that increasing the t/l value could be the best solution to enhance the bending performance of the NEH-SWB.

Surfactant-assisted preparation of all-gel-state flexible supercapacitor with remarkable electrochemical performance based on polyaniline-polyacrylamide/sodium alginate hydrogels

The electrochemical performance of polyaniline-based all-gel-state supercapacitor (AGSSC) is significantly depended on the dispersity and mass loaded of polyaniline (PANI). In this manuscript, inspired by the properties of surfactant, sodium dodecylbenzene sulfonate (SDBS) was introduced to prepare various PANI-polyacrylamide/sodium alginate/SDBS (PANIy-PSSx) AGSSCs. With presence of SDBS, the electrochemical performance of PANIy-PSSx AGSSCs was greatly improved, displaying a trend of initial rise and then decrease with increasing concentration of SDBS from 0 to 0.75 wt%. As the content of SDBS was 0.5 wt%, the resulting PANI1.0-PSS0.5 AGSSC displayed the optimum electrochemical properties with area capacitance and energy density of 913.79 mF/cm2 and 81.23 μWh/cm2, respectively. The capacitance rate of PANI1.0-PSS0.5 AGSSC was still more than 93 % after 2000 cycles of sequential CV scans at the scan rate of 200 mV/s. These data were greatly higher than many reported PANI-based AGSSCs. Moreover, the resultant PANI1.0-PSS0.5 AGSSC could maintain high electrochemical performance even after various operations, such as compression, puncture, fluctuating temperature, bending situations and various voltage windows and series-parallel connections. The resultant PANI1.0-PSS0.5 AGSSC had the wide potentials to satisfy the real application requirements. This study offered a facile strategy for design and preparation of flexible supercapacitor with excellent electrochemical performance.

Different assembled nano-MnO2 fiber supercapacitors applied for smart wearable clothing

With rapid development in the smart wearable field, new-style flexible energy storage devices are necessary to satisfy the demands of flexible smart clothing. Thereinto, fiber supercapacitors present promising application prospects. This work puts forward a facile and reliable strategy to fabricate coaxial fiber electrodes via binary wet spinning, and further assembles them into parallel or twisted nano-MnO2 fiber supercapacitors. In the obtained fiber electrode, a carboxymethylcellulose layer onto nano-MnO2 not only allows the requisite ion exchange between the electrochemical active materials and gel electrolyte, but also plays the role of separator to protect the two fiber electrodes effectively from contacting a short circuit, greatly ensuring the electrochemical stability of the nano-MnO2 fiber supercapacitors. The parallel nano-MnO2 fiber supercapacitor reaches a maximum CL of 19.7 μF/cm, EL of 0.0027 μWh/cm and PL of 1.49 μW/cm; the twisted MnO2 fiber supercapacitor achieves maximum CL, EL and PL of 49 μF/cm, 0.0053 μWh/cm and 1.0 μW/cm, respectively. Besides, the outstanding softness and tensile properties of the obtained nano-MnO2 fiber supercapacitors also guarantee stable electrochemical performance under bending, knotting or other large-distortion situations, which is beneficial to develop a new generation of metal oxide fiber supercapacitors for smart wearable clothing.

Highly flexible anisotropic magnetoresistance sensor for wearable electronics

The emerging market of wearable devices for tracking and positioning requires the development of highly flexible magnetic sensors. Due to the stable magnetoresistance ratio and simple fabrication process, sensors based on the anisotropic magnetoresistance (AMR) effect have been proposed as promising candidates. However, the stability of AMR sensors under different bending situations has rarely been investigated. In this work, we proposed a flexible AMR magnetic sensor deposited on an ultra-thin Kapton substrate, which exhibits excellent anti-fatigue behavior at different bending curvatures ranging from 1/3 to 1/10 mm−1. Experimental results show that the sensitivity of our proposed flexible AMR sensor remains as high as 0.25 Oe−1 after being bent 500 times, showing promising potential for application in wearable electronic devices.

Application of domain-adaptive convolutional variational autoencoder for stress-state prediction

Applying data-driven methods such as deep learning in material mechanics is challenging because producing a sufficiently large, labeled dataset is costly resource-wise. This paper outlines a new approach to overcoming this difficulty by transferring knowledge from a source domain of finite-element-analysis data to a target domain of real-world test-specimen images so that a model capable of accurate and robust predictions in both domains may be constructed. To achieve this transfer of knowledge, discrepancy-based unsupervised domain adaptation is adopted into a convolutional variational autoencoder structure. To evaluate the proposed approach, a four-point bending experiment was conducted on 6061 aluminum alloy and 316 stainless steel to produce 550 unlabeled target-domain data images. The same bending situation was analyzed using the finite-element method implemented in the commercial software package ABAQUS to produce 6000 labeled, source-domain data images. The proposed domain-adaptive convolutional variational autoencoder was trained using the maximum mean discrepancy method on the target- and the source-domain data. The predictions using the domain-adapted convolutional variational autoencoder were relatively more accurate than those using the model trained only on the source domain. It is expected that the proposed approach can address the scarcity of labeled data in various applications of material mechanics and provide a base technology for the development of various data-driven approaches.

