Smart Materials and Structures最新文献

{"title":"Hierarchical elastic and conductive multiwall carbon nanotube carboxymethylcellulose silica hybrid aerogel for strain sensors","authors":"Chaoming Wang, Shuaiao Xie, Hangyu Hu, Lei Zhang, Junjie Liu, Xiangyu Li","doi":"10.1088/1361-665x/ada1b5","DOIUrl":"https://doi.org/10.1088/1361-665x/ada1b5","url":null,"abstract":"Abstract Flexible and wearable piezoelectric pressure sensors have attracted extensive interest for their potential applications in human health monitoring. However, it remains a challenge to fabricate exceedingly elastic, conductive and steady strain-sensitive aerogels. Herein, an elastic and conductive carboxymethylcellulose sodium/methyltrimethoxysilane/multiwall carbon nanotube (CMC/MTMS/MWCNT) aerogel with interconnected porous microstructure was fabricated by a solution mixing and freeze-drying technique. Owing to covalent, ionic and hydrogen-bonding interactions between flexible CMC chains, MTMS and MWCNTs, the as-prepared CMC/MTMS/MWCNT hydrophobic aerogel with 50 wt% MWCNT loading exhibits good elasticity (1500 steady compression cycles at 30% strain), a broad pressure detection range (0–150 kPa) and reasonable compression sensitivity with gauge factor of 1.02 under 20%–30% strain. Additionally, the CMC/MTMS/MWCNT aerogel was used as a strain sensor and successfully demonstrated human motion detection—not only large-scale actions (finger bending) but also small-scale muscle movements (swallowing). With these results, our CMC/MTMS-50 aerogel is a promising candidate for utilization in flexible and wearable strain sensors.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"34 2","pages":"025020-025020"},"PeriodicalIF":0.0,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147890926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"3D printing for capacitive flexible pressure sensors of small pressure high sensitivity with microdome-labyrinth structure","authors":"Wei Wei, J.Z. Wang, Xinliang Zhang, Xin Luo, Bolin Chen, Xiangyu Shen, Lili Yuan, Yunfei Huang, Yu Long","doi":"10.1088/1361-665x/ad9717","DOIUrl":"https://doi.org/10.1088/1361-665x/ad9717","url":null,"abstract":"Abstract Capacitive flexible pressure sensors have excellent sensing characteristics such as ductility and high sensitivity, and are capable of accurately detecting small pressures generated by human movement and human–computer interaction. However, small pressure sensors fabricated using most conventional preparation methods (e.g. stencil molding) do not provide high enough resolution for small pressure measurements. Therefore, in this paper, capacitive flexible pressure sensors that can be applied to motion signal detection and motion sensing are prepared using digital light processing printing technology. Elastomers with microdome and labyrinth composite structures are prepared using polyurethane acrylate materials. At the same time, the sensor is capable of detecting minute pressures as low as 1 pa and has a wide detection range with a sensitivity S of 0.037 kPa −1 in the 0–20 kPa stress range and 0.007 kPa −1 in the 300–400 kPa stress range.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"34 1","pages":"015012-015012"},"PeriodicalIF":0.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147918371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prototyping sutureless shape memory valve stent via integrated 3D printing","authors":"Meng Yang, Chao Yuan, Xi Chen, Xiaochun Jiang, Tiejun Wang","doi":"10.1088/1361-665x/ad939f","DOIUrl":"https://doi.org/10.1088/1361-665x/ad939f","url":null,"abstract":"Abstract Transcatheter aortic valve replacement (TAVR) has increasingly emerged as a forefront option for treating aortic valve diseases. However, the currently prevalent valve prostheses used in TAVR typically involve stitching biologic leaflets onto metallic stents, which introduces challenges in the durability of leaflets and the biocompatibility of metallic stents. This work proposes an integrated additive manufacturing method for prototyping sutureless prosthetic aortic valves that combine shape memory polymer (SMP) stents and hydrogel valve leaflets. The SMP stent exhibits sufficient toughness to maintain structural integrity upon shape memory programming, while the Fe 3+ -treated hydrogel leaflets possess sufficient swelling resistance to ensure dimensional stability. Finally, the proof-of-concept valve stent is successfully fabricated by integrated 3D printing and validated via an in vitro hemodynamic experiment. Overall, our approach holds promise for prototyping sutureless polymeric valve stents for future generations.