Analysis and Design of a High-Frequency Low-Profile Converter for Bendable Equipment

In this article, a 10-MHz low-profile converter for bendable equipment based on aircore inductor is proposed. The mathematical model and inductance calculation method of the bendable planar circular spiral coil under different bending situations is analyzed. An optimal design method of the T type matching network is depicted in detail which helps to guarantee soft-switching characteristics and high efficiency within the whole bending range by realizing weak inductive equivalent input impedance. A 32 V input, 9V/6.3 W output prototype is proposed in the laboratory and the experimental results verify the feasibility of the proposed optimal design methodology, the system efficiency can be improved by 4% than the traditional method.

Current Rectification and Photo-Responsive Current Achieved through Interfacial Facet Control of Cu2O-Si Wafer Heterojunctions.

Conductive atomic force microscopy (C-AFM) was employed to perform conductivity measurements on a facet-specific Cu2O cube, octahedron, and rhombic dodecahedron and intrinsic Si {100}, {111}, and {110} wafers. Similar I–V curves to those recorded previously using a nanomanipulator were obtained with the exception of high conductivity for the Si {110} wafer. Next, I–V curves of different Cu2O–Si heterostructures were evaluated. Among the nine possible arrangements, Cu2O octahedron/Si {100} wafer and Cu2O octahedron/Si {110} wafer combinations show good current rectification behaviors. Under white light illumination, Cu2O cube/Si {110} wafer and Cu2O rhombic dodecahedron/Si {111} wafer combinations exhibit the largest degrees of photocurrent, so such interfacial plane-controlled semiconductor heterojunctions with light sensitivity can be applied to make photodetectors. Adjusted band diagrams are presented highlighting different interfacial band bending situations to facilitate or inhibit current flow for different Cu2O–Si junctions. More importantly, the observation of clear current-rectifying effects produced at the semiconductor heterojunctions with properly selected contacting faces or planes implies that novel field-effect transistors (FETs) can be fabricated using this design strategy, which should integrate well with current chip manufacturing processes.

A Novel Sensor Foil to Measure Ski Deflections: Development and Validation of a Curvature Model.

The ski deflection with the associated temporal and segmental curvature variation can be considered as a performance-relevant factor in alpine skiing. Although some work on recording ski deflection is available, the segmental curvature among the ski and temporal aspects have not yet been made an object of observation. Therefore, the goal of this study was to develop a novel ski demonstrator and to conceptualize and validate an empirical curvature model. Twenty-four PyzoFlex® technology-based sensor foils were attached to the upper surface of an alpine ski. A self-developed instrument simultaneously measuring sixteen sensors was used as a data acquisition device. After calibration with a standardized bending test, using an empirical curvature model, the sensors were applied to analyze the segmental curvature characteristic (m−1) of the ski in a quasi-static bending situation at five different load levels between 100 N and 230 N. The derived curvature data were compared with values obtained from a high-precision laser measurement system. For the reliability assessment, successive pairs of trials were evaluated at different load levels by calculating the change in mean (CIM), the coefficient of variation (CV) and the intraclass correlation coefficient (ICC 3.1) with a 95% confidence interval. A high reliability of CIM −1.41–0.50%, max CV 1.45%, and ICC 3.1 > 0.961 was found for the different load levels. Additionally, the criterion validity based on the Pearson correlation coefficient was R2 = 0.993 and the limits of agreement, expressed by the accuracy (systematic bias) and the precision (SD), was between +9.45 × 10−3 m−1 and −6.78 × 10−3 m−1 for all load levels. The new measuring system offers both good accuracy (1.33 × 10−3 m−1) and high precision (4.14 × 10−3 m−1). However, the results are based on quasi-static ski deformations, which means that a transfer into the field is only allowed to a limited extent since the scope of the curvature model has not yet been definitely determined. The high laboratory-related reliability and validity of our novel ski prototype featuring PyzoFlex® technology make it a potential candidate for on-snow application such as smart skiing equipment.

Cage-screw and anterior plating combination reduces the risk of micromotion and subsidence in multilevel anterior cervical discectomy and fusion—a finite element study

BACKGROUND CONTEXTAnterior cervical discectomy and fusion (ACDF) is widely used to treat patients with spinal disorders, where the cage is a critical component to achieve satisfactory fusion results. However, it is still not clear whether a cage with screws or without screws will be the best choice for long-term fusion as the micromotion (sliding distance) and subsidence (penetration) of the cage still take place repeatedly. PURPOSEThis study aims to examine the effect of cage-screws on the biomechanical characteristics of the human spine, implanted cage, and associate hardware by comparing the micromotion and subsidence. STUDY DESIGNA finite element (FE) analysis study. METHODSA FE model of a C3-C5 cervical spine with ACDF was developed. The spinal segment was modeled with the removal of the anterior longitudinal ligament (ALL), posterior longitudinal ligament (PLL), and discectomy was then implanted with a cage-screw system. Three models were analyzed: the first was the original spine (S1 model), the second, S2, was implanted with cages and anterior plating, and the third, S3, was implanted with a cage-screw system in addition to the anterior plate. All investigations were under 1 N•m in flexion, extension, lateral bending, and axial rotation situations. RESULTSFinite element analysis (FEA) demonstrated that range of motion (ROM) at C3-C4 in the S2 model was significantly reduced more than that in the S3 model, while the ROM at both C4-C5 in the S3 model was reduced more than that in the S2 model in all simulations. The ROM at C3-C5 in the S1 model was reduced by over 5° in the S2 and S3 models in all loading conditions. The micromotion and subsidence at all contacts of C3-C5 in the S3 model were lower than that in the S2 model in all flexion, extension, bending, and axial simulations. The subsidence and micromotion could be seen in the barrier area of the S2 model, while they occurred near the edge of the screw in the S3 model. CONCLUSIONSThese results showed that the cage-screw and anterior plating combination has promising potential to reduce the risk of micromotion and subsidence of implanted cages in two or more level ACDFs. CLINICAL SIGNIFICANCEThe use of double segmental fixation with cage-screw anterior plating combination constructs may increase the stiffness of the construct and reduce the incidence of clinical and radiographic pseudarthrosis following multilevel ACDF, which in turn, could decrease the need for revision surgeries or supplemental posterior fixation.

Improved performance characteristics of violet InGaN MQW LDs through asymmetric W-shaped quantum wells

Abstract This study focuses on the numerical study of the built-in electric field effects, induced by spontaneous and piezoelectric polarization, on the performance characteristics of violet InGaN MQW LDs. The simulation results indicate that the induced electric field significantly deteriorates LDs performance due to QCSE, band bending, and consequent separation of the electron and hole wave functions. A new asymmetric W-shaped QWs structure is proposed to overcome QCSE, and enhance the overlapping of electron and hole wave function, and to improve the band bending situation. The In0.16Ga0.84N/InyGa1-yN/In0.16Ga0.84N QWs LDs improve the overlapping of electron and hole wave functions from 52.52, 26.39, and 4.47% for QW1, QW2, and QW3 of conventional LD structure to 48.33, 48.12, and 53.12%, respectively. Improved distributions of the electron and hole carriers in the active region, along with a higher electron and hole overlapping, result in enhanced radiative and stimulated recombination rates, hence, higher output power, and lower threshold current. The proposed W-shaped QW LDs improves threshold current and output power from 82.87 mA to 15.89 mW to 60.67 mA and 20.69 mW, respectively.

A white-box impersonation attack on the FaceID system in the real world

The arcface model maximizes the classification boundary in the angular space, and is one type of the best models in the current face recognition model. We propose a mask sticker attack method to realize the impersonation attack of arcface model. The method specifically uses a parabolic transformation to simulate the bending situation of a sticker on a mask, and uses a multi-stage PGD attack to generate a adversarial sticker. Finally, the adversarial sticker is attached to the mask worn by the attacker to perform an impersonation attack. On targets of different skin colors, ages and genders, the method proposed in this article has an attack success rate of 0.65, and the final cosine similarity between attacker with mask sticker and target can reach about 0.5-0.7. In addition, we discuss the effect of sticker location and size on attack effect, as well as the generalization of this method on other models.