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"34 1","pages":"015003-015003"},"PeriodicalIF":0.0,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://iopscience.iop.org/article/10.1088/1361-665X/ad939f/pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147882758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polydopamine-modified MXene-integrated photothermal responsive hydrogel for constructing rapid photothermal and self-sensing gradient hydrogel actuators","authors":"Caixia Sun, Xinyi Wang, Shaoshuai Ma, Xinhua Xu","doi":"10.1088/1361-665x/ad9203","DOIUrl":"https://doi.org/10.1088/1361-665x/ad9203","url":null,"abstract":"Abstract Poly(N-isopropylacrylamide)-based stimuli-responsive hydrogel actuators have made significant progress. By introducing responsive modules such as photothermal nanoparticles, the hydrogel can respond to environmental changes and construct anisotropic structures, allowing the hydrogel actuators to quickly bend and realize complex shape deformation. However, there remains a need to enhance the mechanical properties of these hydrogels to accommodate multiple deformation actions and different application scenarios, and enhance the compatibility between nanoparticles and the hydrogels to improve the comprehensive performance of materials are still issues that need to be solved. In this study, we modified two-dimensional MXene nanosheets with polydopamine (PDA) to obtain P-MXene, which served as a photothermal agent and can be stably dispersed within the hydrogel system. We copolymerized thermosensitive N-isopropylacrylamide (NIPAm) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) in situ and used a direct current electric field to induce a concentration gradient distribution of P-MXene nanosheets within the hydrogel, resulting in the preparation of anisotropic gradient hydrogel actuators with good stretchability and conductivity. The hydrogel structure was characterized using scanning electron microscopy and the Fourier transform infrared spectra. The swelling properties, mechanical properties and conductivity of the hydrogel were studied. The actuation behavior of P(NIPAm-DMAEMA)/P-MXene gradient hydrogel actuators under different thickness and electric field intensity was investigated. Additionally, the sensitivity and stability of the conductive hydrogel actuators were tested and the functions of monitoring human health and information transmission were realized. It integrated with rapid photo responsiveness and self-sensing capabilities to monitor the deformation process of the actuators through real-time relative resistance changes during the actuations. This work is expected to expand the application field of soft hydrogel actuators and provide new insights into the design of a new generation of soft robots.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"33 12","pages":"125043-125043"},"PeriodicalIF":0.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147892457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving flexible actuating behaviors of gel-based artificial muscles through chamomile polysaccharide crosslinking","authors":"Junjie Yang, Tao Yu, Jintong Yao, Kang Wei, Mingjian Fang, Zhen Jiang, Tong Sha","doi":"10.1088/1361-665x/ad8f7e","DOIUrl":"https://doi.org/10.1088/1361-665x/ad8f7e","url":null,"abstract":"Abstract The flexible actuating behaviors of gel-based artificial muscles (GBAMs) are contingent upon the properties of their hydrogel actuating membranes. While the current preparation system for these membranes is deemed flawless, the electromechanical characteristics are constrained by the inherent properties of the material. The majority of raw materials used in this process are chemically synthesized; however, Chinese herbal polysaccharides offer a convenient, environmentally friendly, and non-toxic alternative, making them a prime candidate for actuating membrane preparation. The biological activities of chamomile polysaccharide (CP) include anti-inflammatory, lipid-lowering, sugar-lowering, and OH − clearance properties. Therefore, the actuating membrane of GBAM was prepared by crosslinking sodium alginate (SA) with CP. The findings indicated that at a crosslinking ratio of 4:5 for CP-SA, the electrically actuated force density and response speed reached 20.12 mN g −1 and 0.09 mN (g·s) −1 , respectively. Additionally, the working life extended to 781 s, tremor frequency decreased by 47.67%, and tremor amplitude was 19.55% of the control group. The elastic modulus was measured at 15.44 MPa, specific capacitance reached 183.99 mF g −1 , and internal resistance decreased by 13.44%. Charge and discharge time was 5.73 s, maximum energy reached 2.7 J, and specific energy was 12.66 A·J g −1 , representing increases of 2.3 s, 64.63%, and 6.47 A·J g −1 compared to the control group. The deflection displacement of 6.62 mm in the CP-SA group at a crosslinking ratio of 4:5 was found to be 3.06 times greater than that of the control group. In conclusion, the actuating membrane of GBAM, synthesized through the cross-linking of CP with SA at a specific ratio, demonstrated superior properties. This innovation offers a novel perspective and direction for the advancement of GBAMs and is anticipated to significantly contribute to future developments in related fields.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"33 12","pages":"125045-125045"},"PeriodicalIF":0.0,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147916781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Three-dimensional free-standing heterostructures out of MoS2 and rGO with infused PDMS towards electromechanical pressure sensing","authors":"Abdullah Solayman, Baosong Li, Rashid Abu Al-Rub and Kin Liao","doi":"10.1088/1361-665x/ad78cd","DOIUrl":"https://doi.org/10.1088/1361-665x/ad78cd","url":null,"abstract":"The behavior of two-dimensional (2D) materials constructed as three-dimensional structures is studied to bring such materials one step closer to the real-life application. Lattices structures of gyroid triply periodic minimal surface (TPMS) were fabricated out of 2D materials, namely, molybdenum disulfide (MoS2), and reduced graphene oxide (rGO), forming for the first time free-standing MoS2 (FSM) lattice and free-standing hetero-structural lattice of MoS2 and rGO (FSH) out of TPMS. These 2D materials were also integrated with polydimethylsiloxane (PDMS) elastomer, forming FSM/PDMS and FSH/PDMS composites. Mechanical characterization, including compression and cyclic tests, were conducted on FSM, FSH, and the composites. Additionally, electromechanical characterization was conducted to evaluate the sensing potential of these structures. It is worth noting that the elastic modulus of the 10 unit-cells with either FSM or FSH was higher than the other lattices of the same type. FSH tends to have a higher modulus at 1504.4 kPa in the 10 unit-cells. This modulus is even higher at 3 MPa when PDMS is added to the FSH lattice. Due to the brittle fracture, FSM or FSH lattices follow the layer-by-layer failure mechanism. Samples with PDMS are more stable towards such cyclic tests without noticeable failures or a decrease in elastic modulus. Finally, the 10 unit-cell lattices of FSH/PDMS composite have the highest conductivity at 2.5 mA, and a comparable sensitivity at 0.365 kPa−1 over the range of 0–100 kPa.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"1 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An IGBT coupling structure with a smart service life reliability predictor using active learning","authors":"Shizhe Feng, Yicheng Guo, Weihua Li, Haiping Du, Grzegorz Krolczyk and Z Li","doi":"10.1088/1361-665x/ad7659","DOIUrl":"https://doi.org/10.1088/1361-665x/ad7659","url":null,"abstract":"An effective approach is proposed to evaluate the service life reliability of a multi-physics coupling structure of an insulated gate bipolar transistor (IGBT) module. The node-based smoothed finite element method with stabilization terms is firstly employed to construct an electrical-thermal-mechanical (ETM) coupling structure of the IGBT module, based on which the multi-physics responses can be accurately calculated to predict the service life of the IGBT module. By using the high-quality sample data obtained through the ETM coupling model, a Monte Carlo based active learning Kriging metamodel (AK-MCS) is developed to assess the service life reliability of the IGBT module, which can greatly reduce the computational cost needed by the surrogate model construction and reliability analysis. Numerical results show that the proposed ETM coupling structure can produce high-quality sample data of the IGBT dynamics and the AK-MCS machine learning technique can accurately estimate the service life reliability of the IGBT module.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"11 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142268097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonlinear vibration of a loaded string in energy harvesting","authors":"Tao Liu, Chaoyang Zhao, Yaowen Yang and Weifeng Yuan","doi":"10.1088/1361-665x/ad79cf","DOIUrl":"https://doi.org/10.1088/1361-665x/ad79cf","url":null,"abstract":"Designing wideband energy harvesters using beam structures typically involves complexities, particularly in low-frequency and low-energy environments where the limitations of beam structures become more evident. To address these challenges, this study proposed a strategy for energy harvesting using a loaded-string system and established a theoretical model to investigate its performance. A parametric study was conducted for the string system, examining the effects of initial tension, mass location, material stiffness and excitation amplitude. The accuracy of the proposed model was verified through experimental validation. Both theoretical and experimental analyses observed a frequency shifting phenomenon, demonstrating the wideband characteristics of the system. Furthermore, the proposed string structure allows for convenient parameter adjustments, enabling the tuning of its natural frequency and operating bandwidth to meet more stringent practical requirements. The string system provides a new direction for designing energy harvesters to harness low-frequency energy from the ambient environment.