The Influence of Geometry on the Loss of Curved Slot Waveguide

In curved slot waveguide devices, there are often waveguide bending situations. Under certain conditions, the smaller the waveguide bending geometry, the more compact device structure; the smaller the bending geometry, the greater the loss caused by waveguide bending. Based on the study of the loss of a curved slot waveguide, this paper combines the geometric dimensions with it to study the influence of the loss. A new method for calculating the loss coefficient caused by the bending of the waveguide: the effective refractive index method with fixed interference correction. Through this method, the relationship between the bending loss coefficient and the width, height and radius of curvature of the dielectric waveguide is analyzed and calculated. Compare the calculation result with the result calculated by the pattern analysis method. Finally, the results were discussed and analyzed. The conformal transformation method and the normalization method of the geometrical size to the bending loss of the waveguide are analyzed, the relationship between the bending geometrical size of the curved narrow slot waveguide and the bending loss is obtained, and the empirical formula for the bending loss is established. From the formula, four Curves of waveguide bending size and bending loss of a common material. Experimental research results show that with the improvement of bending waveguide loss theory and coupling mechanism, low-loss transmission can be achieved under small bending dimensions, so that the integration of overall geometrical dimensions is the development trend of bending.

Heteroatoms-doped porous carbon electrodes with three-dimensional self-supporting structure derived from cotton fabric for high-performance wearable supercapacitors

In this work, converting cotton fabrics into high-performance flexible carbon electrodes are achieved successfully by using traditional dyeing, flame retardant finishing and carbonization processes for wearable supercapacitors. The optimal carbon electrode (CCF-SP) doped with O, N, P and S heteroatoms, exhibits high surface area (643.7 m2 g−1), porous structure and good hydrophilicity. Because of electric double layer capacitance provided by carbon materials and faradaic capacitance provided by heteroatoms, the specific capacitance of CCF-SP electrode is as high as 3079.8 ± 17.9 mF cm−2 at 2 mA cm−2. After 5000 cyclic tests, residual capacitance of CCF-SP is still 99.3% of the initial value, suggesting good rate property and coulombic efficiency. In addition, flexible supercapacitor (FSC) assembled by CCF-SP electrodes exhibits an excellent energy density of 9.4 mWh cm−3 at power density of 37.5 mW cm−3. This device can power electronic gadgets at bending situation without loss of capacitance. The stunning electrochemical properties of the created carbon electrodes and its FSCs indicate that the method of heteroatoms doping combined with carbonization treatments is cheap and easy to mass produce, which can be utilized to fabricate electrodes for wearable electronic devices in the future.

Refined Zigzag Theory: an appropriate tool for the analysis of CLT-plates and other shear-elastic timber structures

Cross laminated timber (CLT), as a structural plate-like timber product, has been established as a load bearing product for walls, floor and roof elements. In a bending situation due to the transverse shear flexibility of the crossing layers, the warping of the cross section follows a zigzag pattern which should be considered in the calculation model. The Refined Zigzag Theory (RZT) can fulfill this requirement in a very simple and efficient way. The RZT, founded in 2007 by A. Tessler (NASA Langley Research Center), M. Di Sciuva and M. Gherlone (Politecnico Torino) is a very robust and accurate analysis tool, which can handle the typical zigag warping of the cross section by introducing only one additional kinematic degree of freedom in case of plane beams and two more in case of biaxial bending of plates. Thus, the RZT-kinematics is able to reflect the specific and local stress behaviour near concentrated loads in combination with a warping constraint, while most other theories do not. A comparison is made with different methods of calculation, as the modified Gamma-method, the Shear Analogy method (SA) and the First Order Shear Deformation Theory (FSDT). For a test example of a two-span continuous beam, an error estimation concerning the maximum bending stress is presented depending on the slenderness L/h and the width of contact area at the intermediate support. A stability investigation shows that FSDT provides sufficiently accurate results if the ratio of bending and shear stiffness is in a range as stated in the test example. It is shown that by a simple modification in the determination of the zigzag function, the scope can be extended to beams with arbitrary non-rectangular cross section. This generalization step considerably improves the possibilities for the application of RZT. Furthermore, beam structures with interlayer slip can easily be treated. So the RZT is very well suited to analyze all kinds, of shear-elastic structural element like CLT-plate, timber-concrete composite structure or doweled beam in an accurate and unified way.

A Flexible Film with SnS2 Nanoparticles Chemically Anchored on 3D‐Graphene Framework for High Areal Density and High Rate Sodium Storage

The design and construction of flexible electrodes that can function at high rates and high areal capacities are essential regarding the practical application of flexible sodium-ion batteries (SIBs) and other energy storage devices, which remains significantly challenging by far. Herein, a flexible and 3D porous graphene nanosheet/SnS2 (3D-GNS/SnS2 ) film is reported as a high-performance SIB electrode. In this hybrid film, the GNS/SnS2 microblocks serve as pillars to assemble into a 3D porous and interconnected framework, enabling fast electron/ion transport; while the GNS bridges the GNS/SnS2 microblocks into a flexible framework to provide satisfactorily mechanical strength and long-range conductivity. Moreover, the SnS2 nanocrystals, which chemically bond with GNS, provide sufficient active sites for Na storage and ensure the cycling stability. Consequently, this flexible 3D-GNS/SnS2 film exhibits excellent Na-storage performances, especially in terms of high areal capacity (2.45 mAh cm-2 ) and high rates with superior stability (385 mAh g-1 at 1.0 A g-1 over 1000 cycles with ≈100% retention). A flexible SIB full cell using this anode exhibits high and stable performance under various bending situations. Thus, this work provide a feasible route to prepare flexible electrodes with high practical viability for not only SIBs but also other energy storage devices.

Domain evolution in bended freestanding BaTiO3 ultrathin films: A phase-field simulation

Perovskite ferroelectric oxides are usually considered to be brittle materials; however, recent work [Dong et al., Science 366, 475 (2019)] demonstrated the super-elasticity in the freestanding BaTiO3 thin films. This property may originate from the ferroelectric domain evolution during the bending, which is difficult to observe in experiments. Therefore, understanding the relation among the bending deformation, thickness of the films, and domain dynamics is critical for their potential applications in flexible ferroelectric devices. Here, we reported the dynamics of ferroelectric polarization in the freestanding BaTiO3 ultrathin films in the presence of large bending deformation up to 40° using phase-field simulation. The ferroelectric domain evolution reveals the transition from the flux-closure to a/c domains with “vortex-like” structures, which is caused by the increase in out-of-plane ferroelectric polarization. Additionally, by varying the film thickness in the identical bending situation, we found that the a/c phase with a vortex-like structure emerges only as the film thickness reached 12 nm or higher. The results from our investigations provide instructive information for the microstructure evolution of bending ferroelectric perovskite oxide films, which could serve as a guide for the future application of ferroelectric films on flexible electronic devices.

CMOS-Like Logic Circuits With Unipolar Thin-Film Transistors on Flexible Substrate

In this article, the feasibility of CMOS-like logic circuits has been demonstrated on a flexible substrate with only n-type TFTs. Here, a 1-to-2 decoder was realized by bootstrapped inverters and NAND gates. Theoretical analysis and simulation results show low static leakage current and full output-swing features. The effect of applied mechanical strain that causes circuit performance variations is also presented. The decoder is capable of driving the rows of a Quarter-VGA display panel with 60-Hz refresh rate. Experimental results show that the decoder can perform a continuous 48-h crosstalk-free operation under tensile or compressive bending situations, thus proving the effectiveness of bootstrapped logic gates in forming complex multistage digital circuits.

Bending shape memory behaviours of carbon fibre reinforced polyurethane-type shape memory polymer composites under relatively small deformation: Characterisation and computational simulation

Shape memory polyurethanes (SMPU) have been of great interest in biomedical applications because of their unique ability to recover a primary shape by external actuation. This advantage can allow for easy suture and minimum tissue damage caused by surgery. Since SMPU suffer from low stiffness and low strength, carbon fibres have been widely used to reinforce SMPU, and their shape memory properties have been investigated using thermomechanical tensile tests. In reality, however, bending situations are more common than tensile situations, such as human skulls. In this study, carbon fibre reinforced SMPU (CF/SMPU) composites were studied as promising cranial implants that can offer shape memory properties, shape flexibility and high strength. First, the basic properties of pristine SMPU and CF/SMPU composites were characterised, including glass transition temperature (Tg), the viscosity of SMPU, the morphology of CF/SMPU, and their tensile and flexural mechanical properties. Then, a new method using rheometer was developed to study the shape memory behaviours of SMPU and CF/SMPU with three-point bending under relatively small deformations (≤1%), including flexural stress during programming and cooling, and bending recovery force during shape recovery. Finally, due to the invisibility of recovery process that was conducted in an enclosed temperature-controlling chamber of rheometer, the finite element method (FEM) was used to simulate the bending recovery test. The results showed carbon fibres significantly enhanced the mechanical properties (Young's modulus and flexural modulus) of SMPU. In terms of bending shape recovery, compared to pristine SMPU, CF/SMPU composites obtained substantially higher flexural stress during programming and cooling processes, and larger, more stable recovery force during recovery. The FEM results consolidated the peak recovery force of SMPU and the continuously growing recovery force of CF/SMPU as the temperature increased. Our findings on the improved mechanical and shape memory properties can provide a solid foundation for the potential applications of CF/SMPU composites as cranial implants.