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"10 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shape optimization of a non-uniform piezoelectric bending beam for human knee energy harvester","authors":"Haisu Liao, Tsunho Wu, Gang Gao, Xinyu Wu and Fei Gao","doi":"10.1088/1361-665x/ad78ce","DOIUrl":"https://doi.org/10.1088/1361-665x/ad78ce","url":null,"abstract":"Scavenging energy from the human body to provide a sustainable source for electronic devices has gained significant attention. Recently, scientists have focused on harnessing biomechanical energy from human motion. This study was dedicated to developing and optimizing a non-uniform piezoelectric bending beam-based human knee energy harvester. The bimorph non-uniform piezoelectric bending beam consisted of a non-uniform carbon fiber substrate and piezoelectric macro fiber composites. Compared to the uniform piezoelectric bending beam, the non-uniform piezoelectric beam can optimize the shape to improve the average strain, thus improving the energy harvesting efficiency. In this study, eight shape functions, including ellipse, sin, tanh, exponential function, parabola, trigonometric line, and bell curves, were investigated and optimized. The bell curve bending beam was selected and fabricated due to its good performance. Then, a benchmark platform was developed to test the deflection curve and reaction force when the nonuniform bending beam was compressed. Finally, to validate the design, experimental testing on three subjects was conducted when they were equipped with the harvester and walked on a treadmill. Testing results indicated that the non-uniform bending beam-based energy harvester can improve the energy harvesting efficiency by 28.57% compared to the uniform beam-based energy harvester. The output power can reach 18.94 mW when walking at 7.0 km h−1.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"41 2 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A frequency steerable electromagnetic acoustic transducer","authors":"Lucas M Martinho, Luca De Marchi and Alan C Kubrusly","doi":"10.1088/1361-665x/ad78cf","DOIUrl":"https://doi.org/10.1088/1361-665x/ad78cf","url":null,"abstract":"Electromagnetic acoustic transducers (EMATs) are convenient for non-destructive evaluation of plate-like structures since they can generate, without the need for contact with the medium under test, different types of ultrasonic guided waves. Guided-wave EMATs usually generate waves omnidirectionally or in a principal propagation direction. Beam steering is desirable in several applications, such as in inspections of large-area structures. This is usually achieved with several independently controlled elements forming a phased array. Alternatively, mono-element transducers with directional-dependent spectral content can steer the generated wave beam by altering the frequency of the excitation signal. A piezoelectric transducer with this characteristic, namely a frequency steerable acoustic transducer, was previously proposed. Its design was addressed in the wavenumber domain, leading to unconventional transducer shapes, but still reproducible with a piezoelectric patch, albeit unfeasible to implement as an EMAT. Here, we propose a new kind of EMAT, namely, frequency steerable EMAT (FSEMAT), whose design is addressed in the spatial domain in order to ensure its physical realization with a coil-magnet arrangement whilst still effectively presenting steering capability. The novel EMAT was designed to generate the A0 Lamb wave mode in a frequency range from approximately 100 to 600 kHz. The FSEMAT was fabricated and experimentally evaluated in an aluminium plate at different frequencies within the designed frequency range, where each frequency corresponded to a specific propagating direction with high directivity, assessed by half-power beam widths of approximately 10 degrees. Furthermore, its theoretical directivity was computed by means of a wavenumber spectrum-based model, and showed good agreement with experimental results. The new transducer allows great flexibility effectively providing beam steering with a single EMAT.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"196